10 19'
REPORT
ON THE
DAM AND WATER POWER
DEVELOPMENT
AT
AUSTIN, TEXAS
BY
DANIEL W. MEAD
NOVEMBER, 1917
DANIEL W. MEAD
CHARLES V. SEASTONE
CONSULTING ENGINEERS *
MADISON, WISCONSIN
REPORT
ON THE
DAM AND WATER POWER
DEVELOPMENT
AT
BY
DANIEL W. MEAD
NOVEMBER, 1917
DANIEL W. MEAD
CHARLES V. SEASTONE
CONSULTING ENGINEERS
MADISON, WISCONSIN
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TABLE OF CONTENTS
Page
Letter of Transmittal 1
Instructions 3
Resolution 3
Acknowledgments 5
REPORT ON THE DAM AND WATER POWER DEVELOPMENT AT AUSTIN, TEXAS
Method of Financing 7
Plans and Specifications 9
The Reconstruction Work 9
The Contractor for the Work 9
The Bond Issue 11
Work Apparently Nearing Completion 11
Difficulties Arise 11
Financial Collapse i2
Period of Investigation 12
Physical Conditions at the Dam Site 12
The Old Dam 14
The New Structure 14
Plans and Specifications 15
Changes in Plans 15
THE EFFECTS OF CHANGES IN PLANS AND SPECIFICATIONS
Betterments 16
Immaterial Changes 19
DETRIMENTAL CHANGES
Detrimental Changes in the Provisions for a Safe Foundation 20
Grouting 20
Cut-Off Wall above West Section of the Old Dam 20
Cut-Off Walls in Reinforced Concrete Dam 20
Detrimental Changes in the Structures of the Dam and Appurtenances 21
Core Wall 21
Pointing the Old Dam 21
Changes in Gates and Setting 21
Sluice Gates and Sluice Gate Trash Racks 21
Power Plant Accessories 21
The Tail Race 21
Penstocks 23
Fourth Penstock 23
Draft Tubes 23
DEFECTS IN PRESENT CONDITIONS AND STRUCTURES
Foundation Conditions 23
Foundation 24
Riverbed below the Dam 24
Leakage 24
The Structure of the Dam 27
Old Dam Section 27
Crest Gates 27
Sluice Gates 27
Passageway in the Dam 27
Plant Accessories 29
Head Gate Masonry 29
Head Gate Trash Racks 29
Head Gate Hoists 29
Tail Race 29
Draft Tubes 29
Pumps 29
Station Equipment, Etc 29
REMEDIES
Foundation Conditions 29
Foundation at the Heel of the Dam 29
Leaks under the New Section 29
Improvements below the Toe of Dam 30
Dam Structure 30
Crest of Dam 30
Old Dam Section 30
Reduction in Seepage around Dam 30
Walk in Dam 30
Sluice Gates and Sluiceways 30
383394
vi Table of Contents.
Inspection of Foundation under Dam 30
Plant Accessories •
Head Gate Masonry
Head Gate Trash Racks 30
Tailrace 31
Deflecting Wall
Railing
Estimated Cost of Betterments, Changes and Improvements 31
Character of the Estimate 32
Permanency of the Structures 32
Value of Material and Labor in Place
Responsibility for Cost of Betterments
Ultimate Value of the Plant 38
Supervision of the Construction of Betterments 39
APPENDIX 1
HISTORY OF THE AUSTIN, TEXAS, DAM
Beginning of Active Work 40
Change in Plans 42
Data on the Completed Dam 44
Development of Leaks in the Foundation 47
Warnings of Disaster 48
The Silting of the Reservoir 49
The 1900 Failure 53
Investigations and Reports Made After the 1900 Failure 53
The Johnson Contract 56
APPENDIX 2
CONTRACT or WILLIAM D. JOHNSON AND ASSIGNS FOR THE RECONSTRUCTION OF AUSTIN DAM
AND POWER PLANT
Franchise Ordinance 57
Indorsements on Ordinances 61
Letter Filed with City 61
The Contract Specifications 61
Abstract of Contract Specifications 62
Dam 62
Excavation 62
Grouting 63
Cut-Off Walls 63
Supporting Walls 63
Old Portions of Dam 63
Gates and Appurtenances 63
Sluice Gates 63
Core Wall 63
Track— Walk and Pipe Line 63
Reservoir 63
Timber 64
Cement 64
Sand 64
Stone or Gravel 64
Structural Steel and Steel Reinforcement 64
Forms for Concrete 64
Proportion of Ingredients 64
Mixing 64
Placing of Concrete 64
Power House 64
Head Gates and Hoists 64
Intakes 64
Draft Tubes 64
Tail Race 64
Power House Equipment 64
Pumps 64
Transmission Line 64
Engineer 64
Plans 66
APPENDIX 3
WORK UNDER JOHNSON CONTRACT OF 1911 — INCLUDING CHANGES IN PLANS PROGRESS OF
WORK AND DEVELOPMENT OF CONDITIONS
First Change in Plans 66
Approval of Detailed Plans Including Certain Changes 66
Progress and Character of Work 67
Changes Made in Rebuilding the Austin Dam 74
Table of Contents. vii
APPENDIX 4
CONDITIONS AND FACTS ASCERTAINED DURING EXAMINATION BY DANIEL W. MEAD,
AUGUST, 1917
Examination of August, 1917 76
Memoranda Concerning the Foundation Conditions of the Austin Dam from Sketches
and Data Furnished by Mr. Frank S. Taylor 81
General Scheme of Tests 81
Auxiliary Holes Under and Between Diaphragm Walls 86
On the Down Stream Side of the Old Dam 86
Abstract of Record of Drilling Holes and Grouting 87
Notes Based on Information Furnished by Mr. S. S. Posey 92
Cross Walls 92
Leakage 93
Leak under the Dam 94
Seepage in the Old Dam 95
Class of Work 95
Cofferdams 96
General Amount of Pumping 96
Grouting 96
Concrete 96
Reinforcing 96
Power House Foundations 97
Tail Race 97
Penstock and Draft Tubes 97
Conduct of the Work 97
Discussion of Conditions Below the Toe of the Present Dam 98
Relative Elevations of Dam Foundation and Rock in Front of Toe 105
Geological and Physical Conditions at the Dam Site 106
APPENDIX 5
DISCUSSION AND CRITICISMS OF THE CONDITIONS AND STRUCTURES OF THE PRESENT
INSTALLATION
Essential Principles for the Construction of Safe Dams 115
Grouting 118
Deep Seepage Under and Around the Dam 120
Flow Data of Colorado River and Barton Creek 120
The Structure of the Old Dam 124
Stability of the Old Section under Original Conditions 124
The Use of the Old Section for the New Conditions 126
For No Silt and Low Water Conditions 128
For Silt and Low Water Conditions 128
For Silt with a Nine Foot Flood 129
For a Maximum Flood without Silt 129
The Reinforced Concrete Structure 130
Foundation Pressures 130
Hollow Dam Section 133
Design of Reinforced Concrete in the Reinforced Concrete Dam Section 133
Appurtenances 136
Sluice Gates 136
Crest Gates 139
Tail Race 139
Passageway in Dam 139
Railing on Dam 139
Head Gate Masonry 139
Head Gate Racks 140
Head Gate Hoists 140
Penstocks and Draft Tubes 140
Station Equipment 140
Transmission Line 140
Pumps 140
Reservoir 143
APPENDIX 6
A STUDY OF THE STREAM FLOW OF THE COLORADO RIVER AND THE PROBABLE AMOUNT OF
POWER THAT CAN BE DEVELOPED AT THE AUSTIN DAM — WlTH A COMPARISON OF THE REL-
ATIVE VALUES OF 65 AND 60-FooT HEADS
Stream Flow Data 144
Comparison of Published Records and Those Computed for Austin Dam 145
Reliability of Records 146
Hydrographs Based on the Calculations of Stream Flow 146
Power Possibilities Determined from Hydrographs 146
Storage above the Dam 147
Modification of Hydrographs by Storage 147
viii Table of Contents.
Deductions from the Flow at the Congress Avenue Bridge 147
Graphical Representation 148
Power Demand 148
Power Calculations 148
Study of Minimum Power of 830 Horse Power or 600,000 Horse Power Hours per
Month of 30 Days 148
Study of the Development of 1650 Continuous Horse Power 157
Development of 1650 Horse Power under 65-Foot Head 157
Development of 1650 Horse Power under 60-Foot Head 157
Comparison of 65 and 60-Foot Heads for the Development of 1650 Continuous
Horse Power 157
Study of the Development of 3300 Continuous Horse Power 158
Development of 3300 Horse Power under 65-Foot Head 158
Development of 3300 Horse Power under 60-Foot Head 158
Comparison of 65 and 60-Foot Heads for the Development of 3300 Continuous Horse
Power < 158
Effect of Smaller Storage 172
Reduction of Evaporation and Seepage 172
Variations in Load 172
APPENDIX 7
CREST GATES FOB THE AUSTIN DAM
Conditions of Installation 173
Types of Gates Available 174
APPENDIX 8
BETTERMENTS REQUIRED FOR THE SAFETY OF THE AUSTIN DAM
General 179
Foundation 180
Grouting as a Protection against Underflow 180
Foundation Betterments Recommended 180
Stopping Leaks in Panels 4 and 6 181
Effectiveness of Protection 181
Improvements of Conditions Below Toe of Dam 182
Crest Gates 182
Reduction in Seepage around Dam 182
Improvements to Old Dam Section 183
Tail Race 184
Deflecting Wall 184
Head Gates 184
Passageway in Dam 185
Railing 185
Gate Operating Mechanism 185
Sluiceways 185
Sluice Gates 185
Estimates of Cost of Betterments 185
APPENDIX 9
COST OF WORK DONE UNDER THE JOHNSON CONTRACT
Estimated Cost of Reservoir 187
Estimated Cost of Rebuilding Station Including Removing Old Penstocks, Placing
New Penstocks, Rebuilding Transmission Line 188
Machinery and Equipment 190
Construction of the Dam 190
Extra Work 192
Recapitulation of Estimates 193
Contractor's Cost of Constructing Reservoir 194
Contractor's Cost, Schedule A 195
Contractor's Cost, Schedule B 195
Contractor's Cost of Reconstruction of Dam 196
Contractor's Cost of Extras 196
Austin Dam Costs to March 1, 1916 198
APPENDIX 10
Recommendations of Dr. A. C. Scott, March 31, 1915 199
APPENDIX 11
Bibliography of the Austin (Texas) Dam 202
LETTER OF TRANSMITTAL
HONORABLE A. P. WOOLDRIDGE, Mayor,
HONORABLE E. C. BARTHOLOMEW, Supt.,
Parks and Public Property,
Austin, Texas.
GENTLEMEN : In accordance with the instructions contained in a certain resolu-
tion adopted May 30, 1917, by the City Council of Austin, and certain written and
verbal instructions received from you, I have made an examination of the work, ma-
terial and machinery furnished and installed under a contract made between the City
of Austin and William D. Johnson and assigns, dated September 22, 1911.
I have also investigated the physical conditions surrounding this installation,
and in accordance with instructions I submit herewith my report.
In order to present this matter fully, I have found it essential to describe some-
what briefly the history of the Austin dam and the conditions leading up to its de-
struction in 1900. I have also endeavored to explain the conditions and the engi-
neering principles on which the successful consummation of this project must rest,
in as simple and plain a manner as possible, in order that the citizens of Austin may
understand the defects found and the betterments needed to put the installation
into safe condition. I have also endeavored to give the technical information on
which my opinions rest, in sufficient detail that my findings may, if you desire, be
reviewed and checked by other engineers without the further expense of elaborate
investigations and calculations.
It should be understood that the work on the dam was supposed to be practi-
cally complete in 1915, until floods developed certain weaknesses in the structures
and until certain changes in plans, not understood by the City Council, were discov-
ered. At the time of my examination the foundations were under water and could
not be examined in detail at any permissible expense; the conditions leading up to
the contract and the events of construction were matters of history which could not
be ascertained except from the statements of those familiar with them ; the available
plans on which the work was done were not entirely complete and apparently had
not been corrected for possible construction changes; and I have in consequence
been obliged to depend on individual statements, more or less official records and
published articles in the technical press, as well as on my personal examination.
Various photographs, maps and sketches have been included in the report in order
2 ^Report on the Dam at Austin, Texas.
to make clear many conditions which cannot well be understood from a written de-
scription.
It has been my endeavor to investigate this project as fully and accurately as
its importance demands, and to make my report comprehensive, accurate, simpl<
and fair to all concerned.
Very respectfully,
TTP-. . DANIEL W. MEAD.
Madison, Wisconsin.
November 20, 1917.
INSTRUCTIONS
The instructions on which the report is based were contained in the following
resolution :
RESOLUTION
Resolved, by the City Council of the City of Austin, Texas : That the Mayor and
Superintendent of Parks and Public Property of this City be and hereby are author-
ized jointly to engage the professional services of some engineer of high character
and of exceptional ability and experience in such work to carefully examine, upon
the ground and otherwise, into the whole physical situation at the dam and power
house and advise this City as to the character and conditions of these structures and
report fully upon the work done in the rebuilding of the dam, and
Be it Further Resolved: That amongst the matters to be especially referred to
such engineer for investigation and report shall be the determination as to whether
or not the dam, as rebuilt, is rebuilt in compliance with the plans and specifications
provided by the City of Austin for this structure, and if there are any variations
from the original plans and specifications, what they are, and what are their effect
upon the dam, and he is especially instructed to investigate and report as to the ef-
fect upon the stability of the dam of the narrowing of its base from the width of the
base as originally prescribed in the original plans and specifications for the re-
building of the dam, and
i ~
Be it Further Resolved: That he shall be instructed to ascertain what defects, if
any, exist in the dam and how such defects may be remedied, and he is especially
enjoined to investigate and advise as to what things should be reasonably done to
give the dam the greatest practicable stability and safety, and
Be it Further Resolved: That he be instructed to pass upon the efficiency of said
dam and its permanency as to structure for all probable time and suggest such ad-
ditional things, if any, proper to be done to make such structure permanently stable
and efficient, and
Be it Further Resolved: That he is hereby instructed to estimate the cost of
such changes, improvements, betterments and additions to and at the dam as he may
deem proper to recommend to the consideration of the City Council, and
Be it Further Resolved: That he is hereby especially instructed to estimate the
value of the material and labor put into the dam by the present contractors and
builders, and the value of the work done in and at the power house, and the value of
the reservoir, and the value of the equipment at the power house ; such information
to be of such use to the City Council as it may find occasion to make of the same, and
4 Report on the Darn at Austin, Texas.
Be it Further Resolved: That said engineer be instructed to do all reasonably
necessary and proper things to inform the public upon the dam; First, as to its
stability; and second, as to its efficiency, so that in the event the City should either
desire to purchase the dam and its appurtenance properties outright, or to insist
upon the execution of the present contract, with or without modification, it may have
the full and intelligent facts before it upon which to base its future action, and
Be it Further and Finally Resolved: That the employment of an engineer shall
not in any way modify, or waive any provision or obligation contained in the con-
tract made by the City of Austin with Wm. D. Johnson and his assigns for rebuild-
ing the dam across the Colorado Eiver above the City of Austin.
Adopted: May 30th, 1917.
Yeas : 5
Approved: May 30th, 1917,
A. P. WOOLDKIDGE,
Mayor.
To the instructions contained in the above resolution were added further instruc-
tions contained in a letter from the Hon. A. P. Wooldridge, Mayor, dated Septem-
ber 14, 1917, as follows:
"If you consider there are important additions to be made to the dam to
assure its stability, you will separate such additional work as may be called for,
or fairly implied in the terms of the present contract, from those which ought
to be done but yet are not set out in the present contract, nor fairly deducible
from its provisions. * * * In other words, to make myself clear : If there are,
in your judgment, any additional things which ought to be done to assure the
stability of the dam as it now stands, you will please say so, stating if the cost of
these additional things properly devolve upon the Contractors or upon the
City."
ACKNOWLEDGMENTS
The writer desires to acknowledge the valuable assistance and information fur-
nished him during his investigation by Hon. A. P. Wooldridge, Mayor; Hon. E. C.
Bartholomew, Superintendent of Parks and Public Property ; Mr. Guy A. Collett, Re-
ceiver, and Dr. S. W. Simonds of the University of Texas ; also from Mr. Frank S.
Taylor, Resident Engineer, who furnished numerous plans, specifications, data and
explanations, not otherwise available ; also to Mr. S. S. Posey, Inspecting Engineer
for the City, who was present during essentially the entire construction period and
who accompanied the writer during his entire examination; also to Mr. H. L. Cobb,
Assistant Engineer of Construction, for various information and for many photo-
graphs taken during construction and showing conditions otherwise unascertain-
able ; also to Mr. W. P. Johnson, Engineer of the City Power Station ; and to Mr.
Miller who is now in charge at the dam for the Receiver. Various information has
been secured from the technical press and from other sources which the writer has
endeavored to acknowledge in the report.
REPORT ON
THE WATER POWER DEVELOPMENT
AT AUSTIN, TEXAS
The original Austin dam, built across the Colorado Eiver near Austin, Texas,
and completed in 1893, was the consummation of a local ideal that had existed more
than fifty years.
The City of Austin, with a population of less than 15,000, undertook a daring
venture when it expended about $1,600,000 for electric light and water works, and
the construction of the greatest overflow dam that had then been built across a large
and torrential stream. The failure of the venture in 1900, due largely to the engi-
neering and administrative inexperience of the time, was a serious blow to that pro-
gressive City.
After its unfortunate experience, the City did not desire to reconstruct this dam
by direct taxation but elected to make a contract whereby the work of reconstruc-
tion, rehabilitation and maintenance, and the risk involved, were to be assumed by
a private company. This company was to be reimbursed for its expense and re-
warded for its endeavors by a payment of $100,000 in cash on the completion and
acceptance of the work, and by semi-annual payments of $32,400 each for twenty-
five years to be derived from the income of the plants which utilized the power so
developed. On this basis the City entered into a contract in 1911 with Mr. Win. D.
Johnson for the reconstruction of the dam, power station and accessories.
METHOD OF FINANCING
Although the method used for financing the reconstruction of the Austin dam is
a common one for promotive enterprises, it is an unfortunate method to be used in
connection with the construction of municipal public works. For any enterprise this
method of financing is an exceedingly extravagant one, and its general tendency is
toward cheap and faulty construction or exceedingly high costs, or both. Usually a
company is organized for the purposes of promotion is financially irresponsible be-
cause its capital stock commonly represents only anticipated profits. Bonds are usu-
ally issued to meet the entire promoting, financial and construction expenses, and
these bonds, on account of the nature of such enterprises and the risks involved,
must commonly be sold to bond brokers at a heavy discount. The work is com-
monly let to contractors, who in their turn should receive an adequate profit. In
such an enterprise therefore the profit of the Bond Dealer, and the profit of the
Promoter must be included in the cost price of the work.
The total expense to the City of Austin, involved by the franchise during the
25-year period, was $1,720,000, with a present cash value of approximately one mil-
lion dollars. The City Water Works Company, the promoting company organized
8 Report on the Dam at Austin, Texas.
to finance the endeavor, arranged for an issue of $750,000 which it contracted to sell
at 75 per cent, of its face value. Its contract with the Wm. P. Carmichael Company
of St. Louis, provided for the maximum cost of the work to be done at $453,000,
which sum was to include $50,000 profit to that Company. The scheme therefore
stood as follows :
Promoters' Expense and Profit $250,000
Discount to pay Expenses and Profit on Sale of Bonds 187,500
Contractor's Profit 50,000
Estimated Maximum Cost of Work 403,000
Total $890,500
Leaving for Contingent Expenses and Extra Profit for Promo-
tion 109,500
Cost to the City $1,000,000
Thus it was proposed by the Promoters to construct an adequate plant for
$1,000,000, of which only $453,000 was to be paid to the Contractor for the actual cost
of the completed work and the Contractor's profit; and $547,000 was to be used for
financial and promotive expenses and Promoters' profit.
There is nothing necessarily illegal or inequitable in such a financial plan, pro-
vided the plan is fully understood, the financing is on an adequate basis, the bonds
are sold to purchasers who understand the risk involved, and the work is honestly,
intelligently and adequately done. The objections to it are :
1st. The lack of real responsibility on the part of the promoters.
2d. The tendency to false economy to assure or to inflate profit.
3d. The temptation to give false assurances to purchasers as to the safety
of the securities sold.
4th. The large expense involved compared with the actual cost of the work
to be done.
It is recognized by all familiar with the construction of large enterprises that
there is no other method by which work is financed that requires closer scrutiny of
the personnel and experience of the promoters and their engineers, of the financial
and construction plans, and of the contract and specifications in order to assure hon-
est, conscientious and proper work, and a successful outcome of the endeavor. Such
scrutiny is necessary on account of the fact that unless the endeavor is so success-
ful that the promoters will have a considerable equity remaining in the work after
construction and acceptance, they will abandon the enterprise leaving the unorgan-
ized innocent purchasers of securities, and their creditors, as the only parties who
have an actual financial interest in the uncompleted or unsuccessful endeavor, as has
actually occurred in the case at hand.
The Reconstruction Work.
PLANS AND SPECIFICATIONS
The plans and specifications which were the basis of the contract were of the
most general character and not sufficient to afford a basis for a professional opinion
as to their adequacy, without numerous assumptions as to essential matters which
were not shown or explained in detail. The City did not secure independent expert
advice concerning the plans proposed, but a special effort was made in the franchise
ordinance, which constituted the contract under which the work was done, to bind the
promoter and his assigns as to the progress of the work, time of completion, com-
pleteness of equipment, capacity of equipment, maintenance of structures, and for
the minimum power.
The general plans and specifications accepted and made a part of the contract
were to be followed by detailed plans and specifications, but all plans were subject
to any change that the engineers of the promoter might desire, limited only by the
following provision:
"Provided, such changes do not decrease the amount of equipment in the
power house, the height or stability of the dam, the size of the reservoir, or in
any way diminish the capacity or completeness of the installation, or in any way
lower the standard or grade of construction."
THE EECONSTRUCTION WORK
In order to satisfy the contract requirements and to maintain the rate of pro-
gress specified, work was begun on the power station in the fall of 1911 by the City
Water Power Company by day work. A contract was, however, entered into on
June 1, 1912, between the Company and The William P. Carmichael Company to as-
sume the expense of the work already done and to complete the entire work involved
in the contract.
The contractor endeavored to protect itself by a provision in the contract ' * that
said Company (the City Water Power Company) is solely responsible for the suffi-
ciency and correctness of said plans, specifications and designs." This provision
would have been sufficient for the protection intended if the contract had been made
with a responsible or with a successful company, but was without avail under the
actual conditions which afterward obtained.
THE CONTRACTOR FOR THE WORK
The William P. Carmichael Company had constructed the Congress A venue rein-
forced concrete arch bridge at Austin, and had had extensive experience in con-
crete work, but apparently little experience with river work. The work at Congress
Street had practically been done during the year 1909, during which year the mean
annual and the maximum and minimum flows of the Colorado were near the min-
imum (see Fig 1). They began work on this project during 1912, which year had
10
Report on the Dam at Austin, Texas.
the lowest mean flow on record ; but unfortunately they were obliged to confine their
attention largely to construction outside of the channel, and the advantages of this
period of exceptional low water were lost. The work of construction in the chan-
Mtnimum Mean MotifMy ffotv.
Maximum Me&n Monfh/u F/ow.
W7
FIGURE 1 — Mean Annual, Minimum Mean Monthly and Maximum Mean Monthly Flow of
Colorado River at Austin, Texas.
nel was performed during the years 1913 and 1914, during which the mean annual and
the maximum mean monthly flows of the river were the largest of any years of record
except the year 1900. The results of inexperience with river work and the unfor-
tunate conditions of flow were all that could be expected. The frequent destruction
of cofferdams and the work already completed, the extra expense involved by delays,
and other unforeseen contingencies of river work added materially to the expense of
the work.
The Reconstruction Work. 1 1
It was found necessary to add to the anticipated work on the power station, pen-
stocks, station equipment, etc., and the Contractor presented a bill of extras
amounting to about $109,500, making the total claims for work done $563,500 which,
however, was insufficient to make good the cost, for the books of the Contractor
show a total construction cost of $795,332.19, involving a construction loss of
$251,465.70, if the entire amount apparently due is ultimately collected.
THE BOND ISSUE
The bonds issued by the City Power Company were underwritten by Lawrence
Barnham and Company of New York at 75 per cent., and $412,500 par value in
bonds has been taken by the underwriters. It is understood that most of these bonds
are in the hands of individual purchasers who took them on approximately a 98 per
cent, basis. The balance of the bonds, amounting to $337,500, are held by the New
York Trust Company, Trustees.
WOEK APPARENTLY NEARING COMPLETION
In the spring of 1915 the work was apparently nearing completion. The water
reached the level of the crest of the old dam on February 16, 1915, for the first time
since its destruction in 1900. The gates were found to leak badly and stanching
strips were added to tighten them. The turbines and equipment were tested in
March and declared satisfactory. March 31, the Engineer of the City presented a
statement of those things which he considered necessary to complete the contract
ready for the acceptance of the work. (See Appendix 10.) Early in April, the
City, regarding the work as nearly completed, advanced $21,000 to assure immed-
iate completion.
DIFFICULTIES ARISE
The Wm. P. Carmichael Company was to be paid $250,000 by the City Water
Power Company as soon as that value in work had been done under the contract,
and was to receive no further payment until the work was completed and accepted.
The first payment was duly made; the unexpected extra expense, however, embar-
rassed the Contractor and exhausted its resources. The City Water Power Com-
pany was unable to advance further funds until the work was accepted and further
bonds could be sold.
On April 20, 1915, a retaining wall next to the power house went out for the
second time. On April 23, a flood carried out four of the automatic crest gates and
practically filled up the tail race. The gates were replaced and the tail race
cleaned out.
The roofs of some of the sluice conduits were destroyed when the sluice gates
were opened. These had to be replaced and strengthened.
1 2 Report on the Dam at Austin, Texas.
The City naturally refused acceptance until these various defects were rem-
edied. The bond holders advanced about $11,000 to assure the completion of the
work. Certain changes in the plans, unknown to the City Council, were discovered
and their validity was questioned. Two leaks were discovered under the new por-
tion of the dam. A greater flood in September (see Frontispiece) carried away
most of the gates and again filled the tail race.
FINANCIAL COLLAPSE
As the defects became more apparent, the possibility of securing an acceptance
from the City became more remote. The funds available were too small to complete
the repairs which evidently were needed. The Contractor had apparently exhausted
every resource and was obliged to assign.
The Contractor had filed a mechanic's lien on the property for the balance
claimed as still due ($270,983.79). The Engineers of the City Water Power Com-
pany filed liens to approximately $24,200 in addition to a judgment previously se-
cured against the Company for about $1800. Bonds amounting to $412,500 were
outstanding. The apparent claim against the franchise and property at the present
time is therefore $709,483.79.
The City Water Power Company was deeply involved and without resource.
The officials apparently lost interest and neglected or abandoned the work, and by
mutual agreement of all interested parties the Federal Court appointed Mr. Guy A.
Collett as Receiver for the property.
PERIOD OF INVESTIGATION
For two years practically nothing has been done toward completing the plant.
Brief examinations have been made and preliminary reports rendered by various en-
gineers for several interested parties with the hope that in some way the defects
could be remedied so that the installation would be accepted by the City and the
interests adjusted. The City, feeling that no prerequisites for acceptance could be
specified without a detailed knowledge of the defects, decided to investigate the en-
tire matter.
This report is made to afford full information to the citizens of Austin, and as
a basis of action for the City Council in accordance with the resolution of May 30,
1917, that ' ' it may have the full and intelligent facts before it upon which to base its
future action."
PHYSICAL CONDITIONS AT THE DAM SITE
The original dam and the structure built under the Johnson franchise were
built across the canyon of the Colorado River about three miles from the center of
the City of Austin. The entire location is within the Balcones fault zone (see
Fig. 2, page 13), and the entire foundation is on the Edward's limestone forma-
Physical Conditions at the Dam Site.
13
FIGUBE 2— Map Showing Fault Lines of Balcones Fault Zone Near Austin, Texas. (From Aus-
tin Folio, U. S. Geol. Survey)
14
Report on the Dam at Austin, Texas.
tion which has undergone a downward displacement of many feet (see Fig. 3,
page 14). The formations in the river bed at the dam site are jointed and faulted,
the main fault planes undoubtedly extending deep below the river bed. On the east
side of the site there is apparently a block fault in which the strata have been broken
and shattered, and much of the original lime has been leached out by percolating
waters, leaving clay seams and voids in the strata. The physical conditions have
been described in some detail in Appendices 1 and 4 to which reference should be
made for a more detailed description.
\ \
Fee
loo
\ \
Austin chalk.
1 I
1 1
!, 1
Buda(MoaiCre*tflunt3l»a*
Del fio cloys
Fort Worth ifmestonc.
*T"r
S3™
i
sT.-v.r.
M
•sot
Cama.-K/>c.fbo*/im*ftfne
f J 1
I 1
_'_!_
2
G/tJi Rax format fen
W
1 1
1
Travis Fkak formation
^yvi:;'
tySr
- Eagle, forctihatxj
FIGURE 3 — Section Along West Side of Colorado River at Austin, Texas, Showing Local Fault of
Balcones Fault Zone (Austin Folio, U. S. Geol. Survey)
THE OLD DAM
The solid structure of the original dam, finished in 1893, apparently furnished
by its width of base a sufficient resistance to underflow so that it stood for some years.
Various leaks developed, however, near the east end of the structure, especially un-
der the head gates, and were repaired in an imperfect way. One of these caused con-
siderable damage before the completion of the power house. (See Appendix, page
46, Fig. 17.) In 1900 the east half of the original dam over the badly faulted area
failed, due to the erosion of the rock below its toe, the undermining of the toe, and
possibly to the development of leaks under its foundation.
THE NEW STRUCTURE
The structure built under the Johnson contract consisted of a reinforced con-
crete section built in the opening where the previous dam had been destroyed. (See
Fig. 4.) Most of the old structure remaining was utilized practically as it stood and
without material betterments.
Work on the power house and reservoir was apparently immediately pushed to
completion, and operations in the river work were postponed until the years 1913-
14, thus losing the advantage of the lowest average river stages experienced on the
Colorado in twenty years of record and bringing the construction period into two of
the heaviest years of flow on record. (See Fig. 1, page 10.)
Changes in Plans.
15
PLANS AND SPECIFICATIONS
The specifications (see Appendix, pages 61 to 65) and plans (see Appendix, page
65) for the work, submitted with the franchise and made a part thereof, were of the
most general character. Conditions were further complicated by the right received
under the specifications whereby the engineers of the City Water Company were em-
powered to make any changes they desired, provided the stability, capacity, com-
pleteness or grade of construction were not reduced. (See page 9.) Even these
limiting conditions were restricted by the requirement that any difference of opin-
ion between the Engineers of the City and of the Company must be arbitrated, a
process so cumbersome that it seems to have been waived in every case. The En-
gineers of the City could only inspect and suggest, and were practically powerless
to initiate betterments or to resist more than radical defects or changes. Detailed
K 47O' >K S6O'- - - > 0' 50' 100'
UPSTREAM ^-Concrete CvMT Wall u *t / J " " ' " " ' —
-*= *&'* Oriqina/
200'
0>d Masonry CtsrofT Yto//
-i ;_if ; T-.T . .T;xt fc. 'fJ^c.
0/cf Masonry CtsfofF Wall
Origr/naf Masonry Derm >K Hew Spit/way Section-
Floor, El. /75J> £niranc&.j< sCrest-^pf New Spillway
'•Crest of Prigrincrl 'Spit/way
* ^ '
Bottom' of Concrete
CuMFWd/f
Line of SiH- below Dam
fitter Line as shown ty >
Orfgriner/Ar/ngs '
FIGURE 4 — Plan and Elevation of the Reconstruction of the Austin Dam under the Con-
tract with William D. Johnson, (from Eng. News June 3, 1915.)
plans and specifications were to be furnished before work was begun. The City,
however, never received a complete set of plans but in lieu of this the Resident En-
gineer furnished copies of the principal detailed drawings, with a list of other draw-
ings made, and an offer to furnish such as the City might desire. The City on its
part made no demands for complete details and has only an incomplete plan of the
work on file.
CHANGES IN PLANS
The original reinforced concrete structure (see A. Fig. 5, page 17) had
diagonal cross walls, spaced 24-foot centers, and on the basis of the scale of the
drawing was deficient in strength. On Nov. 28, 1911, this plan, with the approval
of the City's Engineer and the City Council, was changed to a type having cross
walls normal to the axis of the dam (see B. Fig. 5, page 17), and spaced 20-
foot centers, and with the interval of the crest piers increased. Both of these changes
were improvements but the plan still remained indefinite in detail and defective in
strength.
In May, 1912, more detailed plans were submitted on which much more definite
information was given. These plans were 'submitted to the City's Engineer who
16 Report on the Dam at Austin, Texas.
after an examination approved them but failed to call the attention of the City offi-
cials to a radical change in width, which change he evidently did not interpret as a
change in stability, capacity, completeness or grade of construction.
The original design and the plans substituted in November, 1911 called for a
dam with a width parallel to the stream of 125'9". The detailed plans of May, 1912
(see C, Fig. 5, page 17), provided for a base width of 93 feet. The new plans
also called for additional thickness in the decks of the structure and gave the
reinforcement in detail, and altogether was a better and stronger structure than in-
dicated by either of the previous plans.
The force diagrams (see B, Fig. 6, page 18) show that the new plan repre-
sents a lighter structure, and in consequence the resultant pressure makes a less
angle with the base line, and theoretically the dam is more liable to slip on its founda-
tions or on any underlying clay seams ; but the improvements in other ways are so
marked that I believe the change in width is of practically no moment. Various other
changes in details were made some of which were material betterments and others,
including the change in width of dam, were undoubtedly made to cheapen construc-
tion; others were forced by physical conditions. The attention of the City Officials
has already been called to many of the changes made, by the report of Mr. S. S.
Posey (see C, Fig. 6, page 18).
THE EFFECTS OF CHANGES IN PLANS AND SPECIFICATIONS
Betterments. — A number of the changes made were distinct betterments to the
plans as originally proposed. Such changes are as follows:
1. Change in Type. — The change in type of dam from diagonal to normal
cross walls was a distinct advantage in that it led to simplicity of design.
2. Change in Spacing of Walls. — The reduction in the spacing of cross walls
from 24 to 20 feet was a distinct betterment, giving a greater number of points
of support to the decks and a better distribution of pressure on the foundations.
3. Increase in Span of Crest Gates. — The original plan provides crest gates
ten feet wide for the new section and eight feet wide for the old section. These
were increased to eighteen feet in width for both sections. This was an improve-
ment, and with stronger gates on a stream carrying little drift this plan might
have given satisfactory results.
4. Foot Bridge on Dam. — The original plans provided for a wooden struc-
ture on I-beam supports across the crest of the dam. This was changed to a
reinforced concrete structure in order to carry a derrick car for the removal of
drift and for the manipulation of the gates. This change was an improvement.
5. Location of Sluice Gates. — The change in the location of the sluice gates
which brought these gates into the stream channel was an improvement.
Changes in Plans.
a. /es. o
-PI an and Section of Com as Ortgina/ '/y Proposed -Sepf. 22 'CSf- /$//.
0 - Section of Dam as Changed and fljo/y/wed • March / 5 (2/3/2.
C. P/an and Section of Oam as Cfiangea" and
flpprovea/ rfay /OH! /9I2 anaf as Construe/fa"-
FIGUBE 5 — Original Plan for Reinforced Concrete Dam at
Austin, Texas, and Successive Changes made in Same.
* a* .ie> ii*«.***> * * « **'
•>»•'« * , «^r'J « **
Report on the Dam at Austin, Texas.
FIGURE 6— Force Diagrams of Original and Final Sections of the Austin Dam.
Changes in Plans. 19
6. Width of Cross Walls. — The base width of the cross walls was shown as
one foot in the original plans. This width was increased to 2'6" in construction,
which was a change for the better.
7. Thickness of Upstream Deck. — The thickness of the upstream deck was
increased from 2' to 2'6" at the base, and from V to 1'8" at the top. This change
was a betterment essential to the safety of the structure.
8. Power House Floor. — The original plans provided for a reinforced con-
crete floor supported on I-beams. The floor as built was supported partially
on earth fill and partially on reinforced concrete beams. Assuming this work
was properly done, this change was an improvement on the plans.
9. Changes in Head Gate Racks. — The racks as originally designed and in-
stalled permitted drift to enter the penstocks, which caused the frequent break-
age of the turbine gates. The change in form of rack later installed, and now
in place, was a decided betterment which accomplished its object, although it in-
terposed too great a resistance to the free entrance of water.
IMMATERIAL CHANGES
1. Change in Width of Plans. — The change in the width of the dam from
125'9" to 93' I regard as immaterial. If the dam were otherwise safe, either
width of dam would be safe and satisfactory. The narrower design is more eco-
nomical and therefore an improvement from an engineering standpoint, but
from the point of view of the City, the change is immaterial.
2. Change in Bascule Castings. — The bascule castings for the gates were
changed from a rack type to a plain type. Either type would have been satis-
factory if sufficiently strong for the purpose, and if the gates were otherwise
satisfactory.
3. Cutoff Walls below Old Dam. — A cutoff wall was planned below the toe
of the old dam but was omitted in construction. If this wall was intended to
cut off flow under the old dam, its presence would have been a detriment rather
than a benefit. Seepage should be stopped at the heel of the dam, and if it
reaches the toe should be removed instead of being prevented, in order to reduce
uplift pressure on the base of the dam. If this wall had been installed, weep
holes in the toe would have become essential. The omission of the wall at the
toe is regarded as immaterial.
4. Change in Concrete Mixture. — A change was made in the mixture of the
concrete used from that required by the specifications by using pit run sand and
gravel instead of a definite mixture of cement, sand and stone or screened gravel
in the ratio of 1 :2 :4. Mr. Posey states (see Appendix, note 18, page 75) that the
pit run gravel was tested frequently for voids, and the voids controlled by the
20 Report on the Dam at Austin, Texas.
addition of sand, gravel or stone, and that an excess of cement was used. The
probabilities are that the concrete produced was equal to that which would have
resulted from the specified mixture. This is confirmed by the appearance of the
finished work.
DETBIMENTAL CHANGES
1. Detrimental Changes in the Provisions for a Safe Foundation
A. Grouting. — The specifications for grouting were very indefinite. Grout com-
posed of cement mixed with three parts, or less, of sand was to be forced into two-
inch holes of unspecified depth which were to be spaced not more than 30 feet apart,
or any other method could be used to render the substrata impervious. (See Appen-
dix, page 63.)
Holes were bored in many cases very close together, perhaps in cases 3 feet or
less apart but near the line of the cut-off wall, and they were all 12 feet or less in
depth. On the lines of the cross walls, the holes in general were bored only about 4
or 5 feet in depth.
The general purpose of this specification was to produce an impervious bottom
"to prevent waste" but the safety of the structure was more particularly involved.
The inadequacy of the work done is indicated by the leaks now in evidence under the
reinforced concrete structure. It is believed that the grouting behind the old dam
is also ineffective in preventing seepage and uplift pressure. This work, which was
indefinitely specified except as to its object, has been done in an ineffective and in-
complete manner, and the conditions resulting threaten the safety of the structure.
B. Cut-off Wall Above West Section of the Old Dam. — The original plans pro-
vide for a cut-off wall adjoining the heel or upstream face of the old dam. Appar-
ently, from the scale of the original drawing this wall was to be about 22 feet or more
in depth. A shallow cut-off wall was built as part of the so-called "core wall" behind
the east section of the old dam. No cut-off wall was built behind the west section
of the old dam but inadequate grouting was substituted in shallow holes of a maxi-
mum depth of 12 feet, to the detriment of the work.
C. Cut-off Walls on Reinforced Concrete Dam. — These walls were to be carried
down to ' ' solid impervious rock which borings indicated to be at least six feet in
thickness." The original drawings indicated that these walls were to be carried to
a depth of 22 feet or more below the rockbed of the river. Under parts of the dam
it is probable that no six-foot strata of solid rock were available, and the specifica-
tions were perhaps impossible so far as that requirement was concerned. These con-
ditions made the deep cut-off proposed imperative for safety, but the only substitute
furnished was to carry the wall approximately two feet into solid rock, and to at-
tempt to solidify cracks and fissures by grouting. In places, however, according to
the evidence of the Inspecting Engineer, not even a wall two-feet in depth was con-
structed.
Changes in Plans. 21
2. Detrimental Changes in the Structure of the Dam and Appurtenances
A. Core Wall. — The core wall as shown on the plans and as described in the spe-
cifications is somewhat indefinite. The original plans submitted with the contract
show the bottom of the east end of the core wall at about elevation 120. The revised
detailed plans of May, 1912, show the end of this wall lowered to elevation 100.
This change is an apparent improvement. The original plans also show the top of
the core wall in front of the gate masonry to be at about elevation 172. Evidently
it was intended to face the head gate masonry with the concrete of this core wall in
order to make the masonry water tight. A slight modification was made in the end
of the core wall as planned when it was constructed, several hundred yards of con-
crete being omitted by the consent of the City's Engineer and approved by the City
Council. As the material at this point was found to be impervious, this change is ap-
parently of little moment. The concrete in front of the head gate masonry was om-
itted, which was evidently a detriment to the work as this masonry is said to leak
when the reservoir is full.
B. Pointing the Old Dam. — While the old masonry has been pointed in part,
this work has not been done in a thorough and workmanlike manner.
C. Changes in Gates and Setting. — The original plans for the gates showed a
fairly well braced gate, but when the gates were widened and redesigned they were
built in two sections joined only by thin plates which were to be supported on small
bascule piers. While neither design is considered adequate, the change is consid-
ered detrimental. The introduction of small center bascule piers to support the gates
and reduce the cost of their construction was a detriment inasmuch as these piers ser-
iously obstructed the flow.
D. Sluice Gates and Sluice Gate Trash Racks. — The design for the original
sluice gates provided for the sluice gate to be set in a recess in the dam, built in
such manner that the hydraulic cylinders would be within the dam and accessible at
all times (see A, Fig. 7, page 22). This plan also provided for T-rail trash racks in
front of the gates to prevent floating matter entering the gateways and interfering
with the proper operation of the gates. In the construction of the plant this plan
was changed. The gates together with the hydraulic cylinders were set on the face
of the dam (see B, Fig. 7) and no trash racks were provided. This change was a
decided detriment.
3. Power Plant Accessories
A. The Tail Race. — Specifications for the tail race evidently anticipated its ex-
cavation through earth and the construction of a tunnel or channel of reinforced
concrete ample for the use of the three turbines installed and for an additional tur-
bine which might be added at a later date. It was found, however, that the surface
of the rock was not far below elevation 100 (low water level) and that much of the
excavation would have to be made in rock ; the sum of about $8,335 was apparently
expended on this excavation. The presence of this rock rendered concrete unneces-
22
Report on the Dam at Austin, Texas.
sary except that a wall might be desirable on the north side of the raceway in order
to keep back the debris from the large mass of rock, dirt, etc., located between the
tailrace and the foot of the dam. (See Figs. 8 and 9, page 25.) While a de-
flecting wall immediately adjoining the power house and north of this raceway is
considered advisable in order to protect the exposed draft tubes, it is not believed
FIGURE 7 — Sections of Sluice Gates as Originally Designed and
as Constructed.
that such a wall extended for the entire length of the raceway in the main channel
would be either effective or desirable. To be effective it would have to be built high
and strong in order to prevent detritus being raised over it in times of extreme
flood. If built high enough for this purpose, it might prove objectionable on account
of creating cross currents near the toe of the dam and by creating a comparatively
quiet pool in the tailrace which would cause heavy silt deposits therein. The re-
quirements for such a wall can best be obviated by the entire removal of this pile of
debris. While the failure to construct a concrete channel is not considered detri-
mental, the failure to construct a proper channel which would not be filled with de-
bris after every flood is considered a serious detriment to the work.
Changes in Plans. 23
B. Penstocks. — The penstocks, or intakes as they are termed in the specifications,
were to be constructed of first class material throughout and the specifications evi-
dently did not anticipate the use of material from the old penstocks installed in 1893,
and which had remained in the old plant until the removal in 1911. This material
was, according to Mr. S. S. Posey, badly corroded but was used for all of the pen-
stock work in the reconstructed plant except for the elbows which were of new ma-
terial. The penstocks outside of the building were covered with reinforced concrete ;
inside the building they were protected on the inside with " smooth-on" but left un-
covered. I have not seen these penstocks in operation and cannot speak concerning
their tightness and effectiveness. It is quite possible that some additional protec-
tion will be needed inside of the power house. While these penstocks as installed
may prove fairly satisfactory, the writer considers the change from the new mater-
ial to the old, even with concrete reinforcement, as detrimental to the interests of
the work.
C. Fourth Penstock. — The specifications provide for four penstocks only three
of which will be used in the present plant, the fourth being reserved for an additional
unit which might be needed later. By the advice of the City's Engineer and with
the consent of the City Council this penstock was omitted and other work substi-
tuted. If the plant is to be utilized finally for 3300 average continuous horse power,
it is believed that the omission of the 4th penstock was evidently a mistake, detri-
mental to the installation. While I am not fully informed as to the load factor of
the Austin electric plant, it is known from experience that the load factors for such
plants are commonly below 35 per cent., and that it is hardly probable even when
Austin is able to utilize the full 3300 average horse power that this load factor will
increase as high as 40 per cent. On the basis of 35 per cent, load factor, the maxi-
mum peak which the plant must carry to utilize the average of 3300 HP would be
almost 9500 HP, and if the load factor reaches 40 per cent, it will still require a maxi-
mum peak of about 8300 HP. In either case the installation of an additional tur-
bine, generator and penstock will finally be necessary to equip the plant to the capa-
city for which it is designed.
D. Draft Tubes. — Both the original plans and the amended plan of Jan., 1912,
showed the draft tubes within the power house and discharging through the founda-
tion walls. On the details of the machinery setting, dated November, 1912, the
draft tubes are first shown projecting in the exposed position in which they were
constructed. This change is detrimental to the safety and continuous operation of
the plant.
DEFECTS IN PRESENT CONDITIONS AND STRUCTURES
1. Foundation Conditions. — Having pointed out the various changes in the plans
and specifications and their effect on the installation, it is necessary, in compliance
with instructions, to point out the defects in the present installation, only part of
24 Report on the Dam at Austin, Texas.
which are due to these changes the remainder being due to their inadequacy and in-
completeness.
The serious foundation conditions at the Austin dam have been discussed at
some length in Appendices 1 and 4, and the defects in the present structures have
been described in considerable detail in Appendix 5. These defects may be de-
scribed briefly as follows :
A. Foundation. — The foundation of the dam, especially of the new part, is in
very bad condition. An attempt was made under the Johnson contract to render
this bottom impervious by grouting which however was inadequate in extent and
ineffective in results. This is perhaps the most serious defect in the work done and
has resulted in two known leaks, and unless remedied will probably result in the
early destruction of the new section of the dam.
B. Riverbed Below the Dam. — The rock below the toe of the new section has been
deeply eroded and is in general considerably below the foundations of the cross
walls of the dam. (See Fig. 12, page 28.) The irregular foundations of these
cross walls are built to different depths and founded on the rough and irregular sur-
faces of different strata of rock, which will prevent the slipping of the dam on its
foundations. However, there is a danger of the entire structure slipping on the clay
seams which are known to underlie at least a part of the structures. A dam with its
foundation above the bedrock immediately in front of its toe cannot be regarded as
a safe structure, and the present condition will undoubtedly be made worse by every
high flood.
C. Leakage. — The large leak in panel No. 6 of the new dam was discharging ap-
proximately 30 cubic feet per second during the writer's examination in August,
1917, when the head on the dam was only 15 feet. This leak is a serious menace to
the structure. The leak in panel No. 4, while apparently small, and such other see-
page as may occur under the old or new structure may increase and give rise ulti-
mately to dangerous conditions.
The observations of the U. S. Geological Survey (see Appendix, page 120) show
that with the reservoir full to elevation 151 there is leakage into the strata and
around the dam of at least 90 cubic feet per second. This leakage if conserved would
under a sixty-foot head generate about 600 continuous horse power, and, with the
power utilized to even half of the rated capacity of the plant, would be of great value
during low water seasons or for about 55 per cent, of the time (on the basis of the flow
for the last 20 years). On the basis of $65 per year per horse power, which is essen-
tially equivalent to one cent per kilowatt hour, the annual value of this loss by leak-
age would be about $17,850, which amount capitalized at ten per cent, would equal
$178,500 which is an approximate measure of the amount which may ultimately be
expended to advantage in stopping such losses.
Changes in Plans.
25
FIGUKE 8— Showing Debris North of the Tailrace and the Filling of the Tailrace by the Flood of Sep-
tember, 1915, also Showing the Exposed Position of the Draft Tubes.
FIGURE 9 — Showing Debris North of the Tailrace and the Filling of the Tailrace by the Flood of Sep-
tember, 1915, also Showing the Exposed Position of the Draft Tubes.
26 ; Report on the Darn at Austin, Texas.
FIGURE 10 — Showing Drift Accumulated above the Dam at Austin during the Flood of
September, 1915.
FIGURK 11 — Showing Drift Accumulated above the Dam at Austin during the Flood of
September, 1915.
Changes in Plans. 27
2. The Structure of the Dam
A. Old Dam Section. — The specifications provide that:
"portions of the original dam as constructed in 1890-1893 will be retained and
used as portions of the finished structure. * * The contractor assumes the
responsibility for the perfect stability and effectiveness of the old dam as part
of the finished structure."
In Appendix 5, pages 124 to 129, 1 have analyzed the section of the old dam under
the various conditions of its past and proposed use and have found that it cannot be
considered as safe under the conditions which do or probably will obtain. The in-
terior masonry is of a poor quality of limestone of local origin, poorly laid in cement
mortar. The dam is faced with a good quality of granite which however is not well
bonded into the interior masonry. Water finds ready access through the voids to
almost every part of the structure. The facing on the east end of the west portion
of the dam is apparently loosened from the underlying masonry and shows signs
of considerable seepage when the reservoir reaches elevation 151 or higher.
I believe there is a real danger of the destruction of the old section if it is al-
lowed to remain in its present condition.
B. Crest Gates. — The gates which were installed on the reconstructed dam were
about 18 feet in width, placed between piers two feet in thickness and spaced 20 foot
centers. The gates were entirely inadequate to meet the contingencies of flood flow
and the piers are so close together as to prevent the passage of the large masses of
drift which come down with the floods of the Colorado. (See Figs. 10 and 11, page
26.)
The expense involved in the construction of the gate piers and gates was not
large, probably amounting to about $40,000, and would have been warranted if the
gates could have been cheaply maintained and successfully operated. I believe how-
ever that practically no gates which can be installed can successfully pass the heavy
drift of the Colorado at times of great floods without great difficulty and large ex-
pense. The construction of any gates which may be expected to take care of these
conditions in a reasonably economical manner will cost about $363,000. (See Appen-
dix 7, page 173.) An analysis of the comparative power which would be available
at 60 and 65 foot heads shows that the extra power available with the 65-foot head
is not sufficient to pay the interest, depreciation and maintenance on such gates and
that the dam can be more economically maintained at the 60-foot head. (See Appen-
dix 6, pages 144 et seq.)
C. Sluice Gates. — The sluice gates are improperly set and poorly designed ; two
of them are now out of use. The sluiceways were partially destroyed on account of
defective design. No racks were provided to prevent the clogging of these gates.
D. Passageway in the Dam. — The passageway in the dam is provided with a
wooden walk which is in a weakened condition from decay and soon will be unsafe.
Its railing has not been painted and is badly corroded.
28
Report on the Dam at Austin, Texas.
C«fsr ft..
tow MCtree • ft..
— < — I -1
" i _-Ji
— V-A_
__^^.
r. J —
— i1 h
- 4 ^
1^— " i^
' PXOf/L£ OF
Af/0
Afe.A
FIGURE 12 — Sections of the Austin Dam Showing Erosion below the Toe
and Depth of Erosion below Foundations of New Dam.
(Fractured and laminated conditions of the f oxidation rock probably exaggerated to illustrate possible danger of sliding.)
Changes in Plans. 29
3. Plant Accessories
A. Head Gate Masonry. — The head gate masonry is said to leak considerably
when the reservoir is full.
B. Head Gate Trash Racks. — The head gate trash racks are improperly built to
admit water freely to the penstock.
C. Head Gate Hoists. — The head gate hoists are of a cheap and inadequate de-
sign, such as are ordinarily used only on country mill dams.
D. Tail Race. — The tail race is partially filled and is probably of insufficient
depth. With the great pile of debris between it and the dam every considerable
flood will obstruct the raceway by washing in material from that source.
E. Draft Tubes. — The draft tubes are exposed to the drift which accompanies
every flood. The north one has already been injured by floating drift. They have
been rendered temporarily tight by the use of Portland cement mortar but are ap-
parently not in satisfactory condition.
F. Pumps. — Of the three pumps of four-million gallons capacity each, furnished
in lieu of two pumps of 6-million gallons capacity each in accordance with the con-
tract, the one installed at the north station has been broken through the discharge
nozzle by the strain set up on account of the imperfect alignment of the discharge
piping. Of the two installed in the main pumping station, one is badly worn with
sand to an extent which must make its operation exceedingly inefficient. The bear-
ings on all of these pumps are said to heat badly during operation.
Gr. Station Equipment, etc. — The general condition of the penstocks, station
equipment, and many other details cannot be well ascertained until the plant is put
into operation. Undoubtedly some defects may be expected to develop in addition
to those enumerated above.
REMEDIES
1. Foundation Conditions
A. Foundation at the Heel of the Dam. — The foundation rock at the heel of the
dam should be rendered practically impervious by grouting through holes spaced not
more than six feet apart, and in two rows spaced about six-foot centers, the holes of
one row alternating with those of the second row. The holes should be at least 50
feet in depth and the grout should be of slow setting Portland cement used neat.
The work must be done with every care and precaution.
A cut-off wall should be constructed above the heel or upstream face of the new
section, and should be carried from 15 to 30 feet in depth, according to the effective-
ness of the grouting work. Unless the grouting work is found thoroughly effective,
a cut-off wall of at least 10 feet in depth should be constructed along the heel of the
old section.
B. Leaks Under the New Section. — These leaks may be stopped by the work
above outlined on the dam foundation. If not they must be shut off by still deeper
30 Report on the Dam at Austin, Texas.
and more thorough grouting at and immediately adjoining the fissures where the
leaks now appear. In any event, the fissures should be well filled with grout, mor-
tar or concrete.
C. Improvements Below Toe of Dam. — The depression below the toe of the new
section must be filled with concrete which must be brought to an elevation above
the footing of the cross walls of the dam in such manner as to give them a substan-
tial bearing and resistance against sliding. This apron should be sufficiently heavy
to prevent further scouring by flood waters and should extend downstream to the
rock ledge on which the mass of debris now lies.
A fifty-foot apron in front of the old section is considered desirable, but possibly
not essential at the present time if the bottom is watched and repaired whenever in-
dications of any erosion by the flood waters appear. Weep holes should be pro-
vided through all aprons to prevent uplift pressure from springs or seepage waters.
2. Dam Structure
A. Crest of Dam. — The crest piers and gates on the dam should be removed and
the crest of the reinforced concrete structure brought to the same elevation as the
crest of the old structure.
B. Old Dam Section. — The foundation and structure of the old dam should be
filled with cement grout and the section should be reinforced with concrete, essen-
tially as shown in Appendix 8, page 183.
C. Reduction in Seepage Around Dam. — The rock bluff west of the dam should
be grouted to reduce or prevent seepage. Excavations should be made along the
east bluff where leakage is known to occur, and all the cavities should be properly
filled and sealed. A careful examination should be made of the pervious strata in
which these leaks occur, and if further work in reducing the leakage seems feasible
it should be undertaken.
D. Walk in Dam. — A reinforced concrete walk should be constructed to replace
the wooden walk in the old dam and the railing should be cleaned from rust and
thoroughly painted.
E. Sluice Gates and Sluiceways. — The sluice gates should be rebuilt or repaired
in a substantial and permanent manner. The sluiceway should be strengthened
where necessary and the one which has not been repaired should be repaired in a
substantial manner.
F. Inspection of Foundation Under Dam. — During the construction of the apron,
the inside of the hollow dam should be cleaned out and the bottom carefully exam-
ined for signs of additional leaks.
3. Plant Accessories
A. Head Gate Masonry. — The head gate masonry should be grouted, pointed
and rendered essentially water tight.
B. Head Gate Trash Racks. — The head gate trash racks should be rebuilt so that
the openings shall be from iy2 to 1% inches in width, and the rack supports should
be strengthened if found necessary.
Estimated Cost of Improvements. 31
C. Tailrace. — The pile of debris between the tailrace and the old dam should be
removed, the tail race cleaned, and sufficient rock excavated to give the waters
from the draft tubes a free discharge and a maximum velocity of not more than
three feet per second.
D. Defecting Wall. — A deflecting wall should be built to protect the draft tubes
from floating drift.
E. Railing. — A railing should be constructed from the face of the old dam down
the abutment and along the retaining wall to the station building to protect the pub-
lie.
ESTIMATED COST OF BETTERMENTS, CHANGES AND IMPROVEMENTS
The following is a summary of the writer's estimate of the cost of the better-
ments previously recommended:
Foundation Grouting and Cut-off Wall:
Grouting, 25,000 ft. of drilling holes at $3 per ft $75,000
Cut-Off Wall New Dam, 5 ft. wide 30 ft. deep
Excavation 3500 cu. yds. at $3 $10,500
Concrete 3500 cu. yds. at $7 24,500
35.000
Old Dam, 3 ft. wide 10 ft. deep 10,000
Apron for Dam, 12,000 cu. yds. at $7 84,000
Cofferdam 50,000
Crest of Dam, Removing Crest Pier $10,000
1,650 cu. yds. Concrete at $20 33,000
140,000 Ibs. Steel at 7c 10,000
— 53,000
Reduction of Seepage around Dam 25,000
Improving Old Dam Section 550 ft. at $210 per ft 115,500
Tailrace, Removal of Debris and Deepening Raceway 15,000
Deflecting Wall, 180 yds. at $12 2,200
Head Gate Racks, Reconstruction 300
Concrete Walk in Old Dam 2,000
Repairs to Sluice Gates and Sluiceways 10,000
Railing along Retaining Wall 100
Cleaning and Inspecting Rock Floor of New Dam 400
$477,500
Engineering and Contingencies and Misc. Expense 20 per cent 95,500
Total $573,000
32 Report on the Dam at Austin, Texas.
CHARACTER OF THE ESTIMATE
In considering the above estimate it is obvious that there are many uncertainties
concerning the costs of some of these items. The structures are built and parts of
them are inaccessible ; their conditions have been judged from the descriptions of
others and from soundings of the rock bottom now concealed by water and debris.
The pervious rock strata along the east bluff are also largely concealed by earth.
The expense which will be involved where such contingencies exist has been cov-
ered by liberal estimates. A contingent item has been added to care for extraordi-
nary conditions of strata, floods, etc., and for other betterments which may be found
necessary when an attempt is made to put the plant into operation. I believe that
the estimates will cover the necessary expense involved in the construction of these
betterments, and it is quite possible that a substantial saving may be effected if con-
ditions are favorable. I do not believe, however, that it is safe to estimate the work
on any lower basis.
PERMANENCY OF THE STRUCTURES
I have been instructed to report on the " permanency of the structures for all
probable time and suggest such additional things, if any, proper to be done to make
such structures permanent, stable and efficient."
I have previously outlined various improvements and betterments which I be-
lieve will render the work permanent, safe, substantial and fit for the service of the
City, provided the execution of the work is thoroughly and conscientiously done.
A detailed analysis of the stresses in the reinforced concrete dam shows that the
structure is safe. The maximum stresses in the steel reinforcement are somewhat
greater than good practice would warrant, reaching as high as 23,000 pounds per
square inch instead of 16,500 pounds which was said (see page 134) to have been the
basis of design. Considering the character of reinforcing steel, this stress is not so
great as to lead to any fear of rupture. I believe, however, that a solid dam would
have been a safer though probably a more expensive structure. Many high reinforced
concrete dams are in use at the present day, though it still remains to be seen how
permanent they will be after long years of service. The dam will, in my opinion,
fulfill its functions for more than 25 years and may ultimately show that the econo-
mies resulting from such a type of design are warranted.
There are two risks involved in this project on which I am unable to give full
assurance :
1st. Will the leakage around and under the dam greatly exceed the esti-
mate of this report?
If the estimated leakage is exceeded, the power estimate will be too high, and
this value of the power which can be generated will be reduced unless the leakage
can be partially or wholly eliminated.
Permanency of the Structures. 33
2d. Will deep leakage under the dam endanger that structure?
The fact that the old dam stood from 1893 to 1900 without developing serious
deep leakage and finally went out from entirely different reasons, is a fair measure
of safety, and I am of the opinion that with the precautions suggested the dam will
remain a safe and substantial structure.
I believe if the betterments outlined are carried out with proper care, the risk
involved in the permanency of the structure will be small. I would advise, how-
ever, that after these betterments are completed and the plant is placed in opera-
tion, the City have an examination of this structure made annually by an engineer
experienced in the construction of dams, in order to detect and remedy any defects
which may possibly develop.
Value of Material and Labor in Place. — The material and labor in place have
been estimated on the basis of prices prevailing at the time the structures were under
construction. These estimates are discussed and shown in detail in Appendix 9.
They are here summarized as follows:
Reservoir $43,650
Power House, Penstocks, Pole Lines, etc 37,773
Machinery and Equipment 99,624
Dam 491,660
Extras 13,792
Total $686,499
In accordance with instructions contained in a letter from Mayor Wooldridge
dated September 14, 1917 (see page 4). I have given thoughtful consideration
to the matter of responsibility for the cost of the betterments necessary to make this
dam a safe, stable and useful structure.
Such a division of responsibility is desirable if possible but such limits are diffi-
cult to fix. The exact line between safety and danger is indefinite. No one can say
that if a certain definite number of dollars are spent on these betterments safety will
be assured, that if a few dollars less are spent the dam will be in danger, and that if
a few dollars additional are expended the money will be wasted. In the construc-
tion of a dam, in order to be safe the design must carry the structure well beyond
the lines of danger and well within the zone of safety in order to provide for those
unknown factors which must always be anticipated in engineering works. It is
therefore somewhat difficult to separate the responsibility for additional work called
for or fairly implied by the terms of this contract from these things which must be
done yet are not specified in the contract which contains a specific guarantee for 25
years maintenance. In such analysis the meaning and intent of the contract are
fully as important as the written word.
34 Report on the Dam at Austin, Texas.
The City of Austin elected to pay a second party a fixed sum plus an annual
rental, to do the work and to assume the responsibility of both constructing and
maintaining this dam for a period of 25 years. This plan seemed plausible and
proper guarantees seemed feasible, and the plan was legalized by an act of the Leg-
islature specifically authorizing this form of contract.
The City failed to see that the responsibility of the promoter was the only ele-
ment that gave the guarantees value, and that the only factors which would render
the guarantees of the promoting company of real worth were:
1st. The money which the City itself must pay to this Company.
2d. The success of the plans which the promoters might elect to carry out.
3d. The money which the promoters might borrow through the faith of in-
nocent parties in the validity of the contract and on the standing of the City of
Austin.
As a matter of fact, if the promoters failed to complete the work the City was out
nothing, but the burden was shifted not to the shoulders of the promoters but to the
shoulders of their creditors. The promoters on their part had nothing to lose and
everything to gain. They did not propose to put their own money into the venture
but to carry their endeavor on borrowed capital, and to shift the risk which they ap-
parently assumed, on innocent parties who had no means of knowing or appreciating
the risks involved.
These promoters proposed to the City of Austin to construct certain works for
payments having an aggregate present value of a million dollars, and they hoped to
secure a return of one-half this amount for promoting and financing the scheme.
They attempted to build for less than $500,000 structures which could not be built
properly and safely under the conditions which obtained during the period of con-
struction, for less than the entire million dollars involved in their contract.
The City fixed its faith on guarantees which were elaborately described in the
franchise ordinance but were, under the circumstances and for the purpose of se-
curing satisfactory construction, the least essential feature of a contract. The pro-
moters furnished incomplete plans and indefinite specifications, and rendered them
both even more uncertain by the provision that their Engineer could modify them
at his will provided that he did not l ' decrease the amount of equipment in the power
house, the height or stability of the dam, the size of the reservoir, or in any wav
diminish the capacity or completeness of the installation or in any way lower the
standard or grade of construction."
Having secured the contract, the promoters immediately began work in order to
fulfill the required terms of progress. A stock company was organized for financ-
ing the proposition, to which the franchise was assigned and by which means all
individual responsibility was avoided. A contractor was induced to undertake the
work for a fixed sum, with a provision that if any reduction in the cost of the work
was possible, two-thirds of the saving would be credited to the promoting company.
Responsibility for Cost of Improvements. 35
Every effort seems to have been made to reduce the cost of every feature of the work
to the utmost.
The City apparently approved these vague and imperfect plans and specifica-
tions solely on the basis of valueless guarantees, and appointed an Engineer who
apparently approved the construction on the same basis. The City naturally has re-
fused the acceptance of the work because these guarantees have not been fulfilled.
There has been expended on this work about $750,000, or more than 50 per cent,
in excess of the cost for which the promoters expected to construct it. To put the
work into safe condition so that it will successfully perform the functions for which
it is intended will cost still more than the promoters ' original estimate for the cost
of the entire work.
Grouting and cut-off walls were required by the contract. The cut-off walls
were eliminated and the grouting might almost as well have been omitted so far as
results are concerned, for the work done was entirely insignificant in view of the
amount of such work required for safety.
The promoters assumed responsibility for those portions of the old dam which
they proposed to utilize, although they knew that conditions might arise under which
it would be unstable. In the original report of their Engineer the statement was
made that:
"The dam therefore will require some additional masonry. This is simply
to assure beyond any possible doubt stability under any flood that may ever
come down the river. The dam may be looked on as reasonably safe as it now
stands. ' '
Their Engineer advised that:
' ; The section of the old dam should be strengthened by the addition of a
mass of concrete well bonded in the granite of the structure. ' '
No such improvement was provided in the plans submitted to the City of Aus-
tin, and even the cut-off wall planned at the heel was omitted. It is my opinion that
the old structure is unsafe as it now stands and that unless radical changes are
made it will be destroyed in less than 25 years unless it is again relieved from danger
by the destruction of the new section which is liable to early failure unless its foun-
dation is rendered stable and impervious.
No provision was made in the specifications for an apron below the toe of the
dam. It was known that a deep trench had been formed along this toe by flood waters
and that the trench was largely responsible for the destruction of the dam in 1900.
The cross walls of the new structure were apparently carried into fairly substan-
tial material yet the average depth of these foundations was left considerably above
the old trench which lies immediately below them. The condition creates a real
danger of the new structure sliding on the underlying strata; and even if it be found
by experience that the conditions have a slight balance of safety, the frequently re-
36 Report on the Dam at Austin, Texas.
curring floods will deepen this channel, undermine the structure, and ultimately de-
stroy it. This condition needs an immediate remedy, and no engineer of experience
would consider the structure safe at the present time ivith the conditions as they now
exist.
The expense of such betterments as described above is essential for the safety of
the structure. In view of the guarantees they cannot be avoided on the grounds that
they were not specified.
For an apron below the old structure, the necessity is not so imperative. An
apron for this portion of the work, if the dam is otherwise properly strengthened, is
a matter of extra precaution and is not immediately needed for safety provided the
toe is carefully watched and repairs are made as soon as their necessity is indicated.
Under the contract the responsibility for this betterment may fairly be said to be
with the City.
I believe that the large expense involved in the construction and maintenance
of proper gates is unnecessary and undesirable. This expense is unwarranted by
the additional power which would theoretically be developed ; and the increased leak-
age, the additional evaporation and the extra stress in the structure which would be
caused by the additional head, still further reduce the desirability of gates. The
loss due to their elimination can be at least partially regained by a reduction in leak-
age through the pervious strata above the dam ; and while the cost of reducing leak-
age except that "immediately" around the old dam is eliminated by the specifica-
tion, the cost of this work and the expense of raising the crest of the new section to
that of the old dam is an inconsiderable substitute for the cost of the installation of
proper gates and their expensive maintenance.
The work on the tail race has not been properly performed and the expense in-
volved in this work is obviously required by the contract.
The draft tubes should not have been constructed in their exposed position.
The deflecting wall to protect these draft tubes is therefore fairly chargeable under
the contract.
The head gate trash racks were rebuilt, I understand, on the design of the City 's
Engineer and according to his instructions, and the reconstruction is justly charge-
able to the City.
The timber walkway inside of the old dam would have to be maintained for 25
years, and its reconstruction in permanent concrete is an economy fairly chargeable
to the promoters.
The repairs to the sluice gates and sluiceways and the construction of sluice gate
trash racks are made necessary by faulty design and neglect, and these appurten-
ances even when repaired will not be in a satisfactory condition. The expense of
placing them in a condition in which they should originally have been constructed is
prohibitive and is not advised.
Responsibility for Cost of Improvements. 37
The railing along the retaining wall is not required for the safety of the struc-
ture and should be built by the City for the safety of the citizens.
It is my opinion that with the exception of the few minor items specifically men-
tioned, the cost of the betterments recommended should fairly be paid by the pro-
moting company under its guarantee to build this dam and maintain it for 25 years.
Such a finding, however, seems absurd where the facts are recognized that the
officials of the promoting company have realized their failure and have abandoned
the work which is now in the hands of a receiver.
Under the conditions that now obtain these promoters have apparently no legal
responsibility and they certainly have few rights in equity which the City is bound to
respect. The promoters, however, transferred their financial responsibility to the
shoulders of their creditors. The creditors consist of the assignee of the Contractor
who performed the work for the Promoters, of the holders of the bonds issued by the
Promoting Company, and possibly of some other legitimate claimants.
On the basis of a moderate prospective profit, the Contracting Company took a
contract for the performance of certain specific things which the City had approved
as sufficient for the purpose, and in their contract specifically disclaimed any respon-
sibility for the plans involved. The work done is apparently first class in every
particular, so far as the limits of the defective plans and specifications provide. The
difficulties that have arisen and the defects that have developed are not those caused
by defective work but were caused by defective or deficient design, for which the Con-
tractor is in no way responsible in equity although it may be in law.
The bond holders who purchased the bonds issued by the Promoting Company are
in equity even less responsible. They purchased bonds on their faith in the City of
Austin and on the franchise, specifications and plans which the City of Austin had
approved and accepted.
These innocent parties, drawn into unfortunate legal complications through the
efforts of promoters to secure undue profits, are worthy of the fairest consideration.
As the enterprise now stands, the interests involved are as follows:
1st. The City Water Power Company, bankrupt with apparently no assets
except a franchise, is in the hands of a receiver.
2d. The Wm. P. Carmichael Company with about $500,000 invested, has
apparently already expended $250,000 in excess of its claim and is in the hands
of its creditors.
3d. The creditors of the Wm. P. Carmichael Company.
4th. The purchasers of the bonds of the City Water Power Company.
5th. Certain creditors who hold claims directly against the City Water
Power Company.
6th. The City of Austin which for almost thirty years had endeavored to con-
summate this project.
38 Report on the Dam at Austin, Texas.
Only the abandoned site and station of the City of Austin are invested in this en-
terprise, with the exception of the $21,000 advanced the Contractor, which is less
than half the value of the water works reservoir, completed in 1912, and used by the
City for the last five years.
The City, however, holds the key to the situation and has a moral if not a legal
obligation to effect some arrangement whereby the situation can be cleared up and
the endeavor carried to a successful consummation with the least possible injury to
all concerned.
From my study of this unfortunate situation I believe the only practicable, legal
and equitable way for a fair adjustment of the cost of the necessary betterments for
this work and of the interests involved in this property is for the City to take over
the property on some fair and equitable basis and :
1. Either make a new contract with the creditors who have valid claims
against the work, on a basis which will enable them to finance the cost of better-
ments and ultimately recover their present and additional investment;
2. Or for the City to undertake these betterments at its own expense, pay-
ing to the legitimate creditors possibly in annual installments, a fair valuation
for the work already done.
The water power property as it stood without reconstruction was valueless.
While the cost of the necessary betterments is large, it is not more than half the legi-
timate cost of a proper reconstruction of the property as it stood in 1910 ; and the
cost of these betterments if added to the legitimate outlays that have been made
under the Johnson contract, will be more than warranted by the value of the prop-
erty to the City.
ULTIMATE VALUE OF THE PLANT
As a basis for the annual payments on the Johnson contract, the value of the
hydraulic power to be delivered from the reconstructed plant was evidently esti-
mated at 0.9c per horse power hour, as the amount of the minimum power (600,000
HPH per month) would on that basis equal the amount of the annual payments of
$64,800 per year. It is not probable that the saving effected by the annual amount
of power used will equal this amount at the present time, as the cost of operation and
maintenance of the hydraulic plant must be paid by the City and the saving at the
steam plant will include only the cost of fuel, certain labor and certain incidental ex-
penses. However, taking into consideration the fact that there would be additional
power besides the minimum, which could promptly be utilized to secure additional in-
come, and that the payment made will ultimately result in the acquisition of the
plant by the City, this annual payment would be entirely warranted. Furthermore,
as the amount of the power demand increases, the cost per unit output will decrease,
and with the rise in the cost of fuel the ultimate value of the horse power hour of
Responsibility for Cost of Improvements. 39
hydraulic power compared with the cost of generating power by steam, may very
properly be estimated at .9c per horse power hour.
On this basis the average annual value of the power available when the plant is
fully utilized is, on the basis of a 60-foot head, equal to approximately $190,000. This
capitalized on a 10 per cent, basis, to cover interest and depreciation, will give an
ultimate value to the installation of approximately $1,900,000, which is a fair measure
of the maximum amount which ultimately could reasonably be expended in the con-
struction of this plant.
t
SUPERVISION OF THE CONSTRUCTION OF BETTERMENTS
The proper construction of the betterments recommended in this report is just
as essential as the betterments themselves, and without proper workmanship the en-
tire amounts estimated may be expended and the dam remain unsafe. No ambition
for authority, no political interference, no desire for profit must be allowed to in-
terfere with thorough, first class work. The work should be intrusted to some one
who has had extended practical experience along such lines of work, and he should
be given such authority as will enable him to complete the work in a thorough and
workmanlike manner. If uncertainties arise in regard to any matter or thing con-
nected with the work, engineers having special experience should be consulted, for
the saving thus affected and the security thus gained will be large. The City ought
not to run further risks in the matter of safety or permanency for lack of sound pro-
fessional advice.
APPENDIX 1
HISTORY OP THE AUSTIN, TEXAS, DAM
For a full understanding of the present (1917) problem of the Austin dam, and
in order to emphasize certain important conditions in relation thereto, it seems es-
sential to review briefly the history of the endeavor to develop power by the construc-
tion of a dam across the Colorado River at Austin, Texas.
As early as January 4, 1839, the water power possibilities of the Colorado River
at Austin were pointed out by the Commissioners for the location of a permanent site
for the Capital of the Republic of Texas.
In 1871, Mayor John W. Glenn had surveys made above and below Mt. Bonnell
to determine the possibilities of developingwater power.
In 1873, a charter was granted to Judge John Hancock and others authorizing
the erection of a dam across the Colorado River at Austin, which was, however, al-
lowed to lapse.
In 1876, an offer from an Eastern capitalist to build a dam just below Mt. Bon-
nell was refused by Mr. P. C. Taylor, owner of the property.
In 1887, Captain W. C. Walsh called attention, in a letter to the "Statesman"
of the possibilities of irrigation from the Colorado River by the construction of a
dam.
On January 1, 1888, Mr. A. P. Wooldridge (now mayor) advocated the construc-
tion of a dam in a communication to the Board of Trade of Austin. The Board of
Trade, after due consideration, engaged Mr. John F. Pope to make a survey and
report on the practicability of the project. Mr. Pope, after an examination and in-
vestigation, reported in favor of such a project and his report was referred to a Com-
mittee composed of Mr. John McDonald and Captain W. C. Walsh, who reviewed
it and submitted estimates of the cost of construction. The feasibility of the project
was urged by Mr. Wooldridge and Mr. John McDonald, the latter running for
Mayor in the fall of 1899 on that issue and being elected by a large majority, to-
gether with a Board of Aldermen favorable to the enterprise.
BEGINNING OF ACTIVE WORK
In February 1890, an appropriation was made for an investigation of this pro-
ject, and Mr. Jos. P. Frizell, a hydraulic engineer of Boston, was employed for this
purpose. On March 26, 1890, Mr. Frizell submitted a report recommending the con-
struction of a 60-foot masonry dam.
Beginning of Active Work. 41
There were practically no hydrographic data of the stream flow of the Colorado
Eiver available at that time. The recollection of the oldest inhabitant established
an extreme flood height above low water in the river, of 45 feet, which Mr. Frizell es-
timated as probably equal to 250,000 cubic feet per second and which he found would
produce a depth of 16 feet on the crest of the proposed dam. Mr. Frizell assumed
that the flow of the Colorado Eiver was :
' * Wholly maintained by springs, issuing from cavities in the rock and is un-
affected by current rainfall until the latter becomes sufficient to cause a flow from
the ground. This is the present condition and I conclude we shall not be far
wrong in taking the present flow of the stream as the quantity that can be de-
pended upon. This, as I have ascertained by careful measurements, is nearly
1000 cubic feet per second. There will no doubt be times during the hottest
weather when the water will fall below this stage on account of increased eva-
poration. I am told however that a month very rarely passes without rains in
some part of the drainage basin sufficient to cause a slight rise at Austin.
"The great extent of the pond will enable a considerable deficiency in the
flow of the stream to be made good by storage. From the best information I can
obtain, the pond will extend some 30 to 35 miles from the dam, with an average
width of 14 of a mile, containing a water surface of some 8 square miles and a
total volume of something like 2,800,000,000 cubic feet of water. Should the
flow of the stream diminish to y2 of the above quantity, a single foot in depth on
the pond will make good the deficiency for a period of five days, and 6 feet will
make it good for thirty days. ' '
Mr. Frizell also calls attention to the possible use of 4-foot flashboards for addi-
tional storage, estimates the average working head from the proposed dam at 57^
feet, and calculates that at 80 per cent, efficiency 5,227 HP could be delivered contin-
uously. On the basis of concentrating the entire weekly flow of the stream into a
working week of 60 hours, he calculated the available power at 14,656 HP. His es-
timate of the cost of the entire endeavor, including the dam, power house, water works
system, electric light system and equipment, was $1,362,781. The general scheme
was approved by Mr. John Bogart, Consulting Engineer of New York.
Soon after the submission of this report, an engineering party surveyed the
flowage above the proposed dam site and determined that the pond would extend
22 miles above the dam. Bids for the proposed issue of bonds and for the construc-
tion of the dam were received on October 15, 1890, and the bid of Mr. Bernard Cor-
rigan, of $501,151 — being the lowest for the construction of the dam and the excava-
tion of the canal — was accepted, and a contract was duly entered into.
Excavation for the foundation of the dam began on November 5, 1890, and the
first stone was laid in the dam on May 5, 1891. The work was delayed to some ex-
tent by the floods of the river, but the last stone in the dam was laid on May 2, 1893.
The upper and lower faces and the dam crest were of red granite from Granite Moun-
tain. The interior of the dam was of the hardest local limestone rubble. All mas-
42
Report on the Dam at Austin, Texas.
onry was laid in Portland cement. The total amount paid to Mr. Corrigan, under
his contract, including extras, was $627,927.90.
The general scheme of development as planned by Mr. Frizell, is shown in Fig.
13.
CHANGE IN PLANS
Early in the year 1892, a serious difference of opinion arose between some of
the Board of Public Works and Mr. Frizell, concerning the location of the power
house (which Mr. Frizell had planned to place some 600 feet below the dam) and
the method of conducting the water to the power house, which Mr. Frizell had pro-
posed to accomplish through an open canal. The Board was of the opinion that a
Hews.
FIGUKE 13 — Plan, Profile and Cross Section of Austin Dam as Originally Designed. J. P. Frizell, En-
gineer; John Bogart, Consulting Engineer. (Eng. News, July 11, 1891.)
safer location would be on the rock ledge below the dam, and that the water should
be conducted to the power house by iron penstocks instead of through an open canal.
In January, 1892, Mr. E. C. Geyelin was employed to report on this matter. His
report was made on February 17, 1892, and the changes in plans suggested were
advised. These changes were opposed by Mr. Frizell, and the Board finally em-
ployed Mr. J. T. Fanning of Minneapolis to pass on these matters. On June 24, Mr.
Fanning submitted his report, recommending the change in the location of the power
house and the use of penstocks instead of an open canal. He also advised a change in
the form of the crest of the dam to that shown in Fig. 19, page 49.
Mr. Fanning was retained as Consulting, and Mr. Frizell resigned his position as
Chief Engineer on June 30, 1892. Mr. E. W. Groves, who had been Assistant Engi-
neer to Mr. Frizell since the work started, was appointed Engineer in Charge of Con-
struction of the Dam. At this time the foundation was in place and the masonry work
above in progress.
Change in Plans.
43
The dam was built on the rock bed of an ancient and greater river than the present
Colorado. The shores of the ancient stream were rock and nearly vertical. The mod-
ern Colorado occupied less than half of the ancient rock channel at this point, and the
remainder of the old channel, including more than its east half, was filled with an al-
luvial deposit 40 feet or more in depth. A narrow cut was made through this deposit
r»C!i.rr»mc. RECORD
FIGURE 14— A. Plan of Original Penstocks and Power House, J. T. Fanning Consulting Engineer.
(Bng. News Jan. 26, 1893.)
B. Section of Original Power House, J. T. Fanning, Consulting Engineer.
(Eng. Rec. July 1, 1983.)
44 Report on the Dam at Austin, Texas.
to the east shore for the purpose of construction of the foundation of the dam. (See
Fig. 15, page 45, also Fig. 16, page 45.)
Mr. Groves stated (see Engineering News May 3, 1900, page 290) that the rock
was good for about 150 feet from the east bluff at which point a fault was encountered
which extended about 75 feet. The rock, however, was found to be poor for about 350
feet farther, when it began to improve, and under the west portion of the dam the
rock was good. He further says :
' ' In the fault there is no semblance of stratified rock except occasionally a de-
tached piece. Most of the material was adobe or pulverized rock with an occa-
sional streak of red clay. The excavation at this place * : * was carried down
8 to 10 feet in the upstream trench, and the trench widened to 10 feet or 15 feet,
the fault extending down indefinitely. ' '
The foundation was not only poor, but the conditions evidently made proper work
difficult. Mr. Groves (see Eng. News, Jan. 26, 1893, page 87) described the founda-
tion work as follows :
"During the laying of the foundation considerable water was encountered,
the excavation in places being carried 11 feet below low water in the river to get
to solid rock. Two 6" discharge centrifugal pumps were used to keep the foun-
dation dry, but in places where it was impossible to get to the bottom of the
trench in good condition to bed stone properly, concrete was used to lead up above
the water. Strong flowing springs were encountered in various parts of the
foundation which gave considerable trouble until wrought iron pipes were made
use of. The water from the springs was conducted to the pumps through pipes
of suitable size, the pipes being covered with masonry, and the springs sur-
rounded by a wall of masonry well built. After the mortar had thoroughly set,
this wall would be filled with rich concrete and no more trouble would be exper-
ienced from that spring. The end of the pipe was stopped with a plug or iron
cap. ' '
DATA OF THE COMPLETED DAM
The data for the dam as completed were summarized by Mr. E. W. Groves, As-
sistant Engineer, as follows:
Length of Spillway 1,125 ft.
Length of Dam, including Bulkhead 1,275 ft.
Height above Low Water 60 ft.
Maximum height above Foundation 68 ft.
Width of Base 66 ft.
Power Available (60 hrs. per week) 14,500 HP
Minimum Flow 1,000 cu. ft. sec.
Maximum Flow 250,000 cu. ft. sec.
Drainage Area above Dam 50,000 sq. mi. •
Length of Lake formed 25 miles
Area of Lake 2,000 acres
Construction of Original Dam. 45
FIGURE 15 — Construction of Original Dam at Austin, Texas, Showing Narrow Trenches on the East Side
of the River, in which the Dam was Constructed. (Bng. News Jan. 26, 1893.)
FIGURE 16 — Headgate Masonry in Process of Construction at East End of Dam, Jan. 4, 1893. Also show-
ing Narrow Trench in which Dam was Constructed. (Eng. News Jan. 26, 1893.)
46
" » ';£ ^2$"°*,**Jo ," o* *
Report on the Dam at Austin, Texas.
FIGURE 17 — Break under Headgates, Austin, Texas May 30, 1893. (Eng.
News July 27, 1893.)
M L
H
SECTION X-Y
FIGURE 18— Plan and Section Showing Leaks at Austin Dam prior to 1900. (Eng.
News Feb. 22, 1900.)
Leaks in the Foundation. 47
Masonry in Dam 95,000 cu. yds.
Minimum Size of Granite used 93.5 cu. ft.
DEVELOPMENT or LEAKS IN THE FOUNDATION
The weakness of the east portion of the foundation was recognized and clay was
dumped against the upstream face to prevent the seepage of water under the struc-
ture. Soon after the dam was completed, springs were discovered just below the toe
and opposite the weak portion of the foundation. (See letter from E. W. Groves,
Eng. News, May 3, 1900, page 290.)
On September 2, 1892, a contract was entered into with Mr. James Waterson
for the construction of the head gate masonry, and this work was finished on May 12,
1893.
On January 20, 1893, a contract was made with Waterson & Wattinger for
building the power house foundations. This work was completed the following
March. On the 30th of May, 1893, a break occurred about 75 feet above the head
gate masonry and the water passed down to a depth of about 25 feet below the mas-
onry and out through a soft stratum of rock into the excavation of the power house,
causing a portion of the head gate masonry to settle, and overturning a part of the
power house foundation. (See Fig. 17, page 46.)
The cause of this break was a layer of loose material in the rock below the foun-
dation of the head gate masonry. As the water was raised in the pond above the
dam, it found access to this seam and washed out the sand or clay which it contained,
causing a settlement of the foundation.
The head gate masonry cracked about 40 feet from the end of the dam along the
line H M, shown in Fig. 18, page 46, and settled. The earth east of the east end of
the head gates settled for a distance of 25 feet. A cofferdam was built from the
east end of the dam to the river bank, about 125 feet above the head gate masonry,
and the flow of the water thus stopped. The broken part of the head gate masonry
was removed, leaving only that portion over penstocks 1 and 2 ; and an excavation
nearly 200 feet long and 70 feet deep, with an average width of 7 feet, was made.
This trench reached to a level of 57 feet below the crest of the dam or within 3 feet
of the level of the toe. The head gate masonry was rebuilt, the excavation beyond
the penstocks being filled by a concrete wall 112 feet long which was 8 feet thick for
the 90 feet next to the head gates, and 5 feet thick for the rest of the distance.
In excavating for this extension wall, alternate layers of hard and soft limestone
were encountered. The bottom layer of the concrete filling was laid on one of these
layers of strata, but it was fully demonstrated that a current of water was running
underneath. Several holes were drilled in which the water rose in jets several in-
ches high ; however, it was thought safe to plug these holes and to ignore the stream
below. (See Bui. 164, Univ. of Texas, by T. U. Taylor, page 31.)
48 Report on the Dam at Austin, Texas.
The bulkhead masonry originally extended to the level RS (see Fig. 18, page
46) or 36 feet below the top of the dam; but as an extra precaution a tunnel ESTU, 6
feet square and 60 feet long, was cut under the bulkhead masonry back to the end
of the dam proper, and this space was filled with concrete. The space below the 42
foot level under the tunnel was not disturbed.
Apparently there had been considerable interference by the Mayor, who was also
Chairman of the Board of Public Works, with the plans of the Engineers both before
and after the resignation of Mr. Frizell. Both the Resident Engineer, Mr. Weren-
skold, and the Contractor for the head gates, Mr. Waterson, had been ordered (in
Nov. 1892) by the Board to follow the instructions of the Mayor (see Eng. News,
June 29, 1893, p. 619), and this constant interference led to the resignation of the
Engineer in Charge, Mr. E. W. Groves, in the spring of 1893. (See Eng. News,
July 27, 1893, p. 78). This interference seems from the evidence to have been large-
ly accountable for the imperfect work at the head gates.
After the completion of the new headworks, the foundation for the power house
was excavated to a depth of more than 80 feet below the crest of the dam. Due to
the excess of water encountered, the original contractors threw up the work, and the
new contractors succeeded in controlling the flow of water through the rock by con-
structing a cement chamber at D (see Fig. 18, page 46) with a 10" horizontal pipe
outlet which projects through the wall of the power house at the point C, about 54
feet south of the crest of the dam. (See also Fig. 21, page 51.)
This water undoubtedly flowed under the head gate foundation, coming indi-
rectly from the lake above the dam. Measurements taken in October, 1895, showed
a discharge from this pipe of 4.6 cubic feet per second.
WAKNINGS OF DISASTEK
On April 8, 1896, Mr. J. P. Frizell wrote Mayor Hancock of Austin, in part as
follows (see Eng. News. Apr. 1900, p. 252) :
' ' In laying the foundation of the dam at Austin, a very friable foundation of
rock was met with some 300 or 400 feet from the eastern end ; in fact, the rock was
poor for the entire easterly half of the dam. I was apprehensive that danger-
ous abrasion might occur here in future, but as this part at the time was over-
hung by a bank of earth 40 or 50 feet high, my plan was to wait until the bank
had disappeared, as it might be expected to do on completion of the dam, and then
to execute some supplementary work of protection. * :
"My purpose in writing is to suggest that you cause soundings to be made
along the toe of the dam to ascertain if dangerous abrasion is in progress in that
locality."
In 1897, Mr. G. H. Palm of Austin, while fishing along the toe of the dam ran his
fishing pole under the toe for a distance of 6 feet, showing conclusively that undermin-
ing had occurred over the weak strata where the dam finally gave way. (See B Fig. 19,
page 49.)
Silting of the Reservoir.
49
In 1899 a leak was also discovered at the point A (Fig. 18, page 46), near the east
end of the dam, and was stopped by filling behind the dam at this point with clay,
loose and in bags. While this filling was in progress, the water discharging from the
10" pipe almost ceased for a few hours, but soon reached its normal amount, being
kept muddy while the fill was in progress.
In the fall of 1899, water was noted disappearing at a point B (see Fig. 18, page
46) only a few feet from the shore. A cofferdam was constructed around this point
A. B.
FIGURE 19 — Sections of Austin Dam. (A) as Constructed upon Recommendations of
J. T. Fanning. (B) Showing Supposed Condition of Undercutting and Silt
Deposit prior to Failure in 1900. (Eng. News May 10, 1900.)
and afterwards filled with some difficulty with hay and earth. The location and
method by which these latter two leaks were remedied are shown in Fig. 22, page 51.
THE SILTING OF THE RESERVOIR
In Water Supply and Irrigation Paper No. 40 on "The Austin Dam," Professor
T. U. Taylor states that in 1890, cross sections of the Colorado River were taken at
sixteen stations above the dam site. Cross sections were again taken by the United
States Geological Survey in May, 1897 and in January, 1900. These sections and the
silt deposit that had occurred between these dates at the various stations are shown
in the diagrams on page 50. Between May 16, 1893, when the water first flowed over
the dam, and May, 1897, 31,667,000 cubic yards of silt, occupying 38 per cent, of the
original reservoir capacity, had been deposited. In January, 1900, this amount had
been increased by 8,429,000 cubic yards, the total silt deposit then occupying 48 per
cent, of the required reservoir volume. In January, 1900, fhe silt immediately above
the dam had reached a depth of 28 feet or a level 38 feet below the crest of the dam
(see B Fig. 19). Concerning the nature of the silt, Professor Taylor says:
"In 1897 this silt, to within two miles of the head of the lake, was a fine, im-
palpable, absolutely gritless deposit, and where newly exposed would not bear an
appreciable weight on its surface. The writer has often tried its resistance all
along the lake, and an oar could be driven into it several feet with moderate pres-
50
Report on the Dam at Austin, Texas.
LOCALITY
D/STANCE
FRO
DAM
CLIFTON
HARRISONS Bff
HO HEY CREEK
HUGHES
SANTA MONICA
SCOTT'S TOWER
MCNEILLS LANE
OGOfflTA
DEVILS HOLLOW
ENNIS FARM
BULL CREEK
DRY CREEH
MORMON FALLS
500
460
650
~''"<"f-ffffff-£s+*'
76O
7QO
950
680
//BO
/300
I7.4O "
/S30 "
I4-.60 "
/3.7C "
IQ.4O "
5.25 "
775 "
TOO "
5.60 "
4.0O "
2.00 "
I.ZO "
0.20 "
FIGUBE 20 — Cross Sections of Lake above Austin Dam showing Accumulation of Sedi-
ment between 1893 and 1897 (Lower Shaded Area) and between 1897 and 1900
(Upper Shaded Area). Numbers above Sections indicate Length in Feet
(Water Supply Paper No. 40 U. S. G. S.)
Leaks in the Foundation.
51
FJGUBE 21 — Leak under Headgates Discharging through 10-Inch Pipe in Foundation
Wall prior to 1900. (Water Supply Paper No. 40. U. S. G. S.)
FIGURE 22 — Showing Location of, and Methods used to stop Leaks above Austin Dam
prior to 1900. (Water Supply Paper No. 40 U. S. G. S.)
52
t on the Dam at Austin, Texas.
FIGURE 23 — Dam and Power Hou^e at Austin, Texas, prior to 1900. (Note Detritus
below Dam.)
FIGURE 24 — Plan Showing Break in Original Austin Dam April 7, 1900. Eng. News
Apr. 19, 1900.)
The 1900 Failure. 53
sure. Shovelfuls of it placed upon boards in a heaped-up mess would immedi-
ately settle and spread so that the upper surface was almost horizontal. ' '
It is evident from the above that the silt under water and in contact with the dam
must have exerted a considerable extra pressure against that structure.
THE 1900 FAILURE
These various indications of weakness seemingly led to only temporary measures
of repair and apparently no general investigation was made or radical betterments at-
tempted. The rock below the eastern portion of the dam was covered with alluvium
during the construction of the dam, and this was washed away by the occasional floods
of the river after the dam was completed. The rock had therefore never been examined
nor its condition ascertained. It was apparently, however, of the same friable nature
as that in the foundation of the dam as described above. On this soft deposit was ex-
pended the energy generated by the falling waters of the passing floods. While the
change in the cross section of the dam was undoubtedly an improvement in the con-
dition of hydraulic flow, yet the toe of the dam was too short to give flood flows a hori-
zontal direction, and the tremendous energy developed by the falling waters (amount-
ing to about 360,000 HP in the flood of 1900) was partially expended in tearing up
and displacing these rocks and depositing them on a bar below (see Fig. 23, page 52),
or washing them away ; at the same time the back current was undermining the struc-
ture itself (see B Fig. 19, page 49). The discharge of the waters from the wheels along
the toe of the dam developed velocities altogether too low to have had any serious ef-
fect in eroding this rock, but the cross currents produced at times of flood by the pres-
ence of the alluvial deposits in the old river channel below the eastern portion of the
dam, may have added seriously to the erosion.
On April 7, 1900, with the water 11 feet above the crest of the dam, the dam gave
way at B (see Fig. 24, page 52) about 300 feet from the east end, and two sections, AB
and BC, each about 250 feet long were shoved downstream a distance slightly greater
than the width of the dam, into positions A'B' and B'C'. There was no overturning of
the structure which held its section for some time after the break. The section B'C'
finally disintegrated, falling upstream, and the eastern end of the section A'B' was
soon after broken up and disappeared. The water from the dam broke through the
windows of the power house, and later on the recession of the flood caused the
north end of the power house walls to fall outward, taking with them the roof over the
dynamo room and wrecking the corresponding part of the east wall.
INVESTIGATIONS AND BEPORTS MADE AFTER THE 1900 FAILURE
After the destruction of the dam various investigations and reports were made,
and various projects considered for its reconstruction. On June 9, 1900, Professor
T. U. Taylor of the University of Texas, made soundings, and ascertained the founda-
tion course of the dam and several feet of the underlying rock has been washed out
by the 1900 flood. (See Eng. News, Dec. 6, 1900, p. 390).
54
Report on the Dam at Austin, Texas.
Later, an estimate on reconstruction was made by Mr. W. F. Foster to the City
Government. This was followed, in 1905, by a report by Mr. Geo. E. Evans of
Boston for the firm of Stone and Webster.
FIGUBE 25 — Location of Borings Made in 1907.
'ast_Portidn West Portion oTDam.
FL Ffinf
L&- Lime-stone
/lard Limestone
3L5. Soft Limestone
CHLS. Ctia/ty Limestone
Cfiv. Cavities
0 20 40 60 iO 100 100
ca/ ScaJe -FECT- Horizontal Scale
FIGURE 26 — Rock Sections as Disclosed by Borings of 1907.
In 1907, the Consolidated Construction Company was granted a franchise by the
City Council to reconstruct and maintain a dam at or near the old site, to be paid
for in 40 annual installments. Mr. Walter G. Kirkpatrick was retained and reported,
in 1908, to the Water and Light Commission on the rebuilding of the dam. Under
Mr. Kirkpatrick 's direction, 26 borings were made of the dam site under the imme-
diate direction of Mr. A. C. Blanton. The locations of these borings are shown on
Investigations after the 1900 Failure. 55
Fig. 25, and their depth and the general information disclosed are shown in Fig. 26,
page 54. Of these borings Mr. Blanton says:
"The stratification disclosed by the core borings was of alternate moder-
ately hard limestone, soft adobe and cavities."
These borings, he further states :
11 : * demonstrated indisputably the very undesirable condition existing
at the site." See Eng. News, Apr. 22, 1915, page 78.)
On account of the conditions developed, Mayor Maddox refused to sign the fran-
chise ordinance of the Consolidated Construction Company, and arranged for a re-
port by a Board of Engineers, consisting of Arthur P. Davis, Chief Engineer of the
United States Reclamation Service, Louis C. Hill of the Reclamation Service, and
Professor T. U. Taylor of the Engineering Department of the University of Texas.
This Board, with the assistance of Dr. F. W. Simons, Professor of Geology in the
University of Texas, inspected the series of borings above described, considered the
geological formations both at the dam and at Mt. Bonnel, and recommended the con-
struction of a new dam at Mt. Bonnel rather than at the old site, provided borings
showed formations as favorable as surface conditions seemed to indicate. If, how-
ever, the City decided to rebuild at the site of the old dam, this Board advised :
1st. That a deep curtain wall be constructed near the upstream face of the dam
to cut off percolation under the dam so far as possible in order to reduce upward
pressure to the minimum. This curtain wall they advised should be six feet in thick-
ness and be connected by steel rods to the main dam. It should be carried to depths
to be determined by local conditions as the work proceeded, but in general to a depth
of 20 to 30 feet below the original foot of the dam and below any cavities disclosed
by borings or otherwise.
2d. They further advised the increase in the mass of the dam in order to in-
crease its resistance to sliding, the increase to be so located as to utilize the pressure
of water on the dam so far as possible.
3d. They further advised that the foundation at the toe of the dam should be re-
paired and extended by monolithic reinforced concrete to add to the resistance to
sliding and to protect the toe from further erosion.
4th. They further advised the entire reconstruction of the east abutment and
bulkhead walls, and that the body of the main portion of the dam which was to be re-
placed should be built of concrete with granite facing on its lower slope and about
10 feet below the crest on the back of the dam.
The cross sections proposed by this Board are shown in Fig. 27, page 56.
On April 5, 1910, the City Council was authorized by a vote of the citizens of
Austin to make a contract with Dumont-Holmes Steel Concrete Company to erect and
maintain a dam 65 feet high above low water at the old site, which contract expired by
limitation on January 23, 1911.
56
Report on the Dam at Austin, Texas.
THE JOHNSON CONTRACT
On September 11, 1911, a franchise was granted to William D. Johnson which pro-
vided for the construction of a dam and power plant under conditions which are con-
sidered in considerable detail in Appendix 2.
- eefvf/es TO EXIST/MS Poerjotj OP OHM
110 /60 ISO I4O /JO no I/O 100 90 SO 70 60 SO 40 JO 20 10 0
90
SO
70
to
so
40
30
20
IO
New DGM IH BROKEN SFCTION
- SECTION or* Peoooseo
QlTE
FIGURE 27 — Cross Sections for the Austin Dam as Proposed by Messrs, Davis, Hill
and Taylor, 1908.
APPENDIX 2
CONTBACT OF WlLLIAM D. JOHNSON AND ASSIGNS FOE THE RECONSTRUCTION OF AUSTIN
DAM AND POWEB PLANT
As the purpose of this Report is an investigation of the reconstruction of the dam
and power house under the above contract, and a determination of any changes that
have been made from the requirements thereof, it becomes necessary to consider the
ordinance, specifications and plans, which together constitute this contract.
FRANCHISE ORDINANCE
The ordinance is a document of some 24 sections, couched in the usual legal
phraseology and which, for the purpose of a clear understanding, is here abstracted as
follows :
Section 1. William D. Johnson and his assigns are granted the right and fran-
chise to erect a dam across the Colorado River at or near the location of the former
dam. Such grant is for a period of two years for the purpose of construction, with
such extensions as are made necessary by conditions beyond control, and for the ad-
ditional period of 25 years from the date of completion.
Section 2. Provides that Johnson shall have the use of all poles, wires and equip-
ment on the lines between the original dam and the City power house, and all mater-
ial contained in the original dam adjacent to the power house, for use in construction ;
none of this material can be sold, however, until $25,000 has been expended on con-
struction work.
Section 3. The City of Austin leases, transfers and delivers to the said Johnson
during the life of the ordinance all materials in the dam, headgates and power house,
and all of its rights, titles and interest in the lands occupied by these structures, and
all land owned by the City adjacent to the dam and downstream from a line 20 feet up-
stream from the crest of the dam, together with all necessary flowage rights.
Section 4. Grants Johnson the privilege to assign his rights to any person, firm
or corporation, and the right to pledge, mortgage and assign to any trustee all of the
rights, power and franchise granted.
Section 5. Provides that Johnson shall indemnify the City of Austin against any
damage to the property of the City and to hold the City harmless from any damage
occasioned by any act or negligence of Johnson, his assigns or agents.
Section 6. Provides that Johnson shall construct a dam, at or near the site of the
dam formerly constructed by the City of Austin, in strict compliance with certain
plans and specifications ; the said dam shall be five feet higher than the crest of the
original dam and shall be fully equipped in accordance with said plans and specifica-
58 Report on the Dam at Austin, Texas.
tions. The equipment shall include headgate masonry, head gates, forebay racks,
flumes, turbines, draft tubes, and tail race.
The said Johnson shall further supply the equipment of the power house, which
shall include three vertical turbines of not less than 2400 horse power each when op-
erating under a head of sixty feet ; three 6600 volts, 3-phase, 60-cycle electric genera-
tors, to be directly connected to said three 2400 HP vertical turbines, and capable of
generating not less than 6000 HP of electrical energy; two direct current exciting
generators of such capacity that either one shall be able to furnish the necessary full
load exciting current for all three of the 3-phase generators; two electric pumps,
each of which, when pumps are working together, shall be capable of delivering
6,000,000 gallons of water per day of twenty- four hours or 12,000,000 gallons total
for the two pumps, at a point two hundred and fifty-five feet higher than the crest
of the original dam, through a 24-inch delivery main, and which pumps shall be con-
nected to the water suction and delivery mains at the present City pumping station,
the City to supply suction and delivery mains for said pumps, and to operate and
maintain said pumps; a transmission line from the power house at the dam to the
City's steam power plant, and a reservoir of ten million gallons capacity, to be lo-
cated at such point as the City may direct.
Section 7. Provides that Johnson shall begin actual work upon said dam within
sixty days after the final passage of the ordinance, and shall have expended on con-
struction, within 7 months from said date, the sum of $25,000 and shall have fully
equipped and completed the dam and other work provided for, and shall have said
dam and equipment ready for operation within two years from the date of the final
passage of said ordinance; provided, that should any of said work be delayed by
labor strikes, excessive floods or other causes not under the control of Johnson, an
extension of time equal to the time lost by reason of any of the above causes shall
be allowed.
Section 8. Provides that Johnson shall deposit with the City of Austin the sum
of $25,000, and deliver a full set of plans and specifications, which are to be held by the
Mayor upon the following conditions:
Johnson agrees to expend within 90 days after the date of the final passage of
the ordinance, and within the next four succeeding 60-day periods, not less than $5,000
in each of said periods for material and work. If said amounts are not expended
within the time specified, Johnson shall pay as liquidated damages to the City of Austin
the sum of $5,000 for each period in which default has been made. If, however, John-
son commences said work within 60 days, and complies with all the requirements, and
expends $25,000 in actual work and material according to said plans and specifica-
tions, within the 7 months next succeeding the passage of the ordinance, then the
sum of $25,000 shall revert to and be paid by the City of Austin to Johnson.
Section 9. Provides that Johnson shall prosecute work so that for each 60-day
period, with the addition of such time as is herein provided for after the aforesaid
7 months, there shall be expended not less than $6,000 in labor and material under the
terms of this ordinance until the completion of the concrete work on the dam.
Franchise Ordinance. 59
Section 10. Provides that if defects develop in the dam, reservoir or other ap-
purtenances, or in the power house flumes or tail race, that if leaks, seepage or other
waste of water through, under or immediately around the end of the dam, headgate
masonry or core wall occur, materially affecting the use of the water above the dam
for power purposes, then the payment of the installments provided by the ordinance
shall be suspended until repairs are made. That repairs shall be commenced at once
and prosecuted diligently and be completed within a reasonable time, and shall under
any circumstances be completed within 18 months from the date of written notice
from the City of Austin demanding such repairs. That in the event of repairs not
having been made within 18 months, the City at its option may discontinue payment
of further installments or power rentals, and may terminate all privileges and fran-
chises, and may take immediate possession of all work and material on the premises.
Section 11. Provides that Johnson shall furnish the City all the water power of
said dam and shall guarantee that two of the three generating units will continuously
generate at least 3,300 HP of electrical energy; and Johnson further warrants that
said machinery shall be sufficient to generate 600,000 HPH of electrical energy within
any 30 consecutive days during the life of this contract. While the water is flowing
over the crest of the dam, or has a level of one foot below the crest, the power will
exceed the minimum named and need not be measured. When the water of the lake
is reduced to a level one foot below the crest of the dam, which is called the deficiency
period, the City shall measure the power used by it, and shall continue to measure
same during the period when the water shall be below such level. The City may, dur-
ing such period, use the water in the development of power at such times and in such
quantities as it may choose, but shall not, without the consent of Johnson, reduce the
level of the lake more than 18 feet below the crest of the dam. If during such period
of less than 30 days, it should not be possible with the water power of the dam and
with the machinery and equipment installed, to develop electrical energy at the rate
of 600,000 HPH for each 30 days so measured without lowering the lake more than
18 feet below the crest of the dam, then for the difference between the amount which
said Johnson binds himself to furnish at said rate of 600,000 HPH per 30-day period,
and the amount actually furnished, the City shall make a charge of $.0135 per horse
power hour against Johnson and assigns, and such amount shall be deducted from the
next installment due from the City.
Section 12. Provides that all power due the City shall be measured at the point
where it is used, i. e. at the present power plant of the City or at any sub-station of
said plant or at any pump installed at the dam.
Section 13. Provides that the City shall control, operate and maintain all tur-
bines, generators, machinery and apparatus in the power house at the dam, and the
transmission line from the dam to the City's present steam power plant, and the elec-
tric pumps to be installed in present City pumping station ; and the City shall have
the right to change, substitute or add to said turbines, generators, machinery and ap-
paratus, and that Johnson shall maintain and keep in repair the dam and its appur-
60 Report on the Dam at Austin, Texas.
tenances, core wall, head gate masonry, head gates, flumes, draft tubes, reservoir and
its appurtenances, power house, and the structural work of the tail race.
Section 14. Provides that the City of Austin will pay Johnson or assigns one
installment of $100,000 and 50 installments of $32,400 each; the first installment to
be $100,000 due and payable upon full completion of the work, the starting of the plant
and acceptance of same by the City; the next 50 installments of $32,400 each to be
paid semi-annually, the first $32,400 installment to be due and payable 6 months after
the completion and acceptance of said work, and the remaining installments to be due
and payable one each 6 months thereafter until all are paid. Said installments to
be paid from the gross earnings of the water, light and power plant of the City, and
in no event are any taxes to be levied on the taxable property within the City for the
purpose of paying any sum of money which may become due to Johnson and his
assigns.
Section 15. Provides that the City of Austin will, during the construction work,
furnish Johnson the use of electrical energy up to 50 HP, or water of equivalent
value. Any electrical energy or water of equivalent value in excess of said 50 HP,
to be paid for at the current rates charged the City's regular consumers.
Section 16. Provides that the City of Austin shall have the use of the water
power developed by the dam and power equipment and shall at all times own and
control the lake formed by the dam.
Section 17. Provides that Johnson shall lay across the dam a 24-inch main as
provided for in said plans if the City shall direct the construction of the reservoir
on the west side of the Colorado Eiver.
Section 18. Provides that at the expiration of the term of the franchise, the
dam, its equipment and all the property embraced and comprehended in the ordi-
nance, shall become the absolute property of the City.
Section 19. Provides that the City may have access to the books and accounts
of Johnson during the period of construction and that the City may appoint an en-
gineer or inspector to see that all work done and material used are in strict accord-
ance with the plans and specifications.
Section 20. Provides that all notices to be given by the City to Johnson and
assigns shall be sufficiently given by a simple statement in writing deposited in the
post office of the City, addressed to the bank or other agent ; and during the term of
construction, the engineer employed by the said Johnson in charge of said work, shall
be the proper party to which any such notice shall be addressed.
Section 21. Provides that in case of disagreement between the City and John-
son, the same shall be left to arbitration by the selection of one party by the City and
one party by Johnson, the two so selected to select a third party, and the judgment
of the majority of the Committee so selected shall be considered as a final deter-
mination.
Franchise Ordinance. 61
Section 22. Provides that the City shall have the license and authority to use
all parts, contrivances and devices used on the work, which may be covered by letters
patent during the life of this contract and at all times thereafter.
Section 23. Provides that the contract between the City and Johnson shall be
held to have been fully made and agreed upon by the due enactment of this ordi-
nance, and the terms of said contract shall be evidenced by the plans and specifica-
tions and duplicate copies of this ordinance, duly approved by the Mayor and at-
tested by the City Secretary, under the corporate seal of the City and the signature
of the said Johnson.
Section 24. Provides that all ordinances in conflict are repealed.
APPROVED
J. Bouldin Rector
City Attorney
PASSED: Sept. 7, 1911 APPROVED:
ATTEST : Sept. 11, 1911
Jno. 0. Johnson A. P. Wooldridge
City Clerk Mayor
William D. Johnson gives Frank S. Taylor authority to sign contract, specifications,
&c. June 17, 1911
Contract with Wm. D. Johnson dated Sept. 22, 1911
Voted by people Aug. 30, 1911.
Contract published in Austin Daily Tribune Sat. and Sun., July 29 and 30, 1911
LETTEB FILED WITH CITY
Austin, Texas, July 29, 1911
Hon. A. P. Wooldridge, Mayor of Austin, Texas.
Dear Sir:
I have read over the proposed ordinance * * * and I agree to the terms and
obligations contained therein. I have today deposited with you as Mayor a full set
of plans and specifications referring to said proposed work and the sum of $25,000,
said plans and specifications and the said sum of money to be held by you upon the
conditions contained in said proposed ordinance.
Very truly yours,
(Signed) Wm. D. Johnson.
THE CONTRACT SPECIFICATIONS
The specifications accompanying the above ordinance and made a part of the
contract are exceedingly general in character and intended to be supplemented by
detailed specifications to be afterwards furnished. A few of the important features
of these specifications are abstracted as follows, italics are used to call attention to
62 Report on the Dam at Austin, Texas.
important passages and the paragraph numbers are used for convenience in refer-
ence and are not a part of the original :
ABSTRACT OF CONTRACT SPECIFICATIONS
1. These specifications are intended to include the work, material, machinery,
etc., necessary to the erection and completion of a dam across the Colorado River at
Austin, Texas, at or near the location of the dam formerly erected across said river
by the City of Austin ; the construction and equipment of a power plant at said dam ;
the construction of a ten million gallon reservoir; the furnishing and setting of two
electric motor driven centrifugal pumps in the City 's pumping station ; the construc-
tion of a transmission line from said power plant at the dam to the City's steam
power plant, and all connections and appurtenances pertaining to these several items ;
all to be done for the City of Austin, Texas, by Wm. D. Johnson and his assigns, in a
thorough and workmanlike manner, and in accordance with the general specifications
hereinafter set forth.
2. It is specified and understood that these plans and specifications are meant to
embrace every essential element necessary to the building, furnishing and completing
of the dam, core wall, headgate masonry, headgates, power house, flumes, draft tubes,
transmission line, two electric motor driven centrifugal pumps, reservoir, and all
work embraced in these several items, and any essential element not mentioned here-
in shall be considered as much a part of these specifications as if specifically set
forth herein. It is also understood that all the work and materials specified or im-
plied herein, or intended to be covered by these specifications, shall be performed or
furnished by Wm. D. Johnson and his assigns (hereinafter called the Contractor)
unless otherwise stated herein.
3. These specifications and the accompanying designs and drawings are subject to
any changes that may in the opinion of the Engineer-in-chargef be desirable; pro-
vided such changes do not decrease the amount of equipment in the power house, the
height or stability of the dam, the size of the reservoir, or in any way diminish the
capacity or completeness of the installation, or in any way lower the standard of the
grade of construction.
4. Dam. — Specifies materials, tools, etc.
5. Excavation. — All loose material lying above the rock bed of the stream shall
be removed from the site of the dam by sluicing or otherwise, and sufficient excava-
tion for each cross wall shall be made into the rock, to secure, in the judgment of the
engineer, good foundation and prevention against slipping of the dam — all decayed
or otherwise unsuitable portions of rock being removed.
6. Trenches for cut-off walls, at least two feet and for core wall at least three
feet in width, and extending downward at least two feet into the solid rock, shall be
made across the stream on the up stream and down stream sides of the new portion
of the dam, and along such portion of the old dam as borings shall indicate to be nec-
essary and in accordance with plans.
Abstract of Specifications. 63
7. Grouting. — Liquid grout, composed of a mixture of cement, fine sand and
water, in proportions determined by the engineer (but not with more than three
parts of sand to one part of cement), shall be pumped into two-inch drill holes made
in the rock every thirty feet or less, if necessary, along the upstream face of the en-
tire dam, under a pneumatic pressure of not less than fifty pounds per square inch.
The object of this is to cause the rock underlying the up stream face of the dam below
bottom of cut-off wall to become saturated with the grout, if it be porous or "seamy"
or otherwise pervious, in order to prevent waste of water by percolation through
the strata below the cut-off walls of the dam. In case cavities are discovered by this
drilling, or in case any other unusual arrangement of the strata is discovered, the
arrangement of holes may be changed, and the rock under the up stream face of the
dam may be filled and made impervious in any other practical manner.
8. Cut-off Walls. — In the trenches for cut-off walls, excavated two feet wide and
down to solid, impervious rock foundation, which borings have indicated to be at
least six feet in thickness, etc., etc. (This is followed by a brief description of the
width of the walls and the composition of the concrete of which they are to be con-
structed and authorizes the filling of additional trench back of the walls, with clay
puddle.)
9. Supporting Walls. — Describes the walls supporting the deck, and describes the
deck of the dam.
10. Old Portions of Dam. — Portions of the original dam, as constructed in 1890
and 1893, will be retained and used as portions of the finished structure to be com-
pleted under these plans and specifications. This old work shall be thoroughly in-
spected, and wherever there are loose stones or imperfect joints in the masonry, the
work shall be made good to the satisfaction of the engineer. Pointing of the joints
shall be done where necessary.
11. Great care shall be taken to thoroughly bond the new work to the old struc-
ture, drill holes being made into same in order that anchor bars may be continued
into the new work, to thoroughly tie the structure together. The contractor assumes
the responsibility for the perfect stability and effectiveness of the portions of the
old dam as parts of the finished structure.
12. Gates and Appurtenances. — Describes flood gates to raise water five feet
above the crest of the old dam and permit the passage of floods of 200,000 cubic feet
per second.
13. Sluice Gates. — Describes sluice gates and discharge passages.
14. Core Watt. — Describes wall 300 feet long to be built in front and east of
head works.
15. Track — Walk and Pipe Line. — Describes track and walk on top of gate piers
and 24" cast iron water pipe to be laid if City so elects.
16. Reservoir. — Describes reinforced concrete reservoir of 10 million gallons
64 Report on the Dam at Austin, Texas.
capacity, the excavation of which is not to exceed an average of 4 feet beyond which
extra compensation will be required.
17. Timber. — Describes timber used as a permanent part of structures.
18. Cement. — Describes cement to be used.
19. Sand. — Describes sand for concrete.
20. Stone or Gravel. — Describes stone or gravel for use in concrete.
21. Structural Steel and Steel Reinforcement. — Description.
22. Forms for Concrete. — Description.
23. Proportion of Ingredients. — Described.
24. Mixing. — Described.
25. Placing of Concrete. — Described.
26. Power House. — Described.
27. Head Gates and Hoists. — Described — also forebay and racks.
28. Intakes. — Described.
29. Draft Tubes. — * * * The material of the intakes or draft tubes now forming
a part of the old plant may be used, if suitable, but in any event the metal must be
of reasonably uniform thickness and strength throughout. These draft tubes must
be properly and adequately supported in a thoroughly workmanlike manner.
30. Tail Race. — It is understood that the outlet for water from the turbines used
in the old power house, is buried with earth at the present time a considerable num-
ber of feet and that the contractor shall uncover these openings and excavate a trench
through the earth embankment at an an angle of approximately sixty degrees to the
north and south line of the power house, in a downstream direction from the portion
of the old power house now standing, to the river at low water. In this trench is to
be placed a tunnel, or channel, of reinforced concrete, of ample capacity to remove
the tail water from the turbines, which will be installed by the contractor at the pres-
ent time, and also from the 1000 HP additional turbines for which the contractor is
to provide intake, when all of said turbines are operating at full gate.
31. If channel be used, the wall on the upstream side of the channel wall shall
be so buttressed as to withstand any outside pressure that is likely to be brought to
bear upon it, and it shall be of such a height that any flood water cannot wash earth
or silt into the channel over the top of said wall, either at the time said channel is
constructed, or at any subsequent time.
32. This tail race tunnel, or channel, shall rest upon a good foundation, and shall
be anchored to rock at intervals of not more than twenty-five feet, and shall be of suf-
ficient strength to withstand any pressure from within or without to which it is likely
to be subjected.
33. Power House Equipment. — Described.
34. Pumps. — Described.
35. Transmission Line. — Described.
36. Engineer. — Wherever the word "Engineer" is used in these specifications,
the engineer representing Win. D. Johnson, and his assigns, is meant. The City of
Austin shall have the right, however, to appoint a supervising engineer on the work,
Abstract of Specifications. 65
whose duty it shall be to see that the specifications and plans are observed and fol-
lowed in every material particular; and whenever in the judgment of the City's said
representative engineer, the contractor is doing work or furnishing material which
is not in accordance with plans or specifications, or which is otherwise improper, it
shall be his duty to call the attention of the contractor's engineer to the discrepancy,
and if the two engineers should fail to agree, then the City's engineer shall report to
the proper City official the difference of opinion, and the circumstances in full. Said
City official, on receipt of the information as set forth, may then immediately proceed
as provided under the Arbitration Clause, Section 21 of the ordinance concerning the
rebuilding of the dam, dated September 11, 1911.
37. It is expressly understood that the above specifications and the plans accom-
panying same, are intended to cover, in a general way only, the work, materials of
construction and the equipment referred to, and it is hereby further required that the
contractor shall furnish, in duplicate, detailed plans and specifications of all materials
to be furnished, work to be done, and equipment to be installed, to the City of Austin,
Texas, at as early a date as possible after the signing of the contract ; and in any
event such detailed plans and specifications shall be furnished the City, concerning
any and all work to be done or equipment to be installed, or material to be furnished,
before said work begins, or equipment is placed, or material is furnished.
38. The City's engineer shall have access at all times to all plans and specifica-
tions which the contractor may desire to use, and the opportunity to consider same
before the work represented thereby begins.
PLANS
The plans which, together with the ordinance and specifications, constituted the
contract between Wm. D. Johnson and the City of Austin, consisted of seven sheets as
follows :
1. General Plan and Elevation of Proposed Dam, Power House and Connec-
tions.
2. Section of proposed reinforced Concrete Dam with Elevation and Plan
showing Proposed Arrangement of Walls, Piers, etc. Piers 18" thick 12' c to c
Upstream deck (by scale) 21" thick at base, 12" thick at top of dam; downstream
deck by scale 12" thick. Width of dam, 125' 9".
3. Section showing Old and New Portions of Dam. Gate Pier on Old Dam
10' c to c.
4. Section showing Sluice Gates on Reinforced section of Dam, each Sluice
Gate 8' deep 3y2' wide. Hydraulic Cylinders for operating Gates inside of Dam.
5. Plan showing Location of Sluice in Proposed Dam. Four double gates.
6. Plans of Automatic Crest Gates, Bearings and Pivot Castings.
7. Isometric Drawing of Crest Gates.
The type of reinforced concrete dam which was shown in these plans was appar-
ently based on Patent 1,010,612, granted to C. F. Doebler, Dec. 5, 1911.
APPENDIX 3
WORK UNDER JOHNSON CONTRACT or 1911 — INCLUDING CHANGES IN PLANS PROGRESS OF
WORK AND DEVELOPMENT OF CONDITIONS
The work under the Johnson franchise contract of 1911 was started on Septem-
ber 22, 1911, and prosecuted by force account until June, 1912, when a contract was
entered into with the William P. Carmichael Company of St. Louis.
First Change in Plans. — A new general plan, numbered "Gen. 8", apparently
based on Patent 1,010,131, granted to W. S. Edge, Nov. 28, 1911, was substituted and
approved by A. C. Scott, Consulting Engineer for the City, on March 15, 1912. This
change was approved with the knowledge and consent of the City Council. This
new plan shows a rearrangement of the interior walls of the dam which were oblique
to the axis of the dam in the original plans, normal to the axis in the new plan.
The spacing of the gate piers was also changed from 12 foot centers on the new por-
tion of the dam and 10 foot centers on the old portion of the dam, to 20 foot centers
on the entire dam.
Mr. Wm. D. Johnson assigned his rights and franchise (in April, 1912) to The
City Water Power Company (a Connecticut corporation) organized to carry out the
proposed work. Mr. Lamar Lyndon was employed as Consulting 'Engineer and Mr.
Frank S. Taylor as Resident Engineer, and the work was carried out under their
direction. Dr. A. C. Scott of Dallas, was appointed Consulting Engineer for the
City, and about October of 1912, Mr. S. S. Posey was appointed Inspector for the
City.
Approval of Detailed Plans Including Certain Changes. — In May, 1912, a set of
nine detailed plans (numbered C-9 to C-17 inclusive) were submitted by Mr. Taylor
to Dr. Scott, and after examination were approved by him in a letter dated May 20,
1912, to the Wm. P. Carmichael Construction Company. The original plans filed
with the ordinance and specifications, as before noted, were very general in character
and the adequacy of the structure outlined therein could hardly have been deter-
mined from the data given therein without additional assumptions.
Apparently no attempt was made on the part of the City to determine the safety
or adequacy of the structure proposed, but full reliance was placed on the guarantee
(see Sees. 10 and 13 of franchise ordinance).
The detailed plans, C-9 to C-17 inclusive, were in sufficient detail to permit of
analysis. The new plans were not compared by Dr. Scott with the original plans for
the reason above stated. (See letter from Dr. Scott to E. C. Bartholomew, dated
April 6, 1916, on file with City) and Dr. Scott did not notify the City of the changes
in the detailed plans from the original plans.
Progress and Character of Work. 67
These plans were furnished in accordance with paragraph 37 of the foregoing
abstract of specifications. Under paragraph 38 of the abstract (page 25 of the orig-
inal), the Company was obligated to furnish such plans for the consideration of the
City's Engineer before beginning work, but no provision of the contract required the
approval of the City Council, although if changes were involved outside of the limits
prescribed in paragraph 3 of this abstract (page 2, original), they could not be legally
made without such approval.
The principal change made in those detailed plans was a reduction in the width of
the dam from 125' 9" (shown on Drawing 2 of the original) to 93 feet (shown on
Drawing C-17 of the new plans), and a rearrangement of the dam crest made neces-
sary by the reduction in width. (See Fig. 5, page 17.)
The City Council, not having its attention called to this change, remained un-
aware of the same, and the Contractor on the basis of the approval of the plans by the
City's Engineer, proceeded with the construction in accordance with those plans.
Progress and Character of Work. — Work was apparently begun at an early date
on the power house. The remains of the original power station were extended north
about 30 feet (see Fig. 29, page 69) and the plan of the equipment was changed
from the original plan (see Fig. 14, page 43) to that shown by Fig. 28, page 68. The
turbines, electrical machinery and centrifugal pumps for the City water works were
received and set in the spring of 1913. The test of the pumps showed that they had
only about two-thirds of the guaranteed capacity. After various tests, it was finally
agreed (in 1915) that the Company should install an extra pump, thus giving the City
three pumps, each of a capacity of four million gallons per day instead of the con-
tract requirements (see Sec. 6 of the ordinance) of two pumps each of a capacity of
six million gallons per day.
The reservoir specified in the contract was completed in July, 1913, and, it is be-
lieved, has been in continuous use to the present time.
The work on the foundation of the dam was constructed at times when the con-
ditions of the flow of the river would permit.
Much difficulty and delay were occasioned by frequent floods in the Colorado
River, and the cofferdams built for construction purposes were washed out some
twelve or thirteen times while the work was in progress. In general, the work seems
to have been well and properly done so far as the plans and specifications provided.
In minor instances, objections were made by the Inspector, Mr. Posey, principally
as to the depth to which the cut-off and core trenches were carried and as to the mix-
ture used in the foundation concrete. These matters were adjusted from time to
time by the Consulting Engineer, Dr. Scott.
The concrete work seems sound and impermeable though somewhat rough. This
roughness is of no serious importance except in the gate piers where the roughness of
the work together with the swelling of the forms has apparently made it difficult to fit
the crest gates so as to permit of the automatic action, for which they were designed,
and at the same time to prevent serious leakage.
68
Report on the Dam at Austin, Texas.
A general plan and elevation of the work as constructed are shown in Fig. 4,
page 15. The foundation work was described in an article written by Mr. Frank S.
Taylor for the Engineering Record of May 29, 1915, as follows :
"The cutoff wall was carried down, in many instances, a considerable depth
below the footings of the buttresses. This wall, on the upstream side of the dam,
was poured in a trench which had previously been tested by numerous drill
FIGUBE 28 — Reconstructed Power House and Arrangement of Machinery as Installed
under the Johnson Contract. (Bng. Rec. June 10, 1915.)
holes, put down in the bottom of the trench. Where defects were found, they
were remedied by grouting. The test holes were first spaced 12 feet apart in the
bottom of the trench. Compressed air was turned into them, one by one, to dis-
cover underground connections between adjacent holes. Wherever the com-
pressed air would blow out of one or more of the other holes, it was considered
that the entire seams or crevices between the two holes were reached by the drill
holes then made. Grout would then be forced into one of the holes until it began
to blow out of the others. It was then considered that the rock lying below the
cutoff wall trench and between the holes had been made tight. Wherever no
connection could be established between the holes 12 feet apart, intermediate
holes were drilled, thus making the drill holes only 6 feet apart along certain
Progress and Character of Work. 69[
111 T 1
FIGURE 29 — Power House during Reconstruction,Showing Addition to Remains of Old Station.
FIGURE 30 — Rock Trenches for Foundation Wall of New Dam.
io'A Report on the Dam at Austin, Texas.
FIGURE 31— Rock Trenches for Foundation Wall of New Dam.
FIGURE 32— Concrete Foundation of Cross Walls FIGURE 33— Concrete Mat in Front of Sluiceways
and Excavation for Concrete Mats for Sluice-
ways. (Note Narrow Trenches.)
Progress and Character of Work. 71
portions of the cutoff-wall trench. If, after this was done, no connection would
be established between adjacent holes, additional holes intermediate to those 6
feet apart were drilled, bringing the distance to 3 feet.
"In nearly every instance where these holes were made water flowed freely
through them, sometimes spouting up 3 or 4 feet, thus proving conclusively con-
nection between the holes made inside the cofferdam and the surrounding body of
water. As grout would be forced into the holes, the velocity of water flowing out
of them would gradually diminish, until it would entirely stop. In many cases,
where grout was forced into a hole, the flow of water through other holes, some-
times as far distant as GO feet, would be stopped and the grout would finally show,
rising out of adjacent holes, proving that the underground seams between these
two holes had been thoroughly filled with grout. In placing the grout the pres-
sure on the liquid mixture was gradually increased from a few pounds to a max-
imum of 80 pounds. ' '
As stated by Mr. Taylor, the cutoff walls and all of the foundation walls of the
new dam seem to have been constructed in narrow trenches through rock which was
found unfit for foundation purposes. (See Figs. 29, 30, 31, 32 and 33, pages 69 and 70.)
In consequence of this method, it is quite apparent that the Engineers or Contractors
on the work never had a comprehensive view of the foundation rock as a whole but
examined it only along the narrow lines' of these excavations.
The foundation work as above described temporarily fulfilled its purposes, and
the Engineers of the City, Messrs. Scott and Posey, in their report to Superintendent
E. C. Bartholomew, stated :
"The Sluice gates were closed on December 12, 1914, and on the same date,
work on the last cofferdam (below the dam) was started and rushed forward day
and night to completion. This cofferdam, when completed, inclosed some ten
or twelve acres of the river bed, and after being pumped out for service, an in-
spection of the foundation walls and general condition of the partially completed
structure was readily made. Such inspection disclosed a significant fact, viz:
that while the head of water on the structure at the time was about fifty feet,
the leakage through the same was entirely insignificant in quantity; which
showed that the cut-off wall, foundation structure and upstream deck had been
made impervious as required. Further evidence that satisfactory construction
work had been done, was shown by the fact that only one eight-inch pump was re-
quired to keep the water out of the large area inclosed by the cofferdam, while
the downstream deck construction was in progress; and practically all of the
water which was thus pumped came in from the downstream side of the basin
through the sand bank constituting that portion of the cofferdam."
On May 20, 1914, part of the retaining wall along the river between the power
house and the dam, which had been constructed under the franchise, fell out into the
river and was reconstructed, apparently on original plans.
72 Report on the Dam at Austin, Texas.
On February 16, 1915, the water above the dam first reached the 60-foot level
(the height of the original dam) since the failure of the original dam in 1900.
The roof of the conduits leading through the dam from the sluice gates were
destroyed by the pressure of the discharging water, apparently some time early in
1915.
In March 1915 the turbines were tested and are reported to have given results
better than the guarantees, although I have not been able to secure copies of the
test.
Early in April, 1915, the work being regarded as nearly complete, the City ad-
vanced the Carmichael Company the sum of $21,000, which had been assigned to the
Contractor by the City Water Power Company from the first payment due on accep-
tance of the work. This was done by the City in order to secure the prompt comple-
tion of the work.
In the flood of April, 1915, four of the large crest gates went out but were re-
placed immediately thereafter. A considerable amount of drift was caught and held
by the gates and piers. The gates were found to leak badly, and a device for stanch-
ing was applied which prevented their free action and later is believed to have been
one of the causes of their destruction when the gates were suddenly opened by the
excessive rise in the river.
Previous to the destruction of the old dam in 1900, much rock was torn out by
the floods from the river bed immediately in front of the dam and thrown up in a
pile, the face of which averaged about 90 feet from the toe of the dam. (See Pig. 23,
page 52.) When the old dam was destroyed, this pile of rock was augmented by rock
from the old dam, although much of the rock previously deposited and much of the
material from the old dam were carried farther down the stream. In the construc-
tion of the new tailrace, a somewhat shallow channel was cut through the bar below
the rock pile, but no wall was constructed as provided in the contract to protect the
raceway from filling. (Sec. 31, Abstract of Specifications, page 64.) In the flood of
April, 1915, this raceway was partially filled by debris from this pile of rocks.
On April 20, 1915, the brick retaining wall between the power house and dam
again fell out carrying with it a portion of the wall of the power house. About this
time a leak appeared below the cutoff wall in panel number six.
These various mishaps apparently created a suspicion on the part of the City
officials that the work as constructed under the plans was not entirely in accordance
with the spirit of the contract, and the City refused to accept the work until it was
entirely completed in an acceptable manner.
The City Water Company had originally issued $750,000 in bonds, but had taken
down and sold bonds of a par value of $412,500 on which they realized 75 per cent,
or $309,375, of which amount apparently $261,640.07 was paid to the Contractors, and
the balance went to pay various other expenses. The Contractors, W. P. Carmichael
& Company, had already expended a considerable amount in excess of their guaran-
teed maximum contract price and were apparently unable or unwilling to furnish
Progress and Character of Work. 73
additional funds for this work until they were assured of its final acceptance. It was
to complete the work that the City advanced the sum of $21,000 before mentioned.
Under these conditions a committee of the bond holders had been organized, and,
with the hope of completing the work so th at it would be accepted and additional
bonds could be taken down and sold to meet the indebtedness of the City Water
Works Company, advanced the Contractors the sum of $11,242.62.
About this time (May, 1915), the J. G. White Engineering Company of New York
was appointed engineer for the work. The retaining wall which had twice failed,
was rebuilt on apparently substantial lines, and various other work toward complet-
ing the plant was carried out. The extra pump before mentioned was purchased and
installed. The replacement of the roof of the discharge conduits, which had failed,
was started, but the available funds were exhausted before this work could be com-
pleted.
In September, 1915, a still greater flood occurred in the Colorado River. Twenty
of the large crest gates went out (see Fig. 8, page 25) together with most of the
small ones. The tailrace was again partially filled (see Fig. 9, page 25), and the
turbine draft tubes blocked (see Figs. 8 and 9, page 25), and the work on the pro-
ject practically ceased.
About this time the City Officials became aware that the dam had been reduced
in width. The various difficulties with the crest gates convinced them that a ma-
terial change in the design of the crest of the dam would be essential. The leak under
the dam was also an unknown factor which involved much uncertainty.
In order to determine the changes that had been made from the original plans,
Mr. S. S. Posey, Inspecting Engineer, who had been on the work practically from the
beginning, was requested to submit a report on the subject. His report is as fol-
lows:
Austin, Texas, May 20, 1916.
Mr. E. C. Bartholomew,
Supt. Water and Light Dept.
Dear Sir:
. At your request, I have gone over the plans and specifications for the re-
building of the Austin Dam and made a list of the changes which the engineers
have made in building the structure. I may have omitted a few minor changes
but the more important ones, whether favorable or unfavorable, have been noted.
Trusting that the attached list will meet your requirements, I am
Yours very truly,
(Signed) S. S. Posey,
Inspecting Engineer.
74 Report on the Dam at Austin, Texas.
CHANGES MADE IN REBUILDING THE AUSTIN DAM
1. The Eansome type was proposed, the Edge type was used. This change
was taken up with the City Council and considered principally in a re-arrange-
ment of the supporting walls. On the original drawings some of the walls were
not at right angles to the decks or to the axis of the dam. As built, they are at
right angles to both and are spaced 20 ft. apart instead of 24 ft.
2. The base of the dam was narrowed up from 125' 9" to 93' 0", modifying
the crest so that it overhangs the upstream deck. This did away with one of the
longitudinal walls bracing the upstream deck.
3. Large crest gates increased in length from about ten to eighteen feet.
4. Small crest gates increased in length from about eight to eighteen feet.
5. Foot bridge on top of dam changed from steel I-beam and wood construc-
tion to reinforced concrete and wood, to make it strong enough to support the
derrick car which they expected to use for handling the crest gates and drift.
6. The specifications call for a reinforced concrete floor supported by I-
beams in the Power House; built partly on earth fill and reinforced concrete
slab supported by reinforced concrete girders.
7. Large crest gates made in two weakly connected halves instead of one
well-braced whole, as shown on sheet No. 6 of the original drawings.
8. Middle bascule and intermediate pier introduced in center of openings
for large crest gates, adding an additional obstruction to drift.
9. Bascule castings changed from rack type to plain.
10. Location of sluiceways changed from the original plan, three being lo-
cated in the river channel instead of one.
11. Thickness of supporting walls changed from one foot at base to two feet
six inches at the same point, diminishing to one foot at the top, thus increasing
the bearing on the foundation.
12. Thickness of upstream deck slab increased at bottom from two feet to
two feet six inches and at the top from one foot to one foot eight inches. The
steel in the same decks, as well as that in the downstream deck, has been re-ar-
ranged for the better, though the amount used remains practically the same.
13. Cut-off walls on both upstream and downstream sides of the old dam
omitted, except for about one hundred feet immediately west of the head gate
masonry. This was left to the discretion of the City Water Power Company's
Engineer unless the City wished to invoke the arbitration clause. In the in-
stance mentioned, the upstream cut-off wall was not, in my opinion, carried two
feet into good rock (though I was over-ruled by Dr. Scott, who passed on it as
satisfactory, because of its impermeability, as shown by holes drilled in the
trench and attempts made to force grout under pressure into it.) Under the toe
of this same portion of the old dam, and under the ragged break at its west end,
a cut-off wall eighteen inches thick (instead of two feet as specified) and six feet
Changes Made in Rebuilding Dam. 75
in height, was built to protect the toe from scour, but the material upon which it
rests is soft enough to be easily scratched by the finger nail, which was not, of
course, according to specifications.
18. The specifications require that the proportions of material in the con-
crete shall be : one part cement, two parts clean sand, and four parts, crushed
stone or screened gravel. The engineer for the City Water Power Company al-
lowed the contractors to use pit-run gravel, i. e., sand and gravel mixed as it
comes from the river beach, getting the proper proportions by adding stone or
sand as determined by taking voids by means of water. Also keeping the voids
in the aggregate within certain limits by the same means. An excess of cement
was required and used because of this change.
19. The fourth penstock, as required by the specifications, was omitted by
permission of the City Council. First class material was specified for these
tubes. Old ones, some of which were badly pitted by rust, were used. Outside
of the Power House these penstocks were well covered with reinforced concrete ;
inside of the building on both the inside and outside of the pipes and outside of
the building on the insides of the pipes, "smooth-on" was used on the joints and
defects, besides being coated with a wash made of retempered cement.
20. The core wall was not carried as deep, as high, nor as far into the bank
as specified, but this was passed upon by the City's representative as being all
right because of the impervious character of the "adobe" on which it rests and
because the head gate masonry was considered sufficiently tight without the pro-
tecting wall. The water does, however, percolate through it in places in small
quantities.
21. The tail race as described in the specifications has not been built up to
the present time, this being according to a verbal understanding among those
concerned, if certain conditions were met.
22. The pointing of the joints of the masonry of the old dam was not done
because considered unnecessary by the Engineer for the City Water Power
Company. The seepage at the east end of the old part demonstrates the neces-
sity for pointing or grouting.
(Signed) S. S. Posey,
Inspecting Engineer.
The City was unprepared to advance more money until the work was placed in
acceptable shape, and was unwilling to specify just what it would require before the
work would be accepted. The bond holders on their part were naturally unwilling
to add more funds unless they could be assured that such additions would complete
the work to the entire satisfaction of the City Council, and the Contractors were
obliged to make assignments. While the conditions have been hastily examined by
various engineers and brief reports have been made in the interest of the bond hold-
ers and various other interested parties, nothing has been done toward completing
the plant for about two years.
APPENDIX 4
CONDITIONS AND FACTS ASCERTAINED DURING EXAMINATION BY DANIEL W. MEAD — AUG-
UST, 1917
Early in July, 1917, the writer was engaged by the City of Austin to investigate
the conditions and to report on the situation as it now obtains at the Austin Dam.
Before commenting on the present plant and outlining the betterments which should
be made in order to place the same in safe condition for proper operation and main-
tenance, it is necessary to review the physical conditions which exist at the site of
the works.
It is obvious that the examination of a completed structure with the water stand-
ing 10 to 20 feet above the foundation is attended with much difficulty, and that to
draw conclusions from any examination which can be made under such conditions,
without incurring a prohibitive expense, makes it necessary to depend largely on
the statements of those who have been in personal touch with the work during its con-
struction, at the same time checking up such statements by comparison with those
made by different witnesses, and by the facts that can be definitely determined. Pre-
liminary to his examination the writer read all of the articles which he could secure
that have been written on the Austin dam, a list of which is given in a later appendix.
On reaching Austin, the writer visited the City office and discussed the matter at
some length with Mayor Wooldridge, Superintendent Bartholomew, and the mem-
bers of the City Council. He also had access to the various letters, papers and
plans which are in possession of the City. He also discussed the matter in detail
with Mr. Guy A. Collett, Receiver for the City Water Power Company, who placed all
plans and data which he possessed at the disposal of the writer. The writer also
secured considerable information from Mr. H. L. Cobb who was Assistant Engineer
in charge of the grouting and other construction work. Mr. Cobb furnished a large
album of photographs showing various views taken during the construction and at
various periods in the work. Other views, especially of the older work, were ob-
tained from the engineering papers, the local photographers and others. A number
of these views are reproduced in this Report and show clearly the conditions which
existed at various periods, which can be clearly understood now only by the informa-
tion these views contain.
Mr. S. S. Posey, who had been Inspecting Engineer for the City during the con-
struction work, spent most of his time with the writer during his stay in Austin.
Mr. Posey 's knowledge of the conditions greatly facilitated the writer's examination.
Mr. Frank S. Taylor, who was Resident Engineer during the construction, placed his
information and data at the writer's disposal, and furnished much information of
Foundation Walls.
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Report on the Dam at Austin, Texas.
the conditions which developed during construction, and of the foundation depths and
conditions. This information was quite indispensable to the conclusions of the
writer.
Mr. Frank S. Taylor was Resident Engineer of the work done under the fran-
chise given Mr. William D. Johnson. He was in immediate charge of the construe-
FIGUBE 40 — Sketch showing Depth, Thickness and General Arrangement of the Foundation Walls.
tion from the beginning of the work until it was practically discontinued early in
1915. Mr. Taylor furnished the writer with a series of seven sketches, copies of
which are shown in Figs. 34 to 40 inclusive, which sketches show in general the
depth to which the foundation walls were taken, and the thickness and general ar-
rangement of such walls. Mr. Taylor also furnished a detailed memorandum con-
cerning the holes drilled for the purpose of grouting the foundation, and the results
of the grouting, which throws much light on the conditions of the bottom as deter-
mined during construction. He also furnished a blueprint plan of the foundations,
showing the location of all grout holes, which (with some additions) is reproduced in
four sections, shown in Figs. 41 to 44, pages 82 to 85 inclusive.
Foundation Conditions. 81
MEMORANDA CONCERNING THE FOUNDATION CONDITIONS OF THE AUSTIN DAM FROM
SKETCHES AND DATA FURNISHED BY MR. FRANK S. TAYLOR
Concerning this work, Mr. Taylor says:
* * The attached logs of drill holes and subsequent grouting operations in the
Austin Dam are approximately correct. The lines showing the probable direc-
tion of permeable parts of the foundation are indicated as follows:
"All foundations east of No. 44, impermeable.
"Possible permeable lines thru dam foundation as indicated by numbered
holes on the 'Grout-hole Chart':— 44 to 68, 59 to 98, 78 to 117, 81 to 108, 136 to
153, 141 to 165, 152 to 166, 159 to 180, 171 to 182, 210 to 208, 223-228 to 236, 242
to 247, 252 to 261, 255 to 263, 271 to S. W., 277 to S. W. (These 'possible per-
meable lines' have been indicated by lines on the diagram, shown on pages
82 to 85 inclusive. D.W.M.)
' ' Nearly every hole in the cut-off-wall foundation which proved to be in per-
meable strata, was found to be in permeable strips, bounded by more or less defi-
nite lines running parallel to a South West direction thru it.
* ' The lake was filled while operations were still in progress on the spillway.
There was then a cofferdam across the river down stream ; a 4,000,000 gallon per
day pump working less than half of the time kept out all water from the coffer-
dam until the water ran over the dam at elevation 151. At this time, however,
the flow of the river at the rapids, about 1000 feet below the dam, indicated that
about three times as much water was flowing there as was pumped out of the
coffer. ' '
This last statement would seem to indicate that while there was little seepage
under the dam, and rising inside the cofferdam, that about twice this amount was
rising as springs in the river below the cofferdam and above the rapids referred to.
In the following pages, abstracts have been made of the records of the grout
holes through which a considerable amount of grout was forced into the foundation.
The grouting work was done by means of a grouting cylinder under pneumatic
pressure. The cylinder was 18" in diameter and 42" in height, connected with an
Ingersoll-Band air compressor with an intervening air receiver of about 100 cubic
feet capacity (see Fig. 45, page 99.) Mr. Taylor says:
"General Scheme of Tests. — It was decided to make the holes first grouted
24 feet apart. It was assumed, and afterwards did develop, that the grout
would, in many cases, go from one hole to another through crevices and between
strata of limestone. After the adjacent 24 feet holes were grouted, another
hole was drilled midway between these two, making the holes 12 feet apart. The
log of this intermediate hole was carefully watched, as, from the indications
found in the drilling, we could determine where grout had sealed all crevices be-
tween the two holes 24 feet apart. If, as in many cases, we found that there
were some crevices which were not filled by either one of the first two holes, the
82
Report on the Dam at Austin, Texas.
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Record of Drilling and Grouting.
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Report on the Dam at Austin, Texas.
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86 Report on the Dam at Austin, Texas.
grouting machine was placed on the intermediate holes, and, in fact, our prac-
tice was to place the grouting machine on this intermediate hole even if we found
no indication of permeability. In some locations it was found that even this
short space was not sufficiently close together to satisfy us, and, in such cases,
other holes were bored between the 12 foot spacings and the operation just de-
scribed repeated, reducing the distance to 6 feet apart. In a few cases we found
that holes between the 6 foot borings were necessary to give us a satisfactory
evidence of impermeable foundation.
''Auxiliary Holes Under and Between Diaphragm Walls. — A great many
holes were bored, as shown, only 5 feet deep, but these holes were bored on the
downstream side of the cutoff wall, which has been made impermeable, as al-
ready described, and the purpose of the 5 foot holes was to determine only the
solidity of the foundation for bearing our walls. In a great many cases, water
was found in these shorter holes, and wherever the findings of the drill indicated
a cavity or seam, that hole was grouted in exactly the same manner as if it were
in the cutoff wall. It is probable, however, that all of the water that developed
in the shorter holes came from downstream pressures, the mouth of all of these
holes being from 8 to 15 feet below the level of the water on the downstream side
of the lower cofferdam.
"On the Downstream Side of the Old Dam. — A number of holes were bored
on this part of the structure, as shown on the chart, and the grouting machine
was placed on same for the purpose of testing the permeability of the strata un-
der the toe of the dam, but little grout was forced into these holes, the testing
being done with water only. In two or three holes the test proved that there was
a permeable strata under the toe of the western end of the old dam, but our op-
erations afterwards, on the upstream side of this same section, comprehended
the entire length of the dam and to a depth of 12 feet, so that there is every rea-
sonable indication that the grouting hereinafter described filled cavities that
were discovered by the tests on the downstream side of the old dam."
In the abstract of the record of the grout holes, shown on plans Figs. 41 to 44
(see pages 82 and 85) are given:
1st. The number of hole.
2d. El., the elevation referred to a horizontal plane 160 feet below the crest
of the dam, or approximately 100 feet below the average low water level.
3d. "D", the depth of the drill hole below the elevation given; and
4th The amount of grout forced into the hole, indicated in cubic feet.
The grout was a mixture of one part of cement and two parts of fine screened
sand, with water to make a grout of creamy consistency (each charge from the cyl-
inder being equal to about 2 cubic feet of grout). The word "attempt" is used to ex-
press each separate operation of the grouting machine. The records of all holes
that took no grout are omitted from this abstract :
Record of Drilling and Grouting. 87
ABSTRACT OF RECORD OF DRILLING HOLES AND GROUTING
(NOTE — The numbers serve to locate the position of each hole on the Grouting Charts)
40. Elevation 86; depth 12 ft.; no cavities. First attempt blew grout out in
trench at lower level about Station 22. Later, second attempt showed oozing of
grout in side of trench above top of hole, stopped during discharge. Third at-
tempt, refusal.
44. Elevation 82; depth 11 ft. in cracked rock. Two inch cavity at 4th foot; 37
full discharges of grout forced into pipe. Crack extended across cutoff wall from
northeast to southwest and was from 14" to 6" wide. The 37th charge filled all
crevices to refusal.
54. Elevation 81 y>; 9 ft. hole; 2 ft. in soft rock; cavity for iy2 feet then 4y2
feet of good rock ; then about one foot of soft rock ; balance • hard rock. First at-
tempt discharged grout through crevices. Several charges attempted with thicker
grout evidently discharging through crevices. Later, y2 charge oozed through crev-
ices and cracks stopped.
58. Elevation 81 feet; 10y2 ft. hole; 5" cavity in 5th foot; soft rock 9th foot;
balance solid. First attempt forced grout through crevices at pier footings between
diaphragm walls 5 and 6, about 70 ft. from No. 58. Twenty-two full charges were
put in before refusal.
59. Elevation 81 ft.; depth 10 ft. Water appeared at 4th foot; soft rock at 6th
and 7th foot; balance good rock. First attempt forced water and grout to surface
in the vicinity of hole. Nine charges put in before refusal.
61. Elevation 81 ft.; depth 8 ft.; soft rock in 3d, 4th and 7th foot; balance good
rock and grout. Four full charges.
64. Elevation 81 feet; depth 9 feet. One foot of soft rock. One foot of soft
rock in 7th foot. Six full charges ; 7th attempt discharged grout in vicinity of No.
72 and filled holes Nos. 65 and 66. Later, after grouting Nos. 70, 71 and 72, made
8th attempt nearly full discharge. Total about 7 charges.
68. Elevation 81; depth 11 ft.; Sy2 ft. good rock and grout; 6" soft rock; balance
good. Continuous grouting for about 25 hours. Forty-eighth charge showed indica-
tions of grout all along line of crevice encountered at No. 44, also at No. 65 and No.
66. Fifty-six full charges before refusal.
NOTE. — Operations from No. 44 to No. 69 were evidently contiguous to the crack
described in No. 44, which follows the general direction of the larger fault lines of
the Balcones fault zone. The fault lines found in the limestone across the river at
the dam are nearly vertical, and, with the exception of this crevice and one described
as crossing the cut-off wall at about Station 8 + 25', the lines are cracks, which evi-
dently do not change the solidity of the stone, nor cause a break in the lines of stra-
tification.
88 Report on the Dam at Austin, Texas.
72. Elevation 81 ft. ; depth Sy2 ft. in good rock and grout except one crack in
4th foot. First and 2d charge forced grout through crevice near by. Later 20
charges put in; 23d attempt, refusal.
76. Elevation 81 ; depth 5 ft., when drill stopped in crack. Good rock. Grout
came into this hole from No. 78. Hole piped above footing course of wall No. 6
later. First attempt forced grout around footing near by; second attempt took full
charge; third attempt, refusal.
78. Elevation 81 ; depth 10 ft. Soft spot in 6th and 8th foot. Third attempt
forced water from Nos. 76 and 77. Thirteenth attempt forced air through crevices
at about No. 73 ; with 41 full charges, all crevices filled to refusal.
90. Elevation 82 ; depth 10 ft. Cavities and soft rock in 7th, 8th, 9th and 10th
foot; balance good. First attempt blew air and water in No. 89; second attempt
showed at No. 108 ; 6th attempt stopped indications at 108 ; water again running from
108 and oozing nearby after 7th attempt. Grout still going in with 16th charge;
17th charge oozed nearby and in excavations for Nos. 7 and 8 diaphragm walls ; 28th
charge forced water and red mud 25 feet south of hole ; 35th attempt forced grout
through crevices ; 36th attempt still forcing air out of trenches of diaphragm walls
Nos. 6 and 7. Same conditions with 47th attempt; 54th attempt showed clean grout
forced from every place where air had been noted ; 63 full charges put in with prob-
able loss of about 10 per cent.
92. Elevation 81 ; depth 10 ft. ; solid rock and grout except 7th foot which was
soft and cavity. Sixth charge showed water running freely through crack nearby;
llth attempt spouted water and grout in foundation of diaphragm wall No. 10 and
forced air through crevices in No. 9 diaphragm wall; 40th attempt, refusal; 48
charges put in.
95. Elevation 81 ; depth 10 ft. ; 8th and 9th foot soft ; balance good rock. First
attempt blew grout and water out of No. 96 ; 5y2 charges put in.
98. Elevation 80 ft. ; depth 10 ft. ; 5th, 6th and 7th foot soft ; balance good rock.
First five charges forced air and water through No. 101 ; 8th attempt, refusal ; total
8 charges.
108. Elevation 82^ feet; 10 ft. hole. Eock seamy but hard; 3 charges put in.
117. Elevation 83 ; 10 ft. hole ; solid rock except crack in 2d foot and soft rock in
9th and 10th foot ; 7 full charges put in with nearly full charge and refusal at 8th
attempt.
136. Elevation 8£y2 ft. ; 11 ft. hole in solid rock except soft spot in 7th foot. First
attempt forced water through crevices; 4 charges before refusal.
141. Elevation 84y2 ft.; depth lift. First 8 feet solid, then iy2 feet soft; bal-
ance good. Second, 3d and 4th charges blew yellow mud from 145a, and water and
grout continued to flow from 145a with 7th and 8th attempts ; 10th to 18th attempts
forced grout and water through 148. Nineteenth and 20th attempt forced grout
from No. 144; pipe at 144 then plugged. Thirty-first attempt, refusal. About 27
full charges.
Record of Drilling and Grouting. 89
147. Elevation 84; 11 ft. hole. Soft spot in 2d, 5th and 7th foot; balance good
rock. At 5th foot water flowed from hole ; nearby water was flowing from crevice in
rock in which a 3" pipe had been cemented, confining the flow from crevice to said
pipe. First 11 charges each forced water out of 3" pipe ; 12th charge forced grout
from 3" pipe, and the latter was plugged. The 23d charge, plug removed from 3"
pipe. Grout going in slowly with the 58th charge. Sixty-third attempt refusal.
Machine moved to 3" pipe with refusal at first attempt. Total, 62 charges.
153. Elevation 83. This hole was one of the core bore holes made previously
by the City of Austin, being No. 19 on chart herewith (see page 54). Depth about
20 ft. This hole was in foundation of diaphragm wall No. 16, and the water was
piped up and the wall concreted. Water rose in pipe to water level (outside coffer).
First attempt, full charge ; afterwards charges were put in rapidly without appreci-
able resistance until pipe was full; 157 charges.
155. Elevation 85; 11 foot hole; in good solid rock except soft in 8th and 9th
foot. First attempt forced grout from around footing and in pump sump at north
end of diaphragm wall No. 17. Thirteenth attempt, all blew out at sump. Stopped
at this point because all grout was lost. Probably about net 12 charges.
160. Elevation 85 feet. Cemented pipe in crevice at this location. Put in 41
charges when cofferdam failed and water covered the hole. After break in coffer,
refusal at 43d attempt ; total 43 charges.
161. Elevation 85; 5 ft. hole in good rock except cavity and soft spot in 4th foot.
First 5 attempts forced grout from crevice in all directions within radius of 15 feet.
Forced water and mud from No. 167 and grout at 20th charge. After plugging No.
167, refusal at 77th charge; total about 75 charges.
166. Elevation 86 ; depth 5y2 feet. Water bearing sand in 4th foot ; balance solid ;
4th attempt forced air and water to crevice in lower end of trench of No. 18 diaph-
ragm wall. Second and 3d attempts filled all crevices and forced grout from No.
180; total, 11 charges before refusal.
171. Elevation 87; depth Iiy2 feet. Four feet hard rock; iy2 ft. soft; then 2y2
ft. solid followed by iy2 feet soft rock; balance good rock. First 7 attempts dis-
charged water and mud from No. 162 and in various nearby crevices. Hole cleaned
and left ; later, successive attempts after the 8th showed same indications ; 18th at-
tempt forced water from 173. Indications of permeability decreased and practically
stopped at about 40th charge. Total 43 charges.
177. Elevation 87; depth 43,4 ft. Solid rock with seam at 3y2 ft. depth. Grout-
ing in this hole showed increase of water in Nos. 179, 178, 184, 183, 182 and 181. This
hole took 19 full charges before refusal.
179. Elevation 86^; depth 5 ft.; solid rock but water flowed from the hole.
Three holes were drilled in this vicinity, water flowing from each one. The flow was
greater after subsequent blasting of trench foundations; evidently the water in all
of those holes came from the same seam. First charge showed grout coming up in
No. 182; total of 22 full charges.
90 Report on the Dam at Austin, Texas.
182. Elevation 87y2. This was one of the holes mentioned in No. 179; 10 full
charges before refusal.
187. Elevation 88. This hole was piped up through footing of diaphragm wall
No. 20. Took 12 charges, after which grout began to flow from seams near footing.
Seams were calked and later 5 more charges were forced into the hole. This caused
grout to show in No. 186. Total of 17 charges before refusal.
210. Elevation S9y2. Near this hole, water coming from crevices in foundation
nearby, also water coming into cofferdam through large hole about elevation 90.
First charge at low pressure and charges continued. Grout color showing from
various crevices even to a distance of 120 feet to the big pump sump hole. Moved
grouting machine at about the 90th charge to No. 214, then back to No. 210 ; then
moved to No. 192 which took no grout ; then back to No. 210 ; with total of 115 charges,
springs stopped and the big hole was bailed out by hand.
212. Elevation S9y2 ; depth 10 ft. ; good rock. Put in 11 charges when it was
evident that grout was being forced out of nearby crevices as fast as put in. Three
days afterwards, another attempt was made without success. Second attempt, re-
fusal.
214. Elevation 91 ; depth 11 ft. Good rock except soft in 7th foot. Five charges
put in, blowing out at 213 and near 210. After grouting No. 210 several days after,
machine was again put on No. 214 with refusal at 4 different attempts.
222. Elevation 92; depth Iiy2 feet; 8ft. solid rock, then 1 foot soft; then 2y2
feet solid rock. Took 10 full charges before refusal.
225. Elevation 92 ; depth ll1/^ feet. Solid rock except soft in 8th foot. Water
flowing. Three full charges.
226 Elevation 92 ; depth 12 feet ; solid rock. Water seam about 10th foot. Hole
took 47 full charges.
229. Elevation 92 y2. This was one of the bore holes made by the City some
years ago. First charge forced grout into No. 228 which had not yet been grouted,
and in No. 231, and showed air bubbles within a radius of 10 or 12 feet. First few
charges stopped all leaks. Eleven full charges put in.
232. Elevation 92y2. No log of drilling. Took 17 full charges.
235. Elevation toe of old dam; about 9 foot hole; 5 feet in grout and 4 feet in
limestone and mortar. Poured in water and it ran through the hole. Put on grout-
ing machine and it took one full charge ; afterwards 10 charges ; later about y%
charge; total 10y> charges.
236. Elevation toe of old dam. Depth about 4y> feet. Water ran freely through
hole; took 12 full charges without showing any indications from outside or in water
below the dam. Thirteenth charge blew out through the joints in the granite nearby.
After cleaning the hole and plugging the joints, replaced machine and the hole took
nearly one full charge before refusal. Total about 13 charges.
Record of Drilling and Grouting. 91
242. Elevation 93y2 ; 11% ft. depth. Solid rock except slight drop 19th foot.
Water flowed freely from hole. First few charges blew out in No. 244 and evidently
forced grout around No. 240, because water began to flow from that hole although
it had previously been grouted. This flow finally stopped. The vicinity of this hole
was covered with mud and the operations were conducted with care, observing all
possible leaks of grout. After a few charges, all indications of bubbling in the water
or color of grout ceased. Ninety-three full charges ; then refusal.
.243. Elevation 93y2; depth Iiy2 ft. Solid rock except soft spot in 8th foot.
Water flowed freely from hole and showed bubbles in crevices about 60 feet up-
stream. Charges went in without indications of leak after the first 2 or 3 up to the
37th, when grout came through No. 245. Plugged this pipe and continued until 47
charges had been put in.
244. Elevation 94 ; depth 11 ft. Solid rock with soft spot in 8th foot. Twenty-
four full charges were put into this hole under maximum pressure for each charge.
246. Elevation, toe of the dam; depth 11 ft. Total of two charges before re-
fusal.
255. Elevation 95 ; depth 11% ft. Solid rock except soft in the 8th foot and last
foot. Air and water forced in this hole proved it to have outlets. First few charges
with no surface indications. This hole grouted to refusal with 60 full charges.
258. Elevation about 95; depth 11 ft. Two full charges and then grout blew
through crevices around hole ; 4 additional charges were probably largely lost ; prob-
ably about 3 full charges.
260. Elevation 95; depth 11 ft. Solid rock except soft places in 9th and 10th
foot. Took 7 full charges with no indications of leaking nearby.
261. Elevation, toe of old dam. Depth 11 y2 ft. in granite, limestone and mortar.
Last foot soft material. Water ran freely through this hole and 93 charges were
placed without evidence of loss. Grout was forced in with light pressure except last
few charges. Final refusal at 80 pounds pressure.
263. Elevation below toe of dam. About 11 foot hole in granite, limestone, mor-
tar and flint. First few charges showed leaks nearby which finally ceased. Took
43 full charges.
271. Elevation 95% feet. Depth about 18% ft.; 6% ft. solid rock; one foot
water bearing, soft ; balance rather soft but solid. Water rose when drill reached
about 8 feet. Fourteen charges put into this hole under maximum pressure of 70
pounds.
276. Elevation about 96 ; depth 11% ft. ; 7 ft. solid rock, then one foot cavity ;
afterwards 3% feet of solid rock. This hole when tested, evidently had openings un-
derneath the dam, shown by bubbles in water below toe of the old dam — reported by
laborers afterwards. This hole took a number of charges, probably 25, without max-
imum pressure, after which charges were put in with gradually increasing pres-
sure. Total of 57 charges put in with refusal.
92 Report on the Dam at Austin, Texas.
277. Elevation about 96 ; depth about 10 ft. ; 4 ft. solid rock and about y2 ft. soft
rock or clay ; then 5 ft. of limestone. Water leaked away rapidly. Grout forced at
about y2 maximum pressure up to 20th charge. Put in 27 charges, the last at about
60 pounds pressure. Breakdown in machine stopped operations and before resump-
tion concrete had set in the cracks. Number 278 was then drilled which took about
y2 of a charge.
NOTES BASED ON INFORMATION FURNISHED BY MR. S. S. POSEY
(Mr. Posey was Inspecting Engineer for the City of Austin, beginning his work at
the Dam some time after excavation had begun but before the first concrete was
poured. He began his inspection about October 20, 1912.)
The information furnished by Mr. Posey was of much value, and for the pur-
pose of this Report has been abstracted as follows:
The structure now constituting the Austin (Texas) Dam consists, in its western
portion, of about 500 feet of the original structure, built in 1893, 560 feet of the new
structure, built under the contract of 1911; and on the east of about 60 feet of the
original 1893 structure, also the original head works and a core wall extending about
300 feet east from the east end of the spillway. The so-called core wall consisted
of a narrow concrete wall, built in excavation, north of and adjacent to the original
head work masonry and extending easterly therefrom. From the west end of the
head work masonry the bottom of the cut-off wall dropped downward, holding a
depth of approximately two feet below the rock bottom or about one foot below the
cross walls of the dam.
Cross Walls. — The cross walls (i. e. the walls at right angles with the face of
the dam) are numbered from the east, the one at the end of the new work being
number 0.
In general, the trenches for the cross walls of the dam, penetrated the surface
rock approximately one foot. Walls 4, 5, 6, 7, 8, 9 and 10 were built in trenches ex-
cavated to an extra depth, wall 8 being the deepest and extending down 22 feet below
low water. Beyond wall 8 the condition of the rock of the bottom improved in qual-
ity somewhat and the cross walls were carried to a less depth. At wall 18 and be-
yond, the excavation for the cross walls was made with pot shots. The depth below
low water to the rock surface being about 12 feet at wall 18 and sloping upward to
a depth of 9 feet at wall 27. From wall 18 to wall 27 the cut-off wall was carried
down below the surface of the rock about two feet. From wall 15 to wall 27 the gen-
eral slope of the foundation rock is down stream and is about two feet in the width
of the dam. The cut-off wall was carried westward to the end of the new work and
no further and no cut-off wall was placed either at the heel or toe of the west portion
of the old dam.
A curtain wall about 18 inches in thickness and 6 or 7 feet in depth was carried
from the head gate masonry westward along the toe of the east portion of the old
Leakage. 93
dam underneath the new construction and underneath the broken end of the old dam
until it encountered the cross wall of the new construction.
Leakage. — Near the east end of the west portion of the old dam for about 80
feet, the grout that was forced into the 11 ft. holes under 80 Ibs. pressure came out
of the old dam masonry joints at the first, second, third and possibly the fourth
joints above the foundation.
On the toe of the west portion of the old dam a number of two inch holes were
drilled through the masonry and to a depth of about 11 ft. Water came through the
toe from some of these holes. Air forced into some of these holes at perhaps 60 to
70 Ibs. pressure appeared in the drill holes above the dam and in the cracks of the
foundation rock. Water also rose and overflowed through a hole drilled into the
face of the dam about 8 feet above the toe.
With the lake full, water seeps around the west end of the old dam through the
rock and appears as seepage on the face of the bluff to a point perhaps ten feet be-
low the top of the dam and springs apparent along the bluff for a distance about 100
feet below the dam. Evidence of leakage into the natural rock on the east side of
the river was found at the following points:
1st. Under the new forebay wall, in the dry wall of the old forebay and east
of the northerly end of the boom.
2d. Under the masonry of the City wharf about 200 feet north of the dam.
3d. In Walsh's Slough near the northerly end of an old clay dam which was
constructed by Mr. Walter Johnson to save water during the operation of the
old plant.
4th. In the upper end of the Taylor bluff, perhaps a half mile north of the
dam.
It is Mr. Posey's belief, from the direction of the opening from hole number
one, that the "corewall" was not carried deep enough to cut off the water from this
source. However, an opening under the westerly penstock, now in place, was cut
off by the "corewall."
From the various openings above described and perhaps from many others not
definitely located, a considerable amount of water seeped into the east bluff above
the dam and appeared as springs and seep water at various points for nearly a half
mile below the dam. Some of these points may be described as follows :
1st. A small pipe near the north end of the retaining wall. This flows very
strong at full lake and is now dry with water at elevation 16.
2d. A small pipe under the north draft tube which flows full at full lake but
is now stopped.
3d. A 2-inch pipe built into the wall facing the bluff and between the two
south turbines which also flows full at full lake level.
4th. The head gate masonry also shows seep water to a considerable height
above the ground.
94 Report on the Dam at Austin, Texas.
5th. There is also seepage through the face of the rock at the south end of
the power house.
6th. In springs which show on the river face of the foundation wall near the
south end of the power house, south of the present draft tubes. At full lake this
spring required a 3-inch centrifugal pump to take care of it while building the
concrete blocks at the ends of the draft tubes, and the water is still flowing with
the lake level at elevation 16.
7th. Seepage through joints in the clay bank, beginning about 200 feet south
of the dam, and extending 1000 feet or more in a southerly direction.
8th. Seepage also appears in the form of springs in three draws south of the
dam, the strongest one being the one farthest south from the dam, which flows
approximately 8 to 12 second feet. The next strongest one was about one-
fourth mile northward toward the dam, which flows strong enough to rapidly
erode the east bank.
Between these two springs the water came out in the alluvial field about 30 feet
above the river to a sufficient extent to destroy a crop of cantaloupes for a market
grower.
The south spring issued first from an opening in the rock 20 feet above the river,
and later appeared at an elevation about 10 feet lower. None of this water appeared
until about a month after the water in the lake rose to the higher levels.
Leak Under the Dam. — As previously noted the walls of panels 4 to 10 were
carried to an extra depth on account of the poor condition of the foundation rock.
After the construction and filling of the dam a leak appeared in the sixth panel of the
new dam about 5 feet down stream from the cut off wall, and near the east side of the
intermediate wall. As the flow from this was very large (perhaps 30 second feet),
an attempt was made to close off this leak. The running water had thrown up a bank
of sand, gravel and mud across the bay to near the surface of the water and a coffer
dam was constructed by driving Wakefield sheet piling into this deposit from the
east wall of the bay to the east side of the intermediate pier. A 4-inch centrifugal
pump and motor were installed. The water did not rise after the construction of
the cofferdam nor was the pump able to lower the water, although it was speeded
up and was attached to a powerful motor. A diver who examined the opening found
that it was of sufficient size so that he could stand in the opening and the surface was
about level with his arm pits. From this position he said he could reach the cut-off-
wall. He also stated that the water appeared to come from a downstream direction
and impinge against the cut-off wall.
An earth cofferdam was built immediately opposite the position of this leak on
the upstream side of the cutoff walls and atove the dam. The water in this cofferdam
could easily be lowered and there was evidently no direct connection through the
rock under the cut-off wall.
Leakage. 95
The opening in the rock, where the leak appeared, was filled with sacks of sand
which were also piled on top with the intent to throttle the flow so that the cofferdam
could be pumped out. After which the leak broke out about ten feet southwest, near
the edge of the cofferdam, coming up through the fill, indicating a continuation of the
rock fissure in that direction. The work was then stopped.
After the reservoir had been filled and when it was lowered to furnish water to
the rice growers near Bay City, while its surface was falling rapidly, a strong flow of
air and water mixed appeared about halfway between Huch and Wright's boat-
house and the mouth of Bee Creek. It was so strong that a good sized motor boat
could not be held over it, the boat each time being swept quickly aside. The flow was
strong enough to raise the surface of the water two or three inches above the sur-
rounding water. After about 24 hours this flow stopped and another flow, not so
strong, appeared about 100 feet above the dam near the west end of the new portion.
This stopped after about half a day. In Mr. Posey 's judgment this indicated that a
cavern or underground passage was being emptied when the head was reversed by
the lowering of the lake level or that the air and water had been confined in a cavern
and the pressure was strong enough to overcome the head of water above its out-
let.
There was also a spring near some sheet piling about walls 17 and 18, about 30
feet from the cut-off wall, both during construction and when the water in the reser-
voir was lowered.
During the work on the leak in panel six the water was clear and much cooler
than the water in the river but later with a slight rise in the river making the water
of the stream murky the water from the leak appeared to be of the same color.
Seepage in the Old Dam. — Near the east end of the west portion of the old dam,
where the new work joins it, the breaking away of the portion of the original struc-
ture, washed out by the 1900 flood, shelled away the granite facing so that at the
break one's arm could be thrust between .it and the limestone core. The mortar
joints were broken in places also, so that now when the water in the lake is standing
at 51 ft. or higher, the spillway face of the old dam is kept constantly wet for a dis-
tance of about 125 ft. on a line which slopes to the west. The highest part is only
5 or 6 ft. below lake level and the lowest part in the neighborhood of 10 ft. above low
water. The masonry above the toe is wet constantly. These conditions show that
the limestone core of the gravity section is quite porous. Another evidence of the
porosity of the masonry of the old dam is the fact that water stands only a few feet
below the lake level in the most easterly one of the six inch well holes drilled through
the dam from top to bottom and at lower levels in the other two.
Class of Work. — The class of work in general done by the sub-contractor was
good but very rough as to finish. The forms were not held rigid to position, partic-
ularly as to the crest gate piers, and consequently trouble was experienced in get-
ting the crest gates fitted to place in the openings ; a great deal of chipping was
96 Report on the Dam at Austin, Texas.
found necessary because of the swelling of the pier forms. The trenches for the foot-
ings of the supporting walls were filled with concrete entirely, thus sealing all exca-
vations of this character and helping to prevent scouring by the flood waters. Mr.
Posey does not consider that the cut-off wall trench and some of those for the trans-
verse walls were carried deep enough for safety at various points, although the depth
was approved by the City's representative.
Cofferdams. — Sand and rock cofferdams were used to exclude the water from the
underwater work. These were easily destroyed by slight rises in the river and were
partially or entirely rebuilt thirteen times.
General Amount of Pumping. — A ten-inch centrifugal pump and a twelve inch
dredge pump of the same type usually handled the water, but on one occasion an eight
inch was needed in addition. A large pulsometer was all that was needed in the cut-
off wall trench in most cases, but sometimes a smaller one of the same type and a
four-inch centrifugal were also needed.
Grouting. — The plan of grouting relied upon to cut off the flow of water in the
foundation of the dam was carried on conscientiously and as continuously as possi-
ble. In one instance at least it was not effective, and Mr. Posey thought at the time
the work was being done that some of the soft material in the cavities and between the
hard strata was simply being compressed. If water managed to percolate through
it, a larger opening could easily be made by it when under flood head. That cones of
grout were formed around the grout pipes was demonstrated by holes drilled through
the grout after it had hardened, but Mr. Posey believes that inverted cones of com-
pressed mud were also formed between them. In other cases he thinks the grout
followed the irregular cavity . where it was free to do so.
Concrete. — The concrete was supposed to be a 1 :2 :4 mix with the aggregate sep-
arated. The engineers for the City Water Power Co. saw fit to change this to a
mixed aggregate with stone or sand added as shown to be needed by voids deter-
mined by means of water. If the percentage of voids ran about 24 or 25 per cent., the
material was considered all right. This aggregate ran up to 2 and 2y2 inches and
down to the finest sand. Four sacks of cement were used in each yard. Mr. Posey
considers the concrete mostly good above elevation 100, but below that some of it did
not test out as it should have done though this was probably offset by the increase
in thickness of footings and the courses immediately above them. The upstream
deck was made water tight by the use of hydrated lime, and this showed exception-
ally tight for all heads of water.
Reinforcing. — The reinforcing was carried out closer to plans than Mr. Posey
ever saw attempted in large work of this character and he believes the structure to be
sufficiently reinforced to withstand every strain to which it may be subjected unless the
flood water head should be increased. The only walls not strongly reinforced are
the cross walls supporting the dam on the inside. The bars are used here princi-
pally around openings. These walls are not bonded well to the .spillway deck and
Conduct of the Work. 97
make it desirable to repair the remainder of the sluiceway arches so that these walls
will not get strong pressure from the inside when the sluiceways are in use. The
water rises inside the dam to nearly the 30 ft. level at these times.
Power House Foundations. — Considerable blasting and digging were required to
get the old foundations of the power house out of the way. Some of them had to be
taken down to the level of the granite wall and these and the stone bluff were blasted
off about four feet for the space occupied by the new turbines. The space under the
old wooden floor, where space was not needed, was filled and a concrete floor built on
top of this fill. No change was made in the foundation of the part of the old building
left standing. Thirty-three feet were added to the length of the house.
Tail Race. — The tail race was not built according to plans, but was made an
open channel about fifty feet wide on the bottom with a depth of five feet below low
water at the end next to the draft tubes and three feet below the same level at its
river end. An attempt was made to wash it out with the water from the turbines
but without success. Two rises partially obstructed the channel with rock and drift
and in both instances the draft tubes were blocked so that the turbines could not be
used.
Penstocks and Draft Tubes. — The penstocks and draft tubes were built mostly
out of the old tubes installed about 1893, the elbows where the penstocks connect to
the turbine chambers and the elbows in the draft tubes being new. The penstocks
were protected on the outside of the building by a covering of wire mesh and
concrete but not on the inside of the power house. They were also treated with
smooth-on and a wash of retempered cement. No leaks of consequence appeared
during the test in these pipes, but on account of a failure at first to provide large
enough air relief pipes the one on the east side collapsed under the north building
wall and for about 30 feet each side of it. The pipe was jacked into shape and large
relief pipes added. The draft tubes had to be recalked at the test to get a proper
vacuum and at last some of the leaks were stopped with Portland cement.
Conduct of the Work. — The sub-contractor agreed, so Mr. Posey was told, to carry
out the work according to a certain scheme laid down before the work was started,
and on this account the excavation was commenced on the higher levels in the core
wall trench when the river conditions were exceptionally favorable for work in the
river. The delay caused the river work to go over into two unusually wet years
when flood conditions were very bad and made the work drag along for two years
longer than it should have done. No equipment for rapid excavation was on hand
except two cableways, and this part of the work was slow. Concrete was first laid
in wall No. 17 which was where the rock was first exposed. The entire foundation
area was not exposed to inspection except the position upon which the walls actually
rested. The footing forms for wall No. 17 were sunk in the sand by digging out on
the inside. The concrete had to be underpinned afterwards. The rock for two panels
east of wall No. 17 was washed fairly clean by sluicing and that in the "Gap" be-
98 Report on the Darn at Austin, Texas.
tween walls No. 17 and No. 27 was also cleaned, but sand afterwards covered the
lower portions and the forms had to settle into it. In all other cases the trenches
were dug for the footings and such mateiial as could be piled up in the spaces be-
tween them was so disposed of.
DISCUSSION OF CONDITIONS BELCW THE TOE OP THE PRESENT DAM
It is apparent that the conditions of the river bottom below or downstream from
the toe of the dam were not investigated tither before the construction of the original
dam in 1890-93 or prior to the reconstruction in 1911-15.
The eastern part of the original dam was constructed in a wide trench excavated
through the alluvial deposit that occupied more than the east half of the original can-
yon of the ancient Colorado River (see Fig. 15, page 45 and Fig. 16, page 45). This
deposit below the dam was gradually removed by the flood waters which were also
known to be seriously eroding the rock below the dam, for these floods were con-
stantly adding to the pile of rock which had formed below the dam and which is
clearly shown in Fig. 23, page 52.
In spite of this gradual accumulaticn, which could come from no other place
except from the river bottom immediately below the dam, the City apparently made
no soundings, and the condition remained unknown except from a cursory examina-
tion made by Prof. T. U. Taylor who states (see W. S. & I. Paper No. 40, page 46)
that he made certain soundings from the toe of the dam in March 1899, and at or near
the point where the break in the dam afterwards occurred, was unable to reach the
bottom at 9.5 feet below the water surface. Prof. Taylor further says (ibid page
47):
"During a freshet in 1892 the overfall cut through this hard strata, tore up
large pieces (some of them 10 feet long, 4 feet wide, and 2.5 feet thick and of 7 to
8 tons weight), and deposited a whole quarry in a confused and irregular pile
about 150 to 200 yards farther down the river. These stones remained in that lo-
cation until the big freshet of June 7, 1899, when they were carried away."
Prof. Taylor further describes, in this same pamphlet, the conditions observed
by Mr. J. G. Palm in 1897, as shown by Fig. 19, page 49.
On the destruction of the old dam in 1900, the space below the dam was again
filled by detritus from the old structure ard by the formation of bars of sand and
silt; hence on the reconstruction of the dem in 1911, this space was again covered
(Figs. 46 and 47). The toe of the west portion of the old dam was also covered by a
deep deposit of silt (see Fig. 48) so that the condition there was unknown as will
be noted from the fact that Messrs. Davis, Hill and Taylor, in their report of 1908
assumed that the toe of this section had also been undermined, for they show how
repairs should be made for such a condition (see A Fig. 27, page 56).
These areas were again uncovered by the floods that passed over the dam in 1915
and subsequently. On the writer's visit, soundings were taken below the entire struc-
Conditions below Dam.
FIGURE 45 — Grouting Rock behind West Portion of Old Dam. Bottom Apparently not
Exposed for Inspection.
FIGURE 46 — New Dam as Completed 1915, Showing Fill below Apron.
Report on the Dam at Austin, Texas.
FIGURE 47 — New Dam Nearing Completion 1915, Showing Fill below Apron.
FIGURE 48 — New Dam after Completion 1915, Showing Fill below Apron.
Conditions below Dam.
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Conditions below Dam. 105
ture. The results of these soundings are shown by Figs. 49 to 52, pages 101 to 104, in-
clusive, the location of which, relative to the dam, can be determined from the pier
numbers on the dam.
From these soundings it will be noted that the rock below the west half of the
structure is still intact, and that the toe cf this section never had been undermined
by the flood waters. On the other hand, the bedrock below the new structure had
been deeply eroded by the flood waters over the old dam, and perhaps during the
subsequent failure. This investigation shows that with very few exceptions the rock
bottom in front of the new section of the dam is considerably below the foundation of
the piers or cross walls. This fact will also be seen more clearly perhaps from the
following table which shows the elevation of the piers or cross walls at the front of
the new dam, the lowest elevation of the low point in the rock in front of the pier,
and the relation of the rock -f (above) or - - (below) the dam foundation.
EELATIVE ELEVATIONS OF DAM FOUNDATION AND BOCK IN FRONT OF TOE
Belation
No. Pier Elevation Bock Elevation — Lower
+ Higher
0 90 80 —10
1 88.8 82 — 6.8
2 88.5 82 — 6.5
3 88.5 84 — 4.5
4 84.5 81 — 3.5
5 84.5 81 — 3.5
6 83.4 83.5 — .1
7 83.4 82 + 1.4
8 80.8 84 + 3.2
9 82.2 84.5 + 2.3
10 83.5 84 + .5
11 84.5 79.2 — 4.3
12 84 83 — .1
13 85 84.5 — .5
14 87.2 82 — 5.2
15 87.25 83 — 4.25
16 86.9 84 — 2.9
17 86 84.5 — 1.5
19 87.4 85 — 2.4
21 86.7 85 — 1.7
23 87.4 86 — 1.4
From this table it will be noted that with the exception of piers 8, 9, and 10, which
are below the rock bottom, all of the remaining piers are from .5 foot to 10 feet above
106 Report on the Dam at Austin, Texas.
the lowest point in the rock bottom immediately in front of the piers. This condition
is shown by comparison of the diagrams furnished by Mr. Taylor and shown on pages
77 to 80, with the diagrams of the soundings shown on pages 101 to 104. Two of the
worst conditions are illustrated by the A. and B. Fig. 12, page 28.
GEOLOGICAL AND PHYSICAL CONDITIONS AT THE DAM SITE
To what extent the conditions at the dam site were appreciated by geologists at
the time of the original construction in 1890-93 is unknown, but it seems doubtful if
any adverse comment was then made as to the location. It is a fact that the influence
of such conditions on the safety of such structures was not as well recognized at that
date as at present, and it is probably true that no professional advice from geologists
concerning the advisability of the location was sought.
Following the date of the construction of the original dam, the Austin area was
examined in detail by the geologists of the United States Geological Survey, and in
May, 1902, the Survey published a report on the Austin quadrangle, in which the gen-
eral conditions in this district were outlined in considerable detail. Previous to this
publication, Messrs. Eobert T. Hill and T. Wayland Yaughn had prepared an elab-
orate article on the "Geology of the Edward's Plateau and Bio Grande Plain adja-
cent to Austin and San Antonio, Texas, with Reference to the Occurrences of Under-
ground Waters. ' ' This was published in 1898 as a paper in Part II of the 18th An-
nual Report of the Director of the U. S. Geological Survey for the year 1896-1897.
The general geology of this district, as a part of the Black and Grand Prairie Region
of Texas, was also discussed in an elaborate monograph prepared by Dr. Robert T.
Hill, which was published in 1901 as Part VII of the 21st Annual Report of the Di-
rector of the U. S. Geological Survey for the year 1899-1900.
These various publications have set forth in considerable detail the conditions
which obtain at Austin and vicinity, and have made available data sufficient to show
the great difficulty of attaining safe construction at the present site of the Austin
dam.
This dam site is located on the Colorado River where the river discharges from
the deep canyon of the Edward's Plateau into the shallow valley of the Black
Prairie Region. The strata of the Edward's Plateau, which begins a mile or more
above the dam site, are firm and horizontal, and the stream in this section flows over
ledges of firm and solid rock, which would probably make a suitable and stable foun-
dation for dam construction. Within the area on which the dam is located and east
of the plateau region, the strata are joint ed and faulted, and constitute what is
known to geologists as the Balcones Fault Zone. A section along the south side of
the Colorado River, showing the general extent and displacement resulting from
these faults, is reproduced in Fig. 3 page 14, and a map showing the geographic
location of the principal fault lines in the vicinity of Austin is shown by Fig. 2 page
13.
Geological Conditions. '•.• ,Jj) lt)7
FIGURE 53 — West River Bluff below Dam showing Nature of Rock.
FIGURE 54— Minor Block Fault on the North Side of Bee Creek near the Mouth and
Adjacent to the Austin Dam.
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Report on the Dam at Austin, Texas.
FIGURE 55 — One of the Group of Mormon Springs.
FIGURE 56 — Rock Outlet where Mormon Spring is said to Discharge with High Water in Reservoir.
Geological Conditions. 109
The geological formation in the bed of the stream within this area is quite dif-
ferent from that in the canyons of the Edward's Plateau. Here the bedrock con-
sists of the Edward's formation exceedingly porous and soluble, while in the canyons
above, the strata are less soluble and more durable. Subterranean waters acting
on the Edward 's limestone have resulted in caverns and crumbling strata even where
the surface rock is apparently solid and durable.
In the Walsh quarries, about 1000 feet from the dam site, was formerly an open-
ing into a cavern, which was said to be quite extensive. Mr. A. C. Blanton, who su-
pervised the borings at the dam site in 1908, visited this cavern at about that date,
and in a letter to the Engineering News (Aug. 22, 1915) makes the statement that
this cavern extends southwesterly nearly to the dam site and probably under the
river. Others state that it extends south easterly toward the capitol. The shaft
leading to the cavern was covered with quarry strippings at the time of the examina-
tion by the writer, and its exact location was unknown. In any event, it indicates the
cavernous nature of the rock closely adjoining the dam site.
Similar indications are furnished by the voids found by the drill in the borings
of 1908 (see Fig. 26, page 54) and are evidenced by the washout under the head-
works in 1893 (see Fig. 17, page 46) and by the spring (see Fig. 21, page 51) which was
cut off by the corewall constructed by the City Water Power Company.
The weak condition of the bed joints and the vertical fissures in the strata imme-
diately above the river bed and below the location of the dam, are shown in Fig.
53, page 107 ; and the general condition of the faults may be judged from the photo-
graph of the minor block fault which may be seen on the northerly side of Bee Creek
near its outlet into the Colorado River, shown on page 107.
The main fault planes extend in a vertical direction hundreds of feet below the
surface and cut the water bearing strata of the lower geological deposits. Deep ar-
tesian springs of great volume and pressure well up through the joint planes and
fissures in this formation. The Mormon Spring, about one mile north of the dam site
and on a fault line that passes under or close to the dam, is a conspicuous example
of such springs. This spring apparently discharges through various outlets from the
same fissure, according to the stage of the river, and the resistance of the overlying
alluvial deposits. In August, 1917 several springs of this group were seen of which
Fig. 55, page 108 is one. When the water is raised by the dam, the discharge is said
to occur higher and higher up the hill, at the same time reducing in quantity, and at
the reservoir full stage is said to discharge through the fissures shown in Fig. 56,
page 108.
Barton Spring, used as a bathing pool, is still better known to the citizens of
Austin. Its discharge, varying from 15 to 20 cubic feet per second, occurs through
cracks and fissures that are readily visible in the adjacent rock bank of the spring
and through the clear water on the bottom of the pool. (See Figs. 58 and 59, page
111.) These waters undoubtedly come from the source tapped by the artesian wells
110
Report on the Darn at Austin, Texas.
of Austin, and originate from the outcrops and percolating waters which reach these
water bearing deposits at and near their outcrop on the western edge of the Edward's
plateau. These springs occur at the points on the fault lines where the weakest
conditions exist, and doubtless many minor springs occur along such lines in the
FIGURE 57 — Section through Panel No. 6 of the New Dam Showing Possible Condition of Leak.
gravels of the river and below the river surface, but are of such small volume as to
be unknown or unnoticed.
The site of the dam across the river is almost at right angles with one of the
most conspicuous of the fault lines, and the unfortunate condition in the east half of
the foundation results. The water encountered in the foundation of the original
dam (see page 44) and in the present construction (see page 71) was probably from
this source, and the low water flow of the leak in panel No. 6 below the cutoff wall
of the dam is undoubtedly from this source. When an attempt was made by the
Receiver, Mr. Guy A. Collett, to investigate and repair this leak, the temperature of
the river water was 88° Fahr., while the water from the opening in the rock in panel
Geological Conditions.
Vii
FIGURE 58 — View of Barton Spring. Discharge Occurs through Fissures in Rock
near Water Surface.
FIGURE 59 — Barton Spring showing Fissures in the Rock Bed.
*•'* * *^0 * rC^* 0 ** * > ^%i
] 1 2 Report on the Dam at Austin, Texas.
FIGURE 60 — Rock from Foundation Deposited below Dam.
FIGURE 61 — Rock from Foundation Deposited below Dam.
Geological Conditions. 1 1 3
No. 6 was 74° Fahr., and on the same day the water at Mormon Springs was 73%°
Fahr., and at Barton Springs, 73y2° Fahr. These same fissures when under pres-
sure from the reservoir above the dam or from the higher waters outside of a cof-
ferdam are evidently capable of absorbing water under these higher heads, trans-
mit it laterally and discharge it at the lower levels ; and some of the water encoun-
tered during construction probably came from these sources. In the investigation
carried out by Mr. Collett, it was found that when the water above the dam was al-
lowed to rise 6 feet, the water discharged from the fissure in panel No. 6 began to
change in character, became cloudy and increased in temperature, showing that un-
der these conditions it was beginning to discharge river water. During the writer's
examination of the dam, in August, 1917, with about 15 feet of water behind the dam,
the discharge was much more turbid than the river water below the dam, and the
current from the panel was visible for some distance below the toe of the dam.
An ideal section through Panel No. 6 and the fissure from which the leak de-
veloped, is shown by Fig. 57, page 110. The water first broke through at A and
under low water conditions came up through some line of weakness, AB. With
high water above the dam, the fissure discharged water received into the fissure
from some unknown point above the dam C, which was transmitted laterally through
the weak fissure, C, D, E at an unknown depth. When an attempt was made to
check the flow through A by filling the opening with sacks of sand, etc., the water
broke out to the southwest at F, after which the attempt to close the leak was aban-
doned for fear that conditions might be made worse before more radical and effec-
tive measures were taken.
It is obvious that these fault lines must extend through the dam foundation and
to hundreds of feet in depth. Before the development of the fissures in panel No. 6,
no spring of any considerable size had developed at the immediate dam site, but the
pressure due to a full reservoir gradually developed the weakness in this fault line
under the narrow cutoff wall, and has produced an opening which connects with the
subterranean sources and also with the reservoir above the dam at one or more
points along the fault line.
There appear to be numerous lines of weakness subsidiary to the principal
fault line under the structure of the dam. During the grouting of the foundation,
the passage of the grout for considerable distances along these lines made them man-
ifest, and those so developed and noted are described by Mr. F. S. Taylor on page
81 and are shown by the diagonal lines on the sketches on pages 82 to 85.
The log of the grout holes (see pages 87 to 92) shows that the strata of the
foundation limestone, at least on the east side of the stream, are interbedded with
clay so soft that it was frequently expelled through the drill holes by the grout
pressure from other holes where grouting operations were in progress. Much of
this foundation limerock is solid and substantial, but the cracks and fissures and the
, interbedded clay make it liable to destruction from water under pressure or at high
1 1 4 Report on the Dam at Austin, Texas.
velocities. The condition of the solid stone can be judged from the blocks which
have already been torn up from in front of the dam or under the old dam at the time
of its destruction and deposited 500 feet or more below the site, where much of it still
remains (see Figs. 60 and 61, page 112.) The photograph, Fig. 62, page 121, also
shows the rock of the river bed which was cleared at a point just above the junction
of the new dam with the west portion of the old dam during the construction work.
The soluble nature of this deposit is evident from the depression in its surface. The
foundation of the new dam was, however, placed in trenches excavated several feet
below the surface shown.
APPENDIX 5
DISCUSSION AND CKITICISMS OP THE CONDITIONS AND STRUCTURES OF THE PRESENT IN-
STALLATION
Essential Principles for the Construction of Safe Dams. — The general princi-
ples for the construction of safe dams may be briefly stated as follows :
First. — Dams must have suitable foundations to sustain the pressure transmitted
through them.
The pressure which can be safely applied to foundations varies with the nature
of the material in the foundations. In good practice, the allowable pressures are
usually taken about as follows :
Tons per Sq. Ft.
Eock equal to Best Ashler Masonry 25 to 30
Bock equal to Best Brick Work 15 to 20
Bock equal to Poor Brick Work 5 to 10
Clay in Thick Beds — always dry 4 to 6
Clay in Thick Beds — moderately dry 2 to 4
Second. — Dams must be stable against overturning.
The resultant pressures which must be provided for to safely fulfill these first
two principles should take into account all the forces which will be active after the
completion of the structure, and should include:
The weight of the structure itself.
The pressure of the water and silt impounded by the dam.
The upward pressure of water which may seep under the dam.
The back pressure of the tail water below the dam.
These must be considered under the most severe conditions which are liable to
obtain, and for safety should answer the requirement that the resultant pressure of
all forces acting on the dam shall pass within the middle third of the section in order
to eliminate tension in the upstream face of the structure.
Third. — Dams must be safe against sliding on their bases or on any section of
the dam itself.
To be safe from the danger of sliding, the tangent of the angle made by the re-
sultant with a vertical line must be less than the coefficient of friction for the ma-
terial. The coefficient of friction is about .7 for masonry against masonry or mas-
onry against solid ledge rock. This means that for such conditions the angle made
by the resultant with a horizontal line should not be less than 55°. For a dam built
I 1 6 Report on the Dam at Austin, Texas.
on a foundation of clay, the coefficient of friction may, however, be as low as .35, in
which case the angle of the resultant with the horizontal should not be less than
70°40'. When, however, the base of the dam is built on a rough and irregular solid
rock unlaminated and not interbedded with clay seams, the shearing strength of the
rock is introduced and the coefficient of friction may be regarded as increased to 1.4
or more ; and if the toe of the dam abuts solid rock that can be maintained against the
erosive action of floods, even a greater resistance is introduced.
Fourth. — Dams must have sufficient strength to withstand the strains and shocks
to which they are subjected.
Fifth. — Dams must be practically water tight.
Sixth. — Dams must have essentially water tight connections with their beds and
banks, and, if the bed or banks are pervious, with some impervious stratum below the
bed and within the banks of the stream.
In lieu of this requirement, the construction must be such that any seepage be-
low or around the dam shall be forced to travel such a great distance that its head is
used up in friction, and its erosive power thus destroyed.
Seventh. — Dams must be so constructed as to prevent injurious scouring of the
bed and banks below them.
The application of the above principles depends on the material from which the
dam is to be built and on local conditions. The important questions at the Austin dam
are: Have these requirements been fulfilled '•? If they have not been fulfilled to a
safe degree, what will be necessary to be done in order to secure safety?
Foundation Conditions. The foundation conditions have already been described
in some detail and were apparently well known to the engineers of the City Water
Power Company.
After the closure of the dam, Mr. F. S. Taylor, in the Engineering Record of
May 29, 1915, describes the foundation conditions as follows :
"The river bed for many miles up and down stream, and, in fact, practically
all the underlying rock of the country, i s limestone, varying from so-called
"dobe, " a disintegrated limestone, to the hardest variety. The river bed is
seamed with fissures, and there are small cavities of frequent occurrence, rang-
ing from a few inches to several feet in largest dimensions. These cavities are
encountered sometimes as far as 20 feet below the surface of the river bed."
Again, in an article in the Engineering News of June 3, 1915, Mr. Taylor
writes :
' ' The river bed and the whole surrounding country are underlaid with lime-
stone, which has many crevices, seams and cavities at varying depths below the
surface. About 12 years ago (?), two U. S. Government engineers made a short
report for the City of Austin, in which they gave an adverse opinion concerning
the character of the river bottom for supporting a dam. About six years ago
Foundation Conditions. 1 1 7
the City had a number of borings made to definitely determine the character of
the river bed. It was then found that there were considerable amounts of broken
limestone, soft limestone, cavities, seams and fissures underlying the dam, and
the records obtained from these borings proved that in order to build a dam
across the river at this point the defects in the strata underlying it would have to
be corrected. It was decided to fill all the underlying seams and cavities with
grout, and on the reconstructed river bed to build a hollow dam of reinforced con-
crete of such form that there could be no uplifting force from any leakage of
water under it. Furthermore, as a portion of this new section, a cutoff wall
would be sunk in a trench cut in the rock on the upstream side and carried to
such a depth that its lower edge would be below all permeable strata."
It should be noted that Messrs. Davis, Hill and Taylor, the Government En-
gineers referred to in the above extract from the Engineering News, made their re-
port in 1908 and had the advantage of an examination of the core drillings made
in that year and which are not now available, and in the light of such knowledge
condemned the foundation at this location as untrustworthy. They advised, if this
location was to be utilized, the construction of a solid dam, a core wall 20 to 30 feet or
more in depth at the upper line of the dam and extending across the entire river,
and the construction of a 100 foot apron below the toe of the old and new sections
(see page 56). Even with these precautions they recognized the possibility of danger
from deep seepage under the dam.
The original specifications provided that the foundations below the dam should
be made tight by grouting through drill holes (no depth specified) or by some other
means (see paragraph 7, page 63). In paragraph 8 of these specifications (see
page 63), as well as on the detailed drawings furnished and approved by the City's
representative in May, 1912 (Drawing C-10), it was provided that "cutoff walls
must be carried at least 2 feet into sound rock, which has been shown by borings to be
at least 6 feet thick." Both the original and the detail plans provided for a cutoff
wall in the bed of the stream both above and below the old structure. The actual
construction, as described by Mr. Taylor (see Engineering News, June 3, 1915) was
quite different:
''The longer part of the old masonry dam, that on the western side, was
not protected by a new cutoff wall but was grouted beneath through the test holes
which had been drilled on the upstream side of the section. The downstream
test holes were left open as indicators of possible leakage and to release any pos-
sible upward pressure from such leakage." * :
"Trenches were cut in the rock to receive the wall footings, and in the bot-
tom of these trenches, at intervals, drill holes were made 4 feet in depth. Where-
ever these drill holes passed continuously through solid rock, the trench was ac-
cepted as suitable to receive the footing. Wherever the rock was hard but a cav-
ity was encountered, grout was forced into the cavity and allowed to harden be-
1 1 8 Report on the Dam at Austin, Texas.
fore the footings were built upon it. Wherever soft and defective stone was
found below the bottoms of the building trenches, the excavation of these trenches
was continued until some point was reached below which the thickness of the good
rock was at least 4 feet. ' '
The deep cutoff wall advised by the Government Engineers and indicated on the
original drawings, was not constructed as noted in the above quotation, and depend-
ence was placed on grouting from shallow drill holes. The holes drilled for grouting
were in no case more than 12 feet in depth ; although in grouting hole No. 153, which
was one of the test holes (No. 19) drilled for the City in 1908 (see page 89) and which
was about 20 feet deep, 314 cubic feet of grout were used. This amount was greatly
in excess of the grout taken up by any other hole in the series, and clearly indicated
the presence of voids below the plane of 12 foot grouting.
The record of drilling showed that not even the four feet of sound rock men-
tioned by Mr. Taylor in the above extract from the Engineering News was present in
all cases. For example the record shows:
Hole No. 44 2" cavity at 4th foot
No. 46 2" cavity at 4th foot
No. 50 Drill dropped about 6" in 3d foot
No. 51 Soft spot in 3d foot
No. 53 Third foot soft
No. 63 Soft rock in 2d foot
No. 65 6" soft rock in 4th foot
No. 66 6" soft rock in 4th foot
No. 67 2" soft rock in 2d foot
No. 69 6" soft rock in 3d foot
No. 79 6" soft rock in 3d foot
No. 80 1.5' soft rock in 3d and 4th foot
No. 164 6" soft rock in 3d foot
No. 167 Seam at 3y2 feet
No. 174 Seam at 2y2 feet
No. 177 Seam at 3V2 feet
No. 180 Water seam at 3 ft.
No. 201 2 ft. solid, 8" drill dropped, 8" solid, 6" soft, li/2" solid.
The record of the majority of the drill holes show four feet or more of solid
rock. The holes, which admitted a considerable amount of grout, are shown on
the diagrams, Figs. 41 to 44, pages 82 to 85.
It seems apparent from the reduction of the solid rock requirement from 6 to
4 feet that the conditions were worse than were anticipated.
Grouting. — Grouting has been extensively used for filling the voids back of shaft
and tunnel walls, both in dry and wet work, and in sealing the cracks and fissures in
Grouting Foundations. 1 1 9
rock in advance of shaft and tunnel work so as to make the shaft or tunnel excavation
through such strata safer and less expensive. It has also been used to some extent
for similar purposes in dam foundations but apparently with less uniform success.
Its success depends on the equipment used, the extent to which the work is carried,
and the care with which it is done. While it has been found perfectly feasible to
force grout into the open spaces and voids of broken stone and into the open fissures
and cracks in masonry and rock strata, it has been found impracticable to force the
grout into seams or voids filled with sand or fine disintegrated rock unless the sand or
other fine material is first washed out, leaving the void and cracks free and open.
The mere passage of grout from one drill hole to another does not indicate that the
entire weak strata between the two holes have been filled. Under pressure grout will
follow the line of least resistance and will wash out channels and passage along such
lines, appearing at considerable distances from the point of entry and yet filling only
this limited channel, leaving other portions of the strata in their original condition,
unfilled and still in a dangerous state. In some of the holes, during the Austin grout-
ing operations (see No. 90 page 88, also No. 161 and No. 171, page 89), the pres-
sure of the grout forced soft clay from adjacent cracks and drill holes, but probably
removed but a small fraction of this material which lies interbedded with the lime-
stone of the foundation.
The grouting operations at the Austin dam are subject to several criticisms :
1st. Only one grouting cylinder was used, and the operation could not there-
fore be made continuous, giving the smaller crevices a chance to clog and hence
remain unfilled.
2d. The grouting at the cutoff was practically confined to a single row of
holes across the river, not giving sufficient breadth of the grouted zone to give
reasonable assurance of satisfactory results.
3d. The depths of the grout holes were entirely too limited for effective re-
sults under the conditions.
4th. The grout used was a mixture of sand and cement, where, under the
conditions at Austin, the grout should have been composed of neat cement only.
Concrete, consisting of cement, sand and stone, is often used for under water
work when it is deposited in mass. Grout composed of cement and sand is some-
times used for work where only large cavities are to be filled ; but where small cracks
and fissures are to be filled, it is found that if sand is used in the grout it is apt to
separate, to clog small openings and to result in imperfect work. In some cases,
grout of neat cement has been used even when masses were necessary but where the
separation of the sand might endanger the results desired, as in the case of the
Astoria tunnel caisson. (See Trans. Am. Soc. C. E. Vol. 80, p. 643, et seq.)
The ineffectiveness of the grouting at the Austin dam is shown by the large leak
that has already appeared in panel six and the smaller leak in panel four.
1 20 Report on the Dam at Austin, Texas.
Deep Seepage Under and Around the Dam. — Section 10 of the franchise ordi-
nance (see page 59) provides that Johnson shall prevent or remedy leaks or seepage,
through, under or immediately around the end of the dam, where such leaks shall
materially affect the use of the water for power purposes.
It is apparent that, with the reservoir full to the dam crest, a large amount of
water leaks around the dam and appears in the river below. This condition is de-
scribed at some length in the abstract of information by Mr. Posey (see pages 93 to
95).
The approximate loss, with the reservoir full to elevation 151, is shown by the
following measurements made by the U. S. Geological Survey :
FLOW DATA OF COLORADO EIVEE AND BARTON CREEK
(Flows in cu. ft. per second)
Flow of Barton Flow at Con- Inflow between
Date, Flow at dam Creek gress Ave. dam and Con- Remarks.
1916 bridge gress Ave.
Aug. 29 231 32.9 337 73 4 days after reservoir
was emptied
Aug. 31 179 30.5 238 28 6 ditto
Sept. 2 157 30.1 190 3 8 ditto
Sept. 6 109 28.2 141 4 12 ditto
1917
Feb. 21 236 343 90 Reservoir filled
Feb. 23 17 . 2 Assumed constant
Flow at Barton
Creek Feb. 21 to 23,
inclusive
NOTE : July 9, 1916, started to release water from the reservoir. August 26, reser-
voir was emptied and normal flow allowed to pass dam until September 8, when
gates were closed and water stored, and natural flow allowed to pass over crest
until released in the autumn of 1917 ; 1916 discharge measurements at the dam
were made about 100 feet above the structure, but the discharge measurement made
at the dam on February 21, 1917, was made just above the rapids a few hundred
feet below the dam.
These measurements show that the inflow between the dam and Congress Street
bridge, eliminating the flow of Barton Creek, was as follows :
With Reservoir filled 90 cu. ft. per sec.
4 days after Reservoir was emptied 73 cu. ft. per sec.
6 days after Reservoir was emptied 28 cu. ft. per sec.
8 to 12 days after Reservoir was emptied 3 or 4 cu. ft. per sec.
Deep Seepage.
121
FIGURE 62— Bed Rock above Dam near West End of New Structure during Construction.
FIGURE 63 — Rock at West End of Dam where Leakage occurs.
22
Report on the Dam at Austin, Texas.
FIGURE 64 — Rock Bluff below West End of Dam.
FIGURE 65 — Pervious Strata under the Forebay Wall.
Deep Seepage. 1 23
It is possible that 3 or 4 cubic feet of the inflow may come from springs in the
river bed, in which event the losses from seepage around the dam are apparently
about 86 cubic feet per second.
It is by no means certain that the above measurement represents the total loss
by seepage, especially with a 65 foot head on the dam, and it is quite likely that some
of the leakage finds its way into the country rock away from the river and does not
augment the river flow above the gaging station. It is certain however that the loss
is at least equal to the above amount.
Such leakage is to be expected from the geological conditions which have been
described, and while these losses may be reduced they can probably never be entirely
prevented. Some of this leakage undoubtedly passes immediately around the dam,
but most of it passes into the rock face of the canyon walls for a long distance above
the dam, and probably travels through pervious strata and possibly fissures far back
from the end of the dam. For the losses entering the side walls at considerable dis-
tances above the dam, the City Water Power Company can not be held accountable,
under their contract except as these losses reduce the power output below 600,000
horse power hours for each 30 day period as provided in Sec. 11 of the franchise or-
dinance (see page 59).
Leakage immediately around the dam occurs at the west end of the dam (see
Fig. 63, page 121). Here even with the head of 15 feet, which obtained during the
writer's inspection in August 1917, a considerably leakage was evident. This in-
creases with higher heads and can be followed for 100 feet or more below the dam
with the reservoir full, as reported by Mr. Posey. From the conditions shown in
Fig. 64, page 122, it may likely follow weak strata even to greater distances below
the dam.
Another loss which may or may not occur immediately around the dam is mani-
fest in the spring which issues under the south end of the power house.
The most serious leak undoubtedly occurs through the porous strata that gave
serious trouble in the original dam. The weak strata that caused the washout under
the head gates (see Fig. 17, page 46), and the leaks shown in Fig. 21, page 51, are
common to the entire district. These strata apparently outcrop on the east rock
bluff of the river, both above and below the dam, although in general these strata are
covered with soil and allvium. These porous strata absorb water from above the
dam when the head waters are raised above them. Through the voids, water is
readily transmitted and finds egress through cracks and fissures in the strata below
the dam or through the soil that covers them.
When the old dam was in use, serious losses of water occurred through these
strata, and various abortive attempts were made to remedy this condition. One
of these crevices through which the water was known to escape prior to 1900 is in
the loose rock under the forebay wall (see Fig. 65, page 122). Others are in various
1 24 Report on the Dam at Austin, Texas.
outcrops, presumably of these same strata, in Walsh's Slough (see Fig. 73, page 131)
and at other known points described by Mr. Posey. (See page 94.)
The Structure of the Old Dam. — The broken ends of the old dam reveal a poor
quality of masonry work for such an important structure. (See Fig. 74, page 131.)
The interior of the dam is built of native limestone, poorly laid in cement mortar.
The joints between the adjacent stones are poorly filled and it is evident from an in-
spection that water under a head can readily penetrate the structure to almost every
part. Holes drilled into the face of the dam during reconstruction permit water to
seep out, and it was still slowly running from these holes at the time of the writer's
inspection.
The grouting logs (see log of holes 235, 236 and 261) show that water flowed
readily into the structure and its foundations when holes were drilled into or through
the apron, and that during grouting, air forced into these holes found its way en-
tirely under the dam and showed above the dam. (See Mr. Posey 's evidence, page
93.)
Stability of the Old Section Under Original Conditions. — The principles of safe
dam design construction were not so well understood or appreciated in 1890 as at
present. The relations between the weight of the structure and the pressure of the
impounded water, and the danger of sliding and of undercutting at the toe, were un-
derstood, but the danger due to the upward pressure of water under the dam, trans-
mitted through cracks and fissures in the foundation rock, was often disregarded.
Uplift can sometimes be disregarded with safety on foundations which are practically
impervious or where the fractures in the rock are few and small, and hence the area on
which this upward pressure is exerted is of limited extent. The numerous accidents
which have occurred to dams during the last twenty-five years, have emphasized the
necessity of taking into account possible upward pressure, and of designing the dam
with sufficient section to withstand the pressure which is likely to obtain. It has also
developed, largely through the experience at Austin, that when large quantities of silt
will be deposited behind a dam, that the extra pressure against the structure due to
this silt must be considered in the design.
In the original section of the Austin dam, the height of the crest above the rock
foundation averaged about 66 feet; and while its total base width is 66 feet (see
Fig. 66, page 125), the effective width for the purpose of conservative estimating and
so far as resistance to overturning is concerned, is only about 42.75 feet, for it is
evident that the long slender apron of the dam, built of poorly laid masonry faced
with granite, would immediately break off near this point were the dam actually to
overturn. According to the principles previously stated (see second principle, page
115), the resultant pressure of the force acting on the dam should pass through the
base not more than 28.50 feet from the upstream face.
It is evident that in the original design, the presence of clay seams was ignored,
and the foundation was assumed to be solid limestone. It is also apparent that no
Stability of Old Dam.
125
allowance was made in the design for silt pressure above the dam or for upward water
pressure from underneath the dam, for it is found that with water at the spillway
level, and with no water below the dam, the resultant pressure passes within the mid-
dle third (see Fig. 66, page 125). The resultant R makes an angle of 63°45', with the
base, giving the value of .49 for the tangent of the angle of friction ; while any value
below .7 would be considered safe for masonry on masonry or for masonry on lime-
stone rock (see third principle, page 115). The dam would therefore be considered
safe for the conditions assumed.
W.L.E/. teo.o
£/ 99 O?
Condi f ions as Probably Original /y flssvmed.
Head Wafer £/eisafior> • J6O O Assumed
Tai/ - $4 O »
Si/f -None
Upward Pressure »
FIGURE 66 — Force Diagram of Old Dam with no Tail
Water Upward Pressure or Silt.
Condi f/ofi of £o» Wafer about Me Year /9OO
Head Wafer £/evafion - /ffO. O
To// " - 99. 0
5//f " /22 O
We/gfif af3'/tper Cu. ft. - //O. O *
Upward pressure Assumed at r/ee/ of Dam -Ay// Head.
„ * Toe S feet
FIGUEE 67 — Force Diagram of Old Dam with Low
Tail Water Full Upward Pressure with Silt be-
hind the Dam.
With the conditions that actually exist at the dam site, the above assumptions
are not adequate for safety.
In the first place, the fractured and seamy condition of the foundation and the
porous nature of the masonry admit the water pressure into and under the structure
of the old dam. For safe construction, this pressure should under the present con-
dition of the structure be assumed equal to the full pressure due to tlie head at the
upstream face of the dam, and may be considered as decreasing to zero at the outer
edge of the toe if the toe is properly drained.
In the second place, with the deposition of silt against the dam, as shown by the
investigations of Prof. T. U. Taylor (see Fig. 19, page 49), it is evident that the
pressure due to this deposit must be considered.
1 26 Report on the Dam at Austin, Texas.
These assumptions produce a very different position and angle of the resultant
pressures from that evidently assumed in the original design of the dam, as will be
noted from Fig. 67, page 125. This diagram shows that under these conditions
the resultant pressure falls outside of the middle third of the base, and while this
condition does not necessarily involve failure, it indicates an undue reduction of the
factors of safety and a departure from the principles of present good practice.
In the third place, the rock foundation below the apron and on the east half of
the dam was in such a cracked and fissured condition and probably so interspersed
with clay seams that it was rapidly eroded to a depth below the plane of the founda-
tion of the dam, and the toe of the dam was undermined by the currents produced by
the falling waters. In this manner, the toe resistance of the section of rock and other
material below the toe of the dam was removed, the length of seepageway from
above to below the dam, shortened, and the security of the dam left dependent upon
the frictional resistance, which was quite likely reduced by the seepage which had
developed. The probable coefficient of friction under these conditions was reduced to
perhaps .4 or less, while the tangent of the angle with the resultant with the vertical
was 1.01, and all factors were therefore favorable for disaster.
During the flood of April, 1900, the conditions shown by Fig. 68, page 127 ob-
tained. Under these conditions the resultant passed outside of the effective toe of
the dam, and the tangent of the angle of friction increased to 1.23. It is also prob-
able that a partial vacuum was formed on the lower side of the dam under the sheet
of falling water, which would in effect add to the head above the dam; and under
these conditions, failure resulted.
That the old dam was stable until the resistance was removed from below its toe,
and perhaps until some considerable seepage had developed underneath it, is shown
by the fact that it actually stood for some seven years (from 1893 to 1900). The fact
that its failure was due to the gradual developments of weakness in the foundation
seems established by the fact that the western portion of the dam, where the ma-
terial below the toe was more resistant and was not removed by the impact and en-
ergy of the flood waters (see soundings on pages 101 and 104) still stands, although
some seepage had undoubtedly developed in that section as well. It is nevertheless
true that the section of the old dam even with the rock below the toe intact, has too
low a factor of safety and is in an unsafe condition.
The Use of the Old Section for the Neiv Conditions. — The new conditions, under
which the remaining part of the old dam constitutes about half of the reconstructed
dam, are described by Mr. F. S. Taylor in the Engineering Eecord of May 24, 1915, as
follows :
"In order to get the proper amount of power and lake storage, the water
level would have to be raised from the old elevation of 60 feet to 65 feet above
low water, which meant that with 11 feet of water over the crest during flood,
the maximum water level would be 76 feet above the low water instead of 71
Stability of Old Dam.
127
feet. The portion of the old section which had given way failed under a 71 foot
water level, and it was imperative that the portion of the old section remaining
should not be subjected to as great stress as it had previously withstood. This
required that the maximum water level should never rise even as high as 71 feet
above low water. It appeared as if these two conditions could not be reconciled.
However, after considerable study, a type of crest gates * * * was adopted.
"With this arrangement, the new section of dam was built only 51 feet high
from low water to crest, or 9 feet lower than the old section. The crest gates
WL£t\ mOf
W.L&. I6S.O
66.O'-
Cond/ttons at Time of /9OO Fai/ure
Head Wafer £/eraf/on - /?/ O
To// •• -
We/aht of Si/t per Ca ft - //O. O #
Upward Pressure assumed of- flee/ of Oa/n - fo>/ rfead.
Toa » ' 24 f-ff*
FIGUBE 68 — Force Diagram for Old Dam under
the Conditions at Time of Failure.
Condition of iow Wafer tv/M Gates,
tieod Water £/er at/on • /65 O
Tot/ •• •• 99. 0
SS/t ' Worte
Upward Pressure Assumed at Heef of Dam - /*/// Head
• Toe - •' 5 feet
FIGURE 69 — Force Diagram for Old Dam with
Gates under Low Water Conditions.
on the old section are 6 feet high, and those on the new section, 15 feet, so that
the upper edges of the crest gates are all at the same level, 66 feet above low water.
* * #
"It is estimated that with a discharge of 200,000 second feet, the thickness
of the water over the crest of the new section will be 18 feet, and over the old
section 9 feet. This means that the present dam will pass 50 per cent, more
water than did the old dam when it failed, but the elevation of the water in
only 9 feet above the crest of the old dam, while it was 11 feet above the crest
when the weak section went out in 1900."
Under the new conditions it will be noted that five feet of head are added to the
water behind the old section by the installation of crest gates. It was apparently
128
Report on the Dam at Austin, Texas.
the theory of the design that silt could be kept away from the back of the dam by
the use of sluice gates. It is the opinion of the writer that silt cannot be drawn from
behind the old section by the flow through these sluice gates, and that for safety a
height of silt even greater than that which had accumulated above the old dam at
the time of its destruction should be assumed behind the old section. The old
section has therefore been analyzed for the following conditions, with the results
shown :
1. For no Silt and Low Water Conditions (see Fig. 69, page 127). — The resultant
passes dangerously near the toe of the effective section, and the tangent of the
W.I £/. /69. 0
WL& I65.O
Conditions of Low Wafer with- Gates ana Probable Maximum SiM
r/ead Wafer Elevafion - J65.O
To/7 - . 99.O
Si It ' /45.0
Weight of Sift per Ct/ ft - //O. O*
Upward pressure assumed a/ rfee/ of Pan? - Fu// rfead.
" - • • Toe - >• 5 r~eef.
FIGURE 70 — Force Diagram for Old Dam with
Gates under Low Water Conditions and with
Silt behind the Structure.
Conditions of Ord/narg 9' F/ood over •Spillway with Probable
Maximum 3i/f.
Head Water F/e ration - /69.O
To// " H- - /2a<y
Si/t " - /45.O
Weight of Si/ f per Cu. ft - //O. 0 *
Upward pressure asst/mea1 of r/ee/ of Perm - Fu// Head.
» « Toe • ' 26 riser.
FIGURE 71 — Force Diagram for Old Dam with
Nine Foot Flood over Spillway and with
Probable Maximum Silt.
angle of the resultant is so high (1.09) that only the resistance of the rough bottom
and the abutting rock below the toe will keep it from sliding. This is the condition
which had already obtained when the water was raised to elevation 165, after the
new dam was closed. The fact that it did not fail under these conditions is no
evidence that it was not close to disaster.
2. For Silt and Low Water Conditions (see Fig. 70, page 128). — This analysis
shows that under these assumptions the resultant pressure passes outside of the ef-
Stability of Old Dam.
129
fective toe, and the dam would probably crack the masonry of the apron and tip
over. The deposition of silt would therefore create an extremely hazardous condi-
tion, probably resulting in failure.
3. For Silt With a Nine Foot Flood (see Fig. 71, page 128). — This analysis is
made on the basis of a flood of nine feet over the old dam, as outlined by Mr. Taylor
in the above quotation. Silt pressure is also assumed with the silt surface 15 feet
below the old crest of the dam. This condition is still more hazardous than that
shown in case 2.
W.L.&. I74..p~y
Conditions of Probab/e Max/mc/m f/ood.
Head Wafer &avat/on - /74.O.
Tart . •• J40.O.
Silf •• S/one.
Upward Pressure assumed of /lee/ of Dam - fV// Head.
•• Toe . „
FIGUKE 72 — Force Diagram for Old Dam under Probable Maximum Flood Conditions
and with no Silt.
4. For a Maximum Flood Without Silt. — It is generally conceded that a max-
imum flood may occur which would flow 23 feet deep over the crest of the new
section and 14 feet over the crest of the old section (see Fig. 72, page 129). Even
without any extra pressure due to silt, this condition would be dangerous as the re-
sultant pressure would pass through the effective toe. With silt behind the dam, the
resultant pressure would pass beyond the effective toe of the dam and apparently
assure failure.
In some of the above cases, in which the resultant pressure passes outside of the
middle third of the base width of the dam, analyses will show that the resultant pres-
sures for horizontal divisions of the dam above the base will also pass outside of the
130 Report on the Dam at Austin, Texas.
middle third of the base line of such divisions. It is almost as essential to correct
the section of the dam for these conditions as for the same conditions of the base.
The actual tensile and shearing strength of the masonry, which is ordinarily not con-
sidered in the calculations for such structures, may however be relied upon to de-
velop practically a greater strength than will exist between the masonry and the un-
derlying rock.
The assumptions made in these analyses are in no sense extreme and are no
greater than good practice requires or than the writer would assume were he con-
sidering the dam for his own use.
The Reinforced Concrete Structure. — It has already been noted (see page 67)
that the width of the new dam as originally specified was reduced from 125'9" to 93'
on the detailed plans submitted in May, 1912, and approved by Dr. Scott, without
the knowledge of the City Council of the reduction made. It is apparent, however,
that under the terms of the contract, such knowledge or consent of the City Council
was not necessary, provided the stability of the structure was not impaired. The
reasons for reducing the width of the dam are set forth by Mr. F. S. Taylor, in the
Engineering Record of May 29, 1915, as follows:
"Owing to the difficult character of the foundation, * * * it was desirable
to make the distance through the bottom of the dam, measured from upstream to
downstream side, as short as possible. In the usual form of design the inclined
deck goes up to the elevation of the crest of the dam, where it joins with the
spillway. The form of the spillway is determined by the application of the or-
dinary parabolic formula, and this gives a certain distance, measured horizon-
tally, from the crest of the spillway down to its toe. As shown in the typical sec-
tion, the spillway was designed in accordance with the usual method, and the
sloping deck made to intersect it at some 25 feet farther downstream and 6 feet
lower vertically than in the customary design. By this method a proper length
of theoretically designed spillway was made available, as well as an inclined deck
of substantially the total height up to the spillway, and, at the same time, the
length through the dam from front to back was reduced about 25 feet, diminish-
ing in like proportion the length of the transverse walls, the length of each trans-
verse wall foundation, and eliminating one longitudinal wall. While the saving
in material and labor, due to this form of design, for a given factor of safety,
was greatly reduced by the adoption of this design, the cost of the form work was
increased so that the net saving effected, though considerable, was not so great
as would at first appear."
Foundation Pressures. — The foundation pressures under the new structure are
regarded as dangerous with the exposed condition of the strata below the toe of the
dam, but entirely safe if the foundation rock is rendered stable by proper protection
below the toe. The writer is unable to understand why the difficulties of the foun-
Seepage.
FIGUBE 73 — Pervious Strata at Entrance to Walsh's Slough.
FIGURE 74 — Broken Section of Original Dam Showing Pervious Nature of Masonry.
^^"''•j i i « '
• Report on the Dam at Austin, Texas.
FIGURE 75 — Arrangement of Foundation Walls and Sluiceways of New Dam.
FIGURE 7G — Foundation Rock for Mats in Front of Sluiceways.
Reinforced Concrete Dam. 1 33
dation made it desirable to narrow the width of the dam section (as stated by Mr.
Taylor in the above quotation). The cheapening of the cost of construction is a more
obvious explanation.
The weight of the dam and the water pressure on the upstream deck were re-
duced somewhat by the change in design ; and the resultant pressure, due to the com-
bined forces acting on the dam, intersects the horizontal at a less angle in the new
section than in the original design (see Fig. 6, page 18), thereby increasing slightly
its tendency to slide on the foundation, or for the foundation to slide on the clay
seams which are known to exist beneath the structure. However, the effect of this
change is regarded as of little consequence so far as the stability of the structure is
concerned, and if the dam constructed on the original lines could be considered safe
under the other conditions of construction, the new design would be considered
practically as safe. The change in the width of the dam is considered as quite in-
significant as compared with other and more serious defects in the design and con-
struction of the dam.
The clay seams under the foundation and the trench in the rock below the toe
create a real danger of sliding, and the writer regards either the old or the new de-
sign as unsafe under the foundation conditions as they now exist.
Hollow Dam Section. — As already noted (principle 6, page 116), the foundation
of a dam must be practically impervious, or the dam must be so designed that any
seepage water will be forced to travel such a distance that its erosive power will be
consumed in friction before it discharges below the dam.
The advantages of a hollow dam, in obviating upward pressure on the dam base,
as stated by Mr. Taylor (see page 117), are largely imaginary. If the foundation is
pervious, and its upper four or six feet are by construction rendered tight; the up-
ward pressure will be exerted on the foundation rock so tightened. If the founda-
tion is pervious, the cutoff wall (in this case about 30 inches wide) is all that divides
the tail water from the head water, and the line of friction resistance is too short.
If the new section had been made solid, it is probable that it would not be leak-
ing at this time, and although it might be subject to upward pressure at the point
where the leak has now developed, and possibly at many other points, it would still
be safe if designed for such conditions, and it would have afforded a resistance to
the travel of seepage water 70 or more feet in width instead of 30 inches.
Design of Reinforced Concrete in the Reinforced Concrete Dam Section. — A typi-
cal section of the new reinforced concrete dam is shown by Fig. 6, page 18. Two
views showing the arrangement of the foundation walls, sluiceway arched roofs and
the sluiceway protecting mats during construction are shown in Figs. 75 and 76, page
132. The following is taken from the article by Frank S. Taylor in the Engineering
News of June 3, 1915, and indicates the basis of design :
"As indicated, it (the new dam section) is a reinfo reed-concrete structure,
having an inclined upstream wall, making an angle of 42° to the horizontal. At
1 34 Report on the Dam at Austin, Texas.
a point about 2y2 feet above low water level, this slope of the wall ends, inter-
secting a narrow horizontal bench, and from the upstream edge of this bench a
vertical wall goes straight down into the rock and forms both the lower por-
tion of the deck and the cutoff wall.
"The object of the bench is to allow flow of water through any completed
section of the dam during construction, the flat horizontal slab, which runs the
entire length of the dam and covers the upper part of the bench, being omitted
until the completion of the work. Normally, during construction the total flow
of the river was taken through the sluice gates in the bottom of the dam, but
during floods the openings through the horizontal bench, together with the area
afforded by the sluice gates, would usually take care of the whole river flow,
with an elevation in the water level of not more than 4 to 6 ft.
"The supporting walls are both longitudinal and transverse. The latter
are parallel to the flow of the stream and are 20 feet apart. The longitudinal
walls are also 20 feet apart, measured from center to center in a direction at
right angles to them, and are inclined at an angle of nearly 90° with the up-
stream deck. Their slope is such that the resultant of the forces which they re-
sist, made up of the water pressure acting against the surface of the deck and
the gravity component of the deck and the walls themselves, has the same direc-
tion as that of the longitudinal walls. The longitudinal and transverse support-
ing walls intersect at right angles and form a series of square openings when
viewed in a direction normal to the deck in which the reinforcing steel is placed
both longitudinally across the length of the dam and transversely up and down
the deck, the bars being laid closer and closer together as they get nearer and
nearer to the middle of each panel.
"All of the steel used was rerolled twisted bars having an elastic limit
above 55,000 Ibs. The stresses allowed in the steel were 16,500 Ibs. per sq. in.
maximum.
"An ample number of expansion joints is provided in the new concrete dam,
every fifth panel being an expansion panel. There are 28 panels in all. The ex-
pansion panels have both the upstream deck and the spillway entirely separated
from the adjacent portions of deck and spillway on either side of it. A joint is
made between the two abutting edges of the concrete slabs, which is water-
tight, but which permits lateral movement of the different sections of the dam
without diminishing the tightness of the joint or rupturing any of the masonry.
This joint is made of 'ingot-iron' plate, y2 x 8 inches. One-half the width of the
strip is cast into the concrete of the abutting edge of a standard panel. This
leaves 4 in. of metal projecting out from the surface of the end of the panel.
The end of the slab, together with the projecting iron, is painted with a heavy
coat of asphalt. The expansion panel is then cast so that its edge abuts against
the edge of the slab of the standard panel. Since its construction the dam has
Reinforced Concrete Dam. 1 35
been subjected to temperatures varying from 32 to 90°. and these expansion
joints have proved thoroughly satisfactory. Before construction was quite
completed and when the whole of the dam was still exposed to the sun and at-
mospheric conditions, it was possible to see the space between the abutting ends
of the panels at expansion joints change more than 14 inch in a few hours. ' '
From an examination of the detailed drawings (C-9 to C-17), it does not appear
that the expansion joints were uniformly placed, one for each five panels, but that
a spacing of one in five, six and seven panels respectively was used.
The drawings further indicate that all of the steel reinforcement in the up-
stream deck consists of %" square bars. The bars near the upper side of the slab
for the bottom, middle and top inclined decks were spaced about 13-inch centers at
the center of the slab, the spacing of the rods increasing toward the supports. The
rods near the lower side of the slab are spaced at 7, 7y2 and 8 inch centers respec-
tively for the bottom, middle and top decks; the spacing applying to the center of
the slab and uniformly increasing toward the supports. The slabs were reinforced
essentially equally in both directions.
In estimating the stress to which the steel is subjected as per size and spacing
shown on the detailed drawings, the loads on the slabs for the bottom deck have
been calculated with the water level at elevation 165. For the loads on the middle
and the top decks, the head water has been taken at elevation 174 and the tail water
at elevation 128. The conditions above will give the maximum loading for the slabs
in each of the three decks. Any extra loading on the deck on account of silt has not
been considered, but it has been assumed that any accumulation of silt immediately
above and adjacent to the reinforced structure can be removed through the sluice
gates.
In the analysis of the stresses to which the steel will be subjected due to the
loading, the recommendations laid down by the Joint Committee on Reinforced Con-
crete have been followed : That is, in the case of continuous beams supported on 45°
brackets, the end of the beam may be taken to be that point where the depth of beam
and bracket equals one-third more than that of the beam. In the case under con-
sideration, viz : the slab forming the upstream deck of the dam, the span length is
taken at 15 feet 4 inches. The actual distribution of the bending moment and there-
fore of the stress is uncertain, and not capable of rigid mathematical analysis. On
the basis of the most logical assumptions, it is believed that the stress in the steel
over the supports may equal but would not exceed 23,000 pounds per square inch.
At the center of the slab, the stress would not exceed 19,000 pounds per square inch.
Considering the character of reinforcing steel used, and the form of the slabs,
it is believed that the structure is safe so far as the strength of the reinforced con-
crete is concerned, although the stresses are somewhat higher than is said to have
been used as a basis of design, and somewhat higher than the writer would consider
as good practice.
1 36 Report on the Dam at Austin, Texas.
Appurtenances. — The appurtenances furnished with the reconstruction are in
general of the cheapest class that could be utilized for each specific purpose.
Sluice Gates. — The original design for the sluice gates showed that the hydrau-
lic cylinders by which the gates can be operated were to be placed on the inside of
the dam where they would be accessible for adjustment, maintenance and repair.
(See A Fig. 7, page 72). The cylinders were, however, actually placed on the up-
stream face of the dam. (See B Fig. 7, page 22 and Fig. 77, page 137.) Mr. F. S.
Taylor, in his article in the Engineering Record, previously referred to, comments on
this change in plans as follows :
"It is to be noted that the cylinders are placed on the deck of the dam instead
of inside, as is customary. In this way the cylinders could be placed much
nearer the sluice gates than if they were inside the dam, and the sluice gates out-
side. This shortens the piston rod, and thus a smaller rod may be used. This
means that the size of the cylinders may be somewhat reduced. Furthermore,
the saving in concrete and form work amounted to some $5,000. Moreover, not
having any inset made in it, the dam is stronger than it would otherwise be.
"This method of installation has the apparent objection that the cylinders
cannot be inspected or repaired, as they are normally under 60 feet of water.
This objection, the designers feel, is an academic one. The extent of opera-
tion of these gates will never be sufficient, in many years, for the element of wear
to have any bearing on the subject. An ordinary Corliss engine, in two hours,
will make more strokes than these cylinders will in fifty years. Metallic pack-
ing is provided so that it is permanent and not subject to deterioration with time,
as most organic substances would be. The pistons are of bronze, so that there
is not the least danger of them sticking or rusting to the interior of the cylin-
ders, and this is further prevented by the cylinders being constantly filled with
oil."
The cylinders in these gates are so small that they have to be operated under
very heavy pressures, and the probability that they will need occasional attention is
quite obvious. After the plant is placed in operation, the emptying of the reservoir
(which must necessarily be done under low water conditions) will involve in each
instance a power loss equal to that which could be generated by the water it will take
to fill it. This is estimated as equal to about 2,000,000,000 cubic feet with 65-foot
head, and to about 1,300,000,000 cubic feet with a 60-foot head. If power is valued
at .9c per horse power hour, the loss caused by the emptying of the reservoir would
be approximately $21,000 with the 65-foot head and $14,000 with the 60-foot head,
for each time the reservoir is emptied to repair the gates or hydraulic cylinders. This
can hardly be called an academic question, and the saving of $5,000 to the City
Water Power Company at such an ultimate inconvenience and expense in the opera-
tion of the plant, is a short sighted policy which should not have been adopted.
Appurtenances.
137
FIGURE 77 — Sluice Gates and Cylinders on Deck of Dam, Gates raised.
FIGURE 78— Accumulation of Drift above the Dam during Flood of September, 1915.
138
Report on the Dam at Austin, Texas.
FIGURE 79 — Accumulation of Drift above the Dam during Flood of September, 1915.
FIGUEE 80 — Drift obstructing Gateways during Flood of September, 1915.
Appurtenances. 1 39
The design of the gate itself is quite as defective as the arrangement of the hy-
draulic cylinders. The bronze strips attached to the face of the gates and to the gate
frames, are % inch in thickness and are designed to be held in place by countersunk
screws. These strips are so light and narow that they cannot be held in place under
the heavy friction of operation, and are now in such bad condition that some of the
gates are leaking badly.
No racks or other protection has been provided for these gates, and water-log-
ged drift has been and will be drawn into them, preventing their closing and their ef-
ficient operation,
Crest Gates. — It is unnecessary to comment at length on the crest gates, as they
have already demonstrated their inadequacy for the conditions at the dam. The
gates are of a light flimsy construction and of entirely inadequate design for a drift
bearing stream. The swelling of forms and the rough concrete work on the gate
piers render it impossible to secure tightness and free action, both of which are es-
sential for such gates.
The gates, swinging in the current, offer a material obstruction to the flood flow
and especially to the heavy drift which is borne by the Colorado. (See Figs. 78, 79 and
80, pages 137 and 138.)
Tail Race. — The specifications for the tail race are quoted in paragraphs 30 and
31 on pages 64. These requirements have not been carried out. Apparently
the discharge from the draft tubes is throttled by a face of rock close in front of them.
The temporary raceway provided is practically filled at various points between the
power house and the river, and every flood will add to the obstruction from the
pile of debris which lies just north of the raceway. (See Figs. 8 and 9, page 25.)
Passageway in Dam. — A plank walk, supported on wooden joists, is provided
through the dam in the interior of the reinforced concrete structure. The decay,
caused by the saturated air in the dam, has already weakened the structure so that it
sags badly, and this walk will have to be replaced for safety within a very brief
period. A gas pipe railing is provided along each side of this walk. This railing has
never been painted and is rapidly corroding ; it will soon be destroyed unless some
attention is given to its preservation.
Railing on Dam. — The railing along the platform on top of the dam is incom-
plete. No railing had been provided or apparently planned from the top of the dam
along the retaining wall to the building. This location is one which sightseers are
apt to visit in order to view the structure, and its unprotected condition is a source
of danger. (See Figs. 9 and 46, pages 26 and 99.)
Head Gate Masonry. — The masonry of the head gate is said by Mr. Posey to leak
considerably whenever the reservoir is filled. As the writer has not personally had
an opportunity to observe this condition, he is unable to say how serious this
matter may become.
140 Report on the Dam at Austin, Texas.
Head Gate Racks. — The original racks installed in front of the head gates are
shown on Construction Drawing F-31. They were built of bars 14" thick, spaced
1%" apart. They were about 10 feet in length and their curved tops, which reached
about one foot above the penstock entrance, were so arranged as to leave an open-
ing about 5" wide and 10 feet long in front of each penstock. As the racks were
deeply submerged, drift readily entered the penstocks from over the racks and
caused considerable breakage of the turbine gates during their brief operation. The
Engineers of the City insisted on a change in the design of the racks, and the new
racks were built with their tops well above ordinary water level, and with a free
opening between the 14" bars of only %". This arrangement, while preventing an
inflow of drift, screens even the finer material from the water and throttles the inflow
to the turbines.
Head Gate Hoists. — The head gate hoists (see Fig. 81, page 141) installed on this
work, are of a cheap type which are seldom used except on small country mill head
gates. On any first class plant the head gate hoists should be of such design that the
gates may be moved rapidly and easily into position, and the best practice would
warrant the use of a hoist electrically as well as hand operated.
Penstocks and Draft Tubes. — The penstocks and draft tubes have been con-
structed mainly from the old material used in the original (1890-93) construction
(see Fig. 14, page 43). The various elbows and bonds are of new material. The pen-
stocks outside of the power house have been reinforced with concrete and are ap-
parently in fair condition, although no examination was possible under service. The
draft tubes are placed in such an exposed position that they are liable to injury from
floating drift during every flood (see Figs. 8 and 9, page 25). They are said to
have leaked air so badly at the time the turbines were tested that they were re-
calked, and finally rendered fairly tight with Portland cement. The north draft
tube has been twisted somewhat out of place, apparently by drift.
Station Equipment. — The station equipment was not examined in great detail,
and no conditions in the station were noted where serious criticism is warranted.
The machinery appears to be in fairly good condition. No definite statement can
be made concerning its character without a more detailed examination under oper-
ating conditions. The machinery has been standing idle for almost two years and
has undoubtedly depreciated to an extent quite equal to two years of active opera-
tion.
Transmission Line. — The wooden pole line, as far as examined, seemed to be in
fairly satisfactory condition ; but the wooden strain towers built to take the stress of
the outgoing lines adjacent to the station (see Figs. 82 and 83, pages 141 and 142)
are an objectionable and unworkmanlike construction which should not have been per-
mitted.
Pumps. — The centrifugal pumps furnished under the contract were found to have
a capacity of about 4,000,000 gallons ; and in order to fulfill the contract, a third pump
of similar capacity was, by agreement with the City Council, furnished by the con-
Appurtenances.
141
FIGUKE 81 — Headgate Hoists.
. •
FIGURE 82 — Power House showing objectionable appearance of Strain Tower of Transmission Line.
142
Report on the Dam at Austin, Texas.
FIGURE 83 — Wooden Strain Tower at Power House Entrance.
Reservoir. 1 43
tractor. Two of these pumps have been erected in the main pumping station, while
the third one was erected in the north pumping station. This pump was connected to
the discharge main by a line of flange pipe and fittings 30 feet or more in length.
This connection, the writer was advised, was when erected some 6 or 8 inches out of
line but was strained into position and the bolts duly tightened. Since its connec-
tion, due to the initial strains caused by this lack of alignment, and perhaps by the
shock and jar due to the operation of the plant, this pipe has broken down, breaking
the discharge flange from the pump and making it necessary to send this unit to the
shops for repair.
The writer also examined one of the pumps which had been dismantled, in the
main pumping station, and found that it is so badly cut by the sand drawn up with
the water supply as to render it practically useless without material repair.
The bearings on all of these pumps are said to heat badly during operation.
Reservoir. — The ten-million gallon reinforced concrete reservoir, furnished un-
der the contract, has now been in service for several years and has apparently given
satisfaction. It seems well built but is of exceedingly light construction. It can
probably be maintained without any undue expense. This reservoir is uncovered,
and the waters are exposed to dust and sunlight. These conditions will give rise to
algae growth in the impounded waters and will cause an unsatisfactory condition of
the water during the summer months, which can be remedied only by emptying the
reservoir and carefully cleaning it as often as the condition becomes sufficiently un-
satisfactory, unless a roof is provided to shut out the dust and sunlight.
APPENDIX 6
A STUDY OF THE STREAM FLOW OF THE COLORADO RIVER AND THE PROBABLE AMOUNT OF
POWER THAT CAN BE DEVELOPED AT THE AUSTIN DAM WITH A COMPARISON OF THE
RELATIVE VALUES OF 65 AND 60 FOOT HEADS
The amount of power that can be developed under various conditions of head
and flow is an important element in the problem of the rehabilitation of this plant.
It is therefore essential to examine this matter in considerable detail.
Stream Flow Data. — The flow of the Colorado is of primary importance in
power development at this plant, and much study has been given to its determina-
tion. The U. S. Geological Survey began to make stream flow observations on the
Colorado at Austin in 1896, but accurate detailed data covering the period before
February, 1898 have not been obtained. For the years 1912 and 1913, no observa-
tions were made by the Geological Survey, but gage readings by the U. S. Weather
Bureau are available.
The sources of stream flow data used in this report are as follows :
No. of Water Supply For
Paper TJ. S. G. S. Page Year
28 124 1898
37 274 1899
50 337 1900
66 64 1901
84 151 1902
99 335 1903
132 38 1904
174 25 1905
210 38 1906
288 29 1907
288 29 1908
288 30 1909
288 30 1910
308 16 1911
Stream Flow Data. 145
No. of Water Supply For
Paper U. S. G. S. Page Year
•Weather Bureau 1912
Weather Bureau 1913
Weather Bureau 1914 (Jan. 1— Sept. 30)
408 18 1914 (Oct. 1— Dec. 31)
408 18 1915 (Jan. 1— Sept. 30)
438 30 1915 (Oct. 1— Dec. 31)
438 30 1916 (Jan. 1— Sept. 30)
**Blue Print 1916 (Sept. 30— Dec. 31)
Blue Print 1917 (Jan. 1— July 19)
While the flow of the stream for most of the years considered has been calcu-
lated and published in the Water Supply Papers named above, it was considered de-
sirable to check the computations in the light of the later flow data which are now
available. A general view of the entire series of observations has led to the con-
clusion that some of the published calculations are somewhat in error, and many of
the earlier discharges have been recalculated in order to give a more accurate basis
for power calculations. These recalculations in detail, together with a discussion of
the basis on which they have been made, with the rating curves used in the computa-
tions, have been furnished to the City of Austin in manuscript form.
In general, these calculations have reduced those given in the published tables,
especially for mean and minimum flow conditions, as will be noted from the follow-
ing comparisons:
COMPARISON OF PUBLISHED RECORDS AND THOSE COMPUTED FOR AUSTIN DAM
Maximum Minimum Yearly Mean
Year Published Report Published Report Published Report
1902 31,250 34,200 180 178 2,224 2,290
1903 33,070 33,100 320 336 2,157 2,120
1904 46,140 29,300 200 147 1,595 1,470
1905 51,190 48,100 175 175 1,918 1,880
1906 70,300 64,400 175 153 3,060 2,950
*From "Gauge Heights" Published by the U. S. Weather Bureau.
**From Blue Print Data furnished by Mr. Glenn A. Gray, District Engineer,
Water Resources Branch, U. S. G. S.
1 46 Report on the Dam at Austin, Texas.
Some of the data used are of such a nature that the results may be somewhat in
error; but in general it is believed that a fair degree of accuracy has been attained.
The reliability of records is regarded as follows:
(By low water is meant a discharge of less than 500 sec. ft.)
Feb. 15, 1898 — June 7, 1899. Low water records reliable.
June 8, 1899— Sept. 20, 1900. Low water records (below 400 sec. ft.) doubtful.
This affects only the low water period of Sept. 1 — Oct. 27.
Sept. 27, 1900— July 12, 1901. Low water records reliable.
July 13, 1901 — Dec. 31, 1901. Low water records reliable.
Jan. 1, 1902 — March 12, 1902. Low water records somewhat doubtful. Should
perhaps be 10 per cent, lower.
Mar. 13, 1902— Feb. 26, 1903. Low water records reliable.
Feb. 27, 1903— Oct. 4, 1903. Low water records somewhat doubtful.
Oct. 5, 1903— April 23, 1904. Low water records reliable. (From Apr. 5-23
should perhaps be 10-15 per cent, higher.)
Apr. 24, 1904 — Oct. 31, 1904. Low water records fairly reliable.
Nov. 1, 1904 — May 8,. 1905. Low water records reliable.
May 9, 1905 — Oct. 9, 1905. Low water records reliable (perhaps somewhat low).
Oct. 10, 1905 — Aug. 11, 1906. Low water records fairly reliable.
Aug. 12, 1907 — Apr. 23, 1908. Low water records doubtful. (Flow perhaps
more rather than less than estimated.)
Apr. 24, 1908— May 21, 1910. Low water records doubtful.
May 21, 1910 — Sept. 9, 1910. Low water records reliable.
Sept. 8, 1910 — May 9, 1913. Low water records doubtful.
May 9, 1913 — Oct. 1, 1914. Low water records doubtful.
Oct. 1, 1914— Sept. 1, 1917. Eecords reliable.
Hydro graphs Based on the Calculations of Stream Flow. — Hydrographs have
been platted which by the height of an irregular flow line above a horizontal base line
show graphically the varying flow of the stream from day to day. As only a small
portion of the high water flow can be utilized for power purposes, the hydrographs
have been drawn to such a scale that the low water flow is clearly shown, while the
high water flow falls above the diagrams and cannot be determined therefrom. Flood
flows are not, however, essential for the purpose of power calculations, except in the
calculations for the available stored supply.
Power Possibilities Determined from Hydrographs. — The hydrographs, showing
the river discharge from day to day will also indicate the power which can be de-
veloped from day to day from this flow with a given head. If the flow needed to de-
velop a given power is determined, a comparison of the power demand with the flow
Storage. 1 47
indicated by the hydrograph will show whether or not there was sufficient water
from day to day to deliver the amount of power considered. When the flow line of
the hydrograph falls below the power line, the diagram shows that the flow for the
day or days so indicated was not sufficient to furnish the amount of power consid-
ered unless the deficiency could have been supplied from the stored water above the
dam.
Storage Above the Dam. — The determination of the amount of storage above
the dam is complicated by the fact that no accurate surveys are available from
which such storage can be determined. Furthermore, if such surveys were avail-
able, the storage would gradually be decreased by the silting up of the reservoir as
occurred from 1893 to 1900. (See page 49.)
The area of the reservoir above the dam is estimated at about 3000 acres at ele-
vation 165, and at about 2000 acres at elevation 160. From the shape of the basin,
the capacity between elevations 165 and 160 is estimated at 690,000,000 cubic feet,
and by drawing the reservoir down 10 feet additional or to elevation 150, an added
storage of a similar amount is estimated as available for power purposes. It is
further estimated that there is an additional capacity of about 620,000,000 cubic feet
below elevation 150 not available for power purposes and which will ultimately be
filled with silt. The total capacity of the reservoir at the present time is therefore
about 2,000,000,000 cubic feet, 1,300,000,000 cubic feet of which would be available
with 65 foot head and only 690,000,000 cubic feet of which would be available if a
head of 60 feet was utilized.
As some of the pondage will undoubtedly be destroyed by the silting of the res-
ervoir, the effect due to a decrease in capacity as follows, has also been considered:
Capacity between 165 and 160 500,000,000 cu. ft. *
Capacity between 160 and 150 500,000,000 cu. ft.
Capacity below 150 .. 250,000,000 cu. ft.
Total Capacity 1,250,000,000 cu. ft.
Modification of HydrograpJis Toy Storage. — In using hydrograph for power cal-
culations, the area below the power line and above the flow line of the hydrograph,
showing a deficiency in the flow of the river for power purposes, so far as power es-
timates are concerned, can be considered as filled from the reservoir, provided the
reservoir is full and to the extent that the flood flow refills the reservoir.
Deductions from the Flow at the Congress Avenue Bridge. — The hydrographs
used are based on flow observations at the Congress Avenue bridge, as previously
noted. The flow at this point is augmented by the flow of Barton Creek and by the
seepage around and below the dam, neither of which would be available for power.
In addition to these losses, there will be a certain evaporation from the entire sur-
face of the lake which is estimated to average 25 cubic feet per second with the res-
ervoir elevation at 165. From the above it will appear that there must be certain
148 Report on the Dam at Austin, Texas.
deductions from the flow shown by the hydrographs before the remainder can be con-
sidered as available for power. These deductions have been estimated as follows :
Barton Creek 15 cu. ft. per second
Seepage 90 cu. ft. per second
Evaporation 25 cu. ft. per second
Total Deductions 130 cu. ft. per second
Graphical Representation. — In each hydrograph these deductions have been in-
dicated by the double diagonal cross hatching at the base of the hydrograph and sub-
tracted from the total flow, to determine the amount of water available for power. On
these hydrographs the available river flow is indicated by cross hatch lines inclined
upward to the right. The deficiency in the river flow from time to time that can be
supplied by the water stored in the reservoir is indicated by cross hatch lines in-
clined downward to the right. The amount of power that cannot be supplied from
water storage but must be supplied by steam, if supplied at all, is indicated by hori-
zontal and vertical cross hatching. From a a study of these hydrographs from month
to month and from year to year, the available power of the river for each year has
been estimated.
Power Demand. — The total output of the City's electric plant in 1916 was about
4,000,000 kilowatt hours or 5,330,000 horse power hours, and the steam used in pump-
ing would probably increase this to about 7,300,000 HPH or practically to the mini-
mum amount of power guaranteed under the Johnson contract. If the hydraulic
power at the dam can be safely assured, the power demands at Austin will undoubt-
edly increase and a consumption of at least double the present demands may be ex-
pected within a few years ; and with the rapid growth of Austin, the utilization of
the entire capacity of the plant can be expected within a short term of years.
Power Calculations. — Based on the above consideration, the various amounts of
power available under heads of 60 and 65 feet, and under various power demands,
have been calculated. It should be noted that these calculations have been made
with a slide rule, and in some cases the results will not check within about one per
cent. The degree of accuracy, however, is greater than the probable accuracy of the
stream flow data.
Study of Minimum Power of 830 Horse Power or 600,000 Horse Power Hours
Per Month of 30 Days. — A study of the hydrographs indicates that with a 65-foot
head and under the assumption made above, the minimum guaranteed power of
600,000 HPH per month or 7,200,000 HPH per year (see paragraph 11, page 59)
could have been maintained continuously throughout the period considered, namely
from February, 1898 to September, 1917.
With a head of 60 feet the same amount of power could have been maintained
Power Calculations. 149
during the same period except for certain years when shortages would have occur-
red as follows :
Year Shortage In Horse Power Hours
1905 66,600
1907 778,000
1910 158,000
1911 124,500
1917 396,000
Total 1,523,100
Average for 19y2 years 78,200 HPH
Average value of power loss per annum, due to reduction
of head from 65' to 60', at .9c per horse power hour . . . $704.00
Study of the Development of 1650 Continuous Horse Power. — The possibilities
of power development at the dam have also been investigated for a continuous out-
put of 1650 horse power for both 60 and 65 foot heads, and the amount of steam
power necessary to maintain this rate of output has been estimated.
Development of 1650 Horse Power Under 65 Foot Head. — The condition of the
development of 1650 horse power under 65 foot head, and the necessary steam power
to maintain this output during low water conditions, are shown on the hydrographs
on pages 150, 151 and 152. The estimates made from these hydrographs are also
shown in detail on page 153.
Development of 1650 Horse Power under 60 Foot Head. — Under 60 foot head the
reduction in pondage necessitates an increase in the auxiliary steam power neces-
sary to sustain the output as will be seen by an examination of the series of hydro-
graphs on pages 154, 155 and 156, and of the detailed estimates on page 157.
Comparison of 65 and 60 Foot Heads for the Development of 1650 Continuous
Horse Power. — Abstracting the tables for 65 and 60 foot heads, it is found that the
amounts of power which would be developed by water and by steam under the con-
ditions assumed will be as follows :
The total horse power hours per year at 1650 continuous horse power are
14,500,000.
HPH Water HPH Steam
Average at 60 Ft. Head 12,921,000 1,617,000
Average at 65 Ft. Head 13,980,000 598,000
Average Annual Difference in Amount of Steam Power Used. . . .1,019,000 HPH
Average Annual Value at 0.9c per Horse Power Hour $9,171.00
It is apparent that if the interest on first cost, maintenance cost and depreciation
of the crest gates is materially less than $9,171 per annum, it will pay to maintain the
50
Report on the Dam at Austin, Texas.
/65O
200
Seepage , Evaporation ancr r/otv of Sarron So
XXXXXXXXXXXXXXXXXXXXXK X
/65O
320
zoo
January February March f)pri/ May June
Of
Juty
September Ocfo&tr November December
Stream F/oiv.
Seepaae, efc.
FlQUEE 84.
Fbfiataae.
Power Calculations.
151
K45
78S
epoqf, evaporation ana/ r~/o>v of oarfon Sprmq
Seepage, Evaporation and f~/o>r of Barfon Sprino
- x x X Xix X x x x vXi*. KX x x* v x" K x
January
eefafrona of rtijdrou/fc RaMrr. fohefooe and necessary 0vxi'//ary Sfron
rr fo Moi"t>'"' ffSO Continuous fforst foirrr under 6JS f&ff Head.
Seepage, etc.
fbndyqe-
ffltxit/crry Steam.
FlGUBE 85.
52
Report on the Dam at Austin, Texas.
S/orn
1650
/Z45
735
320
1650
4l?0
zoo
y////.
Teenage, Evaporation and f/ovr
lL*.^X-^^.>i>.tXXXAXX*lxXA
19/4
>650 |
,245 \
320
0
ZOO
&I6
/650
#45
780
31O
O
Sce/xige, Evaporation ono' f~/o>v of Barfoi*
\ \ i
Spring.
January February rJarc/i
t
fff>r/7 May June Ju/y &uyusS- September October
firveoseaPr/s or cct-oe&oo G/VF& ar fojsr/tj, Texas.
fjptver fo rfo/frfo/n S65O Gpn/rwotjs fforsf ftonvr under ffS feet fleacr1.
November December.
'//////////
X>VVVVVVVVV
^$$^$
Sef/ooye. etc.
fftfxt/i'aro Stean
FlQUBE 86.
Power Calculations.
153
Showing the amount of hydraulic power, in thousands of horse power hours, which could have been
delivered with a 65 foot head by the Austin hydraulic power plant at the switchboard, and the amount of
steam power necessary to maintain 1650 continuous horse power during the years 1898 to 1917, inclusive.
Year
Jan.
Feb.
Mch.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
Annual
Hydraulic
1 235
1 1%
1 235
1,196
1,235
1,235
1,196
1,235
971
1 004
11 738
189S
Steam
o
o
o
0
0
o
o
o
225
231
456
Total
1,235
1,196
1,235
1,196
1,235
1,235
1,196
1,235
1,1%
1,235
12,194
Hvdraulic
994
906
995
1,041
1,235
1,196
1,235
1,235
1,196
1,235
1,1%
1,235
13, 699
1899
Steam
241
211
240
155
0
0
0
0
0
0
0
o
847
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,196
1,235
1,196
1,235
13, 546
Hydraulic
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,196
1,235
1,1%
1,235
14,546
1900
Steam
0
o
0
0
0
0
0
0
0
0
0
0
0
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,196
1,235
14,546
Hydraulic
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,196
1,235
14,546
19O1
Steam
0
o
o
0
0
0
0
0
0
0
0
o
0
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14,546
Plydraulic
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14, 546
1902
Steam
0
0
0
o
o
0
0
0
0
0
0
0
0
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,196
1,235
14, 546
Hydraulic
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14,546
1903
Steam
0
o
0
0
0
0
0
0
0
0
0
0
0
Total
1,235
1,117
1,235
1, 193
1,235
1,196
1,235
1,235
1,1%
1,235
1,196
1,235
14,546
Hydraulic
1 235
1 156
1 235
1 196
1 235
1,196
1,235
1, 235
1,196
1,235
1,196
1,235
14,585
19O4
Steam
0
0
0
0
0
0
0
0
0
0
0
0
0
Total
1,235
1,156
1,235
1,196
1,235
1,196
1,235
1,235
1,196
1,235
1,196
1,235
14,585
Hydraulic
1,235
1,117
1 235
1 196
1,235
1,1%
1,235
1,226
1,187
1,235
1,057
865
14, 019
1905
Steam
0
0
0
0
o
0
0
9
9
0
139
370
527
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14,546
Hydraulic ....
875
802
914
1,196
1,235
1,196
1,235
1,235
1,196
1,235
1,196
1,235
13,550
1906
Steam
360
315
321
0
0
0
0
0
0
0
0
0
996
Total
1,235
1,117
1,235
1 196
1 235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14,546
Hydraulic
720
645
710
706
1 162
1,196
1,230
1,191
1,162
1,235
1,196
1,235
12,388
1907
Steam
515
472
525
490
73
0
5
44
34
0
0
0
2,158
Total
1,235
1,117
1,235
1,196
1 235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14,546
Hydraulic
1,235
1,156
1 235
1 196
1 235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,071
14,421
1008
Steam
0
0
0
o
o
0
0
0
0
0
0
164
164
Total
1 235
1 156
1 235
1 196
1 235
1,196
1,235
1,235
1,196
1,235
1,196
1,235
14,585
Hydraulic
976
867
961
937
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
13,504
1909
Steam
259
250
274
259
o
0
0
0
0
0
0
0
1,042
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14,546
Hydraulic
1,235
1,117
1,235
1,196
1,235
1,066
1,090
1,090
1,133
1,148
836
846
13,227
1910
Steam
0
o
0
0
0
130
145
145
63
87
360
389
1,319
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14,546
Hydraulic
851
935
1,235
1,196
1,235
1,196
1,235
1,235
1,196
1,220
1,181
1,230
13,945
1911
Steam
384
182
0
0
0
0
0
0
0
15
15
5
601
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14, 546
Hydraulic
1 235
1 156
1,235
1 196
1,235
1,196
1,235
1,235
1,196
1,235
981
3.004
14,139
1912
Steam
0
0
0
0
0
0
0
0
0
0
215
231
446
Total
1,235
1,156
1,235
1,196
1,235
1,196
1,235
1,235
1,196
1,235
1,196
1,235
14,585
Hydraulic
1 038
931
1,024
1,013
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
13,769
1913
Steam
197
186
211
183
0
0
0
0
0
0
0
0
777
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14,546
Hydraulic
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,196
1,235
14,546
1914
Steam
0
0
0
0
0
0
0
0
0
0
0
0
0
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14, 546
Hydraulic
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,196
1,235
14,546
1915
Steam
0
0
0
0
0
0
0
0
0
0
0
0
0
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
1,1%
1,235
1,1%
1,235
14, 546
Hydraulic
1,235
1,156
1,235
1,196
1,235
1,196
1,235
1,235
1,196
1,235
927
928
14,009
1916
0
0
0
0
0
0
0
0
0
0
269
307
576
Total
1,235
1,156
1,235
1,196
1,235
1,196
1,235
1,235
1,196
1,235
1,196
1,235
14,585
80S
1 091
1 196
1 048
980
7,898
QA7
298
144
o
187
255
1,776
Total
1,235
1,117
1,235
1,196
1,235
1,196
1,235
1,235
9.674
Total
21, 202
19,475
22, 822
22,535
24,483
23,790
24,363
24, 247
22,618
23,363
21,501
21,768
272,157
Hyd'ic
Period
19
19
20
20
20
20
20
20
19
19
19
19
19.6
Average
1,116
1,024
1,141
1,127
1,224
1,189
1,218
1,212
1,190
1,230
1,131
1,146
13, 980
Total
2,263
1,894
1,878
1,385
217
130
337
453
106
102
1,223
1,697
11,685
Steam
Period
19
19
20
20
20
20
20
20
19
19
19
19
19.5
Average
119
100
94
69
11
7
17
23
6
5
65
89
598
Hydraulic
Steam
1,116
119
1,024
100
1,141
94
1,127
69
1,224
11
1.189
7
1,218
17
1,212
23
1,190
6
1,230
5
1,131
65
1,146
89
13,980
598
Total
1,235
1,124
1,235
1,196
1,235
1.196
1,235
1,235
1,196
1,235
1,196
1,235
14, 578
t Hydraulic ..
Steam
90.4
9.6
91.1
8.9
92.4
7.6
94.2
5.8
99.1
0.9
99.4
0.6
98.6
1.4
98.1
1.9
99.5
0.5
99.6
0.4
94.6
5.4
92.8
7.2
95.9
4.1
154
Report on the Dam at Austin, Texas.
320
* <3OO
POO
600
4OQ
200
400
ZOO
600
.fc ZOO
eoo
4OO
:'^^^ -^88888^ 888^8 88888^
Seepage, frojooraf/ov onaf f/oir of Sorfon Spring
•-
(s <o
February Marcri
ffream r7&>*
May
June Ju/if
Sepfember October Movemiier December
or
ofrofta of rftfCfrovt'o f&vrtr, ftonc/oy* ortcf nece*9on/ Gt*e//f&ry Sfeom
to My/ri 'for'fr /6SO Gyr>tiinv0u9 Horye Power (/rraffr 60 feef ffeao1
Serjoaye. era.
FlGUBE 87.
ary 3 f earn
Power Calculations.
55
too
/650
•$ 600
I
ZOO
6OO
4OO
ZOO
400
zoo
, '//////, Y/////, W////, Y////// 7/77 //,
Seepage, evaporation and f/ov of 3arfon Spring)
< XXXXAx1>Ay\y^xNXXX XXXXXXXXAAXXXX
K///A Y//////AY/////Y/////M
eepage, Eva/oorartofr and f/of of Barfon Spring
>(XXxW^vV .AAAXXX*. X
Seepage, Fvapo/~cr//of? and F/ow of Sarfon 5pr
Y///////////S
Seepage, Cvaporafion crnal f/oir of Barfon Spring.
k '
Seepage, ^aporof/on ana> f/o» Of Barton Spring
September October November December
January february March ffpri/
32O
ring ff*/ationa of Hya'rou/'c Reiver, f&ndaae and necessary 0vxi//ary Sfeon?
Power to sfainfoin /f£0 Confihvota fforae nurtr under 60 fee/ Mead.
FIGURE 88.
56
Report on the Dam at Austin, Texas.
6OO
400
eoo
1918
/650
IZ4S
706
320
O
Sf
«**•• fya'
yorat/on or*
•
* /%>»• of 0
7
January February
ffjsri/ Mat/ */u/?ff •jfc'/y fft/qu&t 3e/?Aes??6er 0G/06er Mere/rro*/- 0ecem£*er.
OF COIO2APO &/V&2 0T avST/Nt
'ona'a&e arrd rtfCf-Ayffr-y &u*/
ffor&e &0>*w (Sf*c/fr 00 feef
Ponc/ay*.
FlGUBE 89,
Power Calculations.
157
Showing the amount of hydraulic power, in thousands of horse power hours, which could have been
delivered with a 60 foot head by the Austin hydraulic power plant at the switchboard, and the amount of
steam power necessary to maintain 1650 continuous horse power during the years 1898 to 1917, inclusive.
Year
Jan.
Feb.
Men.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
Annual
Hydraulic
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,076
765
757
11,116
1898
0
0
0
0
0
0
0
158
429
477
1,064
Total
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
12,180
Hydraulic
748
673
757
880
1,234
1,194
1,234
1,040
832
908
1,194
1,234
11,928
1S99
Steam
486
442
477
314
0
0
0
194
362
326
0
0
2,601
Total
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14, 529
Hydraulic ....
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14, 529
190O
0
o
0
0
0
0
0
0
0
0
0
0
0
Total
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14, 529
Hydraulic
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14,529
1901
Steam
0
0
0
0
0
0
0
0
0
0
0
0
0
Total
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14,523
Hydraulic ....
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14,529
1902
Steam
0
0
0
0
0
0
0
0
0
0
0
0
0
Total
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14,529
Hydraulic
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,110
1,075
14,286
1903
0
0
0
0
0
0
0
0
0
0
84
159
243
Total
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14,529
Hydraulic
1,101
1,025
1,102
1,098
1,234
1,194
1,234
1,234
1,194
1,234
1,083
1,058
13,791
1904
133
127
132
96
0
0
0 .
0
0
0
111
176
775
Total
1,234
1,115
1,234
1,194
1^.234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14,566
1,043
944
1,186
1,194
1 234
1,194
1,234
1,172
1,129
1,234
956
583
13,108
1905
Steam
191
171
48
0
0
0
0
62
65
0
238
646
1,421
Total
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,23'
l,19i
1,234
1,194
1,234
14,529
Hydraulic
575
514
659
1,159
1,234
1,194
1,234
1,234
1,194
1,141
1,070
1,186
12,394
1906
Steam
659
601
575
35
0
0
0
0
0
93
124
48
2,135
Total
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14, 529
455
395
437
430
1,110
1,194
1,221
743
614
1,234
1,194
1,234
10,261
1907
Steam
779
720
797
764
124
0
13
491
580
0
0
0
4,268
Total
1,234
1,115
1,234
1,194
1,233
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14, 529
1 234
1,152
1,234
1,194
1, 234
1,104
1,234
1,234
1,194
1,234
1,194
996
14,328
1908
Steam
0
0
0
0
0
0
0
0
0
0
0
238
238
Total
1,234
1,152
1,234
1,194
1,234
1,194
1,234
1,23'
1,194
1,234
1,194
1,234
14,566
Hydraulic
721
567
617
633
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
12,290
1909
513
548
617
561
0
-Q
0
0
0
0
0
0
2,239
Total
1 234
1 115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14,529
Hydraulic
1,004
881
987
1,194
1, 234
765
730
730
1,003
1,062
543
530
10, 667
1910
Steam
230
230
247
0
0
429
504
504
191
172
651
704
3,862
Total
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14,529
Hydraulic
531
787
1,234
1,194
1,097
756
995
1,234
1,194
818
694
1,013
11,547
1911
Steam •
703
328
0
0
137
438
239
0
0
416
500
221
2,982
Total
1,234
1,115
1,234
1,194
1,234
1.194
1,234
1,23'
1,194
1,234
1,194
1,224
14,429
Hydraulic
1,102
1,073
1,234
1,194
1,234
1,194
933
916
880
1,070
788
801
12,419
1912
132
79
0
0
0
0
301
318
314
164
406
433
2,147
Total
1 234
1,152
1,234
1,194
1,234
1,194
1,234
1,23'
1,194
1,234
1,194
1,234
14,566
Hydraulic
801
731
810
804
1,234
1.194
1,190
983
1,061
1,234
1,194
1,234
12,470
1913
Steam
433
384
424
390
0
0
44
251
13?
0
0
0
2,059
Total
1 234
1 115
1,234
1,194
1,234
1,194
1,234
1,23'
1,194
1,234
1,194
1,234
14,529
Hydraulic
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14,529
1914
Steam
0
0
0
0
0
0
0
0
0
0
0
0
0
Total
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,23'
1,194
1,23'
1,194
1,234
14,529
Hydraulic
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14,529
1915
Steam
0
0
0
• 0
0
0
0
0
0
0
0
0
0
Total
1,234
1,115
1,234
1,194
1,234
1,194
1,234
1,23'
1,19<
1,23'
1,194
1,234
14,529
Hydraulic
1,234
1,152
1,234
1,194
1,234
1,194
1,225
900
867
1,026
752
708
12,720
1916
Steam
0
0
0
0
0
0
9
33'
327
208
442
526
1,846
Total
1 234
1 152
1,234
1,194
1,234
1,194
1,234
1,23'
1,194
1,23'
1,194
1,234
14,566
717
647
712
690
1 000
1,194
650
374
5 974
1917
Steam
517
468
522
504
234
0
584
860
3,689
Total
1 234
1 115
1 234
1 194
1,234
1,194
1,234
1,234
9,663
Total
18,670
17,235
20, 841
21,21)6
24, 185
23, 013
22,986
21, 666
20,714
21,909
19,701
19, 818
251, 954
Hyd'ic
Period
19
19
20
20
20
20
20
20
19
13
19
19
19.5
983
906
1,042
1,061
1,209
1,151
1,149
1,084
1,090
1,153
1,037
1,043
12,921
Total
4,776
4,098
3,839
2,664
495
867
1,694
3,014
1,972
1,537
2,985
3,628
31,569
Steam
Period
19
19
20
20
20
20
20
20
IS
IS
19
19
19.5
Average
251
215
192
133
25
43
85
150
104
81
157
191
1,617
Hydraulic
Steam
983
251
906
215
1,042
192
1,061
133
1,209
25
1,151
43
1,149
85
1,084
150
1,090
104
1,153
81
1,037
157
1,043
191
12,921
1,617
Total
1 234
1 121
1 234
1 194
1,234
1,194
1,234
1,234
1,194
1,234
1,194
1,234
14,538
t Hydraulic ..
Steam
79.7
20.3
80.8
19.2
84.5
15.5
88.8
11.2
98.0
2.0
96.4
3.6
93.1
6.9
87.8
12.2
91.3
8.7
93.4
6.6
86.8
13.2
84.5
15.5
88.9
11.1
1 58 Report on the Dam at Austin, Texas.
head at 65 rather than at 60 feet with a development of 1650 horse power, but that if
the annual cost is equal to or greater than this amount, there will be no logical rea-
son for the increased head.
Interest should be taken at 5 per cent. The annual cost of maintenance and the
depreciation of such gates can hardly be taken at less than 10 per cent. The capi-
talized annual saving due to a 65-foot head may therefore be estimated on a 15 per
cent, basis at $61,140. To this should be added the cost of raising the crest to eleva-
tion 160 feet, which is estimated at $53,000, making a total of $114,140, which is the
maximum that can be expended to advantage for increasing the head from 60 to 65
feet, with a capacity of 1650 horse power.
Study of the Development of 3300 Continuous Horse Power. — The ultimate de-
velopment of the power plant at the Austin dam as now designed anticipates the
output of 3300 horse power. This condition has also been investigated for both 65
and 60 foot heads.
Development of 3300 Horse Power Under 65 Foot Head. — The conditions that
will obtain under a 65-foot development and a continuous output of 3300 horse power
are shown on pages 159 to 163 inclusive, and the detailed estimates are shown on page
164.
Development of 3300 Horse Power Under 60 Foot Head. — The same studies for a
60-foot development are shown on pages 165 to 169 inclusive, and the detailed esti-
mates are shown on page 170.
Comparison of 65 and 60 Foot Heads for the Development of 3300 Continuous
Horse Power. — Abstracting the table for 65 and 60 foot heads, the total horse power
hours per year are found to be approximately 29,200,000, and the comparisons to be
as follows:
HPH Water HPH Steam
Average at 60 Foot Head 21,300,000 7,900,000
Average at 65 Foot Head 23,290,000 5,650,000
Average Annual Difference in Amount of Steam Power Used . . . 2,2 50,000 HPH
Average Annual Value of Steam Power at 0.9c per Horse Power
Hour $20,250.00
With interest at 5 per cent, and depreciation and maintenance at 10 per cent, the
capitalized value of the extra 5-foot head is essentially $135,000. To this, for com-
parison, should be added the cost of removing piers and building up the hollow sec-
tion to 60 feet, amounting to $53,000, and making the total difference in favor of the
65 foot dam $188,000, which is the total amount which can now be expended to secure
the extra 5-foot head. To make the 65-foot head profitable, the expense should be less
than the amount named as with this expenditure the returns would equal only the
estimated annual expense.
Power Calculations.
159
850
350
January February March ffpri/ May Ju,
Sep/ember October A/ore/nber December
e/vee #T flusr/N, Texas.
Sfream f/on-.
e. efc- Pondoqe
FlQUBE 90.
y S/eym.
160
Report on the Dam at Austin, Texas.
Setfioae. Evaporation and f/o# of Sorton Spring.
350
January • fetwary Marcri ffpr/'J May June Ju/tf fiuo/us/ Sepfffntef' Ocfo&er Movembtr
Of
Seepage, tfo.
FlQUBE 91.
Power Calculations.
161
3300
Z35O
I860
850
350
January February March ffpri/ May June July august September October November Cecemder
OF COLOgfiPO e/V££ ffr ffUST/M,
Onrtno getatioru of fftfafrais/fc Power. Poncfage &*& neccasory Gux/'/t'ary
Po#er fo M0/'rjfa'/r> 33O0 Corrfinuoos fforse Pother vna/er C5 ffffff Sfeao.
Sfreom F/o>v. 3ec.?J?f. efo. POncfaye
FIGURE 92.
162
Report on the Dam at Austin, Texas.
§.'000
zoo
8OO
600
4OO
850
350
January Fttwi/orij rlorcn 0pri/
September October November December
_ „ 0/vre ar ausr/N, Tfxas.
Sftoirinq Ke/attoru of Hyc/roulic Ftonrer, Ponctaqe or>& necessary av*i/iory Steart
Power to Maintain 33OO Continuous Hone Po*tr urx/tr fi feet Mead
Stream rtov
3ee/aaiff. rfc
avxi//onf Steam
FlQUBE 93.
Power Calculations.
163
3300
^lOOO
SOO
4OO
January February
flpri/ May June Ji/ty
of coweapo
n33OO
Sepfember Ocfoder Movem&er December
FIGURE 94.
164
Report on the Dam at Austin, Texas.
Showing the amount of hydraulic power, in thousands of horse power hours, which could have been
delivered with a 65 foot head by the Austin hydraulic power plant at the switchboard, and the amount of
steam power necessary to maintain 3300 continuous horse power during the years 1898 to 1917, inclusive.
Year
Jan.
Feb.
Men.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
Annual
Hydraulic
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
2,160
295
2,455
2,455
0
2,455
2,455
0
2,455
2,417
38
2,455
2.10S
347
2,455
2,161
294
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
2,762
693
2,455
2,37:
0
2,375
2,375
0
2,375
2,375
0
2,375
2,37
0
2,37
2,37
0
2,37
2,37
0
2,375
2,375
0
2,375
2,37a
0
2,375
2,375
0
2,375
2,375
0
2,375
2,375
0
2,375
2,375
0
2,375
1,089
1,286
2,375
1,352
1,023
2,456
0
2,45
2,45
0
2,45
2,455
0
2,45
2,455
0
2,455
2,45
0
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
2,267
188
2,455
2,455
0
2,455
2,455
0
2,455
1,100
1,355
2,455
1,802
653
2,455
1,322
1,133
2,455
1,955
500
2,455
2,455
0
2,455
2,455
0
2,455
1,850
605
2,455
1,355
1,100
2,455
2,45
0
2,455
1,48
96
2,45
2,45
0
2,45
2,455
0
2,455
2,45
0
2,455
2,455
0
2,455
2,455
0
2,455
1,951
2,375
0
2,375
1,248
1,127
2,375
2,375
0
2,375
2,375
0
2,375
2,375
0
2,375
2,375
0
2,375
2,375
0
2,375
1,616
759
2,375
2,375
0
2,375
1,208
1,167
2,375
2,375
0
2,375
2,375
0
2,375
1,430
945
2,375
1,982
393
2,375
1,257
1,118
2,375
2,063
307
2,375
2,375
0
2,375
2,375
0
2,375
1,295
1,080
2,375
1,230
1,22
2,45
1,47
98
2,455
2,45
0
2,45
2,45
0
2,455
2,455
0
2,455
2,176
27
2,455
2,455
0
2,455
1,677
778
2,455
1,855
600
2,455
2 311
97
1,40
2,37
2,37
0
2,37
2,37
0
2,37
2,15
22
2,37
2,37
0
2,37
1,419
958
996
1,458
2,455
2,455
0
2,455
2,455
0
2,455
1,802
653
2,455
2,455
0
2,455
1,455
1,000
2,455
1 QOQ
15,311
4,089
19, 400
20, 642
8,263
28.905
28, 905
0
28,905
28,027
878
28, 905
27, 377
1,528
28, 905
26, 670
2,235
28,905
23,109
5,871
28, 980
21,517
7,388
28,905
21,666
7,239
28, 905
19,071
9,834
28, 905
26, 538
2,442
28,980
22,902
6,003
28,905
17,191
11,714
28, 905
20.992
7,913
28,905
18,982
10,098
28,980
21,810
7,095
28,905
28,905
0
28,905
28,905
0
28,905
21,628
7,352
28,980
10,038
9,207
19,245
1898 Steam
; Total
' Hydraulic
995
1,460
2,455
2,455
0
2,455
2,455
0
2,455
1,801
654
2,455
2,455
0
2,455
1,383
1,072
2,455
1,400
1,055
2,455
750
1,705
2,455
698
1,757
2,455
2,348
107
2,455
914
1,541
2,455
1,413
1,042
2,455
835
1,620
2,455
1,781
674
2,455
1,027
1,428
2,455
2,455
0
2,455
2,455
0
2,455
2,311
144
2,455
928
1,527
2,455
898
1,322
2,220
2,220
0
2,220
2,220
0
2,220
1,643
577
2,220
2,220
0
2,220
1,282
1 013
l.OOC
1,45
2,45
2,456
0
2.4K
2,455
0
2,455
2,177
278
2,455
2,455
0
2,455
1,383
1,072
2,455
1,937
518
2,455
818
1,637
2,455
707
1,748
2,455
2,345
110
2,455
865
1,590
2,455
1,418
1,037
2,455
2,455
0
2,455
1,777
678
2,455
1,027
1,428
2,455
2,455
0
2,455
2,455
0
2,455
2,267
1?8
2,455
923
1,532
2,455
1,42
95
2,37
2,37
0
2,37
2,37
0
2,375
2,356
18
2,375
2,375
0
2,375
1,578
797
2,375
2,375
0
2,375
1,680
695
2,375
6SO
1,695
2,375
2,327
48
2,375
945
1,430
2,375
2,375
0
2,375
2,375
0
2,375
2,040
335
2,375
1,085
1,290
2,375
2,375
0
2,375
2,375
0
2,375
2,375
0
2,375
887
1,488
2,375
1809 Steam
Total
Hydraulic
1900 Steam
Total
Hydraulic
1901 Steam
Total
Hydraulic
1902 Steam
Total
i Hydraulic
1903 Steam
Total
Hydraulic
1,520
855
2,375
1,257
1,11
2,375
1,665
710
2,375
2,375
0
2,375
1,737
638
2,375
2,375
0
2,375
1,550
825
2,375
1,165
1,210
2,375
970
1,405
2,375
2,375
0
2,375
2,375
0
2,375
2,375
0
2,375
965
1,410
2,375
1904 Steam
1,062
2,455
755
1,700
2,455
2,100
355
2,455
2,455
0
2,455
1,003
1,452
2,455
2,455
0
2,455
855
1,600
2,455
1,858
597
2,455
1,023
1,432
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
928
1,527
2,455
; Total
2,295
1,264
956
2,220
683
1,537
2,220
635
1,585
2,220
2,208
87
2,295
778
1,442
2,220
1,295
924
2,220
1,355
865
2,220
1,670
625
2,295
933
1,287
2,220
2,220
0
2,220
2,220
0
2,220
2,165
130
2,295
837
1,383
2,220
Hydraulic
1905 Steam
504
2,455
2,455
0
2,455
1,200
1,255
2,455
2,455
0
2,455
2,455
0
2,455
1,096
1,359
2,455
2,455
0
2,455
1,397
1,158
2,455
1,600
855
2,455
2,455
0
2,455
2,455
0
2,455
1,354
1,101
2,455
971
1,484
2,455
Total
Hydraulic
1906 Steam
Total
Hydraulic
1907 Steam
144
Total
2,455
2,455
0
2,455
2,455
0
2,455
1,152
1,303
2,455
1,250
1,205
2,455
1,622
833
2,455
2,455
0
2,455
2,455
0
2,455
2,455
0
2,455
1,719
736
2,455
Hydraulic
1908 Steam
Total
' Hydraulic
1909 Steam
Total
Hydraulic
1910 Steam
Total
Hydraulic
1911 Steam
Total
2,375
1,962
413
2,375
2,375
0
2,375
2,375
0
2,375
2,375
0
2,375
1,944
431
2,375
2,375
0
2,375
1 Hydraulic ....
1912 Steam
Total
Hydraulic
1913 Steam
Total
Hydraulic
1914 Steam
Total
Hydraulic
1915 Steam
Total
' Hydraulic
1916 Steam
Total
Hydraulic
1917 Steam
Total
Total
30, 859
19
1,623
15,786
19
832
1,623
832
2,455
66.1
33.9
28,746
19
1,513
13,733
19
723
1,513
723
2,236
67.6
32.4
33, 374
19
1,757
13,271
19
698
1,757
698
2,455
71.5
28.5
36,377
19
1,915
8,748
19
460
1,915
460
2,375
80.6
19.4
47,433
20
2,372
1,667
20
83
2,372
83
2,455
96.6
3.4
44,347
20
2,217
3,153
20
158
2,217
158
2,375
93.3
6.7
43,566
20
2,178
5,534
20
277
2,178
277
2,455
88.7
11.3
40, 517
20
2,026
8,683
20
434
2,026
434
2,460
82.3
17.7
38, 229
19
2,012
6,896
19
363
2,012
363
2,375
84.7
15.3
38,561
19
2,029
8,084
19
426
2,029
426
2,455
82.6
17.4
34,368
19
1,808
10,757
19
567
1,808
567
2,375
76.1
23.9
33,808
19
1,779
12,837
19
676
1,779
676
2,455
72.4
27.6
450,185
19,333
23,290
109,149
19,333
5,650
23,290
5,650
28, 940
80.5
19.5
Hyd'c Period
' Average
| Total
Ste'm Period
Average
1 Hydraulic
i Total
I % Hydraulic —
i % Steam
Power Calculations.
165
Seepage, Evaporation ancf /"Sow of Borfcm Spring
Septemtw October SS0i/emt>er Oecemtier
January
Stream f/prr.
Sffpoar, ere.
FIGURE 95.
166
Report on the Dam at Austin, Texas.
1200
Y//////////
Y///Y//////////////////,
Y/W//////////,
735
At/aus/ September Oc/oeer
or coweaoo eiYte tfrrJusr/N, Texas.
fr/afior>f -of rfyctroo/ic fbirrr, fbniSoor and ntcessoru 0u*i'//or<f Jfa
*er * Maintain 3300 Cont/'nuout ftonc Potvtr unc/tr eo reef r/ead.
Seepage. «fe. ftortofaife ^Box/Vary aftara
FlGUBE 96.
Power Calculations.
167
Seepage. Fya/oorof/ort and f~/o*r of Sarfon Sprint}
Ju/y ffuyuar Sep/embtr Of/ooer S/ovemticr Becember
February tjffrc*> ffprit May
-TS5
miiy eefaftor*3 of rtyctraut/c tforrfr. Penc/aqrr one? fteceasortf GtsMtttory Sffa
PQ~rr to rloinfoin 33OO CQnftnvOv^ ' fforsc Poirer an&er 6O reer Heoc/,
See/serge, ete. forto/ayf ffvf/7/ary Sfrar*.
FlQUBE 97.
168
Report on the Dam at Austin, Texas.
SttOHrmy &*/a*i0n6 of flydratstic &O"*', Poic/ay* or>& "rcessory **vxf"ary j
Pother fo /*fo*s>fQ/r7 330O Cont»?vOu3 Morse f*ower under €0 feet rteact.
rtcfo?* as>& r>*ce&sortj 0tSJ(i//'ortf $fifo
Seepage, efc
"ana/age
Power Calculations.
169
February March April May June Ju/y
3ef>f-emi>er October JVovemter Oecemhtr
winq Gelations of rtyCfrauhc Power, Forrdotfe ana/ r>ecf&3ori/ 0tfjr/t/arrc/ J
Power fff -rto-infairt 33OO Corrfirtvoua rforje Porver uncftr 60 feet r/faot
Seepage, efc. Pyno/aqe OuxWarif Sftam,
FlGUEE 99.
170
Report on the Darn at Austin, Texas.
Showing the amount of hydraulic power, in thousands of horse power hours, which could have been
delivered with a 60 foot head by the Austin hydraulic power plant, at the switchboard, and the amount of
steam power necessary to maintain 3300 continuous horse power during the years 1898 to 1917, inclusive.
Year
Jan.
Feb.
Mch.
Apr.
May
June
July
Aug.
Sept.
Oct.
Nov.
Dec.
Annual
Hydraulic
1,134
1,878
2,480
2,400
2,230
1,945
2,020
1,140
764
764
16 755
1898
Steam
1,346
522
0
0
250
535
380
1 340
1 636
1 716
7 795
Total
2,480
2,400
2,480
2,400
2,480
2,480
2,400
2,480
2,400
2 480
24 480
Hydraulic
750
697
754
1,275
2,480
2,400
2,480
1,193
880
1,044
2,320
2 480
18 753
1899
Steam
1 730
1,543
1,726
1,125
0
0
0
1,287
1,520
1 436
80
0
10 447
Total
2,480
2,240
2,480
2,400
2,480
2,400
2,480
2,480
2,400
2,480
2,400
2 480
29 200
Hydraulic
2,480
2,240
2,480
2,400
2,480
2,400
2,480
2,480
2,400
2,480
2 400
2 480
29 200
19OO
Steam
0
0
0
0
0
0
0
0
o
o
o
o
o
Total
2,480
2,240
2,480
2,400
2,480
2,400
2,480
2,480
2,400
2,480
2,400
2 480
29 200
Hydraulic
2,480
2,240
2,480
2,400
2,480
2,016
2,165
1,935
2,080
1 802
1 906
1 417
25 401
1901
Steam
0
0
0
0
0
384
315
545
320
678
494
1 063
3 799
Total
2,480
2,240
2,480
2,400
2,480
2,400
2,480
2,480
2,400
2,480
2 400
2 480
29 200
1902
Hydraulic
Steam
1,432
1,048
1,275
965
1,898
582
2,300
100
2,480
0
2,072
328
2,480
0
2,480
o
2,400
o
2,076
404
1,823
577
2,480
o
25,106
4 004
Total
2 480
2,240
2,480
2,400
2,480
2,400
2,480
2 480
2 400
2 480
2 400
2 480
29 200
Hydraulic
2,480
2,240
2,480
2,400
2,480
2,400
2,480
2,352
2 295
2 126
1 126
1 080
25 939
1903
Steam
0
0
0
0
0
0
c
128
105
354
1 274
1 400
3 261
Total
2,480
2,240
2,480
2,400
2,480
2,400
2,480
2,480
2,400
2,480
2 400
2 480
29 200
1904
Hydraulic
Steam
1,087
1,393
1,050
1,270
1,126
1,354
1,432
968
2,480
0
2,400
0
2,440
40
2,240
240
2,355
45
2,480
0
1,260
1,140
1,060
1 420
21. 410
7 870
Total
2,480
2,320
2,480
2,400
2,480
2,400
2,480
2,480
2,400
2,480
2 400
2 480
29 280
1905
Hydraulic
Steam
1,043
1,437
955
1,285
1,850
630
2,400
0
2,480
0
2,400
0
2,480
0
1,637
843
1,282
1 118
1,544
936
1,278
1 122
570
1 910
19, 919
9 281
Total
2,480
2,240
2,480
2,400
2,480
2,400
2,480
2,480
2,400
2 480
2 400
2 480
29 200
1906
Hydraulic
Steam
627
1,853
560
1,680
685
1,795
1,600
800
2,080
400
2,400
0
2,480
0
2,480
0
2,400
0
1,418
1,062
1,075
1 325
1,900
580
19, 705
9 495
Total
2,480
2,240
2,480
2,400
2,480
2,400
2,480
2,480
2 400
2 480
2 400
2 480
29 200
1907
Hydraulic
Steam
460
2,020
390
1,850
440
2,040
428
1,972
2,129
351
2,400
0
2,280
200
743
1,737
640
1,760
2,310
170
2,400
0
2,458
22
17,078
12 122
Total
2 480
2,24
2,480
2,400
2,480
2,400
2,480
2,480
2,400
2,480
2,400
2 480
29 200
1908
Hydraulic
Steam
1,910
570
1,84
480
1,855
625
2,115
285
2,480
0
2,400
0
2,480
0
2,480
0
2,400
0
2,480
0
1,605
795
775
1,705
24,820
4 460
Total
2 480
2,32
2,48
2,400
2,480
2,400
2,480
2,480
2,400
2,480
2,400
2,480
29 280
190
Hydraulic
Steam
610
1,870
56
1,68
625
1,855
710
1,690
2,480
0
2,400
0
2,480
0
2,46
13
2,360
4
2,480
0
2,400
0
2,480
0
22,052
7,148
Total
2,480
2,24
2,48
2,400
2,480
2,400
2,480
2,480
2,400
2,480
2,400
2,480
29, 200
191
Hydraulic
Steam
1,013
1 467
883
1,35
97
1,507
2,320
8
2,267
213
77
1,624
742
1,738
73
1,744
1,28
1,112
1,070
1,410
527
1,873
533
1,947
13, 128
16, 072
Total
2,48
2,24
2,48
2,400
2,480
2,400
2,48
2,48
2,400
2,480
2,400
2,48
29,200
191
Hydraulic
Steam
51
1,96
1,17
1,06
1,97
50
2,32
7
1,952
528
77
1,62
1,48
994
2,31
16
1,94
453
826
1,65
69
1,707
1,62
855
17,609
11, 591
Total
2,48
2,24
2,48
2,400
2,480
2,400
2,48
2,48
2,400
2,480
2,400
2,48
29,200
191
Hydraulic
Steam
1,104
1,37
1,230
1,090
1,58
89
1,87
52
1,946
534
1,66
73
95
1,53
89
1,58
865
1,53
1,410
1,07
77
1,62
79
1,68
15, 095
14,185
Total
2 48
2,32
2,48
2,400
2,480
2,400
2,480
2,48
2,400
2,48
2,400
2,48
29,280
191
Hydraulic
Steam
804
1,67
72
1,512
80
1,67
87
1,52
2,480
0
2,400
0
1,73
74
1,52
95
1,81
58
2,48
0
2,400
0
2,48
0
20,528
8,672
Total
2,48
2,24
2,48
2,400
2,480
2,400
2,48
2,48
2,400
2,48
2,400
2,480
29,200
191
Hydraulic
Steam
2,48
0
2.24C
0
2,48
0
2.400
0
2,480
0
2,400
0
2,48
0
2,48
0
2,400
0
2,48
0
2,400
0
1,860
62
28,580
620
Total
2,48
2,24
2,48
2,400
2,480
2,400
2,48
2,48
2,40
2,48
2,40
2,48
29,200
191
Hydraulic
Steam
2,480
0
2,06(
18
2,48
0
2,400
0
2,480
0
1,98
41
2,48
'0
2,480
0
2,400
0
2,18
29
1,89
506
2,165
31
27,488
1,712
Total
2,48
2 24
2,48
2,400
2,480
2,40
2,48
2,48
2,4(
2,48
2,400
2,480
29,200
191
Hydraulic
Steam
2, 05S
4&
1,76
53
1,59
88?
2,40(1
0
2,480
0
1,823
57
1,70
780
89
1,59
86
1,54
1,44
1,03
74
1,654
71
1,76
18,471
10,809
Total
2,48
2,32
2,48(
2.40C
2,480
2,4(
2,48
2,48
2,4(
2,48
2.40C
2.48C
29,280
2 40C
92
36C
8,101
1 79
R9S
o
1 55
" I •
11,339
24Qfl
2 40C
2 48
2,48
19,440
Hydraulic ....
Steam
l,39r
1,08,
1,30"
95.
1,52
9b
1,831
56
2,237
143
2,11
28
2,07
40
1,80"
67
1,84
55
1,85
62
1,56
83
1,58
89(
21,300
7,920
Total
2,48
2,251
2,48
2,4<X
2,480
2,40i
2,48
2,48
2,4<X
2,48
2.40C
8
29, 220
% Hydraulic
% Steam
56.
43.
57
42
61
38
76.
23.
94.2
5.8
88.
11.
83.
16.
72.
27.
76.
23.
74.
25.
65.
34.
63.
36.
72.9
27.1
Power Calculations.
71
too
80
60
4O
?0
0
100
80
60
/6SO CONTINUOUS HORSE: POWER UNDER 6O FEET HEAD
1893 J899 /900 1901 I9O2 /9O3 /9O4 I9OS 1906 1907 19O8 /909 I9IO 191 / /9I2 /9I3 /9/4 1915 1916 1917
\
I
80
\
40
30
0
100
80
60
40
20
4O
60
80
100
/65O CONTINUOUS HORSE POWER UNDER 65 FEET HEAD
J898 /899 J900J9O/ 1902 1903 1904 /905 1906 1907 1908 1909 1910 191 / 1912 1913 1914 1915 /9I6 1917
330O CONTINUOUS HORSE POWER UNDER 6O FEET HEAD
1898 1899 1900 1901 1902 /903 1904 /905 /906 / 907 1908 1909 19/O 1911 I9IZ J9/3 /9/4 19/5 1916 /9/7
3300 CONTINUOUS HORSE POWER UNDER 65 FEET
1898 /899 1900 1301 1902 1903 1904- /905 1906 I9O7 I908I9O9I9IO 1911 I9IZ 1913 1914 19(5 1916 1917
4O
80
100
60
80
FIGURE 100— Graphical Comparison of Relative Percentages of Hydraulic and Steam
Power to Develop 1650 and 3300 Continuous Horse Power at 60 and 65 Foot Heads.
1 72 Report on the Dam at Austin, Texas.
As a final graphical comparison, the relative percentages of hydraulic and steam
power necessary to develop 1650 continuous horse power under 65 and 60 foot
heads, and for each year from 1898 to 1917, are shown in Fig. 100, page 171.
A similiar comparison for 65 and 60 foot heads and for 3300 continuous horse
power is shown also by these diagrams (Fig. 100).
Effect of Smaller Storage. — Estimates have also been made to determine the ef-
fect of the smaller reservoir capacity mentioned above, and it has been estimated
that for a development of 1650 horse power, the smaller storage would decrease the
hydraulic power about 2.07 per cent for a 60-foot head and about 2.37 per cent, for
a 65-foot head. For 3300 horse power, the reduction in storage would decrease the
hydraulic power about 2.89 per cent, for a 60-foot head, and about 3.01 per cent, for
a 65-foot head. The reduction would, therefore, in both cases be more favorable to
the 60-foot head, but is in any event only a small factor.
Reduction of Evaporation and Seepage. — It should also be noted that the re-
duction of the crest from 65 to 60 feet will not only reduce the storage capacity, but
also the reservoir areas. The reduction of the reservoir area from 3000 to 2000
acres will reduce the evaporation essentially in proportion to the reduction in area.
The reduction in head will also decrease to some extent the leakage at the dam. For
these reasons the estimates above are believed to be more than fair to the 65-foot
head.
Variations in Load. — It should be noted, in connection with these calculations,
that the use of power by the City is not on a uniform continuous load, as would be
indicated by the above calculations, but varies somewhat from month to month, and
to a great degree from day to day and from hour to hour. The hourly and daily
variations can, however, be equalized by the reservoir without modifying the above
calculations. The actual monthly variations which will occur may modify some-
what the proportion and amount of steam and hydraulic power that would be avail-
ble to supply the demand. These modifications, however, would not seriously affect
the comparison of the relative values of 60 and 65 foot heads, and the above esti-
mates are therefore believed to be approximately correct.
APPENDIX 7
CREST GATES FOR THE AUSTIN DAM
Conditions of Installation. — In the flood of September, 1915, the vast network of
drift that accumulated behind the Austin dam is said to have occupied an area of
several acres, and the writer is advised that it came down the river near the crest of
the flood matted together and in almost a single extensive raft. It had apparently
collected for a considerable period in the shallow waters above the pond, or possibly
in the still waters of the pond itself, where there was insufficient current and depth
for flotation. From these points the flood waters dislodged it and carried it down-
stream until it was stopped by the gate piers of the dam. This great mass of drift
apparently accumulated to a thickness of 20 feet or more next to the dam where the
pressure of the water from behind and the resistance of the dam in front, forced
submergence of the front of the raft and the piling up of the material behind. See
Figs. 10 and 11, page 26 and Figs. 78, 79 and 80, pages 137 and 138.
The writer believes that it is impracticable to construct any crest gates in the
Austin dam which will pass without great difficulty such great masses of drift as
came down with the flood of September, 1915 ; and that no gates can be made to work
successfully without the use of drift barriers at the upper limits of the reservoir.
Such barriers would be expensive to construct and maintain, and without such bar-
riers there will be a large expense at each great flood for handling drift. The con-
struction and maintenance of gates will therefore be an expensive matter irrespec-
tive of their design.
From the information available it appears that the destruction of the gates
which were installed on the dam was due not so much to drift as to light construc-
tion, stiffness of action on account of methods of stanching, and to the inertia result-
ing from the opening of the gates at considerable stages of flow.
To secure adequate service, even with much less drift, stronger gates are needed
to stand the great flood flows and the debris. Such gates must also be longer :
1st. To eliminate as many of the gate piers as practicable in order to pass
drift even in small quantities.
2d. To eliminate leakage by the reduction of the number of free gate ends
and to make the friction due to stanching only a minor factor in the operation of
the gates.
To accomplish these objects, it will be necessary to remove at least two out of
three piers from the new portion of the dam. It will probably be safe to retain
1 74 Report on the Dam at Austin, Texas.
the piers on the old portion of the dam as originally installed, if satisfactory gates
are installed on the new section which can be opened in advance of the removal of
the crest gates or flashboards on the old section and thus create a strong and steady
current toward the new section to assure the floating of the drift to the larger
gates. Such an arrangement is suggested simply as a matter of economy as it
would otherwise be preferable to use similar gates on all portions of the dam.
Types of Gates Available. — Divers appurtenances are applicable under different
conditions to temporarily raise the water above the crest of the dam during the low
water stage and which are removable in one way or another during floods, in order
to permit free flow. Flashboards attached to permanent piers or to temporary ad-
justable standards and vertical needles, held by crest blocks and an upper support,
are the simplest forms used for such. They must be placed and removed wholly or
in part by hand, during flood periods and in general are applicable only where flood
periods are not too frequent, are fairly definite in time of occurrence, and can be
foreseen sufficiently in advance to admit of the work of removal of the boards or
needles. Such types are hardly applicable for use on the entire crest under the con-
ditions on the Colorado where floods may occur at almost any period of the year, and
where they commonly occur suddenly and without sufficient warning to admit of
proper preparations. Such devices might be used to advantage on a part of the dam.
If gates are used at all under the conditions at the Austin dam some form of
permanent adjustable apparatus must be used, at least for the new section of the
crest, which will either be automatic in action or which can be readily and promptly
removed and replaced at the approach and after the occurrence of floods.
Of the automatic types, the type already installed by the City Water Power
Company (see page 175) cannot be successfully used as it depends on bearings which
can be successfully applied only to short spans, and the gate even when open ser-
iously obstructs the water and assures either the clogging of the passage with drift or
its own destruction. Two other forms of automatic gates have been successfully
used in Europe. Two types designed by the Stauwerke Company of Zurich are
shown on page 176. Of these gates, Fig. 103, called the Stauwerke automatic gate,
has been used to some extent in this country. One installation has recently been
placed at the Wissota dam of the Wisconsin-Minnesota Power Company on the
Chippewa River in Wisconsin. Fig. 104 (page 176) called the drum gate, is applica-
ble to rivers where ice troubles are not serious, and has also been used in slightly dif-
ferent forms on various dams in the United States. Both of these types have the
advantage of being directly hinged to the crest of the dam, thus giving numerous
points of support, greater strength and hence the possibility of greater gate length.
They also possess an additional advantage over the gate which has been tried at the
Austin dam in that they fold down on the crest of the dam and present no obstruction
to the free passage of flood waters and of drift. On account of the details of the de-
signs, these gates would be limited to a ten-foot height at the Austin dam. The writer
Crest Gates.
175
has not sufficient confidence in the drum gate to feel safe in suggesting its use for the
long spans required on the Austin dam. Its cost would appear to be somewhat less
than that of the other types of gates on which estimates have been made.
Non-automatic gates which have to be raised or lowered by motors or by hand
power are more numerous and more positive in action but are subject to the disad-
vantage that they need attention when used. Of such gates there are numerous de-
Top o< /?o,
_. <*fe« WLotPorxt IWff
e/*s noo
j
te 3 IS'O'tiiyh, !&•(, ' fono
Cfoseat
WL f/er. I5to
FIQUBE 101 — Fifteen-Foot Automatic Gates used on the Austin Dam.
Top of fat/ E/ev l7kO
FIGURE 102 — Six-Foot Automatic Gates used on
the Austin Dam.
signs among which may be mentioned Stoney gates, rolling gates and tainter gates.
There are numerous other crest gates such as hydraulic drum and hydraulic sector
gates which are not considered applicable to the conditions at Austin and are not
here discussed.
The Stoney gates are not believed to be applicable to the conditions at the Austin
dam on account of the width of span required, the great pressure to be carried by
the gates, the long lines where leakage must be effectively prevented, the consider-
able friction of operation and the resulting expense involved.
Rolling gates (Fig. 105, page 177) have been widely used in Europe, and a number
of these gates have also been installed in this country. These gates are supported
76
Report on the Darn at Austin, Texas.
only at the ends, requiring somewhat massive machinery for their operation and
heavy abutments to assure their stability and successful operation. They have
sometimes leaked badly when not properly designed or constructed.
The tainter gates (Fig. 106) are also supported at the ends and do not differ
greatly in weight from the roller gates. They have been widely used in this country
but usually for shorter spans than that required at Austin.
9 Gates SS Ft. Long
f ' Piers
FIGURE 103 — Stauwerke Automatic Gate.
5 Gates WO Ft Long
4- 5 'Piers and 2-s'End Piers
FIGURE 104 — Stauwerke Drum Gate.
In the consideration of the problem of the Austin dam, four conditions, so far as
the crest is concerned, may be considered:
1st. The use of the dam crest as at present constructed without gates.
2d. The use of the dam crest as constructed with gates raising the water
to elevation 165 as provided in the Johnson franchise.
3d. The use of 5-foot gates with the crest of the reinforced concrete struc-
ture raised to 160.
4th. The use of the dam without gates, and with the crest of the new section
raised to elevation 160.
Crest Gates.
77
First. — The use of the dam crest at its present elevation without gates could
be considered only as a temporary expedient as the head and the available storage,
on account of the low crest elevation of the new section (elevation 151) would be so
small that the minimum power could not be maintained without an undue use of
steam.
9 Gafef SI rf Lory
/»' Pitrt.
FIGURE 105 — Rolling Gate.
9 Gaffs 55 ff L
S ' Piers
FIQUBE 106 — Tainter Gate.
Second. — The use of the dam as already constructed with gates of a similar
height to those already used but with an increased length, as previously discussed.
In each case flashboards are considered for use over the old sections of the dam
and gates over the new section. The expense of construction involved, including
the flashboards, is estimated as follows :
10' Stauwerke Automatic Gates and Flashboards $420,500
15' Boiler Gates and Flashboards 597,400
15' Tainter Gates and Flashboards 363,000
The records of the last twenty years show that the flashboards when used for
only half of the dam would not have to be removed more than once in two years,
1 78 Report on the Dam at Austin, Texas.
and if washed out at every great flood the expense of their replacement would be
small.
Third. — The cost of gates might be reduced somewhat if the crest of the new
portion of the dam is raised to the height of the old crest. This would raise the water
level above the dam higher at extreme flood, but as the old dam section is unsafe in
its present condition and must be strengthened in any event, this would not therefore
be considered as an added expense to the lower gates. The cost of raising the crest
of the reinforced concrete dam (which is estimated at $53,000) must however be con-
sidered as a part of the cost of five-foot gates in comparison with the cost of gates
for the dam with its present crest elevation. If the dam crest is raised and five-
foot gates are used, flashboards could not be used successfully as they would go out
with every considerable flood ; and in the narrow openings over the old section, tainter
gates could be used to advantage. The estimates for five-foot gates, 56 feet wide,
over the new portions of the dam and for tainter gates of 18-foot width over the old
dam, are as follows :
With Raised
Gates Only Crest
5' Stauwerke and 5' Tainter Gates $390,200 $443,200
5' Boiling and 5' Tainter Gates 420,300 473,000
5' Tainter Gates 329,000 382,000
It should be noted that a considerable element of the apparently high cost of all of
these different types of gates is due to the necessity of constructing new and heavier
piers from the foundation to and in some cases above the top of the present reinforced
concrete piers; also of constructing a new overhead bridge in order to permit ac-
cess to the gates for maintenance and repairs under all conditions of flow.
Fourth. — The cost of raising the concrete crest of the new dam to elevation 160
is estimated at $53,000. This would reestablish the crest elevation maintained from
1893 to 1900 and, as shown in Appendix 6, will give the most economical develop-
ment.
The writer is firmly of the belief that the increased power obtainable at elevation
165 does not warrant the extra expense, the additional leakage and the additional eva-
poration which will result from the higher head.
APPENDIX 8
BETTERMENTS REQUIRED FOR THE SAFETY OF THE AUSTIN DAM
In the design of engineering works an exact line between safety and danger
cannot be drawn with any great degree of accuracy. The conditions assumed in the
design of any structure will seldom be found to obtain exactly. The exact strength
of the materials used cannot be known. All of these uncertainties must be provided
for by an allowance of extra strength to more than make up for the uncertainties
which may obtain. Of all engineering structures the conditions which surround the
average dam are perhaps the most uncertain. The character of the foundation must
be judged from surface indications, and at best from a limited number of borings.
With all the work that has been done at the site of the Austin dam, there is still
much uncertainty as to the exact physical condition of the underlying strata and as
to the exact extent of the remedies that must be applied to make the dam safe. Un-
certainties also exist as to the maximum river flow. The highest flood that may ob-
tain in time to come can be estimated only on the basis of what has occurred in the
past, and the conditions of silt and drift which may obtain in the future must be
judged in the same way. The dam failed in 1900 because the conditions were not
correctly judged in 1890-93. Leaks appeared under the base of the dam in 1915
and the crest gates proved a failure because the precautions taken in 1911-14 were
not sufficient for their purpose. Just what was necessary in either case to have made
the structure safe without any unnecessary expenditure cannot be told.
The only safe basis of engineering design is to build a structure so safe that
there is no reasonable chance remaining for its destruction. It is also necessary to
remember that neither the City nor the private parties who are interested in the Aus-
tin dam have money to waste and it is essential that nothing shall be expended in
useless work.
In considering the betterments that are justifiable at the Austin dam it is recog-
nized that there is opportunity for a wide difference in the opinion of engineers, ac-
cording to their experience and mental attitudes, as to the extent of the improve-
ments necessary for safety; and preliminary to the recommendations herein con-
tained the writer desires to say that these matters have been carefully weighted,
and the betterments advised are those which he would feel it necessary to carry out
were he the owner of the dam and were it necessary for him to plan its proper re-
habilitation for continued use.
The writer agrees with Messrs. Davis, Hill and T. U. Taylor that the dam
should not have been reconstructed on the present site; that the conditions made
manifest by the first failure and by the various geological and engineering investi-
180 Report on the Dam at Austin, Texas.
gallons which have been described, showed conclusively the dangerous character of
the foundation and that it was exceedingly difficult, at reasonable expense, to build
a structure at this site the safety of which could be positively assured. However,
the City is confronted with facts, not theories. The site has been accepted by the
City, the dam has been reconstructed, a large investment is involved, and it remains
to consider the means necessary to render the structure as safe as it can be made
within practicable limits of expense.
Foundation. — The writer is of the opinion that it is practically impossible to
comply with the requirements of the specifications and find six feet (or even four
feet) of solid rock in the east section of the dam on which to build this structure. He
is also of the opinion that even if such thickness of rock were available, it would
afford no assurance against serious deep underflow. It is therefore essential to take
such precautions as are financially practicable toward improving these conditions
and rendering the substrata practically impervious.
Grouting as a Protection Against Underflow. — The history of the process of
grouting dam foundations has not demonstrated its reliability as a positive method
of preventing underflow. Grouting has usually been applied only as an extra pre-
caution after other practicable and more positive methods have been employed. The
writer considers the conditions of the strata at the dam site as fairly suitable for the
application of grouting methods, and believes grout should be utilized for further
betterments of the conditions.
Foundation Betterments Recommended. — The writer believes that a cutoff wall
about 30 feet below the bottom of the river and across the entire section of the new
dam at its upstream face is the first essential for safety. Such a cutoff wall should
completely fill the rock trench in which it is built, so that the excavation of the strata
will not afford a means of access of water to the upstream rock face of the excava-
tion. He believes that the safety from underflow should be still further assured by
thorough grouting in holes 50 to 60 feet in depth, drilled not more than four feet
apart and in at least two rows across the entire width of the river. The depth, spac-
ing and number of rows of holes should be determined by the condition found during
the execution of the work.
It will probably be desirable and perhaps essential to complete the work of
grouting before the excavation for the cutoff wall is attempted, as otherwise fissures
in the cutoff trench might make it impossible to construct successfully the cutoff
wall. By first grouting the strata, the excavation for the cutoff wall will be less ex-
pensive and the excavation will also demonstrate the effectiveness of the grouting
work. If the grouting is found to be thoroughly effective, it may be feasible to re-
duce the depth of the cutoff wall to 15 or 20 feet and may make it unnecessary to con-
struct a cutoff wall behind the old section. If the grouting is not fairly effective, a
cutoff wall at least ten feet in depth should also be constructed immediately behind
the old section.
Recommended Betterments 181
Stopping Leaks in Panels 4 and 6. — The exact details of the methods necessary
for stopping the leaks in Panels 4 and 6 cannot be foretold accurately without a de-
tailed examination, which the writer has n0t been able to make and which cannot well
be undertaken until the work of rehabilitation is begun. The conditions as known
are described on pages 94 and 110. When the water was lowered above the
dam, the leaks stopped flowing after the water had reached a certain elevation above
the opening through which the leaks appeared. Before grouting above the dam it
will be necessary to construct cofferdams around these leaks to such a height that the
water will rise and become stationary so that there will be no current through the
rock fissures. With this accomplished it may be possible that the deep grouting which
has been recommended to be done above the dam will find its way into the cavities
and fissures through which these leaks occur, and effectively close them. If not, the
rock in the immediate vicinity of the cavities must be cleared of debris and grout
forced deep into the fissures. The leaks cannot be stopped successfully and perman-
ently with a surface deposit of concrete or by grouting in their shallow upper por-
tion but the grout must be forced into these fissures for 15 or 20 feet in depth.
It may be essential to drill one or more holes into the strata through or immedi-
ately adjoining the fissures, and force the grout into the strata from a depth of 15 feet
or more below the surface, until it finally fills these fissures to the surface of the rock.
If the filling cannot be properly made by such means, a pipe may be placed as deep
as practicable in the strata adjacent to the fissures with its top rising above the sur-
face of the water, and a bed of concrete two or more feet in thickness deposited
above the fissure to afford a resistance to the surface outflow of the grout, after
which grout may be pumped into the fissure through the pipe, filling it to a consider-
able depth through the surface resistance afforded by the concrete bed. It is under-
stood that the opening in Panel No. 6 is of considerable size, and a large amount of
grout will probably be required for the complete stopping of this fissure.
In Panel No. 4 it is understood that no examination has yet been made and that
the leak is comparatively small. In this case, unless the fissure is closed by the
grouting above the dam, it will become necessary to drill into the strata in order to
give free access of the grout to the underlying fissures. The exact details to be em-
ployed can best be determined at the time the work is undertaken. After the suc-
cessful stopping of these leaks, it will probably be desirable to lay a reinforced con-
crete floor in the upper portion of these panels as an additional precaution against
further trouble.
Effectiveness of Protection. — With such precautions, it is believed that destruc-
tive underflow can be prevented, although no one can positively say that weaknesses
along the fault lines which may ultimately prove troublesome may not develop even
below the depths mentioned. The fact that the dam stood from 1893 to 1900 without
such developments is, however, an assurance of safety. It is believed that with
182 Report on the Dam at Austin, Texas.
proper care the risk of further trouble will be small, and considering the importance of
the project and the investment already incurred, the expense involved is warranted.
Improvements of Conditions Below the Toe of the Dam. — The conditions below
the toe of the new section have already been described (see pages 98 to 106). These
conditions are sources of danger to the new structure and will become worse with
every large flood. One of the most necessary betterments will consist of filling up
this depression and constructing an apron of sufficient thickness and strength to
both protect the bottom and afford a substantial abutment against which the cross
walls of the new structure will rest. The top of the apron should reach above the
foundations of the cross walls at the toe of the dam and be so constructed as to give
them an ample bearing. It is not considered necessary to bring the top of this apron
to a horizontal plane above the most shallow cross wall but it should have a substan-
tial thickness over the entire section of the trough between the toe of the new struc-
ture and the rock ledge below. This apron should be constructed of cyclopean con-
crete in which should be imbedded a considerable amount of large rock from the de-
bris which is now piled between the toe of the dam and the tail race. In this way
the construction may be cheapened and much of the debris which is liable at any time
to be washed into the tail race will be removed. Weep holes should be provided
in this apron to eliminate upward pressure. With such construction properly plan-
ned the new structure may be regarded as reasonably safe.
While the rock bottom of the river below the structure of the old dam has not
been seriously eroded, if at all, it is believed necessary to protect this rock by a layer
of concrete about 50 feet in width, which should start at elevation 100 at the toe of the
dam but can be decreased to about 2 feet in thickness at its outer limits. Under
this structure drains and weep holes should also be provided to eliminate upward
pressure.
Crest Gates. — The difficulty of maintaining any form of crest gates has already
been discussed, and the expense involved by the erection and maintenance of any
gates which might prove reasonably satisfactory has been shown in Appendix 7.
In Appendix 6 it has been demonstrated that the amount of extra power which
can be secured by maintaining the maximum surface of the water at elevation 165
is not of sufficient value to warrant the expense involved. It is therefore recom-
mended that no crest gates be used but that the gate piers be entirely removed from
the dam and the crest of the new structure be raised to elevation 160. The amount
of hydraulic power thus lost can, it is believed, be more cheaply recovered by a sys-
tematic attempt to reduce the seepage into the rock and around the dam on both
sides of the river.
Reduction in Seepage Around the Dam. — It is believed to be desirable to reduce
the seepage immediately around the west end of the dam by grouting the natural rock
ledge both immediately above and below the west end of the dam. On the east side
of the river opportunities for saving a much larger quantity of water are apparent.
Improvements to Old Dam Section.
183
The nature of the work to be done can be only partially outlined, but it is believed
that the most pervious strata are near the elevation of the old flood plane above the
dam and that these strata should be exposed by a comparatively shallow trench along
the face of the bluff, and the seepage stopped by facing the pervious strata with con-
crete and perhaps in places by grouting. While the results which can be attained by
such work cannot accurately be foretold, it is believed that the seepage into these
strata may be reduced perhaps 50 per cent, or more at an expense which will be more
than justified by the results obtained.
Improvements to the Old Dam Section. — It is quite evident from the analysis
and discussion of the old dam (see pages 124 to 130) that it has too light a section to
W.J.&. 174.0-^).
\M/afc//» 7ft/r<^Sj ft- ^^y^\
7O.O'
FIGURE 107 — Recommended Improvement to Old Dam Section.
be safely stable with its pervious foundation, the silt pressure which must be anti-
cipated, and the conditions of flood flow, even though the crest remain at elevation
160. Its section is also so narrow that the under surface of the flood waters flowing
over it must leave the surface, thus creating a partial vacuum and adding to the
pressure head above the dam. Were the channel clear of the new structure, it might
be desirable to strengthen the old section by addition to the upstream face ; but under
the condition it seems desirable and less expensive to improve its stability and sec-
tion by the addition of concrete on the downstream side, as shown in Fig. 107. It will
also be necessary to seal the base and fill the voids in the structure itself by thorough
grouting which, together with the foundation grouting previously advised, may safely
be assumed to decrease the upward pressure in the foundation to about one-half of
184 Report on the Dam at Austin, Texas.
the pressure due to the head. The addition to the face and the thickening of the toe,
possibly with some heavy reinforcing at that point, may be assumed to so extend the
effective width of base as to throw the resultant pressure with high silt and flood flow
within the middle third of the structure. These improvements, together with the
extension of the apron, elsewhere recommended, will so increase the stability of the
old structure as to render it permanently safe.
Tail Race. — The tail race is seriously throttled by the debris brought in by the
flood of September, 1915. In order to maintain this tailrace it is necessary not only
to clean out the material which has been washed in, but to remove the piles of debris
between the tailrace and the toe of the dam which is the source of the trouble. Much
of the heavy rock in this mass can be used in the cyclopean concrete of which the
apron in front of the dam should be built. The balance should be removed across
the tailrace to the land side and deposited on the shore where it will create no fur-
ther trouble.
The writer has not seen the tailrace in use, but is under the impression that it
has not been excavated deep enough to properly fulfill its functions. The rim of rock
immediately adjoining the draft tubes should be so excavated that the water will have
a free delivery.
Dr. A. C. Scott, in his letter to Mayor Wooldridge, dated March 31, 1915 (see
Appendix 10), states that it is essential to deepen the tailrace approximately three
feet. In its congested condition, the writer had no opportunity to examine this race-
way in detail, and it is possible that with the removal of the rubbish between the race-
way and the dam, a sufficient opening will be available for the free discharge of the
water. In any event, the tailrace should be so deepened as to maintain a velo-
city of discharge of not to exceed three feet per second. If this is done, and the de-
bris removed, there is no apparent reason for requiring the construction of a con-
crete raceway nor a concrete wall north of the raceway as required by the specifica-
tions, except to protect the draft tubes.
Deflecting Wall. — The north draft tube was damaged by drift, probably in the
flood of September, 1915 ; and such damage is very likely to recur with any flood ac-
companied by drift. On account of the exposed position of these draft tubes it is de-
sirable to construct a deflecting wall which should begin essentially at the north line
of the present building with its top somewhat above the top of the draft tubes and
extend in a diagonal downstream direction for about 40 feet. The end of the wall
should be 10 or 12 feet above low water, and the top of the wall should slope or may
be stepped upward to the power house. This wall should be of reinforced concrete,
well bonded into good rock foundation and into the masonry of the power house foun-
dations, and should have a width of not less than 2 feet at the top and 8 feet at the
bottom.
Head Gates. — The racks at the head gates have been discussed (see page 140) and
it has been noted that the openings between these racks are too small for the practi-
Recommended Betterments. 185
cal operation of the turbine units. These racks should be taken down and more than
one-half of the rack bars removed, leaving the free opening between adjacent bars
about ll/2"- It will also be desirable to examine the rack supports and see that they are
sufficiently strong to sustain the racks, should the racks become sealed by leaves and
drift and the water be drawn away from below them, leaving the entire head to be
sustained by the strength of the racks and their supports.
Passageway in the Dam. — As has been noted, the passageway in the dam con-
sists of a wooden walk sustained on the cross walls of the dam. This is sagging badly
and Will have to be replaced at an early date. A substantial reinforced concrete
walk should be built in place of the wooden structure and the railing should be se-
curely anchored thereto. The railing should be thoroughly cleaned and painted with
some preservative which will prevent further deterioration.
Railing. — The railing along the concrete bridge over the dam will be removed
with the piers if the dam is raised to elevation 160 and used without crest gates, as
elsewhere advised. In that event, ample railing will be available to protect the abut-
ment and retaining wall from the dam to the power house. In any event, such a rail-
ing should be provided for the safety of the public. All railing should be thoroughly
cleaned and painted.
Gate Operating Mechanism. — The gate operating mechanism is believed to be
unsatisfactory for a plant of this character. It can however be utilized for the pres-
ent if found desirable. It is recommended that it ultimately be removed and proper
gate mechanism substituted.
Sluiceways. — The sluiceway arches which on account of defective design were
destroyed in 1915 have been partially replaced. It is assumed that this work has
been done on a safe and satisfactory plan, although no details of the new design were
available. One additional arch remains to be replaced and it is understood that
there are some of the arches which were not destroyed that have not been reinforced.
These should be properly strengthened by additional concrete and reinforcement.
Sluice Gates. — The sluice gates are unsatisfactory in design and arrangement and
they should at least be redesigned and rebuilt so that the bronze bearings can be
unquestionably maintained. The position of the cylinders, submerged in the reser-
voir 50 feet below the crest of the dam, is unfortunate and will probably give rise in
the future to considerable annoyance and expense. Backs should be provided to pro-
tect the cylinders and to prevent the entrance of floating matter into the gateways.
The reconstruction of the gates, and their rearrangement in a more satisfactory
manner, would involve a considerable expense and is not recommended at the present
time on account of other large but more essential expenditures which will have to be
made for the safety of the structure.
Estimates of Cost of Betterments. — The contingencies of river construction at
Austin have been demonstrated by the misfortunes of the past, and any estimates for
betterments must be made on a liberal basis. The work required above the dam
1 86 Report on the Dam at Austin, Texas.
will probably involve making certain openings through the reinforced concrete struc-
ture to give vent to the flood waters, in addition to the limited capacity of the sluice
gates. Even with such openings the cofferdams will be drowned out with every con-
siderable rise and any work done above the dam will be expensive. In the estimates
made for the betterments recommended, liberal amounts have been allowed in addi-
tion to a reasonable sum for contingencies. It is quite probable, with favorable
flow and weather conditions during the period of reconstruction, that a considerable
saving can be effected over the estimate made; but such conditions cannot be as-
sumed, and it is believed that the estimates made will cover unforeseen foundation
and flood conditions. For estimates of the cost of the betterments see pages 31 and
32.
APPENDIX 9
COST OF THE WORK DONE UNDER THE JOHNSON CONTRACT
It is obvious that neither the Engineers of the City Water Works Company nor
the Contractor who undertook the work at the Austin dam appreciated the contin-
gencies of river work. The years immediately preceding the date at which the con-
tracts were made were the years of low flow, but an examination of the records of the
United States Geological Survey would have shown that the river was subject to
sudden high floods and years of high flow when work in the river for an entire season
would be practically impossible without large expense. Any estimates of the cost of
such work to be safe must anticipate such contingencies and be large enough to
cover the extra expense involved by the increased cost of construction under such
conditions.
The original cost estimates for this work made by the Engineers of the City Water
Power Company and including $50,000 for Contractor's profit, $12,000 for royalties,
$13,000 for interest during construction, and $22,500 for engineering, was $450,334.54.
The Contractor's estimate, including $50,000 for profit and without royalties or en-
gineering fees, was $453,000.
The writer has estimated the cost of the work done and in so doing has endeav-
ored to take into account only such expenses as he should anticipate under the con-
ditions which he knows would be liable to obtain on river work with the foundation
and flow which should be expected to obtain on the Colorado at Austin. He has eli-
mated as far as practicable his knowledge of actual cost to the Contractor by making
independent estimates without reference to the cost data.
Estimated Cost of Reservoir. — The reservoir included under the contract was
built on the summit of the hill to the north of the City of Austin. Its construction
involved no serious contingencies. Its estimated cost on a unit cost basis is as fol-
lows:
ESTIMATE or COST OF WATER WORKS RESERVOIR
Item Quantity Unit Rate Amount
Concrete (Thin walls) 3,017 Cu. Yd. $11.00 $33,187
Excavation 3,700 Cu. Yd. .50 1,850
Steel Reinforcing 53,700 Lbs. .05 2,685
4" Triangular Wire Mesh 12i/2" Gage 37,275 Lbs. .05 1,864
Steel Plate Expansion Joint 1,850 Lbs. .05 93
$39,679
Contingencies, 10 per cent 3,971
Total estimate of cost $43,650
188 Report on the Dam at Austin, Texas.
This estimate may be compared with the Contractor's Cost Sheet shown on page
194, and shows a close agreement therewith.
Estimated Cost of Rebuilding Station, Including Removing Old Penstocks, Plac-
ing Neiv Penstocks, Rebuilding Transmission Lines, etc. — This work is embraced in
Schedule A of the contract between the City Water Power Company and the Wm. P.
Carmichael Company, and was guaranteed by the City Water Power Company not
to exceed a cost of $20,720.
Estimates. 1 89
The writer's estimate of the cost of this work is as follows:
ESTIMATE OF COST OF BUILDING AND WORK ON PENSTOCKS AND TRANSMISSION LINE
Item Quantity Unit Rate Amount
Reinforced Concrete Floor 170 Cu. Yd. $12.00 $2,040
Plain Concrete Floor and Walls Below
Floor 27 Cu. Yd. 8.00 216
Plain Concrete Paving around Surge Pipes 29 Cu. Yd. 8.00 232
Brick Walls Abv. Floor Level — Sides and
Ends New Part 173 M 30.00 5,190
Brick Walls below Floor End Wall and
Wall in Turbine Boom 172 M 30.00 5,160
Windows 6 at 7'xl9' and 2 at 6'x7' 265
Roof Trusses— Wood 6,000 Ft. BM 50.00 300
Roofing— Slate and Sheathing 24 Sqs. 18.00 432
Crane 15-Ton Hand 49'8" Span 1,200
Crane Runway 65 Ibs. I-Beams 40 Ibs. Rails 24,270 Lbs. .05 1,214
Pilaster Alterations, Corbels and Bolts on
13 Pilasters 195
Plumbing, Painting and Wiring 1,000
Railings, Gallery and Stairs 1,000
Office Room 75
Rebuilding Transmission Line 15,000 Ft.
Poles and Stringing only 3,720
Headworks Alteration to Lower Penstocks
5'6" 500
Relaying Penstocks 3,065
Concrete Reinforcing for Penstocks 2,500
Retaining Wall 76' long 24' high 2' top ... 300 Cu. Yd. 8.00 2,400
Relief Pipes 32" diam. 1 at 52', 1 at 68',
1 at 81' 17,520 Lbs. .07 1,226
Draft Tubes— Elbows 3 at 1920' 5,760 Lbs. .07 404
Penstock Expansion joints and elbows . . . 8,070 Lbs. .07 565
Removal Penstocks, Floor, Found 't 'ns, etc. 500
Excavation Rock under Old Power House 375 Cu. Yds. 2.50 940
$34,339
Contingencies, 10 per cent 3,434
Total $37,773
190 Report on the Dam at Austin, Texas.
This estimate may be compared with the Cost Keeper's account of the Contrac-
tor, given on page 195, and will be seen to be about $15,000 less than the cost there
shown. The writer is unable to account for this difference as he has no reason to
believe that the Cost Keeper's account is otherwise than accurate. While the con-
tingencies of this work are small there is much uncertainty as to the amount of work
which was done, especially in the removal of the old penstocks, the excavation for and
the placing of the new penstocks, and the work done below the floor level of the power
house. Legitimate differences in these items may possibly account for much of the
difference between the writer's estimate and the actual cost. It is evident from the
original estimate of the City Water Power Company that much more work was done
than was anticipated.
Machinery and Equipment, which is Schedule B of the contract between the City
Water Power Company and the Wm. P. Carmichael Company and was guaranteed
in that contract not to exceed a cost of $79,000, is estimated by the writer as follows :
ESTIMATE OF COST OF MACHINERY AND EQUIPMENT — ERECTED
Item Price Each No. Amount
Turbines (2400 HP) and Governors $9,330 3 $27,990
Erection 13 per cent 3,640
Generators 1500 KVA at $7 : 10,500 3 31,500
Transformers 1500 KVA at $2.50 3,750 3 11,250
Switchboard 2,000 1 2,000
Exciters 75 KW Motor Drive at $27 per K. W 2,000 2 4,000
Generator Suspension Bearings 500 3 1,500
Headgates and Hoists 300 3 900
Backs 55,000 Ibs. at 4c 2,200
Pumps and Motors— 6 Mil. Gallon 4,000 2 8,000
Station Wiring 1,000 . . 1,000
Connections to Penstocks, Draft Tubes, Rivetting, Etc 300 3 900
$94,880
Contingencies, 5 per cent 4,744
Total $99,624
A comparison with the Contractor's Cost Sheet, page 195 will show this estimate
to be about $5,930 above the actual cost to the Contractor.
Construction of the Dam. — The writer 's estimate of the contingencies of river
work are partially reflected in the itemized prices for unit quantities and in his es-
Estimates.
191
timate for the probable cost of cofferdams and pumping ; otherwise the ordinary con-
tingent item of 10 per cent, is added to cover this item. His estimate is as follows:
ESTIMATE OF PROPER COST OF WORK DONE ON THE AUSTIN, TEXAS, DAM
Item
Concrete
Below Elevation 100 Footings
Walls, Etc
Above Elevation 100
Dam Cross Section Beams, Decks, Etc.
Longitudinal Walls
Walls under Overhang
Transverse Walls under Deck
Main Piers
Intermediate Piers
Extra in Expansion Panels
Entrances to Dam
Piers on Old Dam
Walkways
Blanket Mat over Old Dam at West
End New Dam
Corewall East End
Excavation
Footings, Etc. in Bock
Reinforcing Steel
Appurtenances
Iron Pipe Bailings
Bails 40 Ibs. for Derrick 2204 lin. ft
Ties for Track 720 6x8—8'
Plank for Walkway Top of Dam
Walkway and Stringers
Steel— Crest Gates Old Dam 25 at 1195 Ibs.
Crest Gates New Dam 28 at 4020
Trunions and Guides
Sluice Gates 5x6)
Cylinders )
Timber
Crest Gates Old Dam
Crest Gates New Dam .
Quantity Unit
787 Cu. Yds.
4,368 " "
8,230
1,348
593
2,480
586
103
289
178
170
340
90
2,900 " "
7,000 " "
884,700 Lbs.
2,313 Lin. Ft.
88,160 Lbs.
23,040 Ft. BM
17,630 " "
7,870 " "
30,000 Lbs.
110,000 "
56 Number
8
Rate
3,750
23,800
Ft. BM
625
50)
50)
Amount
$10
$7,870
12
52,416
12
98,760
12
16,176
12
7,116
12
29,760
12
7,032
12
1,236
12
3,468
12
2,136
12
2,040
12
4,080
10
900
10
29,000
2
14,000
5c
44,235
80c
1,850
5c
4,408
$50
1,150
50
882
50
394
5c
1,500
5c
5,500
$12
672
5,000
1,378
192 Report on the Dam at Austin, Texas.
Concrete
Crest Gates Old Dam 20 Cu. Yds. 12)
Crest Gates New Dam 65 " " 12) 1,020
Stair— Cast Iron Spiral 2 Number 275 550
Erection Crest Gates 25 per cent, of Esti-
mated Cost 2,434
Cofferdam and Pumping 100,000
$446,963
Contingencies, 10 per cent 44,697
Total $491,660
A comparison of this estimate with the Cost Keeper's detailed account of the
actual cost of this work will show the cost to have exceeded the estimate by about
$50,000. How much of this amount may be due to the inexperience of the Contractor
in river work and how much to the writer's failure to make proper allowance for the
necessary cost and contingencies of the work he is unable to say. The writer has en-
deavored however to make a fair estimate based on a somewhat extended experience
on this class of work, and his estimate must be considered with due regard to the
great uncertainties involved.
EXTEA WORK
Various items for extra work which have not been included in the above esti-
mates are found in the Contractor's Claim for Extra Work. In the following table
they are taken at the actual cost figures as the writer has no other method of esti-
mating their actual cost or value.
Estimates. 1 93
EXTRAS FROM COST KEEPER'S ACCOUNTS
Items Amount
Wiring in Dam $ 6.43
Signal System for Sluice Gates 22.58
Wiring in Dam Material 125.28
Wiring in Dam Labor 81.75
Bell Einging Outfit 8.10
Rock Excavation in Tailrace 8,335.38
Grouting Top of Old Dam, 2 holes in west end 178.35
Recording Pressure Gage 7.02
Voltage Regulator 430.78
Sluice Gate Gages Material 72.50
Sluice Gate Gages Labor 58.77
Railings on Stairs 11.87
Third Pump Unit 3,199.77
$12,538.58
Plus 10 per cent 1,253.86
Total $13,792.44
RECAPITULATION OF ESTIMATES
Reservoir $43,650
Power House, Etc. (Schedule A) 37,773
Machinery and Equipment (Schedule B) 99,624
Dam 491,660
Extras 13,792
$686,499
The writer believes the above to be a fair and reasonable estimate of cost of the
work done by the Wm. P. Carmichael Company, not including the cost of repairs and
reconstruction done for the City Water Power Company on account of faulty design.
Equitable charges for such work are a fair charge against that Company but cannot
be considered in making an estimate of the value of the present structures. These
charges made by the Contractor for extra work (see page 197) and not included in the
194 Report on the Dam at Austin, Texas.
writer's estimates, amount to $26,585. The difference between the writer's total es-
timate of the fair cost of this work and the cost as shown by the books of the Wm. P.
Carmichael Company is as follows:
Cost from Books of Wm. P. Carmichael Company $795,332
Writer's Estimated Cost 686,499
Difference $108,833
Carmichael 's Claim for Extra Work — Not included in Writer's
Estimate 26,585
Difference between Writer's Estimate of Cost and Cost shown by
Carmichael Co.'s Books $82,248
Through the courtesy of Mr. M. C. Andrews of the Wm. P. Carmichael Com-
pany, the writer was given the opportunity of examining the accounts of this Com-
pany. No attempt was made to audit the books as such an audit did not appear es-
sential for the purpose of this report. The Cost Keeper's final summary of the ac-
tual cost of the work was however abstracted, and is as follows :
COST OF CONSTRUCTION OF AUSTIN WATER WORKS RESERVOIR
Cost Keeper's Account Wm. P. Carmichael & Co.
Lumber $2,075.77 Minor Equipment $ 86.38
Steel 2,491.51 Supplies 1,140.97
Cement 10,346.70 Liability Insurance 593.69
Aggregate 7,727.81 Fire Insurance 12.95
Fuel, Etc 227.79 Bond Premium 234.24
Rentals 330.83 Traveling Expenses 128.36
Labor 17,455.14 Nails and Wire 201.77
Office 35.46 Hauling, Etc 249.97
Oils and Waste 21.79
Iron and Steel . 2.29 $43,363.42
Contractor's Costs.
195
COST OP SCHEDULE A (BUILDING, ETC.)
Cost Keeper's Account Wm. P. Carmichael & Co.
Lumber
Cement
Aggregate
Fuel, Etc
Rentals
Labor
Steel
Brick and Lime .
Window Frames
Handrail
Explosives
Slate Contract . .
Crane and Track
Plumbing
Stone .
$1,495.43
3,592.44
2,099.04
336.31
781.88
30,289.64
513.45
1,920.92
189.79
544.60
466.86
729.06
1,820.24
196.00
46.00
Painting 600.00
Office Expenses 189.92
Oil and Waste 12.82
Iron and Steel 105.62
Bolts, Nuts, Etc 45.96
Minor Equipment 573.01
Supplies 718.31
Liability Insurance 1,082.72
Bond 144.39
Traveling Expenses 263.21
Nails and Wire 86.84
Hauling, Etc 84.35
Plant Charges 3,741.91
$52,670.72
COST OF SCHEDULE B (PLANT EQUIPMENT)
Machinery $62,919.90
Lumber 287.09
Steel 643.81
Cement 1,310.68
Aggregate 809.23
Fuel, Etc 181.67
Rentals 595.40
Explosives 8.93
Labor 18,502.47
Painting 140.00
Office Expenses
Minor Equipment . .
Supplies
Liability Insurance
Bond Premium ....
Traveling Expenses
Hauling, Etc
156.89
155.87
986.41
858.76
558.45
193.39
60.09
Plant Charge 5,376.43
$93,745.47
196
Report on the Dam at Austin, Texas.
COST OF RECONSTRUCTION OF DAM
Cost Keeper's Account Wm. P. Carmichael & Co.
Lumber $31,678.42
Steel 17,190.20
Cement 62,187.62
Aggregate 21,981.77
Fuel and Power 14,109.82
Rentals 13,411.01
Sluice Gates & Bailings . . . 6,645.25
Cableway 5,589.35
Labor 317,427.84
Explosives 5,187.74
Office 2,765.22
Oils and Waste 1,454.75
Sheet Metal 324.70
Drill Steel 1,144.74
Iron and Steel 1,926.08
Bolts and Nuts 1,251.96
Minor Equipment 12,325.07
Supplies 9,470.88
NOTE: Total cost of dam only given on page 198 dated March 1, 1916,
Amount $545,725.46.
Liability Insurance 14,698.22
Bond Premium 2,271.81
Fire Insurance 179.49
Traveling Expenses 2,938.79
Freight on Equipment 3,446.72
B. B. Fares 665.99
Nails and Wire 3,243.72
Hauling, Etc 1,091.21
Labor 708.79
Misc. Material 316.87
Forebay Excavation, Labor 301.30
Total $555,935.33
Credit — Charged 'to other
parts of the Work 10,249.67
Total Cost $545,685.66
**
**
**
Contractor's Costs. 1 97
EXTRAS
Cost Keeper's Account Wm. P. Carmichael & Co.
Item Quantity Kate Amount
**Wiring in Dam $ 6.43
**Signal System for Sluice Gates 22.58
**Wiring in Dam Material 125.28
**Wiring in Dam Labor 81.75
**B.ell Einging Outfit 8.10
Power House Account 121.38
Equipment Account 684.34
Stanchion's Crest Gates 2,432.46
Back in Head Gates 2,192.11
**Rock Excavation in Tail Race 8,335.38
Grouting, Etc. Top Old Dam— 2 Holes West End 178.35
Recording Pressure Gage 7.02
Voltage Regulator 430.78
Retaining Wall (3d Construction) 2,401.14
Repairing Crest Gates 2,922.05
Engineering— J. G. White 1,208.24
*Paving under Draft Tubes 233.70
Platform over Rack 64.17
Repair Sluiceway Arches 432.26
Bronze Strips on Sluice Gates — Material 187.68
Bronze Strips on Sluice Gates — Labor 477.21
**Sluice Gate Gages— Material 72.50
**Sluice Gate Gages— Labor 58.77
*Corbels on Piers — Material 52.05
*Corbels on Piers— Labor 128.27
**Railings on Stairs 11.87
Sluiceway Arches 8,940.82
Items 21, 24, 25, 26, 27 246.32
Drift Removal 1,097.26
Diving 386.72
Plus Profit, 10 per cent. (4-7-15) 2,086.97
20 per cent 240.65
Profit (9-1-15) 1,067.11
$36,944.72
Less Items marked as Included Elsewhere. . 414.02
$36,530.70
* Included in Writer's Estimate of Cost of Power House.
**Included in Writer's Estimate of Cost of Extra Work.
198 Report on the Dam at Austin, Texas.
Note that the total of the itemized account given above is $646.54 short of the
claims for extra work by the Wm. P. Carmichael Co. as given on this page. This is
essentially the amount of the extra agreement dated 2/29/16 given thereon and
which account was not included in the above list.
AUSTIN DAM COSTS TO MARCH 1, 1916
(Wm. P. Carmichael & Co.)
Dam $545,725.46
Crest Gates 19,036.09
Eeservoir 43,363.42
Schedule A 52,670.72
Schedule B 93,745.47
Extras before 4/7/15 1,443.93
Extras— Agreement 4/7/15 23,762.36
Extras— Agreement 9/1/15 11,738.23
Extras— Agreement to 2/29/16 646.74
3d Pump Unit 3,199.77
Total Cost $795,332.19 $795,332.19
Cash Received:
City Water Pr. Co $261,640.07
Bondholders' Com 11,242.63 272,882.70
$522,449.49 Present W. P. C. & Co. In-
Amt. Due from City Water Pr. Co. 270,983.79 vestment
$251,465.70 Construction Loss. To get
total loss, to this must be ad-
ded General Office and Interest
Charges.
APPENDIX 10
RECOMMENDATIONS OF DB. A. C. SCOTT — MARCH 31, 1915
The following letters from Dr. A. C. Scott, Consulting Engineer of the City of
Austin, outlines the betterments which he, in March 31, 1915, considered necessary
for the completion of the work.
Apparently no action was taken on this matter by the City Council of Austin, and
soon after the April flood occurred which damaged the crest gates, filled the raceway
and caused a suspension of any definite action on the part of the City.
March 31, 1915.
Hon. A. P. Wooldridge, Mayor,
Mr. E. C. Bartholomew, Councilman,
Austin, Texas.
Gentlemen :
In accordance with your instructions and the request of Mr. Rector, City Attor-
ney, I submit a statement concerning such items as in my judgment are significant
and important to effect the complete construction of the dam and its appurtenances,
and the installation of power plant machinery connected therewith.
1. In order to avoid probable future trouble in the operation of the water wheels
a stationary forebay rack should be placed in front of the head gate masonry, ex-
tending over the entire space occupied by the inlets to the three penstocks, and to a
height above the final lake level being placed one to four feet in front of said mas-
onry, which will allow the water to flow through said rack over its entire area. I
would suggest that this rack be made of steel bars 1^" x 3"? same to be spaced and
held in position %" apart ; or, if a rack of equivalent serviceability be constructed,
same would be satisfactory.
2. Six of the sluice gates were open and shut yesterday afternoon, at my re-
quest, and were found to be readily and satisfactorily operable. Each gate was tested
individually; it was first fully opened, the time required for opening being about
four or five minutes ; it was then allowed to discharge water for three or four minu-
tes at the full opening of the gate, and then finally closed. About five minutes in-
tervened between the successive intervals of the openings of the gates, for allowing
the water to drain away from the toe of the Dam, after each gate was closed. No
evidence was found that these gates do not open readily and close properly and com-
pletely. In the event the two sluice gates, which are inoperable at present be not
repaired before the acceptance of the dam be given, the City of Austin should be
guaranteed the right to draw down the lake at any time it is desired to repair said
200 Report on the Dam at Austin, Texas.
gates and The City Water Power Company, or its assigns, should agree to repair
said gates at its own expense, at such time as the lake may be drawn down sufficiently
to do so for that or for any other purpose.
3. I do not consider that a concrete tail race is essential provided that the pres-
ent natural earth tail race be sufficiently extended in width to permit a movement of
the water away from the draft tubes of water wheels Nos. 2 and 1, which is compara-
ble with that from wheel No. 3. The tail race should be deepened, approximately
three feet. If the tailrace construction, called for in the general specifications, be
waived, a supplementary contract should be entered into between the City Water
Power Company, or assigns, and the City of Austin, whereby the City Water Power
Company shall agree to keep the natural earth tail race open at all times and free
from drift or earth and rock debris, which would materially decrease the effective
head upon the water wheels. Also it would appear that this contract should include
an agreement to the effect that whenever a decision of three hydraulic engineers, one
to be appointed by the City of Austin, another to be appointed by the City Water
Power Company, or assigns, and a third to be appointed by the two, shall render a
majority decision that the City of Austin needs a concrete tail race, the City Water
Power Company shall build same at its own expense for the City of Austin, or agree
that the City of Austin may build such concrete tail race and deduct the cost thereof
from the next semi-annual installment to be paid thereafter under the general con-
tract.
4. The west end of the old Dam must be grouted from the top to stop the see-
page through same, if conditions show that, after drilling holes completely through
to the foundation structure of this part of the Dam, it be desirable and possible to
so grout the structure effectively.
5. A recording pressure gage should be properly placed within the Power House
and suitable connections made thereto to provide a daily record of variations in the
lake level.
6. The interior finish of the power house should be completed (not much remains
to be done in this respect).
7. All copper-aluminum joints made in lines and connections of electric circuits
should be clamped independently of solder (this is a small matter to be completed).
8. The "ground wire" in pump suction should be differently connected to
ground.
9. All ground connections on high tension line should be complete and prop-
erly made.
10. All crest gates should be properly staunched to prevent further than reason-
able leakage over the Dam, and properly balanced to operate automatically in open-
ing and closing within one foot difference in the lake level.
11. A concrete floor or basin should be placed around the large vent pipes near
the power house because these pipes act also as relief pipes for the water and same
Recommendations of Dr. Scott. 201
flows over the top of these pipes whenever a large decrease in load on the plant oc-
curs. This concrete floor or basin should be properly built to catch such overflow
water and direct it over the retaining wall into the river.
12. The draft tubes should be caulked wherever any leaks are found and these
tubes should be painted to insure their durability as the water is such as to act cor-
rosively upon unprotected wrought iron or steel surfaces.
13. The penstocks within the power house should be cleaned when necessary
and coated suitable with paint or other material to preserve them.
14. A suitable signal system should ba installed extending between the power
house and the inside of the Dam to be used when the sluice gates are being operated.
15. The clutch pulley which drives the small auxiliary exciter does not properly
do the work required of it, and same should be put into satisfactory serviceable shape.
16. A test has been made on each of the 6600 volt water wheel units at the Dam,
and while a detailed report on same cannot be made now, because of insufficient time
to make it, I am most decidedly of the opinion that the efficiency of this machinery as
a whole is comparatively high.
The motor driven pumps have not been tested as yet because of delays in get-
ting same ready for a test. Such delays having been caused by a combination of cir-
cumstances over which I had no control. Data obtained during a few short runs
made on the pumps to put them in shape for a test, indicate that they will meet the
efficiency guarantees, but a positive statement concerning same can be made only after
test data have been obtained.
With reference to the matter of a conditional acceptance of the Dam and its ap-
purtenances, power house machinery, etc., by the City of Austin, before the above
mentioned items shall have been made complete, I would say that in my judgment this
remaining work to be completed is of comparatively small magnitude when the con-
struction of the Dam and the installation of the machinery together with the building
of the reservoir as a whole are taken into consideration.
It is further my conviction from an engineering standpoint solely that none of
the items mentioned is one which likely to be impossible or very difficult or very ex-
pensive to complete. As an indication of the cost of completion as a whole would say
that undoubtedly the matter of less than $10,000 would be sufficient.
From an engineering standpoint I can see no reasonable objection to the accep-
tance of the Dam and its appurtenances as thus far completed under the general con-
tract, because I believe that good material and. workmanship have been put into the
structure and installation, and that same will be durable and serviceable, provided that
interests of the City of Austin can be satisfactorily safeguarded insofar as the com-
pletion of the balance of the engineering work to be done as above considered is con-
cerned.
Yours very truly,
(Signed) A. C. SCOTT.
APPENDIX 11
BIBLIOGRAPHY OP THE AUSTIN (TEXAS) DAM
(Arranged in Chronological Order)
Report of Jos. P. Frizell on the proposed dam and water works for the City of Aus-
tin, Texas, and the Consulting Engineer's Report. March 26, 1890. Published by
the City of Austin.
The Colorado River Dam at Austin, Texas, Eng, News, July 11, 1891. General in-
formation concerning the project.
The New Water Power and Water Supply at Austin, Texas. Eng. News, Aug. 18,
1892. Extracts from Report of J. T. Fanning on the project.
Austin, Texas, Water Works. Eng. Rec. Aug. 27, 1892. Notes on proposed changes
in Design.
Mr. Fanning 's Report upon the dam at Austin, Texas, by Jos. P. Frizell. Eng. News,
Sept. 29, 1892. Arguments in favor of the original design and comments on Mr.
Fanning 's Report.
The Austin Dam Controversy. Eng. Rec. Jan. 21, 1893. Extract from Annual Re-
port of Austin Board of Public Works.
The Austin Dam. E. W. Groves. Eng. News, Jan. 26, 1893. Description of the con-
struction of the work. This issue also contains the report of the Austin Board of
Public Works for the year 1892.
The Austin Dam Accident. Eng. News, June 29, 1893. Report of failure of the head-
gate masonry.
The Municipal Power, Light and Water Works of Austin, Texas. Eng. Record,
July 1, 1893. Description of project, particularly of the machinery.
The Colorado River Dam at Austin, Texas. Frank E. Snyder. Eng. News, Aug. 2,
1894. General description, giving quantities and costs of the original project.
Annual Reports of the Mayor and Other Officers of the City of Austin, Texas, for the
year ending Nov. 30, 1895, contains :
Report of the Board of Public Works.
Report of J. P. Frizell on the proposed dam and waterworks.
Report of John Bogart, Consulting Engineer.
Report of Emile C. Geyelin.
Report of J. T. Fanning on the dam.
Details of bids received and contracts awarded on the various items.
Sanitary reports by three physicians as to location of reservoir.
Reports on electrical system.
Report on Flowage.
Bibliography. 203
Eighteenth Annual Report of the Director. U. S. Geol. Survey, Part II, 1896-7,
p. 193. R. T. Hill and T. W. Vaughan. Geology of Edward's Plateau and Rio
Grande Plain adjacent to Austin and San Antonio, Texas, with reference to the oc-
currence of underground waters.
Twenty-first Annual Report of the Director, U. S. Geol. Survey, Part VII, 1899-1900,
by Robert T. Hill. Geography and Geology of the Black and Grand Prairies,
Texas, with detailed descriptions of the cretaceous formations and special refer-
ence to artesian waters.
Municipal Ownership at Austin, Texas, by W. D. Hornaday. Electrical World and
Engr. October 14, 1899. Illustrates and describes the serious condition of the
Austin, Texas, dam on the Colorado River.
The Silting up of Lake McDonald and the Leak at the Austin Dam. Thos. U. Taylor.
Eng. News, Feb. 22, 1900. Information relating to amount of silt deposited and
illustrated description of leaks occurring and means of remedying them.
Failure of the Great Masonry Dam across the Colorado River at Austin, Texas. Eng.
News, Apr. 12, 1900. Illust. description of break of April 7, and outline of pre-
ceding troubles.
The Failure of the Austin Dam. Eng. Rec. Apr. 14, 1900. Illustrated description of
the construction.
Failure of the Austin Dam. Eng. News, Apr. 19, 1900. Reports of the failure, by
T. U. Taylor, H. M. Chance and A. B. Roome.
Failure of the Austin Dam. R. D. Parker, Eng. Rec. Apr. 21, 1900. Illustrated
description of the failure.
Thoughts concerning the Austin Dam Failure. Eng. News, Apr. 23, 1900. Letter to
the editor discussing effect of silt on the stability.
The Failure of the Austin Dam. Eng. Rec. Apr. 24, 1900. Letter by Gardner S.
Williams, suggesting the vacuum beneath the nappe as a contributing factor.
The Failure of the Masonry Dam at Austin, Texas. Scientific American, Apr. 28,
1900. Brief description of work with remarks on causes of failure.
More Light on the Failure of the Austin Dam. Thos. U. Taylor. Eng. News, May
10, 1900. Discussion of causes of failure.
Soundings and Measurements at the Break in the Austin Dam. Thos. U. Taylor.
Eng. News, May 11, 1900. Report of soundings made June 9, 1900.
The Austin Dam Failure. C. Baillairge, Eng. Rec. May 19, 1900. Urges design of
dams with thickness equal to height.
The Failure of the Austin Dam. Wm. Von Rosenberg. Eng. Rec. May 19, 1900.
Illust. description of erosion at the toe.
Some Considerations Regarding the Failure of the Austin Dam. Eng. Rec. May 26,
1900. Editorial discussion on importance of foundation conditions.
204 Report on the Dam at Austin, Texas.
Speculation suggested by the Austin Dam. W. E. Hutton, Eng. Eec. June 9, 1900.
Discussion of effect of dam overfall upon the riverbed below.
Concerning the Austin Dam. B. D. Parker. Eng. Eec. June 30, 1900. Eeports from
various sources on the manner in which failure occurred point to undermining as
probable cause.
The Austin Dam. H. B. Patterson. Eng. Eec. July 28, 1900. Description of
causes of failure.
Another Communication on the Failure of the Austin Dam. Eng. News, Aug. 6,
1900. Letter on the probable causes of failure by McCarty & Son and comments by
T. U. Taylor.
The Latest Soundings at the Break in the Austin Dam. Thos. U. Taylor. Eng.
News, Dec. 6, 1900. Eeport of investigations made Oct. and November, 1900.
The Austin Dam. T. U. Taylor. U. S Geol. Survey. Water Supply Paper No. 40,
1900. History and description of the work, specifications, account of the various
accidents and failures which occurred in connection with the original structure,
studies of the silting of the reservoir and report of soundings made after the dis-
aster.
Coefficient of Friction in Dam Design and the Failure of the Dam at Austin, Texas.
H. P. Gillette. Eng. News, May 30, 1901. Discussion of theories advanced to ex-
plain failure.
An Estimate for Eebuilding the Austin Dam. Eng. News, Apr. 3, 1902. Part of
report and estimate submitted to City of Austin, March 24, 1902.
Geologic Atlas of the U. S. Austin Folio, Texas, Eobert T. Hill and T. W. Vaughan,
1902. Geology and Topography of Edward's Plateau and the Coastal Plain with-
in the Austin Quadrangle.
A Eeport on Eebuilding the Austin Dam. Eng. News, Nov. 12, 1908. Extracts from
Eeport by Messrs. Davis, Hill and Taylor.
The Austin, Texas, Dam. Eng. News Supplement Nov. 14, 1908. Comments on pro-
posed plans of reconstruction by W. G. Kirkpatrick, and note of report by Messrs.
Davis, Hill and Taylor.
The Austin Dam. T. U. Taylor. Bulletin Univ. of Texas. Dec. 22, 1910. History
and description of the work and extracts from various reports on the project as
follows : J. T. Fanning, Wilbur F. Foster, Geo. E. Evans, N. Werenskold.
This Eeport also contains :
Proposition of Consolidated Construction Co., Borings at Dam, by Kirkpatrick and
Blanton. Eeport of Government Engineers, Messrs. Davis, Hill and Taylor. Du-
mont Contract or Franchise.
Designs and Contract for Eebuilding the Colorado Eiver Dam at Austin, Texas. Eng.
News, Apr. 14, 1910. Eeviews history of dam and gives summary of contract for
Bibliography. 205
reconstruction. Gives list of previous articles in Eng. News pertaining to Austin
Dam.
The Control of Water. P. A. M. Parker. D. Vanostrand Co. New York, 1913. pp.
393 and 653. Discussion of causes of failure.
Reconstruction of the Austin, Texas, Dam. Eng. News, March 18, 1915. Illus-
trated description of the reconstruction.
Caverns under the Austin, Texas, Dam. Eng. News, Apr. 22, 1915. Letter by A. C.
Blanton concerning borings made in foundation and the findings based thereon.
The New Austin Dam and Power Plant. Elect. Eev. & W. Elect 'n. May 22, 1915.
Description of certain features of new structure.
The New Austin Dam and Power Plant. F. S. Taylor. Eng. Cont. May 26, 1915.
Review history and describes new plans.
Hollow Reinforced Concrete Structure Replaces Dam at Austin, Texas, which failed
15 years ago. Eng. Rec. May 29, 1915, June 5, 1915 and June 12, 1915. History
of structure, work of rendering seamy rock impermeable, and detailed description
of complete work.
Reconstruction of Austin, Texas, Masonry Dam. F. S. Taylor. Eng. News, June 3,
1915. A detailed description of various parts.
Power Development at the Austin Dam. F. S. Taylor, Eng. News, June 10, 1915.
Description of headworks and machinery installation.
Some Questions about the Austin, Texas, Dam. Eng. News, July 22, 1915. Letter
by J. D. Dustin concerning reinforcement, foundations, etc., and answer by F. S.
Taylor.
Hydro Electric Power. Lamar Lyndon. McGraw-Hill Book Co. Inc. New York,
1916, p. 285. Description of automatic crest gates.
More Trouble at Austin Dam. Eng. News, Apr. 6, 1916. Remarks on further dis-
turbances with special reference to crest gates and sluiceways.
Austin Dam Section Criticised. Eng. News. Aug. 3, 1916. Comments on extracts
from report by Bartlett and Ranney on the change in design of the reinforced con-
crete dam section.
The Austin Dam — Waterproofing the Rock Foundation. F. S. Taylor. Municipal
Engr. Oct., 1916. Outline of history and description of work to prevent leakage.
Annual Report of the Water, Light and Power Departments of the City of Austin
for the years 1913, 1914, 1915 and 1916. Contains comments and accounts of var-
ious points concerning the construction of the reinforced concrete dam.
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