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HI STORY AMD CONSTRUCTION OF THE POTOMAC AJUBSUCT
FOR THE 'ffATBR SUPPLY OF WASHINGTON
J. L. AflAMS
JANUARY 13, 1933
This Tnesie has been prepared and presented as a part of the
Initiation of Tau Beta Pi.
F )B£ I A H D
I wisn to extend my appreciation to
Mr. P. 0. Macqueen
Superintendent of the McMillan Faxk
Filter Plant for hie cooperation.
L'Snfact planned fountains in the Public paxris and a cascade of
water in front of the Capitol. The water was to have/ pumped from, local
streams. Well, cistern and spring water was depended on until 1850 for
domestic use. At that time spring water was piped to the Caoitol, White
House and residential sections of the City.
In 1860 CongresB appropriated $500.00 and the City flOOO.000 to
enable tne War Department to make a study/o determine tnejbest method for ob-
taining a water supply for the City, funds limited tais study by Brevet Lieut.
Col. ieorge W. Hugnes to Bock Creek.
In 1852 Congress appropriated $o000.00 for the same Purpose, The
assignment was made to Captain Frederick A Smitn wno did not start on tne
orobie.„ before nis deatn. Lieut. M. C. Meigs took the task and made a lengthy
but interesting reoort to Congress on February 12, 1853. Cories of this re-
port are In existence and will be summarized to sho?/ the completeness of the
SUMMARY CF SURVEY RESULTS AS PRESENTED TO COSGBESS
The water supplies of v?„ | .es of theCountry have been de-
signed on too small a scale and were soon tazed to tneir full capacity -
as New Yoric and Boston wnere tne use of water was restricted for domestic
purposes. Water for fountains and street flushing was not a waste as held
by some CitieB but an actual benefit since it cleaned tne City and improved
sewerage system operation. To carry out the plans of L'Enfnat an ade-
quate supply enoold be obtained.
In 1351 the water consumption of Bailadelthia was found to aver-
age 33 gallons per person. Summer consumption was three times that of win-
ter. At this same time the Croton Board of New Tork recorded 90 gallons
per person per day. All records showed an ever increasing denand for water.
In estimating the population it was assumed that the City would
grow at its present rate of 5,000 persons per year. At that rate the popu-
lation would be 250,000 persons using 22,500,000 gallons of water at a rate
of 90 gallons per person. Meigs also admitted that prosperity would increase
this rate of growth.
Water is free in nature and should he supplied by the Government
at cost. London was pointed to as a City having poor service and contamina-
tion, because six private monopolies controlled the supply. The cities al-
ready mentioned have taken over the duty of supplying water and Washington
should do likewise.
In any system storage should be provided to carry over breakdowns
and to act as a settling basin. It was stated that on occasions when the
supply was unedited that water from the reservoir could be used. Ueigs
proposed two hundred and fifty million gallons of storage whicn was an es-
timated ten day supply for 1890.
Tests of water were takea from Great Falls, Bock Creek, Little
Fails and Geor^etow^ at high and low tide and found to be of unrivaled
purity by professor Toreey of New Tork.
Pumping from Georgetown was proposed but considered unwise be-
cause the river at this point was subject to tides and likely to be con-
taminated from the flats between Georgetown and Long Bridge where sewage
might collect. Also steam engines are a source of danger. The Potomac
nae a narrow valley so floods cannot spread out but rise to great heights,
putting engines at low elevations out of commission. The plan was considered
out of the question and no estimates were made.
The study of Hock Creek was an ercansion of the work by Colonel
Hughes. The chang* was a higher dam further down the stream. Surveys
showed only a limited supply of water of about twenty million gallons.
Millers told of dry seasons with only about one fourth of that amount avail-
able with Btorage 9,860,000 gallons per day could have been Berved during
a 45 day dry spell. The upper watershed was pasture land unsuited as Bource
of water eunply, also being close to town unrestricted factories might pro-
duce contamination. The limited supply does not justify the expenditure
Tnis project included a masonry dam 41 ft. hign and a circular
brick conduit 6' in diameter falling one foot per mile. The project would
nave had small bridges, a receiving reservoir built of ruddied earth cover-
ed by stone paving after tne general mode of practice.
The Great Falls nroject included a dam 1541 f in length and 8' in
height across tne Potomac at Great falls to raise the water at low water
level from 14? to 150 feet above mean tide. A conduit to the tail of Lock
No. 18 with waste weirs to relieve pressure was to be constructed and water
to be taken under the canal by means of pii'es to the gate house. Over head
passages being deentd unsafe and too expensive. Valves in the -*ate house
were to regulate the flow througn a 7' circular conduit to receiving reser-
voir built by damming Little Tails or Powder Mill Creek and a distributing
reservoir further at Dover s Best. Water to a de-ctu of 6' will deliver
36,015.400 gallons Tver day and half full 17,734,300 gallons per day.
The grade of tne conduit would have several tunnels the long-
est 220 feet but in general the cut 6 were light. Cabin John required a
bridge and was to have been crossed by six small arches of 60* span.
By lowering the head five feet in the reservoir it was estimated
142,304,500 gallons of water would be available and 250,000,000 could be
had by reducing the head 14 feet.
Meigs was governed in his planning by the Croton and Cochituate
systems. He showed points where reductions in cost could be made but did
not advise any changes. The estimate was $1,630,618.
The Little Falls layout proposed a canal from Little Falls 6 1
by 100' located between the Chesepeake and Ohio Canal and the river to
get water to a Suitable location and by meanB of water power and a conduit,
conduct the water into a stand t>ipe and reservoir. The amount of water
which could be raised by tnis method was limited at the extreme by 18,000,000
gallons. The cost of tnis estimate was $1,306,739.
Tnis system was a part of Great Falls plan and could eventually
be extended to Great Falls as the puarelng became too great.
"In conclusion I have to recommend as, in
my opinion, the bestjtneans of affording the
City of Washington and Georgetown and un-
failing and abunaant supply of good and whole-
some water the construction of the aqueduct
from the Great F a lls of the Potomac."
"The source is pure and unfailing; the quan-
tity inexhaustible; the expense when compared
witu its objects, moderate. Every dollar of
capital expended will bring for centuries,
nineteen gallons a day of good wholesome
water into the City."
Other comments were the estimate was low and the only change to
be made would be to increase the size of conduit from 7* to 9' and capacity
to 67,595,400 gallons per day v.ith only slight increase in cost.
Meigs acknowl edged the use of the most accurate formulas of
hydraulics by D'Auduisson of Revetment Walls by Poncelet and thickness of
Arches by Feronnet.
To get the supply to the City tne total estimate for the projects
Hock Creek $ 1,258,863
Little Palls | 1,597,415
Great Palls $ 1,921,244
HISTORY AKD CONSTRUCT ICK
Congress accepted the Great Palls plan and appropriated $100,000.
on Marcii 3, 1853 to start surveys, preliminary wor^ and obtaining of the
right of way. The State of Maryland granted its consent to the uroposed work
by a special law on May 3, 1853, w::ich was to take effect when the project
was approved by the Chesepeake and Ohio Canal Company. This was obtained
about a montn later ana tae project was approved by President Pierce, on
June 28, 1853. President Pierce made the decision at this time to use a
She a ditional estimate for the change was $^50,000 or about one
sixth of the 7' estimate. If the 7* conduit had been selected it would have
been necessary to have started construction on an additional new conduit in
1880 after only 20 years service. Construction of a new conduit was actually
started in 1S25 after 6o years of service.
Obtaining right of ways proved to be a long, difficult and ex-
pensive proceedure. Water power rights were protested by the Great Palls
Manufacturing Conroany which claimed ownership of the adjoining land. A
small tract above lock Ho. 20 of the Cnesereake and Onio Canal was obtained
and selected as the starting point, T^e Inlet location was moved down the
river from Conn Island shortening the conduit "by 2, 985'.
In November 1853 work was started near Great Palls on tunnels
1, 2 ana 3 and the crossing of the Canal. In June 1864 the work stopped due
to lack of funds. At this time all needed lend had been condemned and a
sandstone quarry at Seneca seven niles above Great Falls had been ■curcnased.
Work was suspended for a year and Meigs used the time to revise his hasty
plans and estimates.
The appropriation of $250,000 March 4, 1855, made it possible to
resume work. Bids had to be open for sixty days causing some delay. In
1856 $250,000 atrcropriated for existing liabilities did not permit the wcr :
The conduit was about one fifth complete, six tunnels were start-
ed and 2028 feet of conduit were built. So bridges or reservoirs had been
Btarted. The fact that tne suspension of work was increasing the cost and
Bubjecting the structure to deterioration was brought to the attention of
Congress by Meigs with the result that $1,000,000 in 1857 and $800,000 in
1858 was appropriated.
then shortage of funds caused the layoff in June 5, 1857, the
project was 98> complete. Cabin John Bridge was the only large item remain-
ing unfinished. At this time Little Falls discharged in to the Balacarlia
reservoir, Tne conduit was complete from tnere to the Georgetown Reser-
voir and water wae introduced into the City, January 3, 1859.
In 1860 work was resumed with $500,000 appropriated with the
rovieion that Meigs sign checks. He was transferred to Florida September
1, I860, and was replaced by Caotaii. Benham. Benham could not draw money
and Meigs returned as .Engineer February 23, 1861. During the first year
of the Civil far work was again suspended and the labor transferred to
the army to construct entrenchments o.* the Virginia shore.
Ueigs was made quartermaster General of the Army and the aque-
duct was transferred to the Secretary of Interior, Jane 18, 1862. Under
the latter office Cabin John Bridge was completed late in 1863, and a
rock jetty was tnrown out firom the Maryland shore and 2' of Potomac water
was introduced in the conduit December 3, 1863 and flowed in to the re-
ceiving reservoir for two weeks starting December 5.
After use from January 14 to February 24 leaks were repaired at
Cabin John bridge and the conduit placed in regular service July 29, 1364
until September 1391. The upper end was partially drained in 1870 to remove
a rock slide in tunnel No. 1.
ut rock fill jetty from the Maryland shore was replaced by a
masonry dam 600' long out to Conn Island in 1866 raising the water to 4 f
in the conduit. This dam was extended to the Virginia shore during 1855-56
with a crest elevation 148' and length of 2877'. In 1896 the height was
raised to 150.5 giving a 75,o00,000 capacity. Since that time flash boards
have raised the water elevation to 152.5.
For all details of Cabin Joan bridge see "History and Construct-
ion of Cabin John Bridge" by Cnarles MotnerBnead Class '33.
In 1891 the reservoirs were complete and filled to thermit an
inspection made by Colonel Elliot. The recommendation for cleaning were
carried out from 1895-96 removing 8,946 cu. yd. of mud and *bri8 at such
times as the conauit could be arained.
Congress set aside as an emergency fund $5,000 annually to be
used for serious breakdowns. Colonel Longfit started the job of putting
lining in the unlined tunnels In 1911. ty using stored water during low con-
sumption, 20 to 30 periods of 96 hours each could be had a year for tnis work.
The work was continuea under Colonels Langfit, Newcomer, Flagley and Fish un-
til 1918. About 1000 feet of tunnel had besn lined at a cost of over $50,000
and would have taken 28 years to complete.
Studies for a new conduit were under way and due to the shortage of
labor, work was stopped in 1918. In 1925 the new conduit was completed and
placed in service. The old conduit was drained during the fiscal year 1927
while Warren ¥. Brenizer Company, contractors, completely reconditioned the
old structure at a cost of $201,286.24 including cross connections between the
old and new conduit.
The old conduit was placed in service in 1927. It has been oro-
tected by the new construction ^0 ft. away and should continue to give ser-
vice for time to come with low maintenance. No repairs have ever been made on
a two mile section between Delacarlia and Georgetown reservoir b and it appears
to be in good shape just as left by Ueigs.
The road over the aqueduct was first recommended in 1868. Parmer s
living along the conduit began using the clay fill as a highway and the ruts
were so deep in some places as to expose the masonry. A macadamized road was
deemed necessary to protect the aqueduct. This work was carried out 1870-75
at a cost of $46,000. Tne aqueduct maintenance greatly aided but a total of
#200,000 has been spent on the road.
Tne property purchase for tne receiving reservoir at Little Falls
was a part of the Dalecarlia farm and tne name was adopted for the Reservoir.
Early maps nave the name spelled Dalekarlia. According to Mr, Macqueen the
old name Dalecarlia is tne name of a Swedisn province.
construction asp MAiKTSKAKca
Tne work was divided into sections with complete estimates,
mat eriaia available and specifications when advertised for bide. Bidding
was done on tne unit cost "basis because of character of work. Under the
contracts let the contractor was payed on the basis of nine tenths of a
monthly estimate made by the cuiei engineer -orovided there were no labor
liens for the previous month. Claims for extra work had to be authorized
each montn by the engineer.
Tne gdtrnment purchased all material* and supplied forms and
centers for economy. The contractors were fined for waster or misuse.
The nrofiles In the appendix show tne greater part of conduit
was built in open cuts. Thei)reliminary contractor made tne cuts and fills
to the horizontal center line of conduit which defined the grade. The con-
traces for the conduit made the lower half of this excavation about 100*
ahead of completed construction. In thie way the lower half of ring was
layed on solid eartn for about 100'. Forms and centers were erected and
the top half built. Tne excavation when suitable was backfilled on the
completed structure and rammed to give the arch some support. See tyoical
section and conduit specifications is tne appendix.
Tnis method was used in open construction to stay within the
200 • free naul when using wheel-barrows.
In fills the brush, trees, stumos, and top soil were removed.
The fill of earth free from organic matter and large stones was plaeed in
3" layers and rammed by hand. A 6° layer was permitted when puddling
was used. The surface waB roughened between layers to get the proper bond.
The fillB were 44' wide at the top on horizontal center line of this con-
duit with a 1:2 slope. They were then left for one year out usually several
years to settle before the conduit was "built.
With the limited equipment of the time consisting mainly of steam
hoist derricks it was cheaper to tunnel than to make deep cuts. Mr. George
H. Coryell of the Pennsylvania Bailroad was made cnief tunnel engineer. The
original -oalns called for linings in the tunnel* hut in eound rock they were
omitted to reduce the cost. See appendix typical section. A total of 5,392'
of tunneling was done, ranging from 86' to 1437* in length.
Culverts were provided i:* 28 places. They were i: general semi-
circular "brick arches or circular "brick pipes of varied sizes with cut stoned
end. In some places manholes were used to get to the dvert elevation.
Bridges 1, 2 and 3 were small arches of only minor importance.
A gate house was built at Great Falls over the entrance to tne con-
sult and nad ten cast iron gates, 2' x 5' for regulating the flow by raising
or lowering in slots by screw jack action. Tne entrance of the conduit in
the gate house at Great Tails has an elevation of 149.4* on the intrados of
arch ring falling about 9| inches per mile. Water flows 9.28 miles from
there to the Dalecarlia reservoir. In 1895 the original gates were Broken
and replaced waste weirs were constructed to prevent any operation under head.
Breathing towers were constructed to further regulate the flow when only
part full. There was no mention of the breathing towers in the original plans,
Sickness among the men was higa and at several times the work
was closed down due to outbreak of malaria. The sickness season of August,
September and October frequently s.iowed a dr ae labor force. This
became k;»own among the men aid they did not like to work at Great Falls.
The common labor was white and only a few negro slaves were on the
actual construction work between 1857- 1960, The labor force varied from
fifty during lay off to a maximwn of about 4,000 during periods of great
activity. Tnemen lived in boarding houses furnished by the Government.
The Washington Aqueduct was the third to be built in the United
States. To appreciate the engineering feat one need only consider the size
of the oroject and the absence of our modern equipment and methods of con-
SPECIFICATIONS FOR THK Av"KD U CT FRSPAB2D BY U5IGS WHICH ABB
OF PARTICULAR INTEREST
SPECIFICATIONS FOR CONDUIT - the Conduit will be of circular and generally
of nine feet interior diameter; it will when of brick, generally be built of
three separat-e four and a naif- inch rings of hard brick. Where it passes
through the ground risings as hign as the intrados of the arch, the inner
ring will sometimes be omitted, and the brick work reduced to nine inches.
In rock cuts and other deep cuts where suitable stone is on hand,
concrete or rubble stone masonry will be subttiiuued for brick, in whole or in
part, particularly in the lower or reversed, arch.
The center of the conduit at any point is the grade of the aqueduct
at that place. Ine excavations and embankments will be made to the level of
lae grade at eacn place of operations before the contractor for the conduit
will be allowed co commence nis work there. The excavation for the lower
semi-circle or reverseo arch, . owever, will generally be made by the eon-
tractor for the conduit and it will be trimmed out buc little in advance of
the laying of the masonry.
BRICK MASONEY IN CONDUIT - the bricks, at the time of laying, will be thor-
oughly wet; every bricic must be laid and pressed down into a full bed of
mortar, which shall cover its bed and joint; and this bedding shall be done
at one operat-i-n for each brieve, so that no mortar need be worked in after
the brick is placed. The inner edge of the .joint of each course will be the
lease possible to admit of mortar between ihe bricks. The joint of mortar
between eacn two rings will not be less than three-eighte of an inch in
STONE UASOHET Of CONDUIT - This will be made of &■&!! rubble stone, none of
wnich will exceed fourteen inob.ee in widtu. or di . Eacn stone will be laid
in a full bed of mortar and hammered until the mortar ie -r eased out at the
front and the joints are conirletely filled. Its inner surface will be well
plastered with a coat of cement mortar and be floated smooth e nd even.
ORETS - One barrel of cement, (?00 lbs. net) with two and a half barrels
of sand find tnirty cubic feet of stone will malie a batch of concrete. The
mortar having been spread on a bed of plank, the broken stone will be spread
evenly over it and the whole mass turned over twice and thoroughly nixed with
a hoe or snctel. When mixed and laid it shall be rammed into a compact and
water tight mass. (Note-Tnese proportions are roughly 1:2; 10, which is much
weaker than used at present.)
MOSIAR - Tne mortar for masonry will be made of two and a half rarts of sand
to one part of cement. The sandaud cement after being measured, will be mixed
dry and small quantities only taken from the hear, will be mixed with water
as required, (note - the mortar for concrete was made first and amount of water
was kert low. )
CEMENT - all cement must pass the test of setting hard under water and not
breaking uj into lunr. s. fnree hundred pounds net of cement will b3 estimated
as one cask or barrel. (Note — This was of course natural cement as Portland
cement was notmade at that time. It came f r ■■•a Maryland, New Jersey and Penn-
sylvania and was delivered on the dc Georgetown. The inspectors tested
small specimens which were considered gooA if the Bet occurred in 30 minutes
or less. )
SAND - None but good clean sharp flint of silicious sand will be received.
Proposals will state the number of bushels the bidder will undertake to
deliver. |Note - the Contract price was d cents per bushel delivered on the
bank of the canal in bins prepared for It 8 reception. Coronet it ion was brisk
and lower prices were obtained later.)
BRICK - Hone but well made hard burnt bricks, entirely acceptable to the en-
gineer, will be received, and they muBt be made in moulds conforming in size
b ^he municipal regulations of Washington City,
A I 2 & 4 £ I COSTS
Hard rock excavation
Soft rock excavation
Laying stone masonry
Furaiau Seneca Sand Btone
Concrete in place including only transporting
mixing and laying
Masons, stone cutters, plasterers, carpenters
$ .151 cu. yd.
1.25 " ■
.75 » "
2.25 " ■
3.00 ■ ■
.26 cu. ft.
3.25 cu. yd.
6,00 cu. yd,
2.00 -3.00 per day
1.00 -1.25 " ■
1.20 " ■
CLASSIFICATION OF TYFICAL PAYBGLL IK 1853
Assistant Engineers 5
Surveymen t inspectors 50
Skilled mechanics 700
Unskilled laborers 1100
Cooke & wait 60
EUAliD 2 A I A
Drainage Area above Great falls
Average demand of Washington
Maxim-urn demand of Washington
Capacity old conduit
Capacity new conduit
11,050 sq. miles
11,900 cu. ft. per. sec.
8,700 mil. gals, per day.
80 mil. gals, per day.
110 mil. gals, per day.
80 mil. gals, per day.
120 mil. gals, per day.
Dalecarlia fydro Electric Plant using wastewater up to
120 mil. gals, per day.
The quantity of Hater for Power will decrease as the City
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Head Conn Island Original Location of Dam
Actual Location of Dam
Great Falls Below the Bam.
dead of Little Palls from Conduit Road.
Bi- Conduit at Dalecarlia opened for Alterations,
Th.e picture reeeablee prints of actual con-
irate House at Great Falls,
Intake of Old Conduit is Under the Crane. Also
Section of tne Masonry Dam.
Large Calvert Ho. 12
itat ranee of Ma n hole down to circular brick
pioe under Conduit.
Cabin John Bridge or Bridge No. 4. Part of Inverted Siphon
Of New Conduit
Bridge Number 3.
Dale carl ia Reservoir. Small house contains gates
for draining the Reservoir.
Old G-ate House Dalecarlia Reservoir
Breathing Tower and Road.
Up.te Connections between old and new Conduit.
-■ - • ■
Sign Pound at Crossroads along Conduit Road.
Conduit Road & fill over new Condj.it on the
COPIES OF ORIGINAL PICTURES MADE DURING ACTUAL
I [01 FROM CAPT. 11. C. MEIGS SCRAP
SOME ORIGINAL PRINTS CAN ALSO BE POUND AT
OPEN CUT SiiCTTIN'} FLWAI EXCAVATI*!? JUST ahead OF ACTUAL CON-
STRUCTION. PATd AT SIDE IAS PRELIMINARY EXCAVATION LEVEL.
laipu loser brick halt of ring complete, completed
CONDUIT FORMS IN PLACE WITH EARTH BACKFILLED ALMOST
TO END. EXTRA FORMS IB Tdz. BACKGROUND.
BRIDOS NO. TIO UBUSH COHSTHUGTIOH MOUTH OF TUBHEL AI LOT.
MOUTH OF TUffiJriL SBOWIU& TZ&GK CARS AND VOBKUSS. KOIE
SI^: SB BLOCKS.
JTQBKIKS OU GFaH Coi . . BAuKGBOUML.
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MATLOCK, SHGV3L, CROW BARS AND TOOL BOX
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History of the Washington Water Supply by P. 0, Macqueen
- being written -
Captain U. C. Meigs Scrap Book - - War College Library
Annual Report Office of the Washington Aqueduct 1856-87
- Public Library -
Land Condemnation — House Document No, 1400, 62nd Congress
— 3rd. Session Page 62 - - Poblic Library
Construction Authorization — Mar. 3, 1853 — 10 Stat L. ,
— 206 — Library Congress —
Great Palls Dam — July 15, 1882 — 22 Stat L. 1882 —
— Library Congress —
Raising Great Falls Dam — 28 Stat 753 — Library Congress
U. S. Engineering Department — Annual Report of Maintenance -
— 1895 — Public Library
Water Sucply of Wasnington — Col. Alexander M, Miller -
— Public Library —
Military Engineering — Sept. Oct., 1927 — MacMillan Pari
John Clagget Proctor Articles in Washington Star — Collected
in Public Library
S 2U M A E I
The City of Washington was feeling the affects of a limited water
supply in 1850 when a preliminary study was made. Another study was made in
1852 by Lieutenant U. C. Meigs, who submitted rough plans and estimates for
three possible sources, namely, Hock Creek, Little Jails and fir eat Jails,
The last named plan was recommended and accepted because of itB unfailing
Congress appropriated over $3,000,000 for the project at various
times from 1853 until the job was completed in all details in 1885. Water
flowed in conduit in 1863 but actual service started in July 1864.
A dam at Or eat Falls raisesyhead so that water flows by gravity
to a receiving reservoir, Delecarlia, and the Georgetown reservoir a dis-
tance of 11.0s miles*
The famous Cabin John bridge is a part of the aqueduct and was
s largest single stone arch in the world for a number of years.
A new conduit has been built and put into service. Tne old
structure has been completely reconditioned and is still in active service
working at full capacity.