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Full text of "Environmental effects of dredging and disposal in the San Francisco Bay estuarine system : a report to the Association of Bay Area Governments"

SAN FRANCISCO PUBLIC LIBRARY 




3 1223 06899 1570 



ENVIRONMENTAL EFFECTS OF 

DREDGING & DISPOSAL 

IN THE SAN FRANCISCO BAY ESTUARINE SYSTEM 





JANUARY 1978 

I SPECIAL STUDIES PROJECT FOR 



REF 

614. 77 
D63e 



ASSOCIATION 
OF BAY AREA 
GOVERNMENTS 
OABAG 



ENVIRONMENTAL 

MANAGEMENT 

PROGRAM 




PREPARED RY: LOUIS H.DISALVO 



APR 2 8 1978 



DOCUMENTS OCPT 
8.F. PU UG LIBRARY 




San Francisco Public Library 

Government Information Center 
San Francisco Public Library 
100 Larkin Street, 5th Floor 
5an Francisco, CA 94102 



REFERENCE BOOK 

Not to be taken from the Library 




ENVIRONMENTAL EFFECTS OF DREDGING AND DISPOSAL 

IN 

THE SAN FRANCISCO BAY ESTUARINE SYSTEM 



a report to 



The Association of Bay Area Governments 
Hotel Claremont 
Berkeley, California 94705 



Louis H. DiSalvo, Ph.D. 
Marine Science Consultant 
315 Melven Court 
San Leandro, CA 94577 



Cover Design by Pat Wong 



Digitized by the Internet Archive 

in 2014 



http://archive.org/details/environmentaleff1978disa 



TABLE OF CONTENTS 



PAGE 



STATEMENT OF PROBLEM 1 

INTRODUCTION 4 

SECTION I: BASIC CHARACTERISTICS 5 

Structure and Water Circulation 5 

Sediments 9 

Chemical Processes 13 

Biology 16 

Dredging 18 

SECTION II: ENVIRONMENTAL IMPACTS 23 

Direct Effects 24 

Indirect Effects 29 

SECTION II: REGULATION OF DREDGING 37 

CONCLUSIONS 41 

RECOMMENDATIONS 43 

LITERATURE CITED 44 

APPENDIX A 48 

APPENDIX B 52 



3 1223 06899 1570 



STATEMENT OF PROBLEM 



"Dredge Rules Pose Disaster" 

SF Examiner, Oct. 27, 1972 

"A Witches Brew of Waste" 

SF Examiner, Feb. 4, 1973 

"Tougher New Dredging Controls Win Support" 

SF Examiner, March 22, 1972 

"Bay Dredging Controls Held Too Expensive" 

SF Examiner, March 21, 1972 

"Army Bests Navy in Dredging Dispute" 

SF Examiner, Jan. 28, 1972 



The preceding are but a small sample of the headlines which have described 
the often strident controversies which have developed over the conduct of 
dredging, and disposal of dredged material in the San Francisco Bay estu- 
arine system. On the wave of environmental activity of the 1960 's and 70' s, 
many people came to the realization that they lived near the shores of a 
valuable environmental resource. They carried out significant political 
actions which resulted in legislation to stop the filling of the Bay and to 
control development around its shores. Nationwide, environmental awareness 
led to a call for more stringent environment protective legislation, cul- 
minating in passage of a number of Acts of Congress including the Federal 
Water Pollution Control Act, The National Environmental Policy Act, and the 
Marine Research, Protection and Sanctuaries Act, among others. With these 
laws, Congress, representing the people, began a long and tedious process 
aimed at controlling activities deleterious to the environment, including 
the unregulated disposal of dredged material in the nation's waterways. 

As the newspaper articles suggest, people became aware indirectly that es- 
tuaries are natural sediment traps, and that San Francisco Bay was indeed 
trapping large quantities of wastes within its sediments. These sediments 
inconveniently settle out in quiet areas of the Bay blocking harbors and 
waterways of commercial, military and recreational importance. Indirectly, 
the Army Corps of Engineers, which is normally charged with the responsi- 
bility of maintaining the waterways, became involved with wastes discharged 
into the Bay. The discovery that the Bay dredged material was sometimes 
highly contaminated was a finding repeated for a number of the nation's es- 
tuaries. National impetus was given to evaluation of problems, development 
of reasonable rules and regulations for the disposal of dredged materials, 
and far reaching planning efforts to stop contamination of the estuarine 
sediments at the source. 



-1- 



This report summarizes some aspects of the problem as it currently stands 
for the San Francisco Bay system, with a resume of current research begun 
several years ago in response to public demands. Emotionally charged 
debate has at least been supplemented with a resolve to obtain reliable 
scientific information upon which to base environmental management deci- 
sions. Unfortunately, the basic nature of scientific research is that 
it is slow and costly, and that answers are not generated as quickly as 
some would like. It can only be hoped that as future disputes arise, the 
available and emerging scientific information concerning the ecological 
impacts of dredging and disposal will be taken into account by adminis- 
trators, regulatory bodies, expert witnesses, and perhaps even the judges 
who may need to make critical rulings. However, since there is substan- 
tial academic debate in some areas related to dredging and disposal is- 
sues, the mere existence of selected bodies of scientific data does not 
guarantee resolution of an issue. Since the Bay system undergoes multi- 
ple usage by various segments of society, it is of paramount importance 
to realize that ultimate decisions concerning dredging and disposal will 
be based on economic, social, and political realities, as well as knowl- 
edge of the Bay system. 



-2- 



ACKNOWLEDGMENTS 



I wish to thank my colleague, Dr. Harold Guard, and 
research associates Ms. Nina Hirsch and Mr. Robert 
Simon, for aiding in various phases of the develop- 
ment of this report. Special thanks are extended 
to the files section of the San Francisco Examiner, 
the library of the San Francisco District Army Corps 
of Engineers, the Water Resources Library of the 
University of California at Berkeley, and the Naval 
Facilities Engineering Command, 12th Naval District, 
for their assistance. 

I further thank the experts in various disciplines, 
particularly the members of the ABAG Special Studies 
Technical Advisory Committee for constructive sug- 
gestions rendered in the development of this study. 



-3- 



INTRODUCTION 



This study is an attempt to evaluate the current state of knowledge on 
the effects of dredging and disposal practices in the San Francisco Bay 
estuarine system. Estuarine processes are in general complicated, and 
those of the San Francisco Bay system particularly so, which render 
comparison with other estuaries difficult. 

The first section of this report presents some general characteristics 
of the system in simplified terms, and discusses general aspects of 
dredging and disposal. Readers familiar with these topics are asked 
to refer to other references for more detailed discussions (2,3,4,5). 

The second section of this report is devoted to discussions of recent 
research on potential deleterious effects of dredging and disposal in 
the Bay system, with some relevant inputs from the general literature. 
Readers who desire greater detail should refer to the references re- 
viewed, as these without fail contain extensive literature surveys 
in each area. Broad literature surveys in these fields would have at 
least doubled the size of this report. The diversity of estuaries 
and nature of the different sources of wastes on their margins have 
generated a diverse body of literature on the effects of dredging and 
disposal in different esturine systems. In most cases, literature is 
so site-specific that there is little rationale for attempting to 
transfer systems-wide interpretations of effects. There are, never- 
theless, comparisons which may be made between all basic processes, 
such as the fundamental chemistry of sediment-metal interaction. 

The third section of the report has been devoted to a summary of the 
regulation of dredging, its basis, and current trends in regulatory 
criteria. This is a fast-moving field, for which much new information 
has recently been made available. Environmental concern at both na- 
tional and state levels has resulted in a body of legislation which 
has been employed in preventing overt environmental impacts, partic- 
ularly from filling activities. Enforcement of the legislation is 
undergoing an evolutionary process as new research results are made 
available and translated into regulatory criteria. Numerous Federal 
and State agencies affect the granting of dredging and disposal per- 
mits for the Bay. Some agencies have direct permitting power, while 
others have commenting functions which carry great weight in final 
permit decisions. The data base from which sound disposal practices 
may be determined is not complete, although interim guidelines are 
now available. Emerging scientific data are beginning to suggest 
that a number of presently used guidelines for the evaluation of 
contamination of dredged material are probably too restrictive. 



SECTION I 
BASIC CHARACTERISTICS 



Structure and Water Circulation 

The San Francisco Bay estuary, following the definition of Pritchard 
(1), is a semi -enclosed body of water which has free connection with 
the sea (Golden Gate), and within which the seawater is measurably 
diluted with freshwater derived from land drainage, primarily the 
Sacramento and San Joaquin Rivers. Geologically, the form of the Bay 
system was produced by tectonic processes in which movements of the 
earth's crust downfaulted the bay basin and uplifted the surrounding 
hills. The original surface area of the Bay systems was probably 
about 2038 sq km (prior to 1850). It is estimated that there were 
originally about 800 sq km of marshland surrounding different parts 
of the bay, although today, fewer than 325 sq km of marsh remain (2). 
Since 1850, over 600 sq km (30%) of Bay mudflat and marshland have 
been converted for salt production, agriculture, industry, recreation 
waste disposal, transportation, and military use. 

The present Bay system includes four major sub-bays as illustrated in 
Figure 1. Perhaps the most striking feature of the estuary is that 
the single opening to the sea, the Golden Gate, is only one mile wide 
This is in contrast to drowned river valley estuarines on the East 
Coast (e.g., Chesapeake Bay, Delaware Bay) which have broad openings 
to the sea many miles across. The Golden Gate opens to the Central 
Bay, followed by the South Bay to the south and San Pablo Bay to the 
north. The final embayment, Suisun Bay, to the northeast, is con- 
nected to San Pablo Bay by another deep channel, the Carquinez Strait 
Bathymetry of the Bay is shown in Figure 1. Freshwater flows into 
Suisun Bay through the complex inland delta formed by the Sacramento 
and San Joaquin Rivers, at a rate dependent on the annual rainfall in 
the drainage basin of the rivers. In recent years freshwater inflow 
has been reduced by removal of freshwater transferred to Southern 
California (see Special Study, Delta Outflow). 

"The net delta inflow is complicated by tidal action, 
but it is estimated to be about 16.8 million acre-ft. 
per year (57,000 cfs) under present upstream develop- 
ment conditions. Historically, without any flow reg- 
ulation or diversion, Delta input was estimated to be 
30.3 million acre-ft. per year." (3) 

In years of normal freshwater runoff, Suisun Bay is composed mainly 
of freshwater; the first major mixing zone where seawater meets fresh 
water is in San Pablo Bay, although in dry years, reduced flow of 
freshwater allows intrusion of salt-water into Suisun Bay. Table 1 
lists a number of water quality characteristics for the different em- 
bayments as reported by the University of California SERL study (4). 



-5- 



TABLE 1. SUMMARY OF WATER QUALITY CHARACTERISTICS 
OBSERVED IN SAN FRANCISCO BAY 



Partimet'.'i- 


Unit 




South 
Bay 


L.-ve r 


fv.y 


M rtti 
!»iy 


Temperature 


C 


a 

low 

mean 

high* 


9-3 

J." • j 
2« .0 


10-7 
it .8 
21 .0 


10. 1 

19-0 


11 -5 
l-'t • 1 
17. 6 


Oecchi disc 
transparency 


ft 


low 

mean 

high 


0.5 

1 o 

i -y 
I..0 


0.5 

? • J 

6.5 


1.0 
-> • 6 

9.0 


1-5 

5 .9. 
6-5 


pH 




lov 

mean 

high 


!■?. 
R.O 


7-8 

7 

8.1 


7.6 

7.9 

8.1 


7-5 
7.85 

8.0 


Suspended solid.?. 


me/ 1 


low 

mean 

high 


15 


8 
56 


5 
36 


6 

21 
57 


Chloroslty 


3/* 


low 
high 


9-5 

J- > 

19 


13-5 

16 

17 


15-5 

18 


10 
16 
13 


Dissolved oxygen 




low 
high 


0.7 
5 ■ 1 
8-5 


7-0 
7.I1 

8.5 


6.5 

7-5 

3.2 


6.2 

7- 4 

8- 5 


Dissolved oxygen 
saturation 


p 


low 

mean 

high 


9,5 
55 

92 


81 
90 

99 


80 
8lt 
92 


75 
85 
96 


Biochemical oxygen 
demand 


KS>lt 
"<ii 


low 

mean 

high 


0.5 

10 

f pin 


0.1) 

0.8 

1-5 


O.U 
0.7 
1.0 


0.1 
0.7 
1-5 


Aj.unonta nitrogen 


"'r / * 


low 
high 


11 


0.O6 

0.12 

0.21 


0.05 
O.15 
O.'tfl 


0.05 
0.13 
■>.9M 


Nitfute nltro*4<*n 


m.j f 9 


low 
high 


O.O'j 

* • j j 

i.i 


0.08 

0. 3I4 

0.55 


0.16 

0.36 


<>. iP 
'i.?5 
O.38 


RcActive phosphate 




low 
high 




0-5 

0.5 

0.8 


0.2 

0.32 

Q.k 


0.2 
0.2 
' O.U 


Dissolved silica 


voe/t 


low 

mean 

high 


2-3 
8.7 
16 


2-9 

7.7 


l.lt 

3-6 
5-5 


2-5 

u'.B 
6.8 


Coliform bacteria 


MPJ.'/lOO n/ 


low 

mean 

high 


10 

2 x 10* 

3 x 10 s 


10 

5 x 1C ? 
5 x 10* 


2.00 
1 x 10 3 
6 x 10* 


200 
5 x 10* 
1 x 10* 


Total microplar.kton 


ceils/f 


low 

mean 

high 


1.2 X 10 3 
l.i, x 10* 
3.S x 10 5 


3.0 x 10 3 
1.0 x 10* 
1.5 * iO 6 


* ' x 13 s 
5.7 y 10 4 
£.7 / :o« 


-.-. x l.O 3 
'./' .< 10* 

5 . . x 10' 


Total zoopianJcton 


crg/cu r, 


low 

mean 

high 


500 
7,000 
40,000 


5,100 3,000 
5,800 1 7,6y. 
12,00-; j 15,000 


1,000 
£ . ooo 
;.j,ooo 



3a n rtibli 



Bny 




h«y 

1 


8.3 


6-9 


1 ** -9 


1 5 • r> 




21 ■ 5 

i 


0.5 




1 »o 




J ' ? 




7.2 




7 6 1 , 


7 e=; 


7 O 
1 -7 




13 


Jit 


"»? 


W 




1 12 


3.5 


0.02 


10. s 


2 ■ 5 


16 


8.5 


6.8 


6.6 


8.0 


8.1. 1 


9.^ 


I 

10.2 


80 


65 


85 


85 


92 


9lt 


0.1 


O.lt 


0.8 


1 . 1 


1.4 


0.1 


0.06 


0.01 


0.1 c , 


. J 5 1 




0.2'J 


0.03 


O.'J'i 


0.35 


0. ',1 


1.0 


0.0', 


0.2 


0.1 


0.30 


0.20 


O.U 


0.5 


1.4 


1.5 


6.8 


13.6 


lit 


30 


20 


700 


1 x 10 3 


' x "> 3 


1 x 10* 


2 x 10* 


.0 x r, 3 


4 .6 / 10* 1 


.7 x 10 4 


J.C x 10'- ! 



300 

10,000 

sa,ooo 



y/j 
5,000 
15,000 



low = 5 percentile value, 
^igh - 95 percentile -value. 



(from Ref. 4) 



-7- 



Aside from geological origins, estuaries are often classified on the 
basis of their characteristic water circulation and the ways in which 
seawater meets and mixes (or does not mix) with the freshwater inflow. 
Water movement in estuaries is governed primarily by tidal action and 
freshwater inflow. These forces are modified by the action of the 
wind and density currents which are usually of low magnitude but still 
of importance in all discussions of estuarine water movement. Cir- 
culation is further modified by the configuration of the "walls" of 
the estuary, including the shape of its shoreline, bathymetry (depth 
profile), and the presence of islands and peninsulas. Drowned river 
valleys, such as Delaware Bay, have comparatively well-defined water 
flows based on their linear shape. The multiple embayments of the 
San Francisco Bay system produces complicated circulation patterns. 

The volume of the Bay is approximately 6.7 x 10^ cubic meters (5). 
Approximately 24% of this volume is moved in and out of the Golden 
Gate on an average tidal exchange (5). This shows the extremely 
large forces at work when considering the tide as a force in water 
movement. The tides in the Bay system are primarily semi-diurnal 
(two highs and two lows daily), which create strong currents in the 
channels ranging from 225 cm per sec (4.2 knots) at the Golden Gate 
to 100 cm per sec (1.8 knots) at the extreme end of the South Bay. 

A second force driving water movements in the Bay is that of the 
prevailing summer winds and sporadic winter storms. These winds 
create non-tidal water flows amounting to a small percentage of the 
wind speed (5). This circulation is effective primarily in the Bay 
shallows. 

A third force in water movement is the mass flow of freshwater into 
the Northern Bay through Suisun Bay and the Carquinez Strait into San 
Pablo Bay. 

"More than 90% of the mean annual river discharge 
(840 m3 per sec) entering the Bay is contributed 
to the northern reach by the combined flows of 
the Sacramento and San Joaquin Rivers; the re- 
maining 10% is contributed by small tributary 
streams and sewage inflow." (5) 

This force is dissipated in the upper reaches of the Bay. 

Freshwater river inflow is lighter per unit volume than seawater and 
thus tends to flow out on top of seawater, particularly when other 
mixing forces in an estuary are weak. This separation of waters 
is known as stratification . In the San Francisco system, this phe- 
nomenon occurs mainly in the upper reaches of San Pablo Bay and in 
Suisun Bay. Tidal and wind-driven currents tend to mix fresh and 
salt-water in the lower reaches of the Bay. In general, the greater 
the river flow, the greater degree of stratification that can be 
expected. 



-8- 



"For low freshwater inflows (140-280 nr/sec) all 
portions of the Bay system are considered well 
mixed; for inflows 2830 m3/sec, the Golden Gate 
and extreme South Bay areas remain well mixed, 
but mid-South Bay, San Pablo Straint, and 
Carquinez Strait change to a partially mixed 
condition. In the area above Carquinez Strait, 
the flow is highly stratified. For an inflow 
of 5660 rrvVsec (note: extremely wet year), 
there is no evidence of well mixed conditions 
anywhere in the system." (2) 

Stratification of estuarine water produces a fourth major movement of 
water known as density current , or "non-tidal drift" (5). In San 
Francisco Bay, non- tidal drift is a current set near the bottom, run- 
ning northward up San Pablo Bay and into Suisun Bay and may show 
speeds as high as 10 cm per sec. The region where non-tidal drift up 
the Bay is counterbalanced by the magnitude of river flow is known as 
null zone . This zone may migrate northward or southward in the system 
depending on the magnitude of river runoff in any given year (6). 

In summary, the four major embayments shown in Figure 1 constitute four 
(interconnected) functional subsystems of the estuary, each with dif- 
fering major characteristics of bathymetry, salinity distribution, and 
water movement. The South Bay is generally shallow and rarely has a 
major influx of tributary water. It is a high salinity lagoon with 
both tide and wind effects important. The Central Bay is deep, domi- 
nated by tides and rarely stratified. San Pablo Bay is shallow, often 
stratified and affected strongly by both wind and tides. Suisun Bay 
is moderately shallow, often highly stratified, and highly affected by 
river flow, with less influence from tides and wind. Although much 
work has been done, no predictive models are as yet available for water 
circulation throughout the Bay system. 

Sediments and Sedimentary Processes 

The preceding section has provided a broad view of the complex factors 
governing water movement in the Bay. Water movements dominate the 
sedimentary processes in the Bay, which, in turn, govern the needs for 
dredging and mediate the effects of aquatic disposal of dredged mate- 
rials. 

Sediments are aquatic soils commonly known as muds and sands. Sedi- 
ments result from soil erosion and washing of mineral and organic 
matter from the drainage basin into rivers, by which they are carried 
in suspension or dragged along the bottom ( bedload ) until they reach 
estuarine or ocean waters. The parent rock substrate of the Bay 
system (Franciscan formation) is overlain with hundreds of feet of 
sediments deposited since the geological origin of the Bay. 

Sediments are categorized on the basis of particle size as shown in 
Figure 2. Sedimentary particles common in estuaries include micro- 
scopic colloidal particles, clays, silts, with minor amounts of sand. 



-9- 



Scales 



Wemworth (1922) 
after Udden (1898) 



c 



Boulder 



Cobble " 1 

-« 
' -B ' 
Pebble -4 

-2 
-1" 


; 

' +2 

+ 4 

+ 5 
+ 6 
+ 7 
+ 8 
+ 9 
+ 10 
+ 11 
+ 12 
Colloid 



Granule 
Very coarse 
Coarse 
Medium 

Fine 

Very fine 
Coarse 
Medium 
Pine 

Very fine 
Coarse 
Medium 
Fine 

Very fine 



U S. Bureau of 
. Sotte . - 



i 

•«;■. 

f 
1 








IRKS 













5 



i 



31.3 



1 



1.9S 

0.49 
0.24 



Clay 



FIGURE 2. Classification of sediment particle size according 
to standard Wentworth grain-size for sediments. 



-10- 



In addition to terrigenous (land derived) matter, sediments contain 
small fractions of organic and inorganic matter derived from plants 
and animals living in the estuary. The stronger the river or esturine 
current velocity, the larger size and number of particles that can be 
carried in the water column. Conversely, where water flow decreases, 
particles drop out of suspension and settle to the bottom. Sediments 
are sorted by water movement, with the larger sized particles (sand 
and gravel ) coming to rest in deeper, high velocity channels. For ex- 
ample, San Francisco Bar sediments are well-sorted sands. The deep 
channels, including the Golden Gate, are floored with sand and gravel. 
Because of their physiography, patterns of water movement, and physi- 
cal-chemical properties of the water, it is generally recognized that 
estuaries act as sediment traps. Normal sedimentary processes can be 
expected to completely fill San Francisco Bay in a few thousand years. 

Where freshwater mixes with salt-water, finely particulate sediments, 
normally unable to settle out by gravity, undergo an electrochemical 
process called aggregation . In this process, fine particulates join 
to form clusters which are significantly heavier than water and thus 
settle in the water column. As these clusters reach the bottom of a 
basin, they may interfere with each other's settlement ( hindered 
settlement ) and form a light sediment-water suspension termed a floe 
or fluff ." As this suspension loses water, it is termed fluid mud . 
As the fluid mud approaches 400 g sediment per liter of water, it 
fails to flow and bottom deposition can occur. With time, settled 
sediments may become compacted due to the influence of gravity, lose 
water from between sediment particles, and become consolidated . At 
any point in this sequence, strong physical forces can resuspend 
sediments and disperse them back into the water column, and the en- 
tire settling process may recur. Such strong forces include tidal 
currents, wind waves, and dredging and disposal of sediments. 

Sediments arriving in San Francisco Bay are primarily soil erosion 
products from its drainage area (7). About 81 percent of these sedi- 
ments arrive at the Carquinez Strait from the Central Valley. The 
remainder of the sediments arise from local tributary drainage (7). 
The sediments consist primarily of clays (60 percent), silts (30 
percent), and fine sands (10 percent). A majority of the sediments 
are transported during typically strong river flows in winter months. 
The CE estimate of quantitative sediment budgets in the Bay system 
are presented in Figure 3. In this model, sediment not lost to the 
ocean or land disposal is deposited in the Bay system. Part of the 
volume occupied by these sediments is compensated for by the mean 
annual rise in sea level and by geological subsidence (sinking), 
particularly in the South Bay. There is no question that sediments 
are trapped within the Bay system, but the state of the art is 
such that there is continued debate as to the quantity retained. 
Conomos 1 conceptual model (5) suggests significantly more retention 
of sediments in the Bay than does the CE. He suggests that sedi- 
ment lost to the ocean is only 6 percent yearly compared to CE es- 
timates of 50-70 percent. 



-11- 




ANNUAL DEPOSITION 



RESERVOIR (HYDRAULIC MINING) 1.5 B 

(historical inflow from Sierra, stored in San Pablo B. 



RESERVOIR 14.5 B 
(basin sediments) 

Mr MILLION 
B r BILLION 



FIGURE 3. Sediment movement (in cubic yards) in San Francisco Bay 
(from Ref. 3). 



-12- 



The CE suggests that sediments flowing into the Bay in winter season 
are spread throughout the Bay and deposited in the shallows and mud 
flat areas. With the advent of summer winds, these sediments are re- 
suspended, moved with water circulation, and redeposited in deeper 
regions unaffected by wind driven turbulence and strong tidal currents 
Quantities of these suspended sediments are transported to sea with 
tidal currents, and significant amounts settle in the relatively un- 
distributed dredged channels and harbors. Conomos (5) suggests that 
during the winter, a majority of the sediments coming through the 
Carquinez Strait are trapped in the shallows of the null zone (San 
Pablo Bay), and with the advent of summer, winds resuspend sediments, 
and the null zone migrates into Suisun Bay where large amounts of 
sediments are deposited. 

Whatever the eventual resolution of this debate, the fact remains that 
filling up of dredged shipping channels ( shoaling ) occurs at different 
rates in different years. An irregular schedule of dredging is re- 
quired on most projects based on depth measurements made routinely by 
the CE and facilities users. Mare Island Strait Channel shoals rap- 
idly, based on its calm nature and proximity to the null zone where 
sediments are concentrated in the water column. Approximately 2 mil- 
lion cubic yards of sediment are normally removed from this site on 
a twice-annual schedule, making it the most heavily dredge site in the 
Bay. However, in the initial dredging period of 1977, less than one- 
tenth the normal amount of sediment was removed from this site due to 
prevailing drought conditions with concomitant weak river flows which 
failed to deposit a normal winter sediment load. 

San Pablo Bay contains a reservoir of about 1.5 billion cubic yards 
of sediment washed from gold diggings in the Sierra foothils between 
1848 and 1884 (14). This sediment decreased the average depth of 
this embayment by 5 feet. 

Chemical Process 

Salinity distribution in the Bay system (see "chlorosi ty" , Table 1), 
in addition to producing density currents, exerts numerous chemical 
effects. Perhaps the most important of these is causation of parti- 
cle aggregation as mentioned above. Only 1-2 parts per thousand of 
sea salt are required to cause minute sedimentary particles to aggre- 
gate. The presence of salt in the water has a marked effect on the 
distribution of organisms of estuaries, as some species are more 
tolerant to salt than others. 

Estuaries unaffected by man are usually rich in both inorganic nu- 
trients (nitrogen, phosphorus, trace elements) and organic nutrients 
(detritus) derived from biological production upstream of the estuary 
and within highly productive margins of the estuary such as the salt 
marshes. Ammonium nitrogen and orthophosphate are routinely found in 
high concentrations in interstitial waters of most estuarine sediments 
These materials are released into the water column during sediment 
disturbance. Ammonium nitrogen is related to the kjeldahl nitrogen 



-13- 



content of the sediment. Orthophosphate is controlled by the iron con- 
tent of the sediment, as this nutrient is co-precipitated upon forma- 
tion of iron hydroxides when iron in (anoxic) sedimentary interstitial 
waters is released into oxygenated waters. In San Francisco Bay, the 
large amount of iron in the sediments probably results in rapid capture 
of orthophosphate which might otherwise be released during a dredging 
operation. Ammonia release may be a significant occurrence during 
dredging. Dynamics of plant nutrients are covered in the ABAG Special 
Study, Eutrophication in San Francisco Bay (1978). 

The San Francisco Bay estuary, like most of the nation's large estu- 
aries, is a "septic tank of the megalopolis" as described by DeFalco 
(9). The San Francisco Bay system receives flows of wastes from over 
5 million people as summarized in a study completed in 1964 (Table 
2). Projections for the Bay into 1980 (10) predict increases in or- 
ganic waste inflows as growth of the population and expansion of the 
economic base is expected to offset gains realized by the new con- 
struction of waste treatment facilities. 

With regard to dredging problems, it is well known that finely partic- 
ulate sediments are able to scavenge pollutant heavy metals , pesticides, 
and oil pollutants from the water column and carry them into the bottom 
sediments. The dredging of polluted sediments has raised questions 
concerning the possible impact of these materials on the Bay biota, as 
many of the waste compounds concentrated in bottom sediments are known 
to be toxic in their free (dissolved) state in water and when absorbed 
into body tissues from food. A major problem in this area has been the 
method of assaying for toxic metals, as some elements considered to be 
pollutants are found within the basic chemical composition of the sedi- 
ment particles. The Crystalline Matrix Study (11) supported by the CE 
showed that a number of toxic metals were bound in the crystalling ma- 
trix of the sediments. In making bulk (total chemical) analysis of 
sediments to determine their pollutant burden, internally bound metals 
have been included in the analyses in the past. This may lead to false 
estimations of the pollutant potential of a given sediment so tested. 
New research in this area is summarized in the Effects Section. 

Waste effluents and organically enriched bottom sediments consume large 
amounts of oxygen when they are released to the water column, causing 
biochemical oxygen demand (BOD). One concern in the Bay system has 
been the possibility of dredged sediments reacting with oxygen in the 
water to the detriment of oxygen-requiring organisms. This topic is 
further considered in the Effects Section below. 

Normal processes of decomposition produce ammonia and hydrogen sulfide 
in organically enriched estuarine bottom sediments. These substances 
are highly toxic to many organisms if not well diluted. Potential im- 
pact of their release during dredging is further discussed in the 
Effects Section. 



-14- 



TABLE 2. COMBINED MUNICIPAL AND INDUSTRIAL 
MASS EMISSION RATES 



Constituent 


Mass Emission Rate 
Tons/Day* 


Unit Mass Fmissinn Ratp 

will V I IU J J UMI i J J 1 \J ! 1 1 \U L- C 

Ibs/capita-day* 


COD 


810 


0.54 


BOD 5 


271 


0.18 


Suspended Solids 


278 


0.18 


Oil and Grease 


61 


0.040 


Total Nitrogen 


53 


0.035 


NH 3 - N 


33 


0.022 


N0 3 - N 


2.6 


0.0027 


Phosphate 


42 


0.028 


Phenols 


1.5 


0.001 


Gross Heavy Metals 


11.4 


0.0075 


Relative Toxicity** 


700 mgd 


232 gal/capita-day 


Col i form MPN , 


4.34 x 10l7/day 


1.43 x lOU/capita day 


Waste Flow 


690 mgd 


230 gal/capita-day 



*unless otherwise noted 

*waste toxicant flow diluted with non- toxic water that will kill 
one-half the test animals in two days (test animals are stickle- 
backs) 



From: Pearson, E.A. et al , 1967. Summary and 
conclusions. V 7, Comprehensive study of San 
Francisco Bay. Sanitary Engineering Research 
Laboratory, University of California, Berkeley. 
#67-5. 



-15- 



Notes on Bay System Biology 



The scope of this report prevents an extensive description of the biol- 
ogy of the San Francisco Bay system. Interested readers should consult 
the CE Composite Environmental Impact Statement (3) and the Biological 
Community Study (13) which describe numerous aspects of biology and 
provide literature summaries. Nichols (15) provides a comprehensive 
review of biological diversity studies carried out on the benthic (bot- 
tom) organisms of San Francisco Bay. 

The San Francisco Bay ecosystem is dominated by the above-described 
water flows and sediment dynamics. The energetic basis (food source) 
of the estuarine food webs is probably phytoplankton production, sup- 
plemented by tidal flat production from benthic micro- and macroalgae. 
There is probably not much organic matter available from the small 
remaining acreage of marshes and delta outflow, although there may be 
a significant energetic input in the form of dissolved organics from 
waste inflows. Primary production and secondary bacterial production 
supported by dissolved organics is fed upon by the numerous filter 
feeding organisms in the tidal flats and bay bottoms. This is seen 
in the great preponderance of filter feeding mollusks composing the 
biomass as shown by several biological surveys in the Bay. The SERL 
study (4) found total benthic animal "biovolume" of species to in- 
clude 70 percent mollusks (clams, mussels, oysters, and snails), 25 
percent annelids (segmented worms), and 5 percent arthropods (shrimp, 
crabs, and their small relatives). Table 3 summarizes the main habi- 
tats of the system and representative organisms found in them. This 
table is an oversimplification as these habitats have diverse sub- 
divisons, depending on currents, salinity, light penetration, food 
sources, sediment grain size, predation pressure, and pollutant im- 
pacts. Since some of these factors change from season to season and 
from year to year, it is not surprising that experts consulted at the 
California Academy of Sciences considered it impossible to produce 
distribution maps for any given species in the system. Nichols (16) 
ascertained that no major pollutant effects can now be detected in 
the Bay simply by looking at areal differences in species diversity, 
because even near major sewage outfalls species diversity is high. 
In the SRI study (13) the Oakland Inner Harbor station, which might 
be intuitively selected as one of the most polluted in the Bay system, 
contained one of the most populous and diverse faunas in their survey! 
Clam beds are widely scattered throughout the tidal flats but may 
vary in location from year to year. 

Usually, populations of commercial significance are the best docu- 
mented as to location and abundance. Discussion with California State 
Fish and Game personnel conducting the major survey on the Dungeness 
crab ( Cancer magister ) revealed that there is still not enough knowl- 
edge of the life history of juveniles in the Bay to accurately predict 
where these animals will be at any given time. 



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-17- 



Although many different species populate the broad expanses of Bay bot- 
tom, most exhibit few major body types and are very small and inconspic- 
uous. Most are fully adapted to existence in soft mud. In addition to 
the easily visualized market clams, the mud supports large populations 
of tiny clams no bigger than this typescript ( Gemma gemma , Transenella 
tantilla ) . There are a few species of large clam worms sometimes used 
as bait, but dozens of species of tiny worms (1-2 cm) are very difficult 
to identify taxonomically. There are a few species of large crabs such 
as the Dungeness, and the common bait shrimp, and many more species of 
tiny amphipod crustaceans which build protective tubes in the mud. Most 
of these organisms and other miscellaneous species of the Bay bottoms 
are f i 1 ter f eeders which remove particulate foods from the water or 
deposit feeders which sort particulate foods from deposits at the mud- 
water interface. Small benthic organisms from the basis of the food 
web leading to the production of fishes, shrimp, and crabs. 

The benthic community of the Bay is adapted to natural stresses in 
various ways, from physiological adaption to reproductive strategies. 
As it presently stands, the Bay's ecosystem is the product of adapta- 
tion to over 100 years of "industrial man" influencing the estuary. 
This includes waste flows, hydraulic mining debris, and the introduc- 
tion of hundreds of new species, both intentionally (striped bass) 
and unintentionally. 

The concerned reader, aside from reading publications on this topic, 
may obtain an excellent impression of the types and kinds of organisms 
in Bay system bottoms by inspecting the collection of invertebrate 
organisms of the San Francisco Bay system maintained at the California 
Academy of Sciences. 

Dredging and Disposal Practice 

Dredging is the process by which sediments are removed from the bottom 
of streams, lakes, and coastal waters, transported by ship, barge, or 
pipeline, and discharged (as spoil) to land or water. The usual pur- 
poses of dredging are to maintain, improve, or extend navigable water- 
ways, or to provide construction materials such as sand, gravel, or 
shell (12). 

Most of the dredging and disposal in the San Francisco Bay system is 
carried out by the CE, San Francisco District, using West Coast CE 
equipment. Smaller amounts of dredging and disposal are carried out 
directly by the Navy and certain municipalities which own their own 
equipment. A number of private firms are available for dredging ac- 
tivities, mainly in service to corporations and municipalities. The 
Sacramento District, CE, is responsible for maintaining the Sacramento 
ship channel from Chipps Island to Sacramento. 

It is of importance to distinguish between maintenance dredging and 
new work dredgin g. Maintenance dredging is carried out on a routine 
basis, usually on long-term permits or by Congressional authorization. 
This dredging removes sediments which have been deposited in navigable 



-18- 



waters on a regularly scheduled basis to prevent shoaling of routinely 
used channels. This type of dredging removes sediments which have 
accumulated over short periods of months or years at typical rates es- 
tablished for each given locus over long periods of observation. For 
example, the main channel through the San Francisco Bar outside the 
Golden Gate has been dredged annually since 1922. New work dredging 
is carried out by special permit (see regulations section below) in 
areas previously not subjected to dredging. This type of work is more 
likely to release pockets of contamination which represent long periods 
of accumulation. The CE Composite Environmental Impact Statements 
lists their maintenance projects as shown in Table 4. 

Methods of Dredging 

Three major types of equipment used in dredging and disposal are illu- 
strated in Figure 4. In the San Francisco Bay system, the majority of 
sediments are removed from maintenance projects using a hopper dredge . 
This dredge is a self-propelled ship with holds (hoppers) wnich contain 
the dredged material. The ship drags a pair of suction heads through 
the site to be dredged, pumping the sediments into the hoppers. With 
hoopers full, the ship raises the drag heads and proceeds to the (aquat 
ic) disposal site, where doors are opened in the bottom of the ship, 
releasing the dredged material. For example, the CE uses the hopper 
dredge "Harding" for applicable projects in the Bay system. Dredging 
is done in the Mare Island channel on a twice-yearly basis with the 
average amount removed of approximately 2 million cubic yards per year. 
The hoppers of the "Harding" can contain up to 2700 cubic yards of sedi 
ment. The dredge works 24 hours round the clock from September to 
November, removing sediment deposited from summer resuspension and from 
February through April, removing new material brought down the rivers 
in winter from the Napa and Central Valley. In low-flow years, the 
amount to be dredged may be significantly reduced. In the first dredg- 
ing period of 1977, the Mare Island project only required two days of 
work by the "Harding", suggesting the low levels of sediments brought 
in by extremely low river flows, typical of the current drought (or in 
the future by reduced Delta outflow). 

Mare Island dredged material is carried 2.8 miles from the dredging 
site and released at the disposal site on the northern margin of the 
Carquinez Strait. 

Other methods of dredging include the clamshel 1 dredge and hydra ul ic 
cutter head pipeline dredge . The former method employs a clamshel 1 
bucket which removes "bites" from bottom sediments as done by drag- 
lines in terrestrial situations. Clamshell dredging is usually done 
in areas of restricted ship movement such as harbors and marinas. 
Dredged material is deposited in barges, usually with bottom-opening 
doors. Both barges and dredge are moved by tugboat to the dredging 
site and loaded barges are taken to disposal sites by tugboat. 
Pipeline-dredges employ a cutter head which is lowered to the sedi- 
ment and moved across the sediment face. Dredged material is pumped 
to the surface and then into a temporary pipe string which is mounted 



-19- 



TABLE 4. CORPS MAINTENANCE DREDGING PROJECTS 
IN SAN FRANCISCO BAY AREA (Ref. 2) 



Location 



Approximate 
Qty. Dredged, 
Authorize! ion (cubic yard*) 



Ft ■auencv 



I'roposad 

Proposed Data of Haxt Avera^ : Annual 

Disposal Site Ha Intenanca Qty.(c»' • 1c ydu) L 



San Francisco rfirbor 


R&HA 2 o£ 192 7 








FY 


76 






(lain Ship Channel 


and amendments 


1,000,000 


1 yr. 


San Franc leco Bar 


I, 


100,000 


Kock removal 




none 


completed 













Presidio Shoal 




none 


Inactive 










n 
u 






none 


Inactive 


_ 















none 


inactive 













roint m»ox jnoai 






lnac t ive 


_ 











5.F. Airport Channel 




none 


Inactive 


- 











Islaia Creek Entrance 




257,000 


16 yr. 


Alcatraz 


indefinite 




13,000 


San Rafael Creak 


R4HA Of 1919 


260,000 


6-8 yr. 


land 


FY 


7 1 




(4,000 




R&HA of 1930 


396,000 


12 yr. 


San Pablo Bay 


FY 


77 




33,000 


Sun Pablo Bay and Mara 


R&HA of 1927 
















Island Strait 


and amendments 










76 




124,000 


Pinole Shoal Channel 




619,000 


2 yr. 


San Pablo Bay 


PY 


2 , 


Hare Island Strait 




1,250,000 


0.5 yr. 


Carquinec Straits 


FY 


76 


'00,000 


Richmond Harbor 


R&HA of 1917 


480,000 


1 yr. 


Alcatraz 


FY 


77 




.80,000 




and amendments 
















Oakland Harbor 


R&HA of 1874 










76 




i 00, 000 


Oakland Outer Harbor 


and amendments 


300,000 - 


1 yr. 


Alcatrax 


FY 




Oakalnd Inner Harbor 




350,000 


1 yr. 


Alcatraz 


FY 


76 




■50,000 


San Lesndro Marina 


R&HA of 1970 


225,000 


5-6 yr. 


land 


FY 


78 




4 2 , 000 


kedwood City Harbor 


R&HA of 1910 


325,000 


1 yt- 


land 


FY 


76 or 77 




23,000 




and amendments 
















S.P. Hbr. & Bay - Sausa- 


R&HA of 1950 


90,000 


3-4 yr. 


Alcatrat 


FY 


77 or 78 




26,000 


Uto Operatlona Base 


















Suisun Bay Channel 


R&HA of 1919 


1 1 A AAA 

220,000 


1 yr. 


Suiaun Bay 


FY 


76 








and amendments 
















luisun (Slough) Channel 


R&HA of 1910 


180,000 


2-3 yr. 


land 


Indefinite 




72.000 


and amendments 
















New York Slough 


R&HA of 1876 


15,000 


3-5 yr. 


land 


Indefinite 




4.000 




and amendments 
















TOTAL R&HA PROJECTS 














5, 


'23.000 


cm. cord Naval Weapons 


lnter-servlce 


50- 52,000 


2 yr. 


Suiaun Bay 


FY 


78 




25,000 



Station 
Alameda NAS <Navy) 



support agreement 



MOTBA 3 North (military) 

NSC-Oakland (Navy) 

MOTBA East (Navy) 

Point Molate (Navy) 

Gov. Island (Coast Cuard) 

Horseshoe Cove (Army) 

TOTAL INTER-SERVICE PROJECTS 

TOTAL PERMITS 

TOTAL ALL PROJECTS 



900,000 

80,000 
125,000 
120,000 
228,000 
20- 30,000 
10- 15,000 



^ yr 

6-10 yr 
2-3 yr 
3 yr 
2-3 yr 
5-10 yr 
10-15 yr 



Alcatrat and/or 
100- Fa thorn 

Alcatrat 
Alcatraz 
Alcatraz 
Alcatraz 
Alcatraz 
Alcatraz 



FY 76 

Indefinite 
FY 77 or 78 

Indefinite 
FY 77 

indefinite 

Indefinite 



'■00,000 

10.000 
,0,000 
".0.000 
'11,000 
3.500 
..000 



i..;'j,50o 

3,51., 000 
10, 3i'.,500 



1 Average Annual Quantity its the average volume of sediments which would be removed if the project was perforated 
once a year. For example, if 200,000 cubic yards are removed once every 5 yeare, than the average annual quantity 

',3 200,000 divided by 5, or 40,000 cubic yards. 

'Hivers and Harbors Act 
military Ocean Terminal, Bay Area 
S'or any given year that a project 1b dredged, this figure can vary 1 30-40 percent. 



-20- 



Overflow 



Overllou Discharge 




Turbulence By 
Vessel On Bottom 



Ocean going 
Vessel Underway 



Pumps Across section of ship) 

Dragarms (Suction Lines) 
Dragheads 



1 < 

TRAILING SUCTION HOPPER DREDGE 



Dischaige Line 



Overt low D scharte 
From 8 org 



Clamshell iverllo* 




Working Face 



HYDRAULIC CUTTERHEAD DREDGE 



CLAMSHELL DREDGE 



FIGURE 4. Three major types of equipment 
used in dredging and disposal. 



-21- 



on floats and directed to the chosen disposal site. This method is used 
to deposit dredged material in shallow water or land disposal sites due 
to the flexibility of the pipeline system. Specific details on dredging 
technology are found in the CE report on dredging technology (17). Re- 
search is actively being conducted by CE Waterways Experiment Station, 
Vicksburg, Mississippi (WES), on the improvement of dredging technology 
and the mitigation of environmental effects of dredging. Conferences 
with WES personnel in Vicksburg indicated that although some modifica- 
tion of current practices can be recommended to mitigate some dredging 
effects, no momentous new developments should be expected in the forsee- 
able future. 

The San Francisco CE has investigated the effects of dredging and disposal 
on sediment resuspension which will be treated in the Effects Section. 



-22- 



SECTION II 

ENVIRONMENTAL IMPACTS OF DREDGING AND DISPOSAL 



General Considerations 

The broad discussion of the general characteristics of the San Francisco 
Bay system was made in order to foster an appreciation of the dynamics 
in the system. Perhaps the most important factor to be considered in 
all discussions of dredging and disposal in the San Francisco Bay system 
is that it is the only estuary in the U.S. in which the great majority 
of dredge spoil disposal is currently carried out at high energy, deep 
water disposal sites. No evidence of accumulation of disposed sediments 
is evident at the currently used disposal sites in the Bay system (2). 
This is to say, soon after sediments are released at these disposal 
sites, the sediments are dispersed into the water regime of the Bay. 

This method of disposal effectively eliminates many of the comparisons 
which might otherwise be made with dredging and disposal in other es- 
tuaries, particularly with regard to the loss of resources by burial 
in disposed sediment. For example, dredging and disposal carried out 
in some shallow estuaries of the Gulf Coast can be directly observed 
to destroy populations of clams and oysters. Spoil banks persist and 
can be monitored, as can the number of organisms destroyed (20). In 
the San Francisco Bay system gross biological effects would be ex- 
tremely difficult to observe due to depth of dredging and underwater 
disposal, normally high turbidity regimes, and moving waters which ob- 
scure effects such as fish kills which might appear far down-current 
from where they occur. 

There is a serious problem in quantification of resources which might 
undergo adverse environmental impact. There are no firm and reliable 
baseline data for populations of organisms in the Bay as mentioned in 
Section I, Biological Considerations. Thus, any changes in popula- 
tions of organisms due to any cause are difficult to evaluate. Life 
histories of organisms and natural environmental variations can pro- 
duce variations in the abundance of organisms in various parts of the 
estuary through time. Statistically valid sampling in the estuary is 
difficult, and some studies of the Bay system organisms have been 
compromised by lack of effective sampling procedures (15). In view 
of the great difficulties in making direct measurements, most inter- 
pretations of potential effects of dredging in the San Francisco Bay 
system must be of an indirect, postulated nature. 

The following is a resume of potential effects of dredging and dis- 
posal in estuaries in general, each relevant category of which is 
discussed below in relation to possible effects in the San Francisco 
Bay system. 



-23- 



Direct Effects: 

Habitat disruption 

Changed circulation regimes 

Indirect Effects: 

Release of sediment 

Release of sediment associated materials 



Direct Effects 

Direct effects occur when a dredge is removing the sediments from the 
dredging site or disposing of dredge spoils at the disposal site. Typi- 
cal direct effects of dredging include maceration of bottom organisms as 
they are pumped through massive hydraulic pumps. In disposal, the major 
effect is burial under the released load of sediments. Experts con- 
sulted in the State Department of Fish and Game and at the California 
Academy of Sciences did not indicate major objections to the direct ef- 
fects of dredging and disposal, as these effects occur in curcumscribed 
areas which are the same from year to year (Figures 5A and 5B). Major 
concern was expressed for indirect effects which occur due to placement 
of large suspended loads into Bay waters, possible formation of fluid 
muds, and release of chemical contaminants to Bay waters, a problem of 
particular importance to the Regional Water Quality Control Board. 

A sophisticated tracer study carried out by the San Francisco CE showed 
that large volumes of sediment (1.6 m cy) disposed of at the Carquinez 
site were broadly disseminated into the natural sediment regime of San 
Pablo Bay to a depth of as much as 23 cm over a 100 square mile area 
within a month's time (8). About 10-15% of the disposed sediment re- 
turned to the dredging site (Mare Island) in a few month's time. 

Habitat Disruption 

As part of the San Francisco CE Dredge Disposal Study (subsequently 
referred to as the DDS), Stanford Research Institute carried out an 
investigation to provide faunal lists and organism counts at selected 
dredging and disposal stations and unaffected "control" stations near 
disturbed stations (13). This was done to determine impacts on or- 
ganisms at the test sites, to evaluate seasonal changes in organisms, 
and to collect some chemical data for making correlations with faunal 
changes. Stations evaluated were Mare Island (dredge)— Carquinez 
Strait (disposal), and Redwood City Harbor (dredge)--South Bay (dis- 
posal). Information was also obtained at Oakland Inner Harbor, 
Alcatraz disposal site, and Hunters Point disposal site. Extensive 
faunal lists were compiled, counts were made, and chemical parameters 
measured. The study concluded, as would be expected, that disturbed 
sites showed decreased species diversity and numbers. The following 
data (Table 5) from the Main Report (2) shows the effects at Mare 
Island dredging site. 



-24- 




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-27- 



The disposal site in the South Bay which received a single load of 
dredged material showed populations and diversity comparable to the 
control site after a few months. Although extensive surveys of species 
and numbers of organisms were made at study sites, and a number of 
chemical parameters were recorded, it was concluded that "underlying 
relations among biological and environmental variable are complex, and 
that additional field and laboratory studies would be required for 
thorough identification and understanding of such relationships (13)." 
Trends suggested from their data showed small populations and low di- 
versity correlated with high salinity and sediment mercury and sulfide 
concentrations, and high diversity and large populations with high 
dissolved oxygen, turbidity and sedimentary zinc and clay content of 
sediments. This study showed the great difficulties in determining 
gross effects of dredging and disposal in San Francisco Bay as compared 
with the more easily studied quiet, shallow waters. The Stanford sur- 
vey noted marked seasonal variations in organisms. As a specific ex- 
ample of the difficulty and expertise required in this study, over 130 
species of taxa (kinds) or organisms were found in the Oakland Inner 
Harbor station alone, with an average number of organisms per liter 
of sediment being 867.5 (yes, they are small). A total of 131 ,256 
specimens were collected during 5 surveys. 

McCauley et al (22) monitored effects of dredging on the benthic faunal 
abundance of a dredged channel in Coos Bay, Oregon, and found that in- 
fauna readjusted to pre-dredging conditions within 28 days. At the 
spoil site, readjustment took about two weeks. More simplified tech- 
niques were used than the Stanford study, however, pointing out the 
great difficulties in comparing different studies because of the use 
of different methods between research groups. 

In a study funded by the CE Waterways Experiment Station, Vicksburg, 
Mississippi , x personnel of the Moss Landing Marine Laboratories inves- 
tigated recovery of fauna in dredged and disposal areas in Monterey 
Bay. Their findings suggested that communities in areas which are 
normally stressed show more rapid recovery of populations and animal 
diversity than biotic communities which are not normally stressed (23). 
Thus, typically wind and sediment stressed areas in San Francisco Bay 
are probably more resilient to long-term effects of sediment disposal 
than the 100 fathom (Farallon) ocean disposal site which undergoes 
very little natural perturbation. 

Effects of burial on organisms are important in disposal sites where 
mounding of dredge spoil occurs. Another DMRP study, by the Univer- 
sity of Delaware, was carried out to determine abilities of organisms 
to escape burial in various types of sedimentary material (24). 

In laboratory experiments, it was found that numerous types of orga- 
nisms (crabs, clams, snails, amphipod crustaceans, polychaete worms) 
were capable of escaping from as much as 32 cm deep burial. Notable 



*Dredged Materials Research Program (DMRP) 



-28- 



exceptions were small snails, and organisms buried in exotic sediments 
(sediments in which organisms do not normally live). Great variation 
was found with temperature, stress condition of the organisms, and other 
factors; and it was concluded that generalizations as to disinterment 
behavior could not be made between species groups, although knowledge of 
morphology and behavorial characteristics were in general useful in pre- 
dicting migratory behavior. The authors recommended field studies be 
carried out under actual dredging conditions. Presently used disposal 
sites in San Francisco Bay, being in high energy areas, do not allow 
long-term mounding of sediments. Physical smothering of shellfish beds 
is not a problem in San Francisco Bay with current and projected dis- 
posal practices. 

A specific problem related to both direct and indirect impacts of dredged 
material is the possibility of formation of fluid mud flows from dredged 
material. Formation of fluid muds occurs when mixing energy is not great 
enough to totally resuspend sediments in the water column, and dredged 
sediments are caused to flow across bottom environments, smothering resi- 
dent fauna. A DMRP study by the Virginia Institute of Marine Science has 
shown that fluid mud flows induced in the upper reaches of an estuary 
could have significant lethal effects on the macrobenthic organisms (clams 
and insect larvae) although some were more sensitive to this stress than 
others (32). In San Francisco Bay, concern has been shown by the Depart- 
ment of Fish and Game personnel that such fluid muds could severely im- 
pact juvenile Dungeness crabs in certain bottom areas of the Bay. Fluid 
muds are difficult to measure, and may occur due to natural causes. 

Changed Circulation Regimes 

Typical dredging and disposal as currently practiced probably has little 
effect on the circulation regimes in the Bay. The CE, San Francisco Dis- 
trict, is currently preparing an Environmental Impact Statement for the 
Baldwin Ship Channel project which has the potential of increasing sa- 
linity intrusion into the Delta. Dredging of estuarine channels which 
cause significant new salinity intrusions, have the effect of moving the 
null zone upstream, resulting in greater sediment deposition in upstream 
reaches of estuaries (21). This produces new demands for dredging of 
the upper reaches of estuaries, where significant environmental effects 
may accrue. 

Indirect Effects 

Effects which do not occur as a direct result of the activities of dredg- 
ing and disposal include physical impacts of resuspended sediments, 
biochemical oxygen demand of oxygen-reactive compounds stored in bottom 
sediments, and release of toxic or blostimulative materials from sediment 
storage. A number of research projects have recently been completed which 
bear on these potential effects on the estuarine fauna of San Francisco 
Bay. 



-29- 



Two studies were carried out by researchers of the University of California 
Marine Laboratory at Bodega Bay to determine the effects of contaminated 
and uncontaminated sediment loading on the survival of sensitive test or- 
ganisms (26, 27) common in the Bay system. Parameters measured included 
amount of sediment maintained in suspension, temperature, and oxygen con- 
tent of the water. Organisms tested included bay mussels, a clam worm spe- 
cies, an isopod species (Synidotea), Bay shrimp, shiner perch and striped 
bass. These species are widely distributed in the Bay and served as test 
species of ecological importance. In general, invertebrates were highly 
resi stent to the effects of suspended solids in the water (tens of grams 
per liter) and were more effected under conditions of higher temperature 
and low dissolved oxygen. Organisms commonly found in muddy environments 
were least sensitive. Fishes were sensitive to suspended sediment (few 
grams per liter) conditions, particularly at high temperature and low DO. 
The researchers concluded from the results that the organisms would be 
insensitive to suspended sediment loads typical of areas around dredging 
activities determined in CE water column studies (28). These studies have 
shown that the suspended sediment plume does not interfere with the upper 
two meters of water during both dredging and disposal, and that although 
there are dissolved oxygen reductions near the dredge during dredging and 
disposal operations, these effects last only a few minutes due to rapid 
mixing of well oxygenated Bay waters. From these data and the data on 
sensitivity of organisms, mitigation of these localized effects could be 
obtained by restricting dredging to winter months when temperatures are 
low, and disposing of sediments such that they are maximally dispersed to 
minimize oxygen demands around the dredge. 

Sherk et al (29) have found significant lethal and sublethal effects of 
suspended sediments on certain estuarine fishes which are not adapted to 
typical mud bottom conditions. Their results suggest that the more sen- 
sitive fishes such as menhadedn, white perch, bay anchovy and striped 
bass larvae, if unable to escape dredge and disposal plumes for periods 
of days, could be adversely affected by sediments from dredging and dis- 
posal activities. It is unknown if this is likely to occur near San 
Francisco dredging and disposal sites. Comprehensive studies of the 
effects of dredging on the fishes of Chesapeake Bay (3) were unable to 
demonstrate gross effects of overboard disposal of dredged sediments 
using caged fish experiments and commercial type research gillnetting. 
Furthermore, no gross effects could be demonstrated on phytoplankton 
primary productivity, zooplankton, and fish eggs and larvae. A review 
of the effects of dredging and disposal on zooplankton (31) suggests 
that significant effects of suspended sediments can occur if plankton 
populations are localized and not dominated by oceanic processes im- 
pinging on the estuarine habitats. It is suggested that any impact on 
zooplankton can only be determined on a case-by-case basis with exten- 
sive knowledge at hand concerning the biology of the zooplankton popu- 
lations. Since this data is unavailable for San Francisco Bay, no 
predictions can be made concerning zooplankton effects. 



-30- 



Toxicant Release and Uptake 

A great deal of reserach has been carried out recently due to the need 
for determining the effects of deleterious materials released from 
dredged sediments. This work has been carried out mainly in providing 
basic data for the development of dredged spoil disposal criteria 
(DMRP studies) and in determining environmental impacts of toxicants 
released into San Francisco Bay waters (DDS studies). 

A. Heavy metals 

Serne and Mercer (11) have studied the release of the heavy 
metals, Cd, Cu, Fe, Hg, Pb, and Zn from selected San Francisco 
Bay sediments as a function of various physical and chemical 
parameters including Eh (redoxpotential ) and salinity. Sedi- 
ment samples from ten sampling stations were characterized with 
respect to heavy metal content, particle size, mineral content, 
total sulfide, organic carbon, cation-exchange-capacity, and 
PCB content. The release of heavy metals was determined using 
a semi-selective extraction procedure, where the sediment is 
extracted sequentially with interstitial water, ammonium ace- 
tate, hydroxlyamine hydrochloride, hydrogen-peroxide, and so- 
dium citrate dithionate. The greatest portion, 30-97%, of the 
heavy metals, Cu, Fe, Hg, Pb, and Zn, were bound in clay or 
crystalline lattice sites. The greatest portion of Cd was 
associated with sulfide-like sites (extractable with hydrogen 
peroxide). Elutriate test data were also compiled for Fe, Cd, 
Cu, Zn, and Pb. These data are summarized in Table 6. 

Chen, et al (33) have studied the release of heavy metals from 
dredged material. They found no release of Ag, Cd, Hg. The 
metals, Cr, Cu, and Pb were released at levels of from 3 to 10 
times background. Amounts of Fe, Mn, and Zn larger than 10 
times background were released. Except for Fe the amounts re- 
leased are in the sub ppm to ppb range. Most of the soluble 
phase concentrations were well below the allowable levels of 
the ocean water discharge standards. 

Lu and Chen (34) reported a study on the migration of heavy 
metals from polluted sediments into seawater. Reducing con- 
ditions favored the release of Fe and Mn; whereas, oxidizing 
conditions favored the release of Cd, Cu, Ni , Pb, and Zn. 
The migration of metals is controlled by the chemistry of the 
immediately overlying water rather than the type of sediment. 
The factors affecting metal migration were studied, and a 
model is proposed. 

Anderlini, et al (35) have examined the uptake of heavy metals 
by estuarine organisms and sediments during dredging operations 
in the San Francisco area. These authors conclude that dredging 



-31- 



TABLE 6. Release of Metals from San Francisco Bay Sediments 



Elutriate 

Metal Dissolved 02 Ratio* Effect of Salinity 



Fe 


1 ow 


50-3000 


None 




high 


2-9 


None 


Cd 


low 


0.2-2 


Less in higher salinity 




high 


0.2-2 


Less in highest salinity 


Cu 


low 


0.2-8 


Less in higher salinity 




high 


0.3-9 


Less in higher salinity 


Zn 


low 


0.3-7 


Less in higher salinity 




high 


1-7 


None 


Pb 


low 


0.2-6 


Less in higher salinity 




high 


2-9 


Less in higher salinity 



a. Elutriate ratio is the amount released divided by the amount in 
the disposal site water. 



-32- 



does not affect the levels of heavy metals in nearby sediments or 
invertebrates. This observation is likely the result of the un- 
availability of sediment-associated metals since the uptake of 
dissolved chloride salts of Hg, Pb, Cu, Cd, and Ag by Ma coma was 
established in laboratory experiments. 

A similar study (36) has examined the release and uptake of heavy 
metals (Ag, As, Cd, Cr. Cu, Fe, Hg, Mn, Ni , Pb, Se, and Zn) dur- 
ing a dump of 10,000 m3 of dredged material in San Francisco Bay. 
The concentrations of these metals were monitored in selected 
benthic invertebrates, mussels transplanted to the disposal site, 
sediments, settled and suspended particulates, and water before, 
during and after the disposal operations. The results of this 
study are summarized as follows: 



Benthic invertebrates 



No effect on heavy metal 
concentrations 



Surface sediments 



Water 



Transplanted M. edulis 



Higher Fe and Cu levels 
in disposal area 

Short-term increases in 
dissolved Cd, Cu and Pb. 

No effect on heavy metal 
concentrations 



The overall conclusion of this study was "The amount of trace 
elements redistributed annually by all dredging activities is 
much greater than the annual input from the EBMUD outfall, but 
is almost inconsequential in relation to the element redistri- 
bution by settling particulates." 

Neff, et al (37) in an extensive research program on the uptake 
of metals from metal -containing sediments found there were no 
simple principles which covered all organisms, sediments and 
metal contaminants. It was concluded that metals were taken up 
with difficulty by most organisms tested, and that development 
of a simple extraction scheme for predictive effects of heavy 
metal uptake by benthic organisms in general is presently not 
possible. 

Pesticides and PCB's 



Fulk, et al . have reviewed the literature on pesticides and 
PCB's in sediments (38). Algae, suspended solids, bottom sedi 
ments, and water all contain various chlorinated hydrocarbons. 
The studies conducted on the adsorption and desorption of 
chlorinated hydrocarbons on solids have generally found that 
these materials are more readily absorbed than desorbed. 



-33- 



Fulk, et al . (38) have analyzed the sediments from five areas 
for aldrin, dieldrin, endrin, lindane, 2,4-D esters, DDT analogs, 
toxaphene and PCB's. PCB's, dieldrin and the DDT analogs were 
the most prevalent. The desorption of the latter materials was 
studied. No DDT analog release was observed. Release from in- 
terstitial water was negligible. Some Dieldrin release was ob- 
served in the sub ppb range. On the basis of these laboratory 
studies, it appears that release of these water insoluble pesti- 
cides will not occur to an appreciable extent during dredging. 

To my knowledge the release of Kepone from sediments has not as 
yet been studied. The situation in the James River with wide- 
spread Kepone contamination in organisms and sediments may be an 
unusual case. The (water soluble) Kepone may dissolve upon dis- 
ruption of the sediments. 

Anderlini, et al (36) monitored release and uptake of PCB's and 
compounds of the DDT group during a disposal operation in San 
Francisco Bay. Some uptake of p,p'-DDE was observed but the 
levels of the other chlorinated hydrocarbons remained constant 
in Mytilus edulis . Chlorinated hydrocarbons were released to 
the water column resulting in 3-10 fold increases in the chlo- 
rinated hydrocarbon levels in the water immediately after dis- 
posal . 

C. Oil and Grease 

One of the major contaminants in estuarine sediments are "oil and 
grease" residues, consisting mainly of petroleum derived hydro- 
carbons and their breakdown products. A laboratory study recently 
completed by DiSalvo et al (39) exposing mussels, crabs and clams 
from the Bay estuary to heavily contaminated sediments from Puget 
Sound and New York Harbor showed minor uptake of hydrocarbon resi- 
dues from sediments. Field experiments carried out by DiSalvo 
et al (40) showed that hydrocarbons were taken up by mussels sus- 
pended in San Francisco Bay, and it was suggested that weathered 
hydrocarbons in sediments were tightly bound, and that uptake of 
hydrocarbons by uncontaminated mussels occurred from newly released 
pollutants or oil droplets accommodated in the water column (39). 
This research has suggested that bulk analyses should be carefully 
reexamined as a disposal criterion, as this parameter appears to 
have little relevance to possible environmental impacts. Specific 
compounds normally part of the oil grease fraction are the car- 
cinogenic compounds which usually occur in minute quantities in 
sediments. This topic is further discussed in the ABAG Special 
Study: Toxicants in the San Francisco Bay Estuary (1978). 

D. Contaminant microorganisms 

A problem associated with release of dredged sediments is the 
possible dissemination of enteric bacteria, viruses, protozoa and 
other microorganisms which may be taken up by commercially valu- 
able shellfish in their filter feeding processes. 



-34- 



Fecal col i forms and enteric pathogens have been found in bottom 
sediments (41,42). Dredging of the Mississippi River navigation 
channel has been shown to result in increased fecal col i form 
concentrations by a factor of 2-5 in the immediate area of the 
dredging. Highly pathogenic protozoan cysts have been isolated 
from contaminated sediment deposits near New York and Baltimore 
(44). We do not know to what degree the dredged material in the 
Bay. is contaminated with persistent undesirable microorganisms 
from the public health standpoint; further information on this 
topic is available in the ABAG Special Study: An Assessment of 
the Potential for Commercial and Recreational Harvesting: San 
Francisco Bay Shellfish (1977). 

E. Hydrogen Sulfide (H2S) and Ammonia (NH3) 

These two compounds, normally formed in organically rich anoxic 
estuarine sediments, are highly soluble in water. They are both 
toxic to many aquatic organisms and are of interest with respect 
to water quality criteria in the Bay. Since the San Francisco 
Bay system sediments are highly enriched in iron, free H2S is 
expected to react to form insoluble iron sulfides (which color 
the sediment black). Serne and Mercer (11) have verified this 
hypothesis, finding no detectable free H2S which could be re- 
leased from the dredged material. 

Ammonia is one of the potentially toxic materials known to be 
released from anoxic sediments, and routinely found in evalua- 
tions of sediments using the elutriate test.* Anderlini et al 
(35) found minor indications of ammonia increase after a sedi- 
ment disposal operation, with small rises in water near the 
spoiling followed by rapid returns to baseline levels. Ammonia 
is also a plant nutrient and may lead to eutrophi cation pro- 
cesses as discussed in the ABAG Special Study: Eutrophication 
in San Francisco Bay (1978). 

Land Disposal 

Confined or unconfined land disposal of contaminated dredged material 
appears, from literature thus far reviewed, to be an unattractive al- 
ternative to aquatic disposal for a number of reasons. 

1. It is only a temporary solution, as pointed out by Schubel 
and Meade (21) in their description of problems in the 
Delaware estuary. There are limited numbers of receiving 
sites and massive continuous accumulations of sediment 
which must be accommodated. 

2. Land disposal of contaminated dredged materials may have 
worse adverse environmental effects than aquatic disposal 
as contaminated runoff from the material may re-enter 
sensitive inshore nursery areas rather than being sub- 
jected to large forces of dilution based on estuarine 
water circulation (45). 



*See Section III. 



-35- 



3. The properties of Bay mud which is the main material taken 
from maintenance dredging projects is "a soft, plastic, black 
to grey silty-clay or clayey-silt with minor organic material 
and clayey fine grained sand which has been deposited in the 
Bay largely by flocculation" (generally the consistency of 
toothpaste) (2). It has poor bearing capacity, requires ex- 
tremely long times for dewatering, and effectively prevents 
all other land use for long periods of time, including the 
growth of plants and animals (46). Whereas the impact of 
aquatic disposal is not well known, the impact of land dis- 
posal is clear. All life is effectively excluded from the 
disposal area for long periods of time. 

Concluding Remarks on Effects 

Most of the research reviewed here is so new that it has not been criti- 
cally reviewed by the scientific community in general. For the present 
context, the conclusions of the authors have necessarily been taken at 
face value without critical review of the data. Indeed, limited pre- 
liminary critical review made by our group to date indicates that there 
are a few discrepancies here and there in chemical studies which will 
eventually give rise to academic debate concerning the significance of 
some of the results. However, the overview of the research is encour- 
aging, especially in light of the natural processes operating in San 
Francisco Bay which aid in the dilution of wastes and rapid oxygenation 
of Bay system waters. 

Although the studies seem detailed (and expensive), they are only a 
beginning, and the discerning reader will have noted there are few de- 
monstrative experiments which clearly show effect, or lack thereof, of 
dredging and disposal on any particular biological resource of the Bay 
ecosystem. Obviously, this is in the realm of future research needs 
as outlined in our final pages. We cannot emphasize too strongly the 
need for basic research on which to formulate the proper questions 
which will lead to (empirical) demonstrative experiments in the future 
on specific impacts of specific dredging projects. 



-36- 



SECTION III 
REGULATION OF DREDGING AND DISPOSAL 



General Considerations 

The regulation of dredging and disposal is based on the broad action that 
is required to protect the diverse resources which come under the heading 
of "environmental protection." Numerous Federal and State agencies are 
charged with different aspects of environmental resources protection, each 
responsible for evaluation of potential environmental effects of dredging 
and disposal in the San Francisco Bay system. Any real or hypothesized 
impact envisioned by any agency is able to delay or block the permitting 
process. Environmental legislation and the multiplicity of involved agen- 
cies has complicated the permitting process for dredging and disposal be- 
cause of the lack of objective information on environmental effects and 
objective criteria for evaluation of any such effects. New and emerging 
research results, discussed above in the Effects Section, are showing that 
some interim criteria which have been used in the past are of questionable 
value. An in-depth study of the regulation of dredging has been carried 
out by the San Francisco Bay Conservation and Development Commission 
(BCDC) (18) which has proposed numerous suggestions for accelerating the 
permitting process. The following discussion presents an introduction to 
the laws governing dredging and disposal, as applied to the San Francisco 
Bay system. At the heart of the entire matter is the basic assumption 
that scientific research has either provided or is capable of providing 
objective criteria for assessment of the potential impacts of dredging and 
disposal. Costs of research and time schedules required for obtaining the 
results make this assumption problematical. 

Legal Framework 

Dredging and disposal are regulated by Congress through permit processes 
under basic control of the U.S. Army Corps of Engineers (CE) in close 
cooperation with the Environmental Protection Agency (EPA). Under the 
Rivers and Harbors Act of 1899 (Sec. 10) , the CE maintains permit power 
over all dredge and fill operations in navigable waters of the U.S. 
Section 404 of the Federal Water Pollution Control Act (PL 92-500, 1972 
amend .) gives CE permit authority over the disposal of dredge and fill 
material into all U.S. waters (the territorial sea). Ocean dumping of 
dredged materials is regulated by the EPA under Section 102 (a) of the 
Marine Protection, Research and Sanctuaries Act of 1972 (PL 92-532) . 

The preceding Acts form a base of enabling legislation, following which, 
interpretations and explanations of each Act are made by administrators 
charged with enforcement of the Act. This includes rationale, rules and 
regulations, and test criteria to be met in compliance with the Act, as 
well as definitions of terms and permitting procedures promulgated by the 
administrator after his review of the Act, relevant court decisions, and 



-37- 



public comments. Publication of this material is made in the Federal Reg- 
ister. For example, the 11 January 1977 Federal Register includes a final 
revision by the EPA administrator of the ocean dumping criteria originally 
established by PL 92-532. Within this publication it is stated that a man- 
ual will be developed by EPA and the CE to implement the criteria. This 
manual (19) has recently been released and will undoubtedly be revised as 
experience is gained by laboratories and agencies charged with enforcement 
of its provisions. 

An essential part of all regulations on dredging and disposal has been the 
identification of agencies which are to be consulted prior to granting of 
dredging and disposal permits. Federal and State agencies with commenting 
or permit certification power are listed in Table 8. 

The main dredging projects in the San Francisco Bay system are carried out 
by the CE based on direct authorization by Rivers and Harbors Acts of Con- 
gress beginning as early as 1876 (See Table 4). These projects, discussed 
in detail in the CE Composite Environmental Impact Statement (3), fall 
outside the jurisdiction of BCDC. All other dredging projects in the Bay 
system require the granting of a permit by the CE. The CE cannot make a 
decision on the permit until it has received comments from the various 
agencies listed in Table 7 and the State Water Resources Control Board has 
issued a certification of approval. After institutional approval is 
granted, a public notice is posted by the CE and substantive objections 
are taken into account. Any person adversely affected may request a pub- 
lic hearing to express grievances. 

The decision to issue the CE permit is based on public interest, including 
needs for navigation, fish and wildlife, water supply, flood damage pro- 
tection, ecosystems, and, in general, the needs and welfare of the people 
(18). Although the existence of certain environmental impacts has been 
recognized by the San Francisco District Corps of Engineers, they may be 
outweighed by the needs for navigation, national defense, and other con- 
siderations as expressed in the Composite EIS (3). 

Criteria for the Disposal of Dredged Material 

Currently employed criteria applicable to the dumping of dredged material 
in San Francisco Bay and in the ocean were adopted by the EPA Region IX 
administrator based on data published in the Federal Register, 1971. 
Sediments must be analyzed for content of mercury, cadmium, lead, zinc, 
and oil and grease by standard methods which analyze the total sediment 
( bill k analysis ) . Research has shown, however, that there is little cor- 
relation between bulk analysis of sediment and the metals species actu- 
ally available to cause toxic effects in organisms. A new procedure, 
termed the elutriate test was put forth in the 15 September 1975 Federal 
Register. In this test a given volume of sediment is shaken with a given 
volume of water, and the water is separated and analyzed for selected 
toxic metals. If the elutriate water value exceeds disposal site water 



-38- 







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-39- 



by a given factor (1.5), then the dredged material cannot be released in 
aquatic sites. A criticism of this method is that testing for a few metals 
leaves out a whole spectrum of materials that might be toxic for organisms. 
Criteria development proceeded one step further with the publication of the 
ocean disposal criteria manual by CE and EPA (19). This manual specifies 
the use of bioassay testing to evaluate the toxic potential of dredged ma- 
terial by exposing sensitive organisms directly to representative samples 
of the proposed dredged material, and, if any deleterious effects on the 
organisms are caused, for whatever reason, then the dredged material is not 
certified for ocean dumping and must be placed in confined land disposal 
sites. 



-40- 



CONCLUSIONS 



1. Environmental awareness has fostered broad research programs 
throughout the United States designed to determine the extent 
and significance of the environmental impacts of dredging. The 
most significant are the $30 million Dredged Materials Research 
Program (DMRP) managed by the U.S. Army Corps of Engineers, 
Waterways Experiment Station, Vicksburg, Miss., and the $3 mil- 
lion Dredge Disposal Study (DDS) managed by the San Francisco 
District Corps of Engineers. The voluminous results of these 
programs have either been available for short periods or are 
just now emerging from various contractors and universities. 

As a consequence, a great deal of this material has not under- 
gone critical review and synthesis by the scientific community. 

2. The San Francisco Bay Estuarine system is highly complex, both 
physically and chemically, within the scope of an already com- 
plex field of estuarine science. The current state of the art 
does not allow accurate prediction of water currents and sedi- 
ment flows. The estuary undergoes natural stress in the form 
of strong circulation patterns driven by tide, winds, salinity 
gradients, and river inflows. Natural stresses to the biota, 
typical of most estuaries, are the massive sediment inflows, 
variations in salinity with river input, and seasonal tempera- 
ture changes. 

3. Further stresses to the system are imposed by industrial civi- 
lization through removal of river waters, historic hydraulic 
mining for gold, subsidence due to removal of groundwater, 
municipal and industrial waste discharge, filling of marshes 
for agricultural purposes, diking and filling of tidal flat 
areas, introduction of numerous species and dredging and dis- 
posal of bottom sediments. Since natural and man-made stress 
may both cause the same effects on populations of organisms 
with varying conditions of climate, no generalizations can be 
made concerning differences in environmental effects between 
natural and man-induced stress. 

4. The preceding two considerations make evaluation of any specific 
environmental impact, such as dredging and disposal, extremely 
difficult to define with scientific certainty. 

5. Field research in San Francisco Bay has shown significant direct 
impacts of dredging and disposal on the biota at dredge and dis- 
posal sites. Due to the circumscribed dredge and disposal areas, 
these effects can be considered minor within the wide expanses 

of Bay bottom habitat in which these species occur. Should 
dredging and disposal at any site be terminated, the sites can 



-41- 



be expected to repopulate within periods of months by migration 
and natural dissemination of eggs and larvae produced in nearby 
regions of the Bay. 

6. Measurements made upstream and downstream of dredging and disposal 
activities have shown that although there are measurable effects 

on oxygen, ammonia, and some heavy metals in the water, are rapidly 
assimilated by the mixing regime in the Bay. A tracer study showed 
that sediments released at the Carquinez Strait disposal site be- 
come mixed to minute levels in San Pablo Bay sediments, and that 
10-15% of the disposed material is redeposited in the dredged area 
(Mare Island Strait). (See reference 8.) 

7. It can be concluded from the new research data that the method of 
bulk analysis to determine pollutant impacts should be reevaluated, 
as presence of metals in sediments is not correlated in a simple 
manner with their potential for environmental impact on water qual- 
ity or biological resources. The latest criteria for ocean dumping 
of dredged material promulgated by the EPA and Corps of Engineers 
is based on bioassay data where representative sensitive organisms 
are directly exposed to dredged material in the laboratory to de- 
termine its potential toxicity. 

8. There is no evidence, positive or negative, for making generaliza- 
tions as to the effects of dredging and disposal on commercially 
valuable biological resources of the Bay. Only highly specific 
empirical experiments will demonstrate effects, if any, and due to 
the multiplicity of environmental variables, specific cause-effect 
relationships will always be problematical. 

9. Aquatic disposal of sediments in high energy areas of the Bay ap- 
pears from all available information, to be a better alternative 
than land disposal of dredged materials. Land disposal of Bay mud 
has readily vi si bile environmental impact, is only a temporary 
solution, and is fraught with numerous environmental and economic 
drawbacks. 

10. Environmental impact of routine maintenance dredging will be 
different from new work dredging" Maintenance dredging removes 
recently deposited material which may reflect institutional ef- 
forts to remove contaminant sources.* New work dredging may un- 
cover contaminants which have resided in sediment storage for 
long periods of time. 



*Low degree of contami nati on . 



-42- 



RECOMMENDATIONS 



Research 



I. Carry out correlation analysis between fisheries statistics 
for market crab, striped bass, and other fish for which data 
is available and historical data on dredging activity. Com- 
pensation should be made for lag times between dredging ac- 
tivity and effects on fisheries. Significant correlations 
between changes and dredging and changes in fisheries re- 
sources do not prove effects, but aid in obtaining direction 
for future studies. 



II. Develop a routine field monitoring system to determine up- 
stream-downstream differences in water quality dredging and 
disposal sites under different conditions of water circula- 
tion and river input to verify short term water quality 
measurements made by the Corps. 

Water quality measurements downstream of dredging and disposal 
projects to determine loadings of water column with contami- 
nated sedimentary particles for comparison with ambient values 
(note: ambient values will contain background contaminant 
loads from municipal and industrial waste sources). 

III. Bioassay tests should be conducted on all Bay dredged material 
as recommended by EPA and CE based on the guidelines recently 
published (19). ' 

IV. Field experiments should be conducted, placing caged fish and 
shellfish upstream and downstream of dredging and disposal 
activities as reported in reference (30). Organisms of par- 
ticular importance should be determined by personnel of the 
State Department of Fish and Game. Suggested organisms in- 
clude: 

a. gravid female striped bass, salmon, shad, and anchovies, 
which could later be spawned in order to determine per- 
cent of survival of eggs; 

b. molting juvenile Dungeness crabs, through several molt 
cycles, maintained in bottom cages near dredging and 
disposal ; 

c. clams, oysters and mussels which can be sampled to de- 
termine profiles of bacterial, viral, protozoan, and 
other contaminants of public health significance. 



V. A fully detailed study on a small proejct, such as the San 
Leandro Marina to determine actual local effects. 



-43- 



LITERATURE CITED 



1. Pritchard, D.W., 1967. What is an estuary: physical viewpoint. 
Irv: Estuaries, G.H. Lauff, (ed.). Publication No. 83, pp 3-5, 
Washington, D.C. 

2. U.S. Army Engineer District, San Francisco Corps of Engineers. 
1977. Dredge disposal study San Francisco Bay and Estuary. Main 
Report. 

3. U.S. Army Engineer District, San Francisco, California, 1975. 
Maintenance dredging of existing navigation projects in San 
Francisco Bay Region, California. Final Composite Environmental 
Statement. 

4. Storrs, P.N., E.A. Pearson and R.E. Selleck. 1966. Comprehensive 
study of San Francisco Bay, Volume V, Summary of physical, chemical 
and biological water and sediment data. Sanitary Engineering Res. 
Lab., Rept. No. 67-2, University of California, Berkeley, CA. 

189 pages. 

5. Conomos, T.J. and D.H. Peterson, 1977. Suspended - particle 
transport and circulation in San Francisco Bay: An overview. 

In : Estuarine Processes, Vol. 2, pp. 82-97, Academic Press, N.Y. 

6. Peterson, D.H., T.J. Conomos, W.W. Broenkow and P.C. Doherty, 1975. 
Location of the non-tidal current null zone in northern San Francisco 
Bay. Estuarine and Coastal Marine Science Vol. 3, pp. 1-11. 

7. Krone, Ray B., 1976. Ultimate fate of suspended material in estu- 
aries. Proc. Specialty Conference on Dredging and its environmen- 
tal effects. Mobile, Al . , eds., P. A. Krenkle, J. Harrison and 
J.C. Burdick, pp. 180-201. Am. Soc. Civ. Engrs. 

8. Ecker, R.M., J.F. Sustar and W.T. Harvey. Tracing estuarine sedi- 
ments by neutron activation. Proc. 15th Coastal Eng. Conf., Am. 
Soc. Civ. Eng., N.Y. 

9. DeFalco, Paul, 1967. The estuary - Septic tank of the megalopolis. 
In : Estuaries, G.H. Lauff, (ed.), Washington, D.C. 

10. Matern, R.A., 1973. San Francisco Bay. In: Our environment 
the outlook for 1980, (ed.) A.J. Van TassiT. Lexington Books, 
Lexington, Massachusetts. 

11. Serne, R.J. and B.W. Mercer, 1975. Characterization of San Francisco 
Bay dredged sediments - crystalline matrix study. Appendix F, Dredge 
Disposal Study, U.S. Army Engineer District, San Francisco, CA. 

215 p. 



-44- 



12. Boyd, M.B., R.T. Saucier, J.W. Keeley, R.L. Montgomery, R.D. Brown, 
D.B. Mathis and C.J. Guice, 1972. Disposal of dredge spoil, prob- 
lem identification and assessment and research program development. 
Technical report H-72-8. U.S. Army Engineer Waterways Experiment 
Station, Vicksburg, Mississippi. 

13. Liu, D.H., K.D. Martin and C.R. Norwood. 1975. San Francisco Bay 
benthic community study. Dredge Disposal Study, U.S. Army Engineer 
District, San Francisco, California. Appendix D. 

14. Gilbert, G.K. 1917. Hydraulic mining debris in the Sierra Nevada 
U.S. Geol. Surv. Prof. Pap. 105. 45 p. 

15. Nichols, F.H, 1973. A review of benthic fauna! surveys in San 
Francisco Bay. U.S. Geological Survey, circular 677. 

16. Nichols, F.H. 1977. Paper presented at AAAS Meeting, San Francisco 
State University, June 13, 1977. 

17. JBF Scientific Corporation. 1975. Dredging technology study. 
Dredge Disposal Study, U.S. Army Engineer District, San Francisco, 
California. Appendix M. 

18. San Francisco Bay Conservation and Development Commission, 1976. 
The Regulation of Dredging. Staff Report. 

19. Technical Committee on Criteria for Dredged and Fill Material, 1977. 
Ecological evaluation of proposed discharge of dredged material into 
ocean waters. Environmental Effects Laboratory. U.S. Army Engineer 
Waterways Experiment Station, Vicksburg, Mississippi. 

20. Schubel , J.R. and R.H. Meade, 1975. Man's impact on estuarine 
sedimentation. I_n: Estuarine Pollution Control and Assessment, 
Proc. Vol. 1. pp. 193-209. U.S. Environmental Protection Agency, 
Washington, D.C. 

21. Cunnington, E.A., 1968. Survival time of oysters after burial at 
various temperatures. Proc. Natl. Shelf. Assn., Vol. 58. pp. 101- 
103. 

22. McCauley, J.E., R.A. Parr and D.R. Hancock, 1977. Benthic infauna 
and maintenance dredging: a case study. Water Research Vol. 11, 
pp. 253-242. 

23. Oliver, J.S., P.N. Slattery, L.W. Hulberg, and J. W. Nybakken. 
1976. Final report task 1D01. Prepared for Environmental Effects 
Laboratory, DMRP. U.S. Army Engineer Waterways Experiment Station, 
Vicksburg, MI. 

24. Keck, R.T., et al . 1976. Vertical migration of marine benthos in 
dredged material overburdens. University of Delaware, Coll. Mar. 
Stud. Draft Report. DMRP Project 1D03. Lewesand Newark, Del. 130 p. 



-45- 



25. No citation. 

26. Peddicord, R.K., et al . 1975. Effects of suspended solids on San 
Francisco Bay organisms. Report to: U.S. Army Corps of Engineers, 
San Francisco District, Dredge Disposal Study, Appendix G. 158 pp. 

27. Peddicord, R.K. and V. McFarland. 1976. Effects of suspended 
dredged material on aquatic animals. Working draft final report 
task 1D09. Prepared for U.S. Army Corps of Engineers Waterways 
Experiment Station, Vicksburg, MI. 

28. U.S. Army Engineer District, San Francisco Corps of Engineers. 
1976. Water column. Dredge disposal study. Appendix C. 

29. Sherk, J. A., J.M. O'Conner and D.A. Neumann, 1975. Effects of sus- 
pended and deposited sediments on estuarine environments. In: 
Estuarine Research, ed., L. Eugene Cronin, Vol. 2, pp. 541-3F8. 

30. Cronin, L.E., et al . , 1970. Gross physical and biological effects 
of overboard spoil disposal in upper Chesapeake Bay. Nat. Res. 
Inst. Spec. Rep. No. 3. University of Maryland. 

31. Sullivan, B.K. and D. Hancock, 1977. Zooplankton and dredging: 
research perspectives from a critical review. Water Res. Bulletin, 
Vol. 13, No. 3, pp. 461-467. 

32. Diaz, R.J. and D.F. Boesch, 1977. Impact of unconfined overboard 
disposal of fine grained dredged material on benthic communities 
with particular attention to the environmental effects of fluid mud. 
Unpublished report task No. 1D12. Environmental Effects Laboratory. 
U.S. Army Engineer Waterways Experiment Station, Vicksburg, MI. 

33. Chen, K.Y. et al . 1976. Research study on the effect of dispersion, 
settling and resedimentation on migration of chemical constituents 
during open-water disposal of dredge material. Prepared for U.S. 
Army Engineer Waterways Experiment Station, Vicksburg, MI. 221 pp. 

34. Lu, J.C.S. and K.Y. Chen. 1977. Migration of trace metals in 
interfaces of seawater and polluted surficial sediments. Environ. 
Sci. Techno!. 11: 174-182. 

35. Anderlini, V.C. et al . 1976. Pollutant availability study. Dredge 
Disposal Study, U.S. Army Engineer District, San Francisco, CA. 

305 pp. Appendix I. 

36. Anderlini, V.C. et al . 1975. Heavy metal uptake study. Dredge 
Disposal Study, U.S. Army Engineer District, San Francisco, CA. 
89 pp. Appendix H. 



-46- 



37. Neff, J.W., R.S. Foster and J.F. Slowey. 1977. Research study 
to determine the availability of sediment adsorbed heavy metals 
to benthos with particular emphasis on deposit feeding infauna. 
Interim report task 1D06. Prepared for Environmental Effects 
Laboratory, U.S. Army Engineer Waterways Experiment Station, 
Vicksburg, MI. 

38. Fulk, R. , D. Gruber and R. Wullschleger. 1975. Laboratory study 
of the release of pesticides and PCB materials to the water column 
during dredging and disposal operations. Prepared for U.S. Army 
Engineer Waterways Experiment Station, Vicksburg, MI. 88 pp. 

39. DiSalvo, Louis H. , H.E. Guard, N. Hirsch and J. Ng. 1977. Assess- 
ment and significance of sediment associated oil and grease in 
aquatic environments. Draft final report Task 1-D-ll. Prepared 
for U.S. Army Corps of Engineers Waterways Experiment Station, 
Vicksburg, MI. 

40. DiSalvo, L.H. and H.E. Guard. 1975. Hydrocarbons associated with 
suspended particulate matter in San Francisco Bay waters. Proc. 
of American Petroleum Institite, Washington, D.C. 

41. Meadows, P.S. and J.G. Anderson. 1968. Microorganisms to marine 
sand grains. J. Mar. Biol. Assn. U.K. 48: 161-175. 

42. Van Donsel , D.J. and E.E. Geldreich. 1971. Relationships of 
Salmonellae to fecal col i forms in bottom sediments. Water Res. 5: 
1079-1087. 

43. Grimes, D.J. 1975. Release of sediment bound fecal col i forms by 
dredging. Appl . Microbiol. 29(1): 109-111. 

44. Sawyer, T,K., G.S. Visvesvara, and B.A. Harke. 1977. Pathogenic 
amoebas from brackish and ocean sediments, with a description of 
Acanthamoeba hatchetti , n. sp. Science 196: 1324-1325. 

45. Lee, G. Fred. 1975. Significance of chemical contaminants in 
dredged sediments on estuarine water quality. Proc. Estuarine 
Pollut. Workshop, Pensacola. U.S. Environmental Protection Agency. 

46. International Engineering Co. 1975. Final Report: Dredge Spoils 
Disposal Facility, Skaggs Is. (for) Dept. of the Navy, WEST DIV 
Naval Facilities Engineering Command, San Bruno, CA. 



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APPENDIX A 
(References 3) 



CONCLUSIONS 



Based on the results of the various investigations conducted during the 
Dredge Disposal Study (reported in Appendices A through M) the following 
conclusions have been formulated regarding San Francisco Bay maintenance 
dredging and disposal activities: 

o Higher concentrations of contaminants in dredged channels can be 
attributed to the finer grain size associated with maintenance 
dredging. Since dredged channels are out of equilibrium, forming 
lower energy regime, finer sediments will tend to shoal. High 
contaminant levels in San Francisco Bay are normally associated 
with the finer sediments. 

o The type of sediment and the degree to which it is disturbed de- 
termine the amount of sediment resuspension during dredging and 
the immediate release pattern during disposal at open water sites. 
The disturbance, including the adding and mixing with water, de- 
pends on the type and size of dredge, the efficiency of operation 
and the configuration of the shoal. 

o The disturbance during sediment disposal is limited to the bottom 
two meters of the water column regardless of whether the sediment 
mounds or disperses. With hopper dredge operations, the sediments 
leave the disposal site typically within fifteen minutes of re- 
lease and are quickly assimilated into the Bay sediment regime. 

o The sediment regime of the Bay is a very dynamic system. Tests 
in the Bay Area show that within a month, dredged sediments are 
well distributed both horizontally (over 260 square kilometer 
study area) and vertically (in excess of 23 centimeters). About 
ten percent of the dredged sediment returns to the Mare Island 
Strait channel with disposal in Carquinez Strait. The majority 
of samples in the study area had less than four percent dredged 
sediment. Sediments entering San Pablo Bay for the most part 
are not carried directly to the ocean. Sediments are deposited, 
resuspended, recirculated and redeposited elsewhere with a net 
effect of sediment transport toward the ocean. 

o Dredging and disposal in the Bay were not observed to cause 
changes in conductivity/salinity, temperature or pH. Temporary 
but marked water quality changes which were observed included 
reduction of dissolved oxygen, increases in suspended solids, 
and releases of trace elements, chlorinated hydrocarbon and 
nitrogen (nitrate and ammonia). 



-48- 



o Although large changes in water quality were demonstrated, no 
analogous changes in organisms were observed. Thus biological 
impact was not found to be synonymous with measurable water 
quality impact. 

o Significant demonstrated biological effects resulting from in 
Bay dredging and disposal activities are limited to the reduc- 
tion of the number and kinds of benthic organisms immediately 
following an operation and the net reduction of the p, p'-DDE 
desorption rate during disposal. 

o The potential for adverse biological stresses from reduced dis- 
solved oxygen and increased suspended solids concentrations is 
less during winter periods when water temperatures are lowest 
and dissolved oxygen levels highest. Furthermore, during this 
period eggs, larvae and juvenile organisms are at their lowest 
numbers in the water column. 

o Release of toxicants during dredging and disposal operations 
seems to be at such low levels and to last for such short dura- 
tions that their availability for uptake and accumulation is 
extremely limited. 

o Salinity increases significantly intensify the potential for 
release of certain trace elements from resuspended sediments. 
Organisms, however, have been observed to have greater uptake 
rates during periods of decreased salinity and to have greater 
depuration rates in high salinity water. These two opposing 
conditions suggest that there is potentially a natural defense 
mechanism operating in organisms to safeguard them from ex- 
cessive trace element accumulation. 

o Increasing the efficiency of dredging operations in terms of 
minimizing energy losses in disturbing sediments and maximiz- 
ing the collection of sediments whether by hydraulic cutter- 
head, clamshell or hopper dredge, will decrease the potential 
for adverse impacts. 

o Increasing the dispersion of sediments dredged by hopper dredge 
in the Bay could have several positive effects. First, the 
potential of concentrated high suspended solids loading would 
be reduced. Second, both the intensity and duration of dis- 
solved oxygen depressions would be reduced. Since these two 
conditions work synergistically, adverse biological effects 
would decrease. Third, since both toxicant release and uptake 
are concentration dependent, greater dispersion, although in- 
creasing the contact area of sediments for contaminant releases, 
should reduce the potential maximum release (concentration) at 
any one location and thus the potential organism uptake and 
accumulation. And finally, any nutrient or ammonia release 



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would be quickly assimilated into the system, reducing potential 
localized biostimulation or toxicity. Changes in operational 
policies would have to be accomplished without significantly in- 
creasing the time frame of impact. Otherwise, possible mitiga- 
tive advantages might be offset by increasing the duration of 
impact. 

o The potential for long-term accumulation of contaminants by 
organisms from sediments dredged in harbor areas and disposed 
in the open bay is and has been a significant biological con- 
cern because of historically high contaminant levels in these 
harbor areas. Other areas in the Bay also have equally high 
contaminant levels because of their predominantly fine grain 
composition and high transport rate of resuspended sediments. 
Fine grain sediments naturally scavenge contaminants and 
wherever they are concentrated, contaminant levels will typi- 
cally be high. Source control is the only effective method 
for controlling contaminant levels in these sediments. How- 
ever, channel sediment sampling during the last two years 
(1975-1976) seems to indicate that the contaminant levels in 
dredged channels have decreased to levels congruent with open 
areas of the Bay. This is probably the result of the elimi- 
nation or improvement in quality of industrial and municipal 
discharges as required by both State and Federal regulatory 
agencies. As Bay sediment contaminant levels decrease, so 
will the potential for long-term toxicant accumulation. 

o Open water disposal is not considered a significant blockage 
of the channels for mitigation of fish, particularly through 
Carquinez Strait. The plume, as monitored in the field, is 
confined to the bottom two meters of the water column, and 
its cross-section constitutes less than one percent of the 
Carquinez Strait cross-section. The plume occurs in the dis- 
posal site less than one-quarter of the time (ratio of dis- 
posal time to total time). 

o The movement of dredged sediments into the nodal zone in 
Carquinez Strait should cause no more impact on striped bass 
finger! ings and neomysis than those sediments naturally oc- 
curring in this zone. Sediment loading in the nodal zone is 
dependent on tidal forces and freshwater inflow. Dredged 
sediments to replace other sediments in the zone; however, 
unless a contaminant source significantly raises the concen- 
trations in the dredged sediment, the two sediments should 
be physically and chemically similar. 

o The transport of highly contaminated sediments from the Bay to 
deep water ocean disposal sites has the potential for creating 
long-term biological impact. When these sediments are released, 
mounding will generally occur (typically these sediments are 
cohesive and dredged by clamshell operation). These mounds 
will remain intact for long periods because of the lack of high 



-50- 



current velocities to erode and disperse them. Since these con- 
taminated sediments typically contain concentrations of organic 
materials, as well as toxicants, several factors higher than am- 
bient levels, animals may be attracted to them as a concentrated 
food source. While feeding, these organisms are susceptible to 
uptake and accumulation of associated toxicants. This could be 
a particularly significant problem in the Gulf of the Farallones, 
a known nursery area for many commercially important species. 

o The evaluation of potential impacts with with either dispersion 
or mounding must be made on a case-by-case basis, considering 
the release of contaminants, the type of sediment and the sen- 
sitivity of both the water and the sediment system at the dis- 
posal site. 

o Extensive land disposal for maintenance dredging projects does 
not appear to be a viable alternative to aquatic disposal at 
this time because of costs, identified technical difficulties 
and adverse environmental effects which may be involved. Po- 
tential problems include crossing of wetlands, rupture of 
dikes with earthquakes, mudflows, saline water loading and 
loss of irretrievable potential wetlands. 

o Marsh development using dredged sediments should be viable on 
a case-by-case basis, particularly for one time only, small 
dredging projects which are located near suitable diked low 
lands, because of the environmental benefits achieved. Marshes 
are important to the estuary for their ability to oxygenate 
Bay waters, produce nutrients which serve as a base for the 
food web, capture ions, dissipate energy and provide wildlife 
habitat. 

o Contaminant levels in estuarine organisms appear to be con- 
trolled by a limited number of synergistic factors. Suggested 
factors are the long-term process of sediment resuspension- 
recirculation, seasonal fluctuations in salinity and sources 
of contaminants both anthropogenic and geologic. The biolog- 
ical impact may be dependent on the form of contaminant and 
whether or not the sediment system can assimilate the contami- 
nant loading. With the observed sorption-desorption by orga- 
nisms and the fluctuating conditions in the estuary, impacts 
such as high accumulations, mutations and toxicity would not 
be expected unless the contaminant loading is foreign, in the 
case of synthetic chemicals, or above the assimilation capa- 
bility of the estuary with the associated sediment regime, in 
the case of a low energy regime in which the changes in ambient 
conditions are great. 



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APPENDIX B 



LIST OF EXPERTS CONTACTED 



Type of 

Individual Organization Contact 



Dr. Richard Peddicord 

Dr. P.J. Hannan 

Dr. Teng-Chung Wu 

Dr. Donald Girvin 

Mr. L. Thomas Tobin 

Mr. Mike Rugg 



Dr. Jim Sutton 

Mr. Bill Light 

Mr. William Leet 

Mr. Fred Minckler 



Mr. Robert Parker 



Mr. Ted Durst 
Mr. Chris Vais 



Waterways Experiment Station PI 
Army Corps of Engineers 
Vicksburg, Mississippi 

Naval Research Laboratory ph 
Washington, D.C. 

Regional Water Quality Control PI 

Board 
Oakland, California 

Lawrence Berkeley Laboratory, ph 
U.C. Berkeley 

San Francisco Bay Conservation PI 

and Development Commission 
San Francisco, California 

California State Department of PI 

Fish and Game 
Yountville, California 

California Academy of Sciences PI 
San Francisco, California 

National Oceanic and Atmospheric PI 

Administration 
(National Marine Fisheries 

Service), Tiburon, California 

U.S. Army Corps of Engineers PI 
Seattle District Office 
Seattle, Washington 

U.S. Environmental Protection PI 

Agency, Region IX 
San Francisco, California 



Key 



PI = Personal Interview 
ph = Telephone Contact 



APPENDIX B 



LIST OF EXPERTS CONTACTED (Continued) 



Individual 



Organization 



Type of 
Contact 



Dr. H.L. Taten 

Dr. Robert Engler 

Dr. Bill Barnard 

Mr. John Sustar 



Dr. T.J. Conomos 



Mr. Charles Roberts 



Mr. Bob Tasto 

Mr. Phil Swartzell 



Waterways Experiment 
Station, Army Corps 
Vicksburg, Mississippi 

San Francisco District 
Corps of Engineers 

U.S. Geological Survey 
Menlo Park, California 

San Francisco Bay Conservation 

and Development Commission 
San Francisco, California 

California Department of 

Fish and Game 
Menlo Park, California 



PI 

PI 
ph 
ph 

PI 



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