Dredge disposal study San Francisco Bay and estuary, Appendix L ocean disposal of dredged material

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dDREDG
E DISPOSAL STUDI

SAN FRANCISCO BAY
AND ESTUARY

APPENDIX L

TD
224
C2 OCEAN DISPOSAL
U55
1975

SEPTEMBER 1975

DREDGE DISPOSAL STUDY, SAN FRANCISCO BAY AND ESTUARY

APPENDIX L

OCEAN DISPOSAL OF DREDGED
MATERIAL

SEPTEMBER 1975

U.S. Army Engineer District, San Francisco
Corps of Engineers
100 McAllister Street
San Francisco, California 94102

DREDGE DISPOSAL STUDY, SAN FRANCISCO BAY AND ESTUARY

APPENDIX L

OCEAN DISPOSAL OF DREDGED MATERIAL

TABLE OF CONTENTS

Page

FOREWARD a

CONVERSION FACTORS c

INTRODUCTION 1

OCEAN DISPOSAL CRITERIA 2

SUMMARY OF FINDINGS 3

a. Literature Review - Oceanographic Conditions
off the Central California Coast 3
b. Field Studies - Ocean Disposal.of Dredged
Material 4
(1) Sediment Sampling 5
(2) Benthic and Pelagic Faunal Studies 7
(3) Dredge Material Release Study 8

RELATIONSHIP WITH OTHER STUDY ELEMENTS 10

CONCLUSIONS 11

FIGURES
Following Page

FIG 1 - Location of Transects from Golden
Gate to 100-Fathom Disposal and
Study Areas 2

FIG 2 - a. Transect from Golden Gate to
100-Fathom Disposal Area
b. Transect from Golden Gate to
100-Fathom Study Area 4

FIG 3 - Diagram of 100-Fathom Study Area 4

FIG 4 - Ocean Study Area Sediments 5

FIG 5 - Location Farallon Islands Sampling Stations 8

TABLE OF CONTENTS (Cont'd)

TABLES

Page
TABLE 1 - Comparison of Dispersed Grain Size
Distribution in Ocean and Bay Sediments 5

TABLE 2 - Comparison of Contaminant Levels in
Ocean and Bay Sediments 7

TABLE 3 - Water Quality, Study Area Vicinity 9

INCLOSURES

INCL 1 - Literature Review Oceanographic Conditions Off
I the Central California Coast

INCL 2 - San Francisco Bay and Estuary, Dredge Disposal
Study, Ocean Disposal of Dredged Material by
Naval Undersea Center

INCL 3 - Water Quality Monitoring 100-Fathom Ocean Disposal
Study Area (5-6 September 1975)

FOREWORD

In April 1972, the San Francisco District of the United States Army
Corps of Engineers initiated a three and one-half year, $3 million study
to quantify the impact of dredging and dredged material disposal operations
on the Environment of San Francisco Bay and Estuary. The study is
generating factual data, based on field and laboratory studies needed
for the Federal, State and local regulatory agencies to evaluate present
dredging policies and alternative disposal methods.

The study is set up to isolate the questions regarding the environmental
impact of dredging operations and to provide answers at the earliest
date. The study is organized to.investigate (a) the factors associated
with dredging and the present system of aquatic disposal in the Bay, (b)
the condition of the pollutants (biogeochemical), (c) alternative disposal
methods, and (d) dredging technology. The study elements are intended
first, to identify the problems associated with dredging and disposal
operations and, second, to address the identified problems in terms of
mitigation and/or enhancement. The division into separate but inter-
related study elements provides a greater degree of expertise and flexi-
bility in the Study.

This report presents the findings of Appendix L, Ocean Disposal. The
overall study will be the basis for preparation of a composite Environ--@
mental Impact Statement for Dredging Activities in San Francisco Bay
System.

The following is an index of appendices to be published in the Dredge
Disposal Study:

APPENDIX REPORT DATE PUBLISHED

FINAL REPORT

A Main Ship Channel June 1974
(San Francisco Bar)

B Pollutant Distribution

C Water Column
(Water Column-Oxygen Sag)

D Biological Community August 1975

E Material Release

F Crystalline Matrix July 1975

G Physical Impact July 1975

Pollutant Uptake September 1975

I Pollutant Availability

i Land Disposal October 1974

K Marsh Development

L Ocean Disposal September 1975

M Dredging Technology September 1975

CONVERSION FACTORS

If conversion from the Metric to the British system is necessary, the
following factors apply:

LENGTH
1 kilometer (4)=103 meters=0.621 statute miles=0.540 nautical miles
I meter (m)=10 centimeters=39.4 inches=3.28 feet=1.09 yards=0.547 fathoms
1 centimeter (cm)=10 millimeters (mm)=0.394 inches=104 microns (-P)
1 micron ( P)=10-3 millimeters=0.000394 inches

AREA
1 square centimetIr cm 2 =0.155 square inches
1 square meter (m )=10.7 square feet
1 square kilometer (km2)=0.386 square statute miles=0.292 square nautical miles

VOLUME
1 cubic kilometer (km3)=109 cubic meter S=1015 cubic centimeters=0.24 cubic
statute miles 3)=106 103
1 cubic meter (m cubic centimeters= liters=35.3 cubic feet=264
U.S gallons=1.308 cubic yards
* 3
1 liter=10 cubic centimeters=1.06 quarts=0.264 U.S. gallons
1 cubic centimeter (cm3)=0.061 cubic inches

MASS
1 metric ton=106 grams=2,205 pounds
1 kilogram (kg)=103 grams=2.205 pounds
1 gr (g)=0.035 ounce

SPEED

1 knot (nautical mile per hour)=1.15 statute miles per hour=0.51 meter
per second
1 meter per second (m/sec)=2.24 statute miles per hour=1.94 knots
1 centimeter per second (cm/sec)=1.97 feet per second

TEMPERATURE
OC = OF-32 OF = 1.8(OC) + 32
Conversion Formulas 1.8

DREDGE DISPOSAL STUDY, SAN FRANCISCO BAY AND ESTUARY

APPENDIX L

OCEAN DISPOSAL OF DREDGED MATERIAL

INTRODUCTION

The Ocean Disposal Study is one of three studies which address the

feasibility of alternatives to the present system of aquatic disposal in

San Francisco Bay waters. The other two alternative studies are concerned

with marshland development utilizing dredged sediments, and land disposal.

The objectives of the Ocean Disposal Study is (1) to provide a qualitative

description of the physical, chemical, and biological environment in one

area on the continental shelf break in the vicinity of the Farallon

Islands, and (2) to provide a qualitative description of the general

release pattern of dredged material placed on the continental shelf

break.

In order to fulfill the above objectives a brief literature review

was conducted with respect to the continental shelf environment. The

information collected in this review is summarized in Inclosure 1,

Oceanographic Conditions off the Central California Coast. Field studies

at a 100-fathom study area were conducted during 5-7 September 1974 with

the Naval Undersea Center, Department of the Navy, by an interagency

agreement with the San Francisco District, Corps of Engineers. Details

of the field studies and laboratory analysis performed by the Navy are

presented in Inclosure 2. Water quality monitoring was conducted by

personnel of the San Francisco District in conjunction with the field

studies. Water quality data collected are presented in Inclosure 3.

OCEAN DISPOSAL CRITERIA

The discharge of dredged sediments into the territorial sea is

governed by the Marine Protection, Research and Sanctuaries Act of 1972,

Public Law 92-532 and regulations and criteria issued pursuant thereto.

Ocean dumping criteria published in 40 CFR 227 (Federal Register, 15

October 1973, Volume 38, Number 198, Part II, paragraph 227.61) lists

guidelines for classifying dredged material. The three elements of the

guidelines are (1) the type of sediment such as sand versus clays and

organics, (2) adequacy of water quality using state water quality standards

and the health of the biota associated with the sediments, and (3)

standard elutriate (contaminants released to the water from the sediments

using a standard test) within 1.5 times the contaminant levels of

the water at the disposal area.

The Environmental Protection Agency in cooperation with the Corps
of Engineers has established standard aquatic disposal sites in San

Francisco Bay and off the California coast for dredged sediments. The

standard sites include three aquatic sites in the Bay, one on the San

Francisco Bar and one in the ocean at the 100-fathom line south of the

Farallon Islands. The locations of the designated ocean disposal area

and the study area are shown in Figure 1.

123 01 00, 12201 M, t22 01 K), 122 30'.

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3-70
9D
........ ........
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...........
...........
...........

................ ...
FARALLON ISLANDS ................
SA* FRANCISCO:

.............. .

370
.............
Iwo
.............
.............
STUDY AREA ............
..............
150 X 300-METERS
............
............
370 4 V N
123, 7.5' W

.........................
............... V.
.................. .... ..
DESIGNATED ..........................
370
Vl- DISPOSAL AREA ...
1000 YDS. WIDE RADIUS
........ ..... ..
37* 31'45" N .......................
1220 '59'00" W

..........
..........

............

.......................
37 0
................
20,

00
.............

10 0 10

NAUTICAL MILES

LOCATION OF TRANSECTS FROM GOLDEN GATE TO IWFATHOM D ISPOSAL AND STUDY AREAS

FIGURE 1

SUMMARY OF FINDINGS

a. Literature Review Oceanographic Conditions off the Central

California Coast (Inclosure 1). The continental shelf forms a broad

plain beyond the Golden Gate ranging from 15 to 20 nautical miles in

width. The shelf slopes gradually seaward from the7Golden Gate with

average inclinations of 0.2 to 0.3 percent. At depths from 70 to 80

fathoms the slope steepens to 5 to 6 percent forming the continental

shelfl.break and the continental slope.

Sediments on the continental shelf are predominantly sands

while sediments on the continental slope range from fine sands through

fine silts. In several locations along the California coast surface

sediments are bound into aggregate-sized nodules (phosphatic nodules).

These nodules form a surface layer which is a favored habitat of sessile

and borrowing marine organisms.

During the summer, prevailing winds and swells are from the

northwest with some distant storms from the southwest. In addition to

this, two predominant currents influence the central coastal waters: a

southward moving current (California Current) and a northward moving

current (Davidson Current). With these factors, the California coast

exhibits three distinct oceanographic seasons: the Upwelling occurring

in spring with an overturning of the upper layers from moderate depths;

Oceanic in the fall with southward movement of both surface and deep

currents; and Davidson in the winter with northward surface currents

near shore.

Central California coastal waters, particularly the Gulf of the

Farallones, support an immense recreational and commercial fishery.

Most of the important fishes have pelagic eggs which are an integral

part of the plankton community and virtually all depths at the con-

tinental shelf are used either as feeding, spawning, or nursery areas.

There is a subtle biological interrelationship between the Gulf of the

Farallones and San Francisco Bay. Salmon, several species of flatfish,

the Pacific herring, and many other varieties of fishes are dependent on

both the ocean and estuarine (bay) environments. The most productive

areas for all commercially important fish (except salmon) are in the

Gulf of the Farallones and south of the Farallon Islands at depths

greater than 50 fathoms. Some of the most productive areas south of the

Farallones are near the designated 100-fathom disposal area.

b. Field Studies - Ocean Disposal of Dredged Material (Inclosure 2.

The designated disposal area was not used for the field studies because that

area was already disturbed by previous disposal operations. The study

area selected, however, very nearly approximates the disposal area in

terms of topography. Similarity of the two areas with respect to the

continental shelf break is shown in Figures 2a and 2b. The profiles are

plotted along two transects from the Golden Gate as shown in Figure 1.

Exaggerated and true slope are plotted for both transects. In general,

the shelf break along both transects occurs between 70 and 80 fathoms

with the 100-fathom contour lying approximately one mile beyond.

DEPTH(FEET) DEPTH(FATHOMS)' DEPTH(FEET). DEPTH(FATHOM

P
0
0 8 o
8 0,
0 0 0 0 0 0 0 0

m
0- GOLDEN GATE 0- G

(3
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The study area was a 150-meter by 300-meter rectangle with a

northwest to southwest orientation. The site was marked at each corner

with a sonar reflector placed 2 meters from the bottom and with a surface

buoy at the center of the northwest end (Figure 3). Approximately 3,000

cubic meters of dredged material loaded in two bottom-dump barges towed

in tandem were released over the study area. Sediment samples were

collected prior to release and photographic surveys were made both

before and after the release. Sediment sampling sites, path of the

barge, and release stations are also shown in Figure 3.

(1) Sediment Sampling. Sediment samples were collected with

the use of a Shipek Dredge at five locations along a 300-meter transect

which traversed the length of the study area. Dispersed grain size

analysis of the samples collected indicated that the sand fraction in

the sediments varied from 24 to 88 percent. Table I compares the

dispersed grain size distribution of ocean sampling stations with

sediment collected in dredging project areas in San Francisco Bay.

TABLE 1
It
COMPARISON OF DISPERSED
GRAIN SIZE DISTRIBUTION IN OCEAN AND BAY
SEDIMENTS

DISPERSED OCEAN SAMPLING SITES* OAKLAND PINOLE OAKLAND MARE
GRAIN SIZE 1 2 3 4 5 OUTER SHOALS INNER ISLAND

SAND 24 58 72 85 88 65 60 47 1

SILT 56 40 21 13 10 18 23 33 50

CLAY 20 2 7 2 2 17 17 20 49

*See Figure 3.

300-METERS

... .........
.. .......

. ........ ...
370 41'N
1230 07.5'W
ul

..... .....
.........

....... .... ...

L__j

LEGEND

PATH OF VEHICLE

...... PATH OF DREDGE BARGE
x LOCATIONS WHERE DREDGE
HOPPERS OPENED DIAGRAM OF 100-FATWW STUDY AREA
DREDGED MATERIAL
C)

;u 0 SEDIMENT SAMPLING SITES
m
S SONAR REFLECTOR
+ SURFACE BOUY

Sites 3, 4, and 5 contained a greater percent sand than found in typical

Bay samples. Phosphatic nodules were also recovered from the study area

with the use of a basket grab attached to the Naval Undersea Center's

CURV III, underwater tethered vehicle. Three photos of the nodules are

shown in Figure 4. The top photo shows the physical size and shape of

the nodules, the middle photo views a nodule in cross section, and the

bottom photo provides a microscopic view of individual particles within

the nodule. The nodules are generally less than 6 centimeters in diameter

and are comprised of fine sand, shell fragments, and animal tubes bound

together with a phosphate cement.

Sediment samples collected in the study area were also analyzed

for the presence of various contaminants. Table 2 compares contaminant

levels in ocean and Bay sediments. Contaminant levels in Bay sediments

are from 2 to 5 times greater than those found in ocean sediments

sampled.

OCEAN STUDY AREA SEDIMENTS

0 5 10 Is cm

&MEN---

NODULES

41 "T117

2 c m

NODULE

CROSS SECTION

PARTICLES

FROM NODULE

1 UNIT= 10 MICRONS (.01 mm.
FIGURE4

TABLE 2

COMPARISON OF CONTAMINANT LEVELS
IN OCEAN AND BAY SEDIMENTS

Dredged Channels S.F. Bay 100-Fathom (Ocean)
Parameter Mean Concentration Mean Concentration
PPM J/ PPM

Lead 35.6 7.0

Zinc 108.1 40.5

Mercury 0.55 0.17

Cadmium 1.59 0.41

Copper 41.6 9.6
Volatile Solids 6.03 x 10 4 2.01 x 10 4
Chemical Oxygen Demand 4.12 x 10 4 1.51 x 10 4

l/ Dredge Disposal Study, Appendix B, Pollutant Distribution (To Be published)

(2) Benthic and Pelagic Faunal Studies. Speciation and enumeration

of epibenthic macrofauna. were obtained from photographs taken by CURV

III prior to dumping. Animal densities were calculated from numerical

totals obtained from the photographic survey. In addition, three of

macrofauna species were collected with a grasping basket assembly for

an alysis. A Pisaster starfish, a small fish (Mesluccius productus) and

a Heart urchin (Echinocardium) were collected. Each species was analyzed

for mercury, copper, cadmium, lead chromium, and zinc.

The epibenthic macrofauna of the study area was relatively

abundant. The dominant group were arthropods which made up about 70

percent of all bottom animals. In order of decreasing abundance the

remainder were molluscs (13%), bony fishes (10%), and echinoderms (7%).

The density of total animals was relatively high (1801 animals over 1316
M2 or 1.4 animals/m2), but the species diversity was relatively low. In

the three species of epibenthic macrofauna analyzed (wet weight) copper

ranged from 1.74 - 5.87 ppm, cadmium from 0.28 - 1.66 ppm, lead from

2.06 - 7.27 ppm and chromium from 16.7 - 103.3 ppm. Mercury concentrations

(dry weight) on replicate samples of the starfish were 259 ppb and 204

ppb.

(3) Dredge Material Release Study. To determine the dispersal

of the dredged material a grid pattern was first marked on the bottom at

the study area. This was accomplished with the CURV III during the pre-

dump, photographic survey using the skids of the vehicle. The pre-dump

markings consisted of 300-meter long parallel lines at eight-meter

intervals (Figure 3). The dredged material was then released from.two

barges each containing 1,500 cubic meters of material. The barges were

emptied by the time they reached 150 meters into the study area.

Approximately 12 hours after the release of dredged material a second

photographic survey was made. The vehicle followed a track perpendicular

to the pre-dump markings. Interpretation of the post-dump photographs

revealed that the released material passed nearly vertically through the

water column and landed in clumps in the study area. The average depth

of deposition in the study area was about 0.3 meters and the area impacted

was about 10,000 square meters (Figure 3). Based on studies in Appendix

M, Dredging Technology, lack of dispersion was due to the low water

content of the cohesive sediment.

c. Water Quality Monitoring (Inclosure 3). Water quality monitoring

was performed by District personnel in the study area and in four locations

approximately three nautical miles outside of and surrounding the study

area (Figure 5). Pre-dump monitoring was conducted in the upper 80

meters of the water column with an Inter-Oceans Water Quality Monitoring

Probe on 5-6 September 1975. The water quality monitoring was performed

to provide baseline information on water quality conditions in the

surface waters adjacent to the 100-fathom contour. The parameters

measured included conductivity, salinity, turbidity (percent transmission),

turbidity (FTU), temperature, and dissolved oxygen. Table 3 summarizes

the results of the monitoring.

TABLE 3

WATER QUALITY, STUDY AREA VICINITY

DEPTHS WATER QUALITY PARAMETERS
IN SALINITY TURBIDITY TEMPERATURE DISSOLVED OXYGEN
METERS 0/00 % TRANS FTU 0C mg/l

20 33.4 90.4 1.0 12.6 9.6

40 33.5 @91.2 0.7 11.0 7.3

60 33.6 91.0 0.8 10.1 5.5

80 33.7 92.3 0.8 9.5 -

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LOCATION FARALLON ISLANDS SAMPLING STATI ONS FIGURE 5

RELATIONSHIP WITH OTHER STUDY ELEMENTS

Several other Dredge Disposal Study elements provide additional

information pertinent to the consideration of ocean disposal as an

alternative for disposing of material dredged from San Francisco Bay.

Land Disposal, Appendix J, provides an analysis of the relative

costs of various disposal alternatives. In general, the transport of

sediments to the 100-fathom disposal area with theorized systems may

increase dredging costs two fold as compared to present practice of in-

Bay disposal. Removal of polluted materials to land disposal areas

would necessitate a similar cost escalation.

Field work associated with other study elements gives an insight

into release patterns which occur under disposal conditions different

from those found at the ocean disposal area. During studies on the San

Francisco Bar (Main Ship Channel), Appendix A, the sandy sediments were

found to react as discrete particles during disposal, depositing in a

predictable pattern. The study showed a normal distribution pattern

with a maximum deposition of two inches directly beneath the hopper

dredge. During the monitoring of oxygen depression associated with the

disposal of Bay mud at Carquinez Strait (Water Column, Appendix C), an

induced current of one knot perpendicular to the tidal current was

observed at the bottom of the water column. Other monitoring at the

Carquinez Strait site showed complete transport of sediments from the

disposal site during a hopper dredge release within fifteen minutes in

the-bottom one meter of the water column.

The Dredging Technology Study, Appendix M, included laboratory

simulation studies to qualitatively describe immediate release patterns

generated under various disposal conditions. These studies provide,

within the variability of the prototype system, an evaluation of the

loading of the water column, the degree of bottom impact and the rate of

transport from the site. This information will be applied to the

results of other study elements to define the extent of environmental

impact.

The impacts of various levels of suspended sediments in the water

column and various depositional depths upon selected marine organism are

discussed in Physical Impact, Appendix G. The potential release of

heavy metals from sediments, uptake of metals and availability of metals

to organisms are discussed in Crystalline Matrix, Appendix F; Pollutant

Uptake, Appendix H; and Pollutant Availability Appendix I, respectively.

CONCLUSIONS

a. Areas of greatest productivity for all commercially important

fish (except the salmon) along central California waters are in the Gulf

of the Farallones and south of the Farallon Islands at depths greater

than 50 fathoms.

b. Water conditions in the vicinity of the 100-fathom contour show no

signs of degradation.

c. Unlike sediments in San Francisco Bay, sediments in the vicinity

of the 100-fathom study area are generally higher in sand content and

contain aggregate size nodules.

d. Sediments at the 100-fathom study area are significantly less

contaminated than Bay sediments.

e. Cohesive sediments with low water content deposited at 100-

fathom study area fall nearly vertically and concentrate in clumps on

the bottom.

INCLOSURE ONE

OCEANOGRAPHIC CONDITIONS OFF THE CENTRAL CALIFORNIA COAST

PHYSICAL OCEANOGRAPHIC CONDITONS OFF THE CENTRAL CALIFORNIA COAST

The continental shelf forms a broad plain beyond the Golden Gate
ranging from 15 to 20 nautical miles in width. The shelf slopes gradually
seaward from the Gate with average inclinations of 0.2 to 0.3 percent.
At depths of from 70 to 80 fathoms the slope steepens to 5 to 6 percent
forming the shelf break and the continental slope. The 100-fathom
contour lies1two to three miles beyond the break. Though there are
several theories concerning the origin of the continental shelf, it is
rather widely accepted that erosion during periods of glacially lowered

sea level contributed measurably to its formation.

Sediments upon the continental shelf adjacent to San Francisco Bay

are predominantly shell sands, and glauconitic sands while sediments on
the continental slope range from fine green sands through coarse silts
to fine olive-green silts (Bailey, 1966). Along the Central coast,
shelf sediments are generally shallow and are underlain with granitic
bedrock (Moore and Shumway, 1959). In many locations along the California
coast, surface sediments are bound into phosphatic nodules with diameters
up to 6 centimeters (Bailey, 1966). These nodules form a surface layer
which is a favored habitat of sessile and borrowing marine organisms
(Twenhofel, 1950). Phosphatic nodules have considerable distribution in
areas of the ocean bottom which are subject to rapid and large change in
temperatures (Twenhofel, 1950). Rapid changes in temperature occur
offshore from San Francisco as the result of upwelling. The occurence
of the nodular layer in ocean sediments seaward of the Golden Gate has
been documented. In 1952 Chesterfield recovered nodules in dredge hauls

in water depths between 400 to 600 fathoms west of San Francisco and at

depths from 200 to 400 fathoms to the northwest of the Golden Gate

(Chesterfield, 1952).

The physical conditions outside the Golden Gate are quite different

from that of San Francisco Bay. Certain physical factors of insignificant

influence in an estuary become magnified in the great expanse of the

ocean. For example, the subtlety of the earth's rotation and the flow

of the trade winds normally have a minor effect on an estuary but are

important in influencing the surface currents of the ocean. The tides

influencing the continental shelf along central California are semi-

diurnal. During the summer, prevailing winds and swells are from the

northwest with some distant storms from the southwest. In addition to

this, two predominant currents influence the Central coastal waters: a

southward moving current (California Current) and a northward moving

current (Davidson Current).

The California Current is a broad, slow, southward moving, surface

current which emanates from the North Pacific Current that crosses the

North Pacific from Japan. It moves about 0.2 knots and passes through

the Gulf of the Farallones. The width of the current is about 300

nautical miles with a depth of about 180 meters. Eventually it becomes

a part of the North Equatorial Current which flows westward toward

Japan.

The California Current is the prevailing nearshore current off

the central California coast from late winter through fall. From late

summer until the beginning of winter, it is particularly close to shore
and this is when the surface ocean temperatures are highest for the
year, around 150C, off North Farallon Island. A strong vertical temperature

gradient also exists in the upper water column. The surface salinity is

slightly higher than the rest of the year. Transparency of the water

averages 10 to 12 meters and the dissolved oxygen levels range from 9
mg/l at the surface to 4 mg/l several hundred feet deep (Kaiser Engineers,

1969). The time period which is characterized by these event s is known

as the Oceanic Period.

Preceding the Oceanic Period is the Upwelling Period from late

winter to late summer. This time period is characterized by persistent
fog which shrouds the central coast, and by a phenomenon known as up-

welling. During the spring and summer prevailing winds are from the

north and northwest. Due to the prevailing winds and the rotation of

the earth, surface waters at this time move offshore and are replaced by
colder, subsurface water from depths of a few hundred feet. The replacement

of offshore moving surface water by colder subsurface water is called

upwelling, and it is this phenomenon that contributes to the richness of

the fisheries off the California coast. The southward moving California

Current is not as close to shore as during the Oceanic Period due to

upwelling. The nearshore surface water, which moves westward, pushes
the California Current further offshore during this time period.

Between the Oceanic Period and the Upwelling Period, from

November to February, the fast-moving Davidson Current moves northward

pushing the southward California Current offshore. It is this northward

moving current that becomes the prevalent nearshore current during the

winter season. The Davidson Current has a minimum width of 50 nautical

miles and can attain speeds of 0.5 to 0.9 knots over distances of several

hundred nautical miles. Since this current occurs during the winter,

freshwater runoff from the coast augments the northward flow.

In summary, the three oceanographic seasons are listed below:

Median Temperature
Oceanographic Season Duration (OC) Range West of S.F.

Upwelling Period February-July 12.0 - 13.5
Oceanic Period July-November 14.1 - 15.2
Davidson Period November-February 15.0 - 12.0

Figure 1 compositely shows the prevailing California and Davidson Currents

off the central California coast (Brown and Caldwell, 1971).

MARINE BIOLOGICAL CHARACTERISTICS OFF THE CENTRAL CALIFORNIA COAST

a. Plankton. Tidal cycles play less of a factor in affecting

plankton species composition outside the Bay than in the Bay with the

exception of the area shoreward of the sand bar. Seasonal changes,

however, are quite important.

Atmospheric seasons are directly related to the three oceanographic

seasons and affect sunlight intensity over the water and availability of

nutrients to phytoplankon. These, in turn, affect plankton species

composition and numbers. Of the three oceanographic seasons, the Upwelling

Period has the most pronounced effect on phytoplankton. Abundant nutrients

such as phosphates and silicates are brought to the surface from lower

0-30 60 90
Cape
SCALE, NAUTICAL MILES
Mendocino

NEVADA

C,
390N

San
Francisco
k Bay
C, 'P

370 0 Ir, -11,
Monterey
Bay

350 4L

Point Arguello

1270W 1250 1230 1210 1190

DAVIDSON WINTER
CURRENTS CALIFORNIA SUMMER
SUMMER a WINTER

SOURCE: BROWN & CALDWELL. 1971. A PREDESIGN REPORT ON MARINE WASTE DISPOSAL, VOL. 1.

PREVAILING CURRENTS OF THE CENTRAL CALIFORNIA COAST

FIGURE I

depths of the ocean by the upwelling process, and sufficient sunlight is

available during this time of the year to allow optimum phytoplankton

photosynthesis. These conditions result in a population explosion of

the phytoplankton community known as a "plankton bloom." Not all phytoplankton

species bloom during the Upwelling Period. There are species and varieties

that find the other two oceanographic seasons more favorable for growth

and thus blooms can be detected during each oceanographic season.

As in the Bay, diatoms are the dominant phytoplankton

types. Dinoflagellates are less numerous but are, nevertheless, an
integral part of the @hytoplankton community. All phytoplankton form

the nutritional basis upon which all marine animal life are directly or

indirectly dependent.

With respect to zooplankton, the animal portion of the

plankton that typically feeds on the phytoplankton, the variety found in

Central San Francisco Bay is also found in the Gulf of the Farallones.

During the winter or Davidson Period, the zooplankton in the Gulf are

dominated by salps (pelagic tunicates) and copepods. The variety of

types is least during the winter as is also true in the Bay. In spring,

when there is an abundance of phytoplankton to feed on, the variety of

zooplankton is at its greatest. In addition to salps and copepods (of

which there are many species), fish eggs and larvae, cirripeds (young

barnacles) and crab larvae are abounding (Brown and Caldwell Consulting

Engineers, 1971).

Except for ocean shrimp (Pandalus , no zooplankter per se

is commercially or recreationally important. Ocean shrimp are com-

mercially caught north of Point Reyes but none are harvested in the Gulf

of the Farallones. There are members of the ocean zooplankton community

that give rise to commercially and recreationally important species.

The most obvious are fishes and crabs.

Because of the dominating nature of ebb-flood currents through

the Golden Gate, much of the-zooplankton stages of the Dungeness crab

are swept into the Bay during winter when they are most abundant. Those

seaward,of the San Francisco Bar are less influenced by the tides and

thus remain a part of the ocean plankton community. Larvae crabs

voraciously feed on the plentitude of copepods.

b. Fish. Bane and Bane list 172 fish species that are known

to frequent the inshore waters of the central California coast (Bane and

Bane, 1971). The list includes all the anadromous and marine species

within the Bay. Many of these are commercially and recreationally

valuable, of which a few will be discussed in greater detail to depict

the diversity and importance of coastal-marine fishes, and their relation-

ship to the overall ecology of the central California coastal waters.

All of the species to be discussed can be found in the general vicinity

of the Bar and the 100-fathom disposal area.

(1) Chinook salmon. Chinook salmon fishing (all species

of salmon, for that matter) in the Gulf of the Farallones produces the

most consistent salmon yields in the State. This area is heavily,

commercially fished for chinooks and every year over one-half of the

State's sport salmon catch comes from the Gulf (Smith, 1973). This area

is productive because it is in the main migratory route between San

Francisco Bay and the ocean. Salmon fishing in California is exclusively

a troll fishery (hook and line only) regulated by the State. The commercial

fishing season is restricted to the period April 15 to September 30 for

chinooks and May 15 to September 30 for Coho salmon. Chinooks are

mostly caught between 5 to 30-fathom depths at a trolling speed of one

to three knots (Odemar et al, 1968). Peak salmon catches occur in early

summer off San Francisco. Recreational (party boat) fishing for salmon

is extremely popular off the central California coast and landings

always rank among the highest of sport fishes. Recreational salmon

fishing is allowed year-round north of Tomales Point and in San Francisco

Bay but can only be legally taken seaward of the Golden Gate and south

of Tomales Point between mid-February and mid-November. Figure 2 depicts

where most of the salmon are annually caught off central California. In

the ocean, chinooks eat a variety of organisms and show seasonal preferences.

They feed heavily on anchovies, juvenile rockfishes, Pacific herrings,

euphasids (shrimps) and larval crabs.

(2) Rockfish. This group of fishes, belonging to the

genus Sebastes, is extraordinarily diverse in color, habitat, depth

preference, and geographical range. The genus consists of the largest

FT
ARSMA

FT. ROSS

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TOWLES
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LEGEND

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t;;'; LIM THAN 281

210 -2,9911

3,M - 5,91011
slow - I'M --1A

ORIGIN Of AVIERAGIE ANNUAL SALIIIIIIIII
CATCHES BY PARTY BUTS
T

POINT ARENA TO POINT
10 5 0 10 20 30 40 1962 - 19116

SCALE IN MILES
SOURCE: OOKMAR ST AL. OSSIN FIGURE 2

number of marine fishes off California, constituting 58 recognized

species as of 1972 (Miller et al, 1972). Of the 58, 48 are known to

occur off central California and most are considered commercial and

sport fishes. Most are caught in rather deep water, between 70-350

fathoms, and as their name implies, are associated with rocky reefs.

Most spawn during the winter and their eggs are planktonic. Larval

rockfish can be found year-round down to 100 fathoms. As adults, they

actively feed on anything that can be accommodated within their mouths,

including anchovies, lantern fish, young hake, smaller rockfish, sablefish,

squid, euphasiids and tunicates. The most commonly caught rockfish

species by commercial trawlers and party boats along central California.

include the Bocaccio (S. paucispinis), Chilipepper (S. goodei , Splitnose

rockfish (S. diploproa), Widow rockfish (S. entomelas), Speckled rockfish

(S. ovalis), Blue rockfish (S. mvstinus), Yellowtail rockfish (S.

flavidus), Black rockfish (S. melanops , and Canary rockfish (S. pinniger

High catch areas are centered south of San Francisco but waters around

the Farallones also offer excellent fishing for rockfish (Figure 3).

(3) Dover sole. Flatfish as a group (pleuronectiforms)

constitutes a very important commercial fisheries in California waters

averaging several million pounds annually. The single most important

species, poundwise, is the Dover sole (Microstomus pacificus) of which

20 percent of the entire California catch of this species originates

from the central California coast (Odemar et al, 1968). Dover sole is

primarily a deep-water bottom fish, caught at depths between 290-360

PT. Am9mA

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TOWLES
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LEGEND

CATCH IN POUNDS

@Ull THAN 16,11110

11,1011111 - 24,M

rwwwwvv
boosool 25,M - 49,m @ifv. Lee"
OVER 75'm

ORIGIN Of AVERAGE AMVAL"Cjrft
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AN
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10 5 0 10 20 30 40 1062 - 1W

SCALE IN MILES
FIGLAE 3
SOURCE: OCILMAR 9T AL. 90"

fathoms. Peak landings occur during the summer, and for central California,

between Point Montara and Point Ano Nuevo. Spawning takes place in

winter in deep waters between 350-600 fathoms with @he greatest concentrations

between points offshore of Bodega Bay and Point Montara (Odemar et al,

1968). After spawning, the adults again move inshore to their summer

feeding grounds. The eggs are pelagic. The adults, as would be expected

from their bottom nature, feed mainly on the benthos such as snails,

clams, annelid and peanut worms, nematodes, scaphopods (tooth shells),

and ophiuroids (brittle stars).

(4) English sole. This is another flatfish abundantly

taken offshore of San Francisco. In fact, the area between Fort Ross

and Point Montara from 20 to 150 fathoms contains California's most

productive English sole (Parophrys vetulus) fishing grounds (Odemar et

al, 1968). Like the Dover sole, they spawn in the winter but in much

shallower waters (20-60 fathoms). Eggs are pelagic and tend to drift

into nearby bays and protected areas which serve as nursery grounds.

San Francisco Bay and the Gulf of the Farallones are important nursery

areas for the English sole. Juveniles and adults primarily feed on the

benthos. Their dist ribution is reflected by where they are commercially

caught and heaviest catches occur in the Gulf of the Farallones in less

than 100 fathoms and north to Fort Ross (Figure 4).

(5) Petrole sole. The third most important flatfish

landing of central California is the Petrole sole (Eopsetta jordani) of

which 60 percent are commercially caught from the Gulf of the Farallones

ii*-V VT. AMCNA

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00
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LEGEND 000

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CATCH IN POUNDS
84
LESS THAN 18,11111111

10,M 24,M

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"'M 75,M

OVER 75,000
0

%
0
I's

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lo

ORIGIN Of AVERAGE ANNUAL ENGLISH SOLE
CATCHES FROM POINT ARENA TO
POINT LOBOS BY OTTER TRAWLERS
10 5 0 10 20 30 40 1992 - 19416
I - . mmi-.9
SCALE IN MILES FIGURE 4
SOURCE: ODZMAR IT AL. It"

between 180-210 fathoms (Odemar et al, 1968). Spawning occurs in winter

in deep water. One of the most important spawning areas is situated 30

to 40 miles southwest of the San Francisco Lightship in 180-230 fathoms

(Odemar et al, 1968). Adults move back inshore after spawning. Eggs

are pelagic. A year-round fishery exists for the Petrole sole but peak

landings occur during the summer and winter months.

(6) Other flatfish. There are several other flatfish

species of lesser importance but which collectively constitute major

annual landings. These species include the Rex sole (Glyptocephalus

zachirus), two species of sanddabs (Citharichthys spp.) and the California

halibut (Paralichthys californicus); all found in the Gulf of the Farallones.

When all the flatfishes are considered, one can see that they are a.

major resource of the Gulf of the Farallones and support a large segment

of the commercial fishing industry. Figure 5 shows a composite picture

of their concentrations off central California.

(7) Other commercially and recreationally important fishes.

In addition to the above species, many other marine fish are caught by

commercial trawlers and party boats off central California. When treated

as a group, they constitute a sizeable portion of the annual landings.
Many of these species occur in the Gulf of the Farallones, near the sand
bar, and at the 100-fathom disposal area vicinity. They include sharks,

skates and rays, the Pacific hake, White croaker, Jack mackerel, Pacific

mackerel, Pacific bonito, Albacore, surf perches, Cabezon, anchovies,

herrings, Sablefish and Lingcod.

TOM L"
v y
VT.

MARC

'0000

000 MMTMA
PILLM PT.

0406" VT.

"A"A

umm
CAT= 0 re@

::Ait

OVER 75'm

*NNW OF AVERAGE AMPSAL FLATFM
CATCNIES FROIII POW ARENA TO
IPOInT Lob"ll OTTER TRAWLERS
10 5 0 10 20 30 40 low
SCALE IN MILES FIGURE 5
OMMAPI CT Ain N"

(8) From the fin fisheries data, the immense productivity

of the Central California coastal waters, particularly the Gulf of the

Farallones, can be seen. Most of the important fishes discussed have

pelagic eggs which are an integral part of the plankton community. They

use virtually all depths of the Continental Shelf as feeding, spawning

or nursery areas. Extensive use of the bottom by flatfish is obvious

from the above discussion. The subtle biological interrelationship

between the Gulf and San Francisco Bay also becomes apparent from the

above discussion. Not-only are salmon dependent on both the ocean and

estuarine (bay) environments but also several species of flatfish, the

Pacific herring and others. Salmon live their adult lives in the ocean

but spawn in freshwater; several flatfish species use the bays as nursery

grounds for the young; and the Pacific herring lays its sticky eggs in

shallow bays and the young feed in those protected waters. The most

productive areas for all commercially important fish (except salmon) are

in the Gulf of the Farallones and south of the Farallon Islands at

depths greater than 50 fathoms (Figure 6). The productive areas south

of the Farallones are near the 100-fathom disposal area.

c. Other Pelagic Species. There are open water inhabitants

other than fish that are ecologically and commercially important. Ocean

shrimp (Pandalus jordani , for example, are commercially netted north of

Point Reyes (Odemar et al, 1968). They are a part of the plankton com-

munity but somewhat larger and more active than typical plankters. They

-g

PT. AMILNA

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OPT. NO"

a& KZAD
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0%
0 0 0
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ON" OF AVERAM AMMIL GOON OF
ALL SPECIES FRW POWT AMIM TO
POW LOMW LAMM BY 0 1 11 lK NOW
10 5 0 10 20 30 40

SCALE IN MILES FIGUM 6

ODURCa: OPOMM 9T AL. 6M

can be found near the surface preying on other plankters but are more

commonly found in 40 to 65-fathom depths. Squid (Loligo opalescens.) is

another important fisheries product of Californa. In terms of annual

landings, squid rivals the salmon and flatfish, averaging several million

pounds per year. Largest landings are at Monterey and peak catches

occur during the summer. The distribution of the ocean shrimp and squid

extends throughout the Gulf of the Farllones but they are not abundant

(at least, not commercially abundant) in these waters. High catch

statistics of flatfish and rockfish from this area suggest that the

bottom does harbor a rich supply of these smaller animals, and the fact

there is a large population..of shrimps is suggestive of copious amounts

of scavengable food.

d. Marine Mammals. Daugherty lists 34 species of marine

mammals in California ocean waters (Daugherty, 1972). The best known of

the large whales off California is the California gray whale (Eschrichtius

gibbosus) which migrates from the Bering Sea southward to Baja California

during the winter. While migrating south, they are fairly close to

shore and can be seen near the Farallones. There is debate as to whether

they feed while in transit southward. While in the Bering Sea, they

largely feed on zooplankton and to a lesser extent on fish.

Two porpoises, which are related to the whales, are occa-

sionally seen close to shore. These are the Harbor porpoise (Phocoena

phocoena) and the Dall porpoise (Phocoenoides dalli) and both have been

recorded in San Francisco Bay (Daugherty, 1972). They are normally

found offshore and actively feed on fish and squid.

out of the surf zone to bask in the sun and sleep. They may be seen

together with the Elephant seals and sea lions at the Farallones and

other offshore rocks. The Harbor seal feeds on fish, squid, shellfish

and octopus.
Although rare in the Gulf of th@ Farallones, the Set otter

(Enhydra lutris) is a familiar marine mammal of Monterey Bay and south.

They were hunted to.near extinction in the 1800's, but have been protected

since 1911. Like the Elephant seals, they have made a successful

comeback. Infact, there is now a controversy as to whether to control

its population, particularly in Monterey Bay, because of the alleged

competition between sea otters and the abalone fishermen. Besides

having a taste for abalone, they have a large appetite for other shellfish,

octopus, sea urchins, crabs, and some fish.

Seals and sea lions are more common inshore than whales and

porpoises because of their dependence on land - seals and sea lions are

born on land. There are several species that inhabit the waters off the

central coast as exemplified by the name Seal Rocks seaward of San

Francisco. Two species are particularly common: the,Steller sea lion

(Eumetopias jubata) and the darker and smaller California sea lion

(Zalophus californianus). Both occur together except during the summer

and can be found at Ano Nuevo Island (San Mateo County), Seal Rocks, the

Farallones and Point Reyes. The California sea lions are only found

from the Channel Islands south during the summer breeding season.

Stellers breed throughout their range from southern California to-Alaska.

Both feed on squid and fish.

The largest seal is the Northern elephant seal (Mirounga

angustirostris) with the bulls attaining a length of 15-16 feet and

weighing over two tons. Although more common farther south, there is a

breeding population at Ano Nuevo Island during the winter and there are

indications that they have started breeding on the Farallones. Before

these creatures were hunted to near eXtinction in the late 1800's, they

were abundant as far north as Point Reyes. They are now protected and

their comeback has been slow but dramatic over the last century. Elephant

seals feed.mostly on small sharks, rays, ratfish, rockfish and squid,

indicating that they feed in fairly deep waters (Daugherty, 1972).

The Harbor seal (Phoca vitulina) is common outside the

Golden Gate. They are frequently seen close to shore and often haul

BIBLIOGRAPHY

Bailey, E. H. 1966. Geology of Northern California. U.S. Geol. Sur.
Ca. div. of Mines & Geology, Bul. 190.

Bane, G. W. and A. W. Bane. 1971. Bay Fishes of Northern California.
Mariscos Publ., N.Y.

Brown and Caldwell Consulting Engineers. 1971. A Predesign Report on
Marine Waste Disposal, Volume I, Oceanographic and Ecological Base
Data Acquisition and Evaluation of Alternative Locations. Prepared
for the City and County of San Francisco, CA.

Chesterman, C. W. 1952. Descriptive Petrography of Rocks Dredged off
the Coast of Central California. California Acad. Sci. Proc., 4th
ser., v. 27, p. 359-374.

Daugherty, A. E. 1972. Marine Mammals of California. California Fish
and Game.

Hedgpeth, J. W. 1971. Introduction to Seashore Life of the San Francisco
Bay Region and the Coast of Northern California. U.C. Press.

Kaiser Engineers. 1969. Final Report to the State of California San
Francisco_Bay Delta Water Quality Control Program. Oakland, CA.

Miller, D. J. and R. N. Lea. 1972. Guide to the Coastal'Marine Fishes
of California. California Fish and Game, Fish Bull. 157.

Moore, D. G., and Shumway, George. 1959. Sediment Thickness and
Physical Properties, Pigeon Point Shelf, California. Jour..Geophys.
Research, v. 64, no. 3, p. 367-374.
Odemai, M. W., P. W. Wild and K. C. Wilson. 1968. A Survey of the
Marine Environment from.Fort Ross, Sonoma County, to Point Lobos,
Monterey County. California Fish and Game, Mar. Resources Ops.,
@@O Ref. No. 68-12.

Smith, E. J. 1973. Coastal County Fish and Wildlife Resources and Their
Utilization. California Fish and Game.

Twenhofel, W. H. 1950. Principles of Sedimentation. Second Edition.
McGraw-Hill Book Co. Inc.

INCLOSURE TWO

SAN FRANCISCO BAY AND ESTUARY DREDGE
DISPOSAL STUDY

OCEAN DISPOSAL OF DREDGED MATERIAL

BY
0 NAVAL UNDERSEA CENTER

San Francisco Bay and Estuary Dredge

Disposal Study

Ocean Disposal of Dredged Material

Naval Undersea Center

S. Yamamoto and J.B. Alcauskas

Participants in work:

R.T. Bachman

P.R. Kenis

M.H. Salazar

W.H. Shipman

R.H. Wade

H.V. Weiss

Submitted to:

San Francisco District, U.S. Army Corps of Engineers

March 21, 1975

TABLE OF CONTENTS

INTRODUCTION . . .. . . . . . . . . . . . . . .

STATEMENT OF PROBLEM . . . . . . . . . . . .. . .

OBJECTIVES . . . . . . . . . . . . . . . . . .

SCOPE OF WORK . . . . . . . . . . . . . . . . .

LITERATURE REVIEW . . . . . . . . . . . . . . . 3

METHODS AND PROCEDURES 7

RESULTS . . . . . . . . . . . . ... . . . . 15

DISCUSSION . . . . . . . . . . . . . . . . . . 27

CONCLUSIONS . . . . . . . . . . . . . . . . . 37

REFERENCES . . . . . . . . . . . . . . . . . 38

APPENDIX A . . . . . . . . . . . . . . . . . 44

APPENDIX B . . . o . . . . . . . . . . . 50

WENTT17ORTH GRAIN SIZE CLASSIFICATTON 53

INTROD(JCTION

The San Francisco District of the Army Corps of Engineers is con-
ducting a study of the environmental impact of dredging operations in
San Francisco Bay and Estuary. As a part of this program a qualitative
study of the ocean disposal of dredged material was conducted. The re-
sults of that study are presented in this report.

STATEMENT OF THE PROBLEM

Determination of the environmental impact of ocean disposal requiies

(1) knowledge of existing information of the ocean environment at the
disposal site, (2) evaluation of what conditions should be monitored in

assessing environmental impact and (3) evaluation of how the conditions
can be monitored. The purpose of this work was to obtain information
with respect to some of these requirements.

OBJECTIVES

The objectives of the program were (1) to obtain a qualitative des-
cription of the physical, chemical and biological environment at a 100-
fathom disposal site in the vicinity of the Farallon Islands and (2) to
obtain a qualitative description of the general release pattern of dredge

material.

SCOPE OF WORK

. The work items included in this study are a literature review, marine
sediment studies, benthic and pelagic fauna studies and dredged material

release studies.

Literature Review

The literature was reviewed with respect to the physical, chemical
and biological components of the marine environment in the vicinity of
the Farallon Islands as well as the potential impact of open ocean dis-
posal of dredged material.

Marine Sediment Studies

Samples of marine sediments were taken at five sites within the study
area prior to the deposition of'dredged material and analyzed for grain
size distribution, heavy metals (Pb, Hg, Cd, Cu, and Zn), chemical oxygen
demand, and volatile solids. A video tape and 35 mm photographic survey
of benthic sediments was made before release of dredged material to formu-
late a qualitative description of sediment characteristics and bottom
topography.

Benthic and Pelagic Fauna Studies

Three species of the benthic community were selected, identified and
analyzed for heawi metals (Pb, Hg, Cd, Cr, Cu, and Zn). From the photo-
graphic survey the speciation and enumeration of benthic on-fauna
and near bottom pelagic fauna were determined and a qualitative description
of the community in the disposal area was formulated.

Dredged Material Release Study

A video tape and 35 mm photographic survey of the benthic sediments
in the disposal area after the deposition of dredged material was per-
formed to provide a qualitative estimate of the area of disturbance and
the depth of deposition.

LITERATURE REVIEW

The literature was revi@wed to obtain background information about

the environmental conditions in the vicinity of the Farallon Islands and
about the potential impact of ocean disposal of dredged material. Infor-
mation about the former was not readily available and reports on open
ocean dredge disposal studies were lacking.

Detailed and extensive information about the ocean environment in

the immediate vicinity of the Farallon Islands was not available. Most
oceanographic surveys and studies are concerned with gross featurgs of
the Coastal Zone of California, e.g., the California current. However,

some physical and chemical data were available from the California Co-
operative Oceanic Fisheries Investigations (CALCOFI) atlases (State of
California Marine Resources Committee, 1964-1972). A summary of this
data is compiled in "Oceanic Observations of the Pacific" by the Scripps
Institution of Oceanography (1962). The CALCOFI station closest to the
dredge disposal site is located at 350 47.5'N, 1230 15'W which is about
five miles northwest of the site. Water depth at this station is 60
fathoms. Data from this station as reported in "Oceanic observations of
the Pacific" are shown in Table 1. These data are in reasonable agreement
with those measured by the U.S. Army Corps of Engineers (1974) at the
San Francisco Channel Bar. However, dissolved oxygen values reported
by the latter are inordinately high.

A number of reports concerning the disposal of wastes in the open
ocean are available (e.g., Interstate Electronics Corporation, 1973a).
However, there are very few reports which directly address the problem
of ocean disposal of dredged material. In a bibliography on ocean waste
disposal (Interstate Electronics Corporation, 1973b) over 400 documents
are listed, but fewer than 20 were related to dredged materials. The
environmental impact of dredging and the disposal of dredged material
has been studied mainly in bays, estuaries and in the vicinity of eroded

TABLE 1. oceanographic Conditions in the Vicinity of the

Farallon Islands.

OBSERVED INTERPOLATED COMPUTED
z T FS 02 1 6T z T I S 02 at 166T AD
.C 165 C 5 3
In t I ml/L cl;@g In %. ml/L g/L cm7g dyn. rn
BLACK DOUGLAS; October 17, 1955; 1527 GCT; 37*47. 51N, 123*15'W; sounding, 60 fm; wind, 110% force 2;
weather, cloudy; sea, moderate; wire angle, 00'.
0 12.18 33.72 5.76 241 0 12.18 33.72 5.76 25.58 241 0.00
10 12.18 33.72 5.70 241 10 12.18 33.72 5.70 25.58 241 0.02
14 12.17 33.71 5.77 242 20 12.08 33.72 5.73 25.60 240 0.05
19 12.11 33.72 5.76 240 30 11.72 33.72 5.60 25.67 233 0.07
24 11.95 33.73 5.69 236 50 11.18 33.76 5.44 25.79 221 0.12
29 11.75 33.72 5.58 234 75 9.72 33.86 3.78 26.13 189 0.17
33 11.59 33.73 5.61 230
43 11.52 33.74 5.55 228
53 10.94 33.77 5.36 216
62 10.24 33.83 4.51 200
77 9.65 33.86 3.72 188

swimming beaches. The most economically important areas affected by
these operations are shellfish beds and fish spawning grounds (Ingle,
1952; Sykes and Hall, 1970).

Biological aspects of concern for coastal waste disposal include
assessment of dredged material toxicity, smothering of benthic communities,
biostimulation by waste materials, public health concerns from pathogenic
bacteria and viruses, and deleterious sublethal responses to toxicants
(Cronin, 1969). Reviews are available on the impact of suspended and
deposited sediments on estuarine organisms (Sherk, 1971) and the bioz-
logical impact of offshore dredging to replace eroded beach sand (Thof6pson,

1973).

Benthic communities are considered the best indicators of environ-

mental insult from dredging and dredged material disposal (Rounsfell,
1972; Sherk, 1971). Smothering may result from suspended solids at the
dredge dump site, damaging coral reefs, oyster beds, etc. (Courtney,
et al., 1974; Heillier and Kornicher, 1962). oxygen depletion may result
from high biochemical oxygen demands in the sediments (Arnal and Leopold,
1972) or directly from toxic materials contained in the sediments. The
dumping of sediment of high biochemical oxygen demand near Santa Cruz,
California, caused the destruction of botton-dwelling organisms by com-
pletely covering them so that they could not continue their normal and
vital respiratory processes (Arnal and Leopold, 1972).

The effects of burial by sediments have been studied for a variety
of organisms. The organisms most susceptible to burial by dredged material
are the epibenthic species, weak burrowers and suspension feeders. The
strong burrowers, infaunal species and deposit feeders appear to be
most resistant to harmful effects resulting from burying (Stanley, 1970;
Saila, Pratt and Polgar, 1972; Maurer, 1967; Cummington, 1968). Several
benthic species were able to reach the sediment surface after burial in

20 cm of dredged material in a disposal study in Rhode Island Sound.
species colonizing the dredged material were members of the surrounding
benthic community. Species diversity in the dredged material was,high
in some samples, suggesting little disturbance, while low diversities
were found in other samples,suggesting considerable disturbance (Saila,
Pratt and Polger, 1972). Burying of benthic communities by several centi-
meters of sediment was found to be of no significance in shifting sand
environments in San Francisco Bay where strong currents prevailed naturally
(Ebert and Cordier, 1966; U.S. Army Corps of Engineers, 1974). These en-
vironments favor only organisms which are highly motile, resisting burial
by the sediments. Less motile forms s uch as small clams, snails and
amphipods were absent in sediment samples and only a few polychaetes*were

present.

The impact of dredged material discharge on the benthic community,
phyto- and zooplankton, and the nekton was studied in Chesapeake Bay
(Cronin, et al., 1970). After release of the dredged material a 71%. t
reduction in the average number of individual animals occurred in addition
to a 65% reduction in the biomass. After 1.5 years the site re-.:
turned to pre-disposal conditions for species diversity, abundance and
biomass. In Chesapeake Bay, the potential harm from dredge spoils released
in the area of spawning grounds of striped bass and shellfish beds was
alleviated by dumping the material in deep areas of the bay (Gunter, Mackin
and Ingle, 1964). In England deposition of china clay waste in two.bays
has eliminated much of the benthic fauna in the vicinity of'the discharge.
(Howell and Shelton, 1970). Macrobenthic invertebrate assemblages were
examined in the spoil disposal area drid undisturbed control areas near
the mouth of the Delaware BaV (Maurer, et al., 1974). A significant reduction
in density of benthic animals was found at the disposal site.

Physical transport of released dredged material was studied by the
U.S. Army Corps of Engineers (1974) at the San Francisco Bar. The water

depth at the Bar was about 30 feet and approximately 3,000 cubic yards
of material were dumped in less than 5 minutes. The dredged material
did not exceed 2 inches during any one release. Movement of material
on the Bar took place in two strata, the fluid sediment layer and the
turbid suspension layer. The layers are maintained by surge and wave
generated currents and moved by tidal currents. Tidal currents were
found to be the main influence on dispersion of dredge material during
settling and immediately after deposition on the sea floor. Methods have
been developed to predict the fate of discharged dredged materials (Clark
et al., 1971). The physical transport is described in four separate
steps: convective descent, collapse, long-term dispersion and bottom

transport or resuspension.

METHODS AND PROCEDURES

General

The disposal site is located along a 100-fathom contour line at 37'
41'N and 1231 07.5'W. The site is approximately 35 nautical miles west
of San Francisco, California and 5 nautical miles west of the Farallon

Islands (Figure 1). originally a site located 20 miles northwest of the
study area had been selectc-i. However, this site was found to have a
sloping bottom making it unsuitable for conducting the planned survey.
Therefore, the 100-fathom contour line was followed until a flat area
was found. The study area was a 500-foot by 1000-foot rectangle with a
northwest to southeast orientation. The site was marked at each corner
with a sonar reflector placed 6-feet from the bottom and at the center
of the northwest end with a surface buoy (Figure 2).

Approximately 4000 cubic yards of dredged material loaded in two
hoppers towed in tandem were released over the study area. Sediment

Figure 1. Location of the Open Ocean Dredge Material Disposal Site
West of the Farallon Islands.

0
00

Ito
.... .. 50,J 0
Vo
goo
Ito
00b"Jnd

el
\0
0

... . .... .... .

4L@
NZ

0
0

.dOk

...... .. .....

... . ...... .
370 41'N
1230 07.5'W

.........

...... ..... ..... ..... ..... ..... ............... ...................

.. . . ......

- - - - - - - - --

LEGEND

PATH OF VEHICLE N

...... PATH OF DREDGE BARGE
x LOCATIONS WHERE DREDGE
HOPPERS OPENED

SPOIL DISTRIBUTION
I Pi gure 2.
SEDIMENT SAMPLING SITES
Diagram of Study Area Showing Path of cuRv iii During Postdump
Survey, Path of Dredge Barge, Distribution of Disposed t.:ateria.'
on the Bottom and Predump, Sediment Sampling Sites.

and biological samples were collected prior to release and photographic
surveys were made b6th before and after the dump.

The primary vehicle used for the survey was the Naval Undersea Center's
(NUC) Cable-Controlled Underwater Recovery Vehicle, [email protected] (Figure 3).
This vehicle is tethered, unmanned and remotely controlled. Details of
the characteristics of CURV III are presented in Appendix A. The vehicle
was used to place sonar reflectors on the bottom, to mark a grid pattern
on the bottom at the study area and to take photographs. The phbtographic
system consisted of two Vidicon television cameras, four mercury-vapor
headlights, two merc ury-vapor spotlights, and a 500-exposure 35-mm-EGand-G....
color camera with a 250-watt-second strobe. The support vessel for CURV III
during this study was the M/V GEAR.

Marine Sediment Studies

Sediment samples were collected prior to the release of dredge materials
at five sites located at 200 foot intervals, along a 1000-foot transverse
of the disposal study area (Figure 2). Sediment samples were collected
with a Shipek rotary bucket sampler, placed in polyethylene bags, and

frozen immediately.

Each sediment sample was analyzed for copper, lead, zinc, cadmium
and mercury. The sediment samples were also analyzed for chemical oxygen
demand, volatile solids and grain size distribution.

For copper, lead, zinc and cadmium determinations, the sample was
dried at 110*C for 2 to 3 days. It was then "homogenized" by mixing
and stirring in a beaker. A 20-g portion of the sample was refluxed
in 100-ml of concentrated nitric acid until evolution of NO2 gas ceased.
The mixture was centrifuged and the liquid decanted into a 100-ml volumetric
flask. The residue was rinsed twice with distilled water, centrifuged

...........

7j
AL
41'

T
_Tr

o'w

'4 IT .40,*
T;

W4-
near-,

too

Figure 3. Cable-Controlled Underwater Recovery Vehicle,
CURV III of the Naval Undersea Center.

and the rinse water was combined with the extract. The composite solution
was diluted to 100 ml and aliquots from this solution were then analyzed
by Atomic Absorption Spectrometry with a Perkin-Elmer Model 306 spectro-
meter. The method of standard additions was used; three additions were

made for each sample.

Mercury concentrations were determined by neutron activation analysis
(Williams and Weiss, 1973). Approximatelv 2-3 g of frozen sediment was
transferred to irradiation vials prior to irradiation and covered with
concentrated nitric acid. A section of frozen sediment that was in
juxtaposition to the sample was chipped off and its water content deter-
mined by drying at 1100C for 1 hour. The comparator consisted of 10 g
of mercury as the nitrate in 10 ml of concentrated nitric acid. The nitric
acid blank consisted of three irradiation vials each filled with 14 ml of
concentrated nitric acid. Samples, comparators and blanks were irradiated
for 1 hour at a flux of 1.8 X 10 12 neutrons cm -2 sec -1 in a "lazy susan"
which rotated at 1 rpm about the core of the MARK I TRIGA reactor at
General Atomic Co., San Diego,California. Subsequent to irradiation,
sediments were digested in a nitric and sulfuric acid mixture as described
previously. The sediment was prepared further for radiochemical purifi-
cation by addition of 25 ml of concentrated ammonium hydroxide to the
digest, and the mixture was filtered. If at this stage pebbles were
detected in the residual sediment, they were removed and the sample was
corrected for their weight. To the filtrate was added 2.5 ml of freshly
prepared stannous chloride. The precipitated mercury metal was collected
by centrifugation. The precipitate was dissolved in 5 ml al7.ua regia; 5 mg
of copper (as nitrate) was added and the solution filtered. The reduction
of mercury to the metal was repeated and the solid collected by filtration.
The precipitate was again dissolved with 5 ml aqua regia and the solution
was neutralized with 5 ml of concentrated ammonium hydroxide after the
addition of mercury carrier, and the mercuric sulfide was precipitated
and collected for measurement. The processed mercury samples as well as
mercury carrier standards (10 mg mercury) were reirradiated for 5 seconds.

Through comparison of the activity level of the samples and standards#
the carrier yield was computed and the counting rate in the original
irradiation was corrected for this factor. The radioactive measurements
were made with a sodium iodide detector coupled to a 400-channel pulse-
height analyzer. The counts attributable to the 77 keV radiation of 197 Hg
were integrated by the method of Covell (1959).

Chemical oxygen demand (COD) and volatile solids were determined by
procedures described-in Standard Methods for the Examination of water and
Wastewater (1971). Sediment samples were first dried overnight at 1000
1050C. For COD analyses -1-gram (dry weight) aliquots were refluked,in
concentrated sulfuric acid solution containing potassium dichromate. -Silver
sulfate was used as a catalyst and mercuric sulfate was added to remove.
,chloride interference. The excess dichromate was titrated with standard
ferrous ammonium sulfate using ferroin as an indicator. Volatile solids
were determined by heating approximately 20 grams of the dried sediment
at 550*C for 2-hours. The difference in weight before and after heating
is a measure of the volatile solids.

Dispersed grain size distribution was determined using the Wentworth
(1933) grain size classification (Appendix B) and the Emery settling tube
(Emery, 1933). Sand is introduced into the top of the Emery settling tube
(a vertical water-filled tube), and the height of the sand column formed
at the bottom is measured at predetermined times. The amount.-of the
sample which is larger than a given diameter is obtained us*Ag ersp#*cal
calibration curves.

Benthic and Pelagic Faunal Studies

Speciation and enumeration of epibenthic macrofauna were obtained from
photographs taken prior to dumping by CURV III. Animal densities were cal-
culated from numerical totals obtained from the photographic survey. The

mean area covered per slide was estimated to be 2.25 m2 ; and the total
2
area covered by the photographs was 1316 M . The animals on each slide
were enumerated by group. The total for each group was divided by the
total estimated area to obtain density. Species were also identified from

the slides

Three species of macrofauna were collected for analysis with a grasping
basket assembly fitted to the CURV vehicle. A Pisaster star fish, a small
fish Mesluccius productus and a Heart Urchin Echinocardium were collected.
Each species was analyzed for mercury, copper, cadmium, lead, chromium,
and zinc. With the exception of mercury, which was determined by neutron
activation, all metals were analyzed by atomic absorption spectrophotometry.
These samples were ashed overnight at 4700C and the residue dissolved in
concentrated nitric acid. The method of standard additions was used; three
additions were made for each sample. Due to the large quantity of material
required for the atomic absorption analysis only the Pisaster starfish
could be analyzed for mercury.

Dredge Material Release Study

To determine the dispersal of the dredged material a grid pattern
was first marked on the bottom at the study area. This was accomplished
with CURV III during the predump photographic survey using the skids of
the vehicle. The predump markings consisted of 1000-foot-long parallel

lines.at 25-foot intervals.

The dredged material was then released from two hoppers containing
2000 cubic yards each. The hoppers were towed by a dredge barge
starting from a position adjacent to the surface buoy and proceeding
through the study area at a speed of 1-2 knots (Figure 2). The hoppers
were opened 150 feet and 200 feet southeast of the buoy and the material
was released as the vessel proceeded on course. The hoppers were emptied
by the time they reached 500 feet into the study area.

Approximately 12-hours after the release of dredged mate-rial a
second photographic survey was made. The vehicle followed a track per-
pendicular to the predump markings (Figure 2). As each 35-mm frame was
exposed a sequential number was exposed on that frame. This number was
related to a number tally in the CURV III control van on board the M/V
Gear. The position of the dredged material on the bottom was determined
by cross referencing the frame number with the number and position log
maintained in the control van.

RESULTS

Marine Sediment Studies

Copper, cadmium, lead, zinc and mercury concentrations in the sedi-
ments are tabulated in TaJY.I:e-,2-;-. Copper ranged from 4.97 - 7.81 ppm at
four stations and was 21.1 ppm at a fifth station, cadmium levels ranged
from 0.084-1.03 ppm, lead from 5.53 - 9.05 ppm, zinc from 30.9 - 61.5 ppm
and mercury,from 5.1 - 87 ppb at three stations with two stations having
values of 267 ppb and 376 ppb.

Chemical oxygen demand and volatile solids are reported in Table 3.
COD ranged from 12.85 - 20.34 mg/g and volatile solids ranged from 1.6%

to 2.9%.

Dispersed grain size distributions are presented in Table 4 and Figure 4.

Benthic and Pelagic Faunal Studies

The epibenthic macrofauna of the study area was relatively abundant.
A species list is given in Table S. The dominant group were arthropods
which made up about 70% of all bottom animals. In order of decreasing
abundance the remainder were molluscs (13%), bony fishes (10%), and

TABLE 2. Heavy Metal Concentrations in Sediments Collected Septembex,
1974, in the Vicinity of the Farallon Islands, California
(ppm dry weight)

Station No. Copper Cadmium Lead Zinc Mercury

1 21.1 0.084 9.05 61.5 0.087

2 7.81 0.18 6.66 35.2 0.376

3 7.72 0.259 6.25 40.4 0.045

4 6.30 0.518 7.29 30-9 0.267

5 4 @;@,9'7. 1.02 5.53 34.4 0.051

TABLE 3. Chemical Oxygen Demand and Volatile Solid Concentrations of
Sediments Collected in September, 1974, in the Farallon Islands,
California

Station No. Chemical Oxvgen Demand Volatile Solids
% (dry wt.) % (dry wt.)

1 2.03 2.93

2 1.42 1.93

3 1.28 1.83

4 1.36 1.62

5 1.44 1.74

TABLE 4. Grain Size Distribution of the Sediments Collected in
September, 1974, in the Vicinity of the Farallon Islands,
California

Station Median Diameter Mean Diameter Composition
No. mm 4) mm gravel sand silt 'clay
1 0.0337 4.89 0.01901 5.72 0 24 56.5 t 19.5
2 0.0728 3.78 0.06611
3.92 0 58 40.0 2.0

3 0.0661 3.92 0.07911 3.66 0 72.2 21.3 6.5
4 0.1111 3.17 0.10731 3.22 0 85.5 12.5 2.0
1 -T-
5 0.1051 3.25 0.1022 3.29 o .5 9.5 2.0
88

98
Ata 411111 111111 111111
-- ----- 4144-1 1 1 sta HHHHH -
95
-: --- 0'1 sta
J-.
Sta 3
J:,sta 4
sta 1
90 41J

1-77 - z:
80
.41 ------
70 AU . a arm MUMMEMEMED, 14- ------ -
tj i-
60 P ......
7
z 50 T 7M 'w

1-- 40

T
cn 30
ir ------ H+-j--
< - I - - 011111
0
20 --------

-- ---------- ----------- -
Uj
> - - - - - - - - - - - - - - - - - -
--------------
10
iia 4
- --------------
5 -111 Orl V I I
sta @'P'
al Sta
2 ......

MH
I -=sta2 -44[ ------
0.5

0.2

0.1 - - - - - -

0.05
z z
-LL
0.01 ---------
1 2 3 4 5 6 7 8 9 10
GRAIN SIZE IN 0 UNITS

Figure 4. Grain gize distribution for sediments collected in September,
1974, in the vicinity of the Farallon Islands, Calfironia.

TABLE 5. List of Species Identified During Predump Survey of Ocean
Disposal Site in the Vicinity of the Farallon Islands.

Fishes Sebastes zacentrus - Sharochin Rockfish
Sebastes diploproa - Splitnose Rockfish
Sebastes elongatus; - Greenstriped Rockfish
Sebastes saxicola - Stripetail Rockfish
Anaplopoma fimbria - Sablefish
Eptatretus stoutii - Pacific Hagfish
Aprodon cortezianus - Bigfin Eelpout
Unidentified cod - FAMILY GADIDAE
Unidentified prickleback, - FAMILY STICHAEIDAE
Unidentified flatfish FAMILY PLEURONECTIDAE

Echinoderms Allocentrotus fragilis Pink Urchin
Parastichopus californicus - Sea Cucumber

Luidia sp. - Sea Star

Unidentified sea star - CLASS ASTEROIDEA

Arthropods Crago sp. - Shrimp
f-'ancer sp. - Crab

Unidentified crab - BRACHYURAN

Mollusks Pecten sp. - PELECYPOD
Octopus_sp. CEPHALOPOD

echinoderms (7%). The density of total animals was relatively high
(1801 animals over 1316 m2 or 1.4 animals/m 2), but the species diver-
sity was relatively low. About 13 different species were observed but
only four species accounted for 91% of all bottom animals. Most of the
arthropods were decapod crustaceans, probably of the genus Crago sp.
(1235 decapods/1801 animals or 69%) and they were randomly distributed.
The molluscs were composed almost entirely of octopus s -p. (11% of all
animals). Bony fishes were dominated by rockfish, Sebastes sp. (7% of
all animals) and the eciiinoderms by Allocentrotus (5% of all animals.
Figures 5 - 8 are representative photographs of the bottom fauna.

The heavy metal concentration in three species of epibenthic macro-
fauna are shown in Table 6. Copper ranged from 1.74 - 5.87 ppm, cadmium
from 0.28 - 1.66 ppm, lead from 2.06 - 7.27 ppm, and chromium from 16.7
103.3 ppm. mercury concentrations on replicate samples of the starfish
were 259 ppb and 204 ppb.

Dredge Material Release Studies

Photographs indicate that the dredged material was deposited some-
what unevenly over the deposition area. Most of the material fell di-
rectly below the path of the barge, while some spread laterallv to the
edge of the study area and some fell slightly beyond its borders. Photo-
graphs of the dredged material on the bottom are shown in Figures 9 - 11.
Some of the material was deposited in large clumps while the rest was
finer and more widelv disnersed.

The photographic survey indicated that the average depth of deposited
dredged material was approximately 1 foot. Based on the area of depo-
sition this indicates a sediment estimate of 5,000 cubic yards of material
which is in reasonable agreement with the 4,000 cubic yards actually dumped.

,VI,
off
r
Wt r I-I

4,7

Figure 5. Benthic fauna in the vicinity of the Farallon islands:
Sea cucurrbers (Parastichopus californicus) , octopi and
rockfish. Photograph taken with CURV iiI during predump survey

Figure 6. Benthic fauna in the vicinity of the Farallon Islands:
Sea cucumbers (Parastichopus californicus), octopi and decapods.
Photograph taken with CURV III during predump survey.

Figure 7. Benthic fauna in the vicinity of the Farallon Islands:
decapods. Photograph taken,with CURV III during predump

survey.

Figure 8. Benthic fauna in the vicinity of the Farallon Islands;
decapods. Photograph taken with CURV III during predump

survey.

TABLE 6.- Heavy Metal Conc6ntrations of Enibenthic Fauna Collected in
September, 1974, in the vicinity of the Farallon Islands,
California

Copper Cadmium Lead Chromium Zinc Mercury
ppm (wet wt) ppm (wet wt) ppm (wet wt) ppm (wet wt) ppm (wet wt) ppb (dry wt)
Starf ish 5.87 1.66 7.27 2.13 103.3 259/204**

Urchin 1.74 0.28 3.25 0.67 16.7

Fish 2.26 2.06 0.95 54.4

Concentrations below sensitivity of analytical procedure (0.02 ppm).
Assumed Hg carrier yield of 90%.

DISCUSSION

The results of this study indicate that the physical, chemical,
and biological environment at the 100-fathom disposal site in the vicinity
of the Farallon Islands is generally comparable to other nearshore areas

along the California coast. However, there were some significant

differences.

Data reported in the CALCOFI atlases (Table 2, State of California
Marine Resources Committee 1964-1972) show that salinity and dissolved
oxygen concentration near the study area are similar to those in (;the'*r
area along the coast and that water temperature is, as expected, slightly

lower than those of waters further south.

Heavy metal levels in the sediments collected in the study area are
similar to 'those reported in the lite-@ature for natural nearshore sediments.
A comparison of metal concentrations found in this work with those cited
in the literature is presented in Table 7. "Dredge Disposal Site LA-5"

is a 100-fathom.disposal site located 7.7 miles..west of San Diego. Copper
and lead values reported by Riley and Skirrow (1965) are slightly higher
than those found by others. mercury concentrations for the North Slope
of Alaska are the range of values reported by Weiss, et al. (1974) for

52 stations in the Beaufort Sea. The mercury values found in this work
agree well with those of Weiss. Generally higher levels of mercury in
sediments were reported off the coast of Palos Verdes, California,by the
Southern California Coastal Water Research Project (SCCWRP, 1974); the
values ranged from 0.21 - 4.67 ppm. COD for the sediments ranged from
1.42 - 2.03 % (dry weight),which is considerably higher than the range
of 0.17 - 0.68% (with 2.6% at one station) reported by the U.S. Army
Corps of Engineers (1974) for the San Francisco Channel Bar. COD values
ranging from 0.62 - 6.36% have been reported for San Diego Bay sediments
(Peeling, 1975). COD is 'a measure of the amount of material oxidized by

TABLE 7. Literature Values for Co, Cd, Pb, Zn, Hg in Sediments, ppmo

Dry Weight.

Location Cu Cd Pb Zn Hq Reference

Farallon Islands 4,97- 0.084- 5.53- 30.9- 0.045- This work
21.1 1.02 9.05 61.5 0.376

Dredge Disposal 15-24 7.16- 49-68 0.059-
Site LA-5 12.4 0.291

Natural Marine 48 20 Riley & Skirrow
Nearshore Sediment (1965)

Southern 13-25 0.60- 7.1- 54-76 Galloway (1972)

California 1.2 22

Coast

North Slope, 0.029- Weiss, at.al.
Alaska 0.169 (1974)

potassium dichromate in sulfuric acid at reflux temperature. This in-
cludes organic matter, living organisms entrapped in the sediment during
sampling, detritus, etc. Reasons for the high values in the study area
are not known. However, because of the harsh chemical treatment used in
the procedure, COD measurements are of questionable value. Volatile
solids ranged from 1.62 - 2.93% (dry weight). These values are slightly
higher than the average of 1.41% found at a disposal site in Mayport,
Florida (Naval Oceanographic office, 1973) but lower that the range of
1.4 - 9.0% reported for San Diego Bay (Peeling, 1975) and an order of
magnitude lower than that for'dredged material at Mayport. Again.-the
reason for the small discrepancy between volatile solids for the stiidy@@
area and for the Mayport disposal site is not clear.

Dispersed grain size distributions (Figure 4) show that 50% or more
of sediments at Stations 2 - 5 and 80% at Station 1 are finer than 0.06
mm. These sediments are much finer than those from the San Francisco
Channel Bar as reported by the U.S. Army CoXps of Engineers (1974). This
is not unexpected since bottom currents at the study area are much less
than at the Channel Bar (less than 1 knot compared to 2 - 4 knots)'. It
should be noted that the objective of grain size analysis is to characterize'
the nature of the sediment during deposition or after accumulation.,_-Ift"
objective probably is not met@ because the grain size distribution is
necessarily altered during the analysis. The sediment is separated into
two fractions by wet sieving and the fractions are analyzed by different
settling methods, which may cause a discontinuity in the cumulative curve
at the sand-site break (Griffith 1951). However, many workers believe
the discontinuity is real and results from a natural deficiency of fine
sand and coarse silt grain (Udden, 1914, Wentworth, 1933, Hough 1942,
Tanner, 1958; Folk, 1959). It is necessary to attempt to analyze the
size distribution of single grains, which requires the use of a dispersing
agent for sieving and pipet analysis. In the marine environment, however,
fine grains do not settle individually, but rather as aggregates, bonded
electrostatically as a result of ingestion by filter feeding animals
(Arrhenius, 1963). Thus, by necessity, fine particles are not in their

natural state during analysis. Assuming that the sediment grains were
normally distributed when deposited, this would skew the distribution

curve toward the fines.

Results of the benthic and pelagic faunal studies showed a high
animal density in the study area (1.4 animals/m 2). This apparent high
density may be misleading due to the presence of a large number of deca--
pods which were not observed in past work with CURV III in Southern
California. They are relatively small in size and near the limit of
resolution of the CURV III cameras. At about 9 cm in length they were
extremely difficult,to see; however, their detection was faCilitated by
their large eyes, which reflected the light from the vehicle.@- Another..
interesting observation was the relative paucity of echinoderms and:abun-
dance of cephalopods. Most of our benthic surveys in Southern California
have shown the echinoderms to be the dominant group, in mosticases qonsti-
tuting 707.90%.of-the epibenthic macrofauna; whereas in the.Farallon'Island
study area only 7% of the observed animals were echinoderms and no
cephalopods were observed. In addition, the density of all animals was
considerably lower at LA-5 (0.293 animals/m 2). Some of the biota were
analyzed for lead, copper, cadmium, chromium zinc and mercury. With
the exception of lead, the observed heavy metal concentrations are similar
to those reported in the literature. Copper ranged -from 1.74 - 5.87 ppml
Bowen (1966) reports 4 - 50 ppm. Cadmium concentrations of a rstarfish
and urchin were found to be 1.66 ppm. and 0.28 ppm, respectively, at the
Farallon Island site,while Bowen reports a range of 0.15 - 3 ppm. Lead
ranged from 2.06 - 7.27 ppm versus 0.5 ppm in the literature. The apparent
high observed values.are of questionable significance because they only
represent three animals. Zinc was found to be 16.7 - 103.3 ppm, which is
within the range of 6 1500 ppm reported by Bowen. Chromium concentration
ranged from 0.67 - 2.13 ppm,while Bowen reports a rancle of 0.2 - 1 ppm.
Two aliquots of the starfish were analyzed for mercury; the.--observed,i
concentrations of 259 and 204 ppm are comparable to literature valueffi-o'-*.
The many decapods probably play a significant role at the base.-

of the food chain in this area. Although nearly all of the decaDods
were observed on the bottom during the predump survey, they were in
the water column 1 - 3 meters off the bottom during the postdirilp survey.
Since the predump survey was conducted during the day and the postdun.,o
survey conducted at night, it is not clear whether this phenomenon was
due to the effects of dumping or a natural migration for feeding. Similar
animals are known to come off the bottom to feed at night.

The dispersal of dredged material on the.bottom was estimated from
photographs taken after the dump (Figure 9 - 12). Coverage of the bottom
was estimated from the photographs and the track followed by the vehicle
by cross referencing the photographic frame number with the position log.
Coverage of the grid lines laid out prior to the dump did not prove use-
ful in assessing coverage. Photographs indicated that the dredge material
was distributed somewhat unevenly over the deposition area. Most of the
material fell directly below the path of the barge while some spread
laterally to the edge, and some slightly beyond the borders of the study
area (Figure 2). The material was compacted in the barge as it was trans-
ported to the disposal site. Such compacting would vary with the sea con-
ditions during transport, the distance to the disoosal site and the char-
acteristics of the dredge material, and this would affect the distribution
of the material on the bottom. The material released in this study probably
had little affect upon the area as a whole because the coverage was limited.
If the dredge materials were uniformly distributed over the entire area
all of the animals would be affected in some way by smothering or partial
covering. With an uneven distribution of the material animals in the
covered areas might be severely affected but the community as a whole
would be relatively untouched. Photographic evidence indicates that less
than 251 of the study area was covered with dredged material. Re-
peated dumping within the area would increase coverage and ultimately
affect the entire area. Frequency of dumping would also be a factor in

UVIII

k"
4
%

X8I

'40

;j,
41

Figure 9. Released dredged material on the bottom.

f
2

ise
R-M4 !
01, 4 M
@q-
S%

All F"
r@k
S

Ar
Nr, &

rx
M@-
Qg g,

98-- MO.,
ON, w

R -Wp@
nONO A N
MU., AM
M
Z
0
x
j@ @a@w
-N

44
7

OR-
w
M -
M
in.,
M
NEV.
Ve
V
-1 0"1
. . . . . . . . . .---
AD

g,
M

73
-T@, -S,

Figure 10. Released dredged material on the bottom.

Figure 11. Released dredged material on the bottom.

A
V,

iv4Z
A

alk
ir

m2N
ANA,

Figure 12. Released dredged material on the bottom.

the covering and smothering and subsequent reestablishment of benthic
communities. There is insufficient data to speculate'on the point at which
aumping would affect the entire benthic community for a specific area.
If there were significant pollutants in the dredged material there would
probably be a severe effect upon the benthic community whether the material
w-as uniformly distributed or in a clumped distribution pattern. While it
is relatively easy to predict the impact from physical covering or smothering
it is almost impossible to predict the environmental impact from chemical

factors on the biota.

The literature indicates that the most harmful effect of dredge dis-
posal on benthic communities results from smothering or lowered oxygen
concentrations caused by high oxygen-demanding sediments. The response
of benthic organisms to burial by dredge material depends upon the ability
of organisms to move through the material to the sediment surface or
respire successfully beneath the deposited material. Dispersion of dis-
charged dredge material and subsequent covering of benthic communities is
predicated upon the magnitude and duration of the release, sediment density
and grain size, tendency of the spoils to remain in clumps, currents and
depth of the water column and movement of the dredge barge during release.

CONCLUSIONS

On the basis of this study the following conclusions can be drawn:

1. The literature indicated a lack of detailed oceanographic infor-
mation in the vicinity of the Farallon Islands and a paucity of reports
dealing with the disposal of dredged material in the open ocean.

2. Sediment analyses showed that the 100-fathom disposal site is not
contaminated with respect to heavy metals, volatile solids or chemical
oxygen denand (although the last was higher than that reported for bottom
sediments at the San Francisco Channel Bar). The sediment in the study area
consisted of a large amount of fine material; more than 50% by weight was
finer than 0.06 mm.

3. Photographic survey of the bottom''prior to the dump showed that
the area is biologically active. The density of macrofauna was estimated
2
to be 1.4 animals/m . However, species diversity was relatively low. About
13 different species were observed,but only four species accounted for 91%
of all bottom animals. These animals were found not to be contaminated
with heavy metals.

4. The materials release study demonstrated that most material
fell directly below the path of the hoppers,while some spread laterally
to the edge of the study area. Some of the material fell in clumps,probably
because of compaction during transit to the disposal site.

REFERENCES

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Arnal, R.E., and L.C. Leopold. 1972. A short survey of the environment
at the dumping site for Santa Cruz Harbor Dredging. Moss Land ing
M*aNine Laboratories. TP No. 72-6, 20 pp.

Arrhenius, Gustav, 1963. Pelagic sediments, in Hill, M.N., (ed.), The
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Bowen, H.J.M. 1966. Trace elements in biochemistry. New Y@rk; Academic

Press.

Clark, B.D., W.F...Rittall, D.J. Baumgartner, and K.V. Byram. 19 71. The
barged ocean disposal of wastes -- a review of current practice and
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120 pp.

Courtenay, W.R., Jr., D.J. Harrema, M.J. Thompson, W.P. Azzinaro, and
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Cronin, L.E. 1969. Biological aspects of coastal waste disposal; back-
ground paper for coastal waste disposal workshop. Natural.Resources
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Cronin, L.E., R.B. Biggs, D.A. Flemer, H.T. Pfitzenmeyer, F. Goodwyn,
W.L. Dovel, and D.E. Ritchie. 1970. Gross physical and biological
effects of overboard spoil disposal in upper Chesapeake Bay. Natural
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Dunnington, E.A., 1968. Survival times of oysters after burial at various

temperatures. Proc. Nat. Shell. Assoc. 58:101-103.

Ebert, E., and P. Cordier, 1966. A Survey of Marine Resources offshore
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Emery, K.O., 1933. Rapid method of mechanical analysis of sands; Jour.
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Folk, R.L., 1959. Petrology of sedimentary racks; Hemphill's, Austin, Texas.

Folk, R.L., 1966. A review of grain-size parameters; Sedimentalogy 6(73-93).

Folk, R.L., and Ward, 1957. Brazos River Bar, a study in the significance
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Galloway, J.N., 1972. Man's alteration of the natural geochemical cycle
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Griffiths, J.C., Size-frequency distribution of detrital sediments based
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Gunter, G., J.G. Mackin, and R.M. Ingle, 1964. A report to the District
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Chesapeake and Delaware Canal, in Upper Chesapeake Bay. U.S. Army
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Hellier, T.R., Jr., and L.S. Kornicker. 1962. Sedimentation from a
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Sciences, 8:212-215.

Hough, J.L., 1942. Sediments of Cape Cod BaV, Massachusetts; Jour. Sedi-

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Howell, B.R., and R.G.J. Shelton.j 1970. The effect of china clay on the
bottom fauna of St. Austell and Mevagissey Bays. Jour. Mar. Biol.

ASSN. U.K. 50:593-607.

Ingle, R.M. 1952. Studies on the effects of dredging operation upon fish
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Interstate Electronics Corporation, 1973a. Ocean waste disposal in 6elected
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Interstate Electronics Corporation,,1973b. Bibliography on ocean waste
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Johansen, 0., and E. Steinnes. 1969. A simple neutron activation method
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20:751-755.

Krumbein, W.C., 1934. Size frequency distributions of sediments: Jour..
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Maurer, D. 1967. Burial experiments on marine pelecypods from Tomales
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Maurer, D., R. Biggs, W. Leathem, P. Kinner, W. Treasure, M. Otley, L. Watling,
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Studies, Lewes and-Newark, Del. 230 pp.

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Revision 1.

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I

Rounsefell, G.A. 1972. Ecological effects of offshore construction.

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Bd., Can., 30:29@-295.

APPENDIX A

GENERAL CHARACTERISTICS

CURV III

DESCRIPTION

The Cable-controlled Underwater Recovery Vehicle (CURV) program was
begun by NUC for the specific purpose of developing economical systems
to recover test ordnance at NUP's Long Beach and San Clemente Island
test ranges. CURY III is the latest in this series of tethered, unmanned,
remotely controlled vehicles. Originally conceived for use as a search
and recovery vehicle, CURV has evolved into a versatile and easily adapt-
able multipurpose work vehicle capable of performing not only search and
recovery tasks but also of pursuing test, evaluation, exploration, and
work projects. Basically, CURV is a composite of intergrated subsystems
including such items as propulsion, search, and navigation, optics, hydraulics,
and tools. Because-it is unmanned and does not require life support systems
or other complex support systems, CURV is able to perform most undersea
tasks more economically and efficiently than manned systems. Also, since
it is powered and controlled from the surface, CURV has a continuous, un-
limited operating capability. Under emergencv conditions, the vehicle
can operate to 10,000-foot depths. Another feature of CuRV is that it
is easily transported to any spot in the world. The vehicle, control van,
cable, and support gqar can be transported to a work site and mounted on
any suitable ship of opportunitv.

VEHICLE

General

size . . . . . . . . 6.5 ft x 6.5 ft x 15 ft

Weight . . . . . . . . . 4,500 lbs (approx.)
Operating Depth . . . . . . 7,000 ft

Crew 7

Payload . . . . . . . . . 200 lbs max (vehicle only)

2000 lbs max (with assist on

strength member)

10,000+ lbs (with separate surface

recovery line)
Submerged Speed (max) . . . . 4 kts (estimated)
Operating Endurance . . . . . Unlimited

Power Requirements (self contained)

Vehicle Subsystems and Components

Propulsion . . . . . . . . Three 3-phase, 440 VA C, 10 HP,
oil-filled, pressure-equalized

motors with fixed pitch screws;

thrust varied by voltage, max 400 lbs
forward, 250 lbs reverse (each)
Seach and Navigation Straze SLAD-603

-Active Sonar: CTFM 78-82 kHz,

ranges 50 yd, 250 yd, 800 yd

-Passive Sonar: 45 kHz

-Transponder Mode: 50 yd, 250 yd,

800 yd

-Sonar Training Mechanism: Pro-
jector, hydrophone, receiver, and
Passive listening hydrophone; auto-

matic scan 1200 at 26'/sec, tilt

+ 150

Search and Navigation (cont) -Locator: Pinger with 36.5 kHz,
1.5 sec pulse interrupted by
37.2 kHz, 10 msec pulse

-Altimeter: Transducer 100 kHz,
100 msec pulse, ranges 0-10 ft
and 0-100 ft, accuracy �0.5 ft

-Compass: Gimballed rang-core,

flux gate magnetometer
Optics . . . . . . . . . Television Cameras
-Two Hydro Products solid state,

standard scan vidicon cameras;

water corrected lens, 54* view

angle, aluminum housing

Lights

-Four stationary, pressure
balanced mercury vapor 250 watt
flood lights at front of vehicle.
Two 100 watt pressure-balance
mercury vapor spotlights mounted

with TV cameras

Documentary Camera

-one EG&G 35mm color with 200

watt/sec strobe, 1 flash every 8 sec
Optical Pan-and-Tilt Units
-Hydraulically-actuated 3600 pan,

900 tilt

Hydraulics . . . . . . . .. Actuator
-Hydraulic five-function unit. Arm

UP-DOWN, Arm rotate:CLOCK-WISE-

COUNTER-CLOCKWISE; Arm eject;

Wrist:CLOC'@KTNISE-COUNTER-CLOCKWISE

(a xis 900 to arm); Claw: OPEN-CLOSE

Hydraulics (cont) Tools

-13 in. claw, snare, grapnel hook,

noose, marine organism basket,

manipulator, Pyronol torch
Structural Components Buoyancy

-50 3M Co. Syntactic foam slabs.
Each slab:5-3/4 x 11-3/4 x 22 in.

(0.83 cu ft), 38 lbs/cu ft (26 lbs/

cu ft buoyancy)
-Hydrostatic crush: 11,000 feet

maximum

-Water absorbtion: 3% maximum

2.1% average @ 4,500 psi

Total Byouancy

-With approximately 70 lbs forward
lead trim; vehicle 40-50 lbs buoyant

Frame

-Main structure, exclusive of

brackets and bumpers, 6 ft wide
4 ft high, 11 ft lbng of welded

6061 aluminum structural shapes
Interconnecting Cables . . . Cables are pressure-balanced immersed

in oil inside flexible tygon tubing.

Pressure-balanced connectors based

on NUC designs.

MAIN CABLE

Length . . . . . . . . . . 10,000 ft

Diameter . . . . . . . . . 1-1/2 in. O.D.
Weight . . . . . . . . . . 1.25 lb per ft in air, 0.6 lb per

ft in water

SUPPORT AND POWER CONVERSION EQUIPMENT

instrumentation Van . . . . . . . 15 ft long, 9 ft wide, 8 ft high
with air conditioner removed
5 Bay electronic control console:
Display - Sonar, altimeter,
depthometer, locator, vehicle
tracker, TV monitors, vehicle
and ship's compass (with cable

twist counter)

Vehicle Operator Controls - Pro-
pulsion, T.V., 35mm camera

lights, claw
Sonar Operator Controls - Sonar
mode and range scan frequency,

assist on TV on claw

Communication -,Ship intercom,

radio remote station
Vehicle Target Tracking Gear BALD Gear (Directional Hydrophone)

NUC UNLOC

Honeywell Sea-Scannar II-F sonar

Instrument Power Conversion
and Isolation Package . . . . . . One 5 KW motor generator
Three Superior Electric variable
transformers for output of 1000V (max)

HANDLING EQUIPMENT

Crane .. . . . . . . . . . . Hiab Titan articulating crane with
manually-telescoping boom; 5,000 lbs

at 19 ft.

Cable Storage Bins . . . . . . .Two bins 4 ft high, 4 ft wide ,

14 ft long
miscellaneous .. . . . . . Spare parts van portable capstano

Boston Whaler

APPENDIX B

Wentworth Grain Size Classification

The Wentworth grain size classification (Table 3) is probably the
most widely used sediment grade scale. The sample was first divided
into coarse (sand and gravelYand fine (silt and clay) fractions by
wet sieving, using 9.062 mm sieve and 1/4 gm/ml sodium hexametaphosphate
solution (commercial Calgon water conditioner) as a dispersing agent.
Measurement of the amounts of silt- and clay-size grains was done, in -
directly, using Stoke's Law of settling velocities (Stokes 1851):
V 2(d1 - d2)gr2
9m

where: v settling velocity of a sphere in a fluid,

d density of the sphere
d2= density of the fluid
g = acceleration of gravity
m = viscosity of the fluid.

The assumption is made that all sediment particles are spherical, and
that all particles have the same density. The fluid used is Calgon
solution of approximately constant temperature, so that the viscosity
and density may be considered constant.

With these assumptions and conditions, the velocity of a falling
particle is dependent on its size. In other words,

2
v = Cr

These assumptions and conditions are, of course, not entirely correct,
but this method has the advantage of more closely approximating natural
settling and sorting processes than do direct methods of size measurement.

The technique is simply to determine the weight of material which has
-settled out of suspension after a predetermined amount of time. Settling
tires are computed for specific grain sized using the above equation.

Grain size analyses are customarily shown as graphs of grain size
(ip phi units) versus cumulative weight percent (coarser than) on arithmetic
probability paper. In general size distributions are approximately
log-normal (i.e., the cumulative curve is a straight line or nearly so).
Because of the approximately normal distribution of sediment sizes,
several standard statistical parameters have been adapted for describing
sediments. These include mean grain size, median grain size, standard
deviation (called sorting coefficient by sedimentologists), skewness and
kurtosis. These statistics are approximated by the following formulas:

Median = V50 Trask, 1930
Mean = _(A16 + V50 + 9r84) Folk & Ward, 1957
3
Sorting coefficient = (084 - 016) + (095 - 05) Folk & Ward,1957
4 , 6.6

Skewness (016 + 084 - 2(050)) + (05 + 095 - 2(050)) Folk & Ward, 1957
2(084 - 016) 2(095 - V5)

Where: 016 indicates the grain size (in phi unifb) corresponding to the
16th-percentile, etc.

Median, and perferably mean, grain size reflect the overall average
size of the sediment as influenced by source, tran@port, and environment
of deposition.

Sorting Coefficient, or standard deviation, is a measure of the
uniformity of the size distribution. Descriptively, a well sorted sedi-
ment has a narrow range of sizes, while a poorly-sorted sediment has a
broad range of sizes.

Skewness is a measure of.the assymetry of the.distribution.

,Kurtosis is a.measure of the peakedness of.the distribution.

WENTWORTH GRAIN SIZE CLASSIFICATION

Diameter in mm Name Diameter in
units

64 - 4 (64.00-4.000) Peb)Dle -6 to -2

4 - 2 (4.000-2.000) Granule -2 to -1

2 - 1 (2.000-1.000) V. Cse. Sand -1 to C

1 - 1/2 (1.000-.5000) Coarse Sand 0 to 1

1/2 1/4 (.5000-.2500) Medium @and 1 to 2

1/4 1/8 (.2500-.1250) Fine Sand 2 to 3

1/8 1/16 (.1250-.0625) V. Fine Sand 3 to 4
0 1/16 - 1/32 (10625-.0 313) Coarse Silt 4 to 5
1/32 - 1/64 (.0313-.0156) Medium Silt 5 to 6

1/64 - 1/128 (.0156-.0078) Fine Silt 6 to 7

1/128 1/256 (.0078-.0039) V. Fine Silt 7 to 8

1/256 1/512 (.0039-.0020) Coarse Clay .8 to 9

1/512 1/1024 (.0020-.0010) Medium Clay 9 to 10

Diameter -:n 0 units = -log2 of the grain size in mm.

The 0 notation (Krumbein, 1934) is a convenient method for converting
geometric size classes to equal intervals. It is analagous to plotting
on logarithmic graph paper.

INCLOSURE MEE

WATER QPALITY MONITORING
100-FATHOM OCEAN DISPOSAL STUDY AREA
(5-6 September 1975)

Equipment Interoceans Water Quality Monitoring Probe Model 500

WATER QUALITY READINGS
100-FATHOM OCEAN DISPOSAL
STUDY AREA

Depth Tur. Tur.
Station A (Meters) Cond. Sal. (% Trans.) (FTU) Temp. D.O.
(mmho) (0/00) CC) (mg/lF

5.0 39.90 33.50 91.6 0 13.45 10.40
10.0 39.90 33.50 91.5 0 13.45 10.35
15.0 38.85 33-30 92.3 0 .12.45 9.65
20.0 38.45 33.40 92.4 0 11.80 8.70
25.0 38.20 33.45 92.5 0 11.60 7.97
30.0 37.85 33.50 92.6 0 11.15 7.35
35.0 37.70 33.55 92.8 0 11.05 6.82
40.0 37.50 33.55 92.8 0 10-75 6.60
45.0 37.30 33.35 92.8 0 10.55 6.30
50.0 37.10 33.60 92.6 0 10.25 5.92
55.0 37.05 33.60 92.6 0 10.15 5.90
60.0 37.05 33.65 92.8 0 10.15 5.90
65.0 36-72 33.60 92.6 0 9.75 5.35
70.0 36.60 33.68 92.6 0 9.60 5.80
75.0 36.50 33.70 92.6 0 9.50 5.80

Station B
10.0 39.95 33.50 90.1 0 13.50, 10.80
20.0 39.30 33.40 91.9 0 12.75 9.75
30.0 37.90 33.35 92.4 0 11.30 7.90
40.0 37.50 33.50 92.5 0 10.80 7.12
.50.0 37.20 33.55 92.5 0 10.35 6.30
60.0 36.95 33.60 92.4 0 10.05 5.80
70.0 36.62 33.60 92.6 0 9.66 5.40
80.0 36.40 33.70 92.4 0 9.35 5.10

Station C
10.0 39.95 33.45 88.0 1 13.55 10.50
20.0 38.55 33.50 89.6 1 12.20 9.60
30.0 38.20 33-30 90.0 1 11.70 8.85
40.0 37.60 33.35 90.5 1 10.98 7.85
50.0 37.20 33.50 90.7 1 10.52 6.55
60.0 36.90 @3.55 90.7 1 10.05 6.10
70.0 36.75 33.60 90.8 1 9.85 5.90
75.0 36.65 33.65 90.6 1 9.70 5.60

WATER QUALITY READINGS
100-FATHOM OCEAN DISPOSAL
STUDY AREA

Depth Tur. Tur.
Station A '(Meters)',.-,Cond. Sal. Trans.) (FTU) T!!@p. D.O.
(mmho) (0/00) (uC) (mg/1)

5.0 39.90 33.50 91.6 0 13.45 10.40
10.0 39.90 33.50 91.5 0 13.45 10.35
15.0 38.85 33.30 92.3 0 12.45 9.65
20.0 38.45 33.40 92.4 0 11.80 8.70
25.0 38.20 33.45 92.5 0 11.60 7.97
30.0 37.85 33.50 92.6 0 11.15 7.35
35.0 37.70 33.55 92.8 0 11.05 6.82
40.0 37.50 33.55 92.8 0 10.75 6.60
45.0 37.30 33.35 92.8 0 10.55 6.30
50.0 37.10 33.60 92.6 0 10.25 5.92
55.0 37.05 33.60 92.6 0 10.15 5.90
60,0 37.05 33.65 92.8 0 10.15 5.90
65.0 36.72 33.60 92.6 0 9.75 5.35
70.0 36.60 33.68 92.6 0 9.60 5.80
75.0 36.50 33.70 92.6 0 9.50 5.80

Station B
10.0 39.95 33.50 90.1 0 13.50 10.80
20.0 39.30 33.40 91.9 0 12.15 9.75
30.0' 37.90 33.35 92.4 0 11.30 7.90
40.0 37.50 33.50 92.5 0 10.80 7.12
.50.0 37.20 33.55 92.5 0 10.35 6.30
60.0 36.95 33.60 92.4 0 10.05 5.80
70.0 36.62 33.60 92.6 0 9.66 5.40
80.0 36.40 33.70 92.4 0 M5 5.10

Station C
10.0 39.95 33.45 88.0 1 13.55 10.50
20.0 38.55 33.50 89.6 1 12.20 9.60
30.0 38.20 33.30 90.0 1 11.70 8.85
40.0 @37.60 33.35 90.5 1 10.98 7.85
50.0 37.20 33.50 90.7 1 10.52 6.55
60.0 36.90 33.55 90.7 1 10.05 6.10
70.0 36.75 33.60 90.8 1 9.85 5.90
75.0 36.65 33.65 90.6 1 9.70 5.60

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