Environmental assessment : Davisville port expansion

[From the U.S. Government Printing Office, www.gpo.gov]

Coastal Resources Center
HT University of Rhode Island
393 Graduate School of Oceanography
R4 Narragansett, RI 02882
E58 401-792-6224
1981

Ile

Environmental Assessment

Davisville Fbrt Expnsion

Prepared For

The Rhode Island Department of Economic Development
4V,
/Y@ By The
/Y) Coastal Resources Center
Graduate School of Oceanography
University of Rhode Island

1981

The preparation of this report was financed in part by funds from the Office
of Coastal Zone Management, National Oceanic and Atmospheric Administration,
U.S. Department of Commerce, administered by the ENERGY OFFICE, EXECUTIVE
DEPARTMENT, GOVERNOR'S OFFICE, STATE OF RHODE ISLAND.

TABLE OF CONTENTS Page
Part A: Environmental Assessment of Davisville Port Expansion
1. Summary . . . . . . . . . . . . . . . . . . . . . . . . . . 1-1

2. Purpose and Need for the Proposed Action . . . . . . . . . 2-1

3. Summary Evaluation of Alternatives . . . . . . . . . . . . 3-1
3.1 Site requirements and assumptions . . . . . . . . . . 3-1
3.2 Bulkhead construction along Dogpatch Beach . . . . . . 3-2
Description of action . . . . . . . . . . . . . . . . 3-2
Summary of impacts . . . . . . . . . . . . . . . . . . 3-3
Mitigating measures . . . . . . . . . . . . . . . . . 3-4
3.3 Bulkhead construction north of Davisville Piers . . . 3-5
Description of action . . . . . . . . . . . . . . . . 3-5
Summary of impacts . . . . . . . . . . . . . . . . . . 3-5
Mitigating measures . . . . . . . . . . . . . . . . . 3-6
3.4 Reconstruction of Navy Bulkhead . . . . . . . . . . . 3-7
Description of action . . . . . . . . . . . . . . . . 3-7
Summary of impacts . . . . . . . . .. . . . . . . . . . 3-8
Mitigating measures . . . . . . . . . . . . . . . . . 3-8
3.5 Options considered but rejected . . . . . . . . . . . 3-9
Bulkhead between Davisville Piers and the Quonset
State Airport . . . . . . . . . . . . . . . . . . . 3-9
Alternate sites . . . . . . . . . . . . . . . . . . . 3-9
3.6 No construction . . . . . . . . . . . . . . . . . . . 3-10

4. Description of the Affected Environment . . . . . . . . . . 4-1
4.1 Introduction . . . . . . . . . . . . . . . . . . . . . 4-1
4.2 Location and general description of Davisville and
vicinity . . . . . . . . . . . . . . . . . . . . . . 4-1
Introduction . . . . . . . . . . . . . . . . . . .. . . 4-1
Davisville Piers and Dogpatch . . . . . . . . . . . . 4-2
Navy Bulkhead and residential compound . . . . . . . . 4-3
The Airport . . . . . . . . . . . . . . . . . . . . . 4-4
Allen Harbor . . . . . . . . . . . . . . . . . . . . . 4-4
Calf Pasture Point . . . . . . . . . . . . . . . . . . 4-5
4.3 Terrestrial environment . . . . . . . . . . . . . . . 4-7
Introduction . . . . . . . . . . . . . . . . . . . . . 4-7
Surficial. geology and soils . . . . . . . . . . . . . 4-7
Hydrology . . . . . . . . . . . . . . . . . . . . . . 4-10
Vegetation . . . . . . . . . . . . . . . . . . . . . . 4-10
Wildlife . . . . . . . . . . . . . . . . . . . . . . . 4-10
Structure and archeological sites . . . . . . . . . . 4-12

Page

Features of special significance in vicinity of
proposal development at Dogpatch . . . . . . . . . 4-12
The beach and dune . . . . . . . . . . . . . . . . 4-12
The wetland . . . . . . . . . . . . . . . . . . . 4-14
Woods and stream . . . . . . . . . . . . . . . . . 4-15
Abandoned lawns and open fields . . . . . . . . . 4-16
References . . . . . * * ' ' * * * ' * * * * * 4-18
4.4 Geological features of* @he marin*e environment . . . 4-19
Summary . . . . . . . . . . . . . . . . . . . . . . 4-19
Near shore bottom characteristics . . . . . . . . . 4-19
Bathymetry . . . . . . . . . . . . . . . . . . . . . 4-20
Bottom surface conditions . . . . . . . . . . . . . 4-21
Sediment . . . . . . . . . . . . . . . . . . . . . . 4-21
Bedrock . . . . . . . . . . . . . . . . . . . . . . 4-22
Overburden . . . . . * * ' * ' * * ' * * * * ' * ' * 4-23
4.5 Biological features of the marine environment . . . 4-24
Introduction . . . . . . . . . . . . . . . . 4-24
0 . . . . 4-25
Characterization of living cmmunities . . .
Suspended sediments . . . . . . . . . . . . . . . . 4-30
Pollutants . 4-31
Water Quali4* 4-31
Hydrocarbons in sediments . . . . . . . . . . . . 4-32
Metals in sediments . . . . . . . . . . . . . . . 4-35
Metals in clams . . . . . . . . . . . . . . . . . 4-36

5. Environmental Consequences of Alternative Actions 5-1
5.1 Introduction . . . . . . . . . . . . . . . . . 5-1
5.2 Bulkhead construction along Dogpatch Beach . . 5-2
Description of action . . . . . . . . . . . . . 5-2
Terrestrial impacts . . . . . . . . . . . . . . 5-3
Aquatic impacts . . . . . . . . . . . . . . . . 5-5
Mitigating measures . . . . . . . . . . . . . . 5-8
Terrestrial . . . . . . . . . ... . . . . . . 5-8.
Aquatic . . . . . . . . . . . . . . . . . . . 5-9
5.3 Bulkhead between Davisville Piers and the Quonset
State Airport . . . . . . . . . . . . . . . . . . 5-10
Description of action . . . . . . . . . . . . . . . 5-10
Terrestrial impacts . . . . . . . . . . . . . . . . 5-11
Aquatic impacts . . . ... . . . . . . . . . . . . . 5-11
5.4 Bulkhead north of Davisville Pier . . . . . . . . . 5-12
Description of action . . . . . . . . . . . . . . . 5-12
Terrestrial impacts . . . . . . . . . . . . . . . . 5-13
Aquatic impacts . . o . . . . . . . . . . . . . . . 5-13
Mitigating measures . . . . . . . . . . . . . . . . 5-15
5.5 Improvements to property adjacent to Davisville Piers
retained by the United States Navy . . . . . . . . 5-15
Description of action . . . o . . . . . . . . ... . 5-15
Terrestrial impacts . . . o. . . . . . . . . . . . 5-16
Aquatic impacts . . . . . . . . . . . . . . . . . . 5-18
Mitigating measures . . . . . . . . . . . . . . . . 5-20
Terrestrial . . . . . . o . . . . . . . . . . . 5-20
Aquatic . . . . . . . . . . . . . . . . . . . . . 5-20

Page

5.6 Actions with no impact on the Davisville site 5-21
Description of action . . . . . . . . . . . . . . 5-21
Alternate sites . . . . . . . . . . . . . . . . . 5-20
No construction . . . . . . . . . . . . . . . . . 5-22

Part B: Davisville,Port Expansion Assessment: Geology. Technical report
by Dr. R.L. McMaster and S.M. Greenlee.

Part C: Davisville Port Expansion Assessment: Biology. Technical report
by Sheldon Pratt.

LIST OF FIGURES

Figure 1-1 Davisville Port Expansion Alternates

3-1 Davisville Port Expansion Alternates

4-1 Davisville Study Area
4-2 Surficial. Geology of Davisville
4-3 Soil Types at Davisville
4-4 Location of Wetlands, Beaches and Woods at Davisville
4-5 Land Cover at Dogpatch Parcel of Study Area
4-6 Vegetative Cover, Dogpatch Parcel
4-7 Bathymetry
4-8 Side Scan Survey
4-9 Surface Sand Distribution
4-10 Bedrock Depths
4-11 Sediment Overburden Thickness
4-12 Grab Sample Station Locations for Benthic Survey
4-13 Three Benthic Environments in Fry Cove
4-14 Location of Turbidity Stations
4-15 Temperature Section, May 28, 1980
4-16 Turbidity Sections, May 28, 1980
4-17 Turbidity and Temperature Profiles at Two Locations, June
24, 1980
4-18 Station Locations for Water and Sediment Quality Samples
4-19 Metal Levels in Soft Shell Clams

5-1 Selected Port Expansion Plan
5-2 Full Development Port Expansion Plan
5-3 Changes to Dogpatch from Design 2, Incremental Development
5-4 Maximum Expansion Design
5-5 Bulkhead North of Davisville Piers
5-6 Reconstruction of Navy Bulkhead
5-7 Expansion of Navy Bulkhead
5-8 Alternate Sites for Port Expansion in Narragansett Bay

LIST OF TABLES

rable

4-1 List of Common and Scientific Names of Species Observed in
Woods & Stream, Dogpatch Site

4-2 Water Quality Data for Davisville Area

4-3 Summary of Sediment Hydrocarbon Data in Study Area

SYNOPSIS

This environmental assessment report has been prepared by the Coastal
Resources Center of the University of Rhode Island,under contract to the
Rhode Island Port Authority and Economic Development Corporation, RIPA.
Its purpose is to identify and assess the likely environmental effects of the

six alternate designs for port expansion at Davisville, Rhode Island as

proposed by C.E. Maguire, the engineering consultants who developed the

preliminary engineering report. Part A contains the environmental

assessment of the proposed expansion plan and several alternatives, following
the 1978 guidelines developed by the Council on Environmental Quality (40 CFR
pt. 1502). Part B presents the report of geological studies conducted speci-
fically for this project. Part C is a detailed report on the marine biology
of the vicinity of Davisville, including scientific surveys conducted
specifically for this report. It also contains a thorough review of the
relevant scientific literature on the impacts of dredging on marine organisms.
The proposed port expansion design as described in the preliminary engineering
report is in essence a general development site plan. C.E. Maguire recommended
that RIPA have detailed engineering drawings prepared, which is the next step
prior to bidding for construction. Responses to concerns raised in this
environmental assessment of the general plan would be addressed in this next
phase, along with complete specifications for implementing recommended mitigating

measures.

This report was prepared by Donald Robadue, Jr., project coordinator,
Stephen Olsen, and George Seavey of the Coastal Resources Center; Sheldon
Pratt of the Division of Marine Resources; and Dr. Robert McMaster and
Stephen Greenlee of the Graduate School of Oceanography, University of
Rhode Island. Jean Krul typed the entire report with precision and patience.

Lucia de Leiris prepared the geology and biology maps in Parts B and C.

SUMMARY

Since 1975, the Rhode Island Port Authority has leased wharf and land

space at Davisville to several companies which provide services to offshore

oil exploration operations. Several planning and management studies have

indicated that in the event of oil and gas exploration and development

activity on Georges Bank off the New England coast, a considerable increase

in service operations at the Davisville site-could occur. The Coastal

Energy Impact Program, created by the 1976 amendments to the federal

Coastal Zone Management Act, provides funds to states affected by the

impacts of energy-related facility development. The Rhode Island Port

Authority was awarded funds through the Governor's Energy Office, to

conduct port management, engineering and environmental impact assessment

studies as part of the state's effort to accommodate growth in oil industry

operations in a carefully planned fashion. Booz-Allen, Inc. conducted a

management study of port operations. C. E. Maguire, Inc. prepared the

preliminary engineering plans for port expansion at Davisville. The

Coastal Resources Center of the University of Rhode Island provided the

environmental impact assessment of the engineering designs.

Six alternate designs were developed for the Davisville site during the

planning phase of preliminary engineering by the project consultants after
discussions with the Department of Economic Development and the Quonset-
Davisville Planning Task Force; these were presented by C.E. Maguire in

its progress reports with the following designation:

Alternate 1: Original 1977 concept, for Dogpatch; Construction of
.a 2,400 foot bulkhead south of the Navy Bulkhead
parallel to Dogpatch Beach.

1@2

Alternate 2 Incremental concept for Dogpatch; 675-foot bulkhead
along Dogpatch Beach, with the potential for later
expansion to the full length of Alternate 1.

Alternate 3: Maximum Dogpatch concept, 3,200 foot bulkhead filling
a large portion of Fry Cove between Davisville Pier
and the Airport.

Alternate 4: Bulkhead north of Davisville Piers, 2300 feet adjacent
to land presently used for oil support operations.

Alternate 5: Replacement or repair of existing Navy Bulkhead south
of Pier 1.

.Alternate 6: New Pier connected to reconstructed Navy bulkhead as
an expansion option for site.

Dredging is required in every alternate design. In addition, sites

elsewhere in Narragansett Bay for locating offshore oil service base

operators and a 'no'expansion' option were considered.

Alternate 2 was the alternate design preferred by the Rhode Island

Port Authority and selected for the preliminary engineering design study.

Alternate 5 would have less environmental impact. However, the bulkhead is

still retained by the Navy Construction Battalion Center.

Construction of Alternate design 2 will involve dredging 13 acres

of sandy bottom in Fry Cove, constructing a 675-foot bulkhead and filling

behind it to create 18 acres of land for use as a marine transportation

terminal. An estimated 350,000 cubic yards of materials would be removed

to create a 25-foot channel. About 160,000 cubic yards of that total would

be surplus and must be stockpiled on land. Road and rail service improvements

would be made along Marine Road, which passes through the Dogpatch parcel

owned by the RIPA.

With the exception of the Dogpatch parcel, the property adjacent to

the proposed bulkhead has been extensively modified since 1940 by filling,

paving, bulkhead building, pier construction, and Construction Battalion

activities by the Navy. The construction of the proposed bulkhead will have

certain adverse environmental impacts, principally the permanent elimination

1-3

by burial of several acres of Fry Co ve bottom currently containing commercially

harvestable hard clams, Mercenaria mercenaria, and a two-acre marsh, containing

about one half acre of smooth cordgrass, �Rq@rLin
A alterniflora borderin, a

small pool of open water. The Spartina marsh is in turn surrounded by some 1.5

acres of the reed Phragmites.communis. A portion of Dogpatch Beach will be

covered as well. Adverse effects of turbidity during dredging on marine

organisms are not expected if adequate containment and retention of effluent

from hydraulic dredging is provided and the water produced from material

settling is drained to the bottom of the existing channel. Providing rail

and road access to the wharf through the Navy property would reduce

encroachment upon the upland stream and woods. However, if development is

confined to the land between the proposed new road and rail line, the

vegetated area will be protected. A buffer between activity on the wharf

and adjacent Navy housing may be required. The dredged material stockpile,

which will be located south of Marine Road adjacent to the airport, should

be covered or planted to reduce wind and rain erosion (Figure 1-1).

Each of the other designs was assessed by the engineering and envir-

onmental consultants. Alternate 1 would have enabled immediate construction

of the full length bulkhead along Dogpatch Beach, but was rejected by the

Port Authority in favor of the incremental approach incorporated in Alter-

nate 2. The incremental design provides greater flexibility in port

expansion planning. Alternate 3, filling a major portion of Fry Cove,

was too expensive and provided much more land and wharf space than would

be needed. A bulkhead could be built north of the existing piers, following

the plan of Alternate 4, avoiding some of the terrestrial impacts at

Dogpatch and retaining the integrity of Davisville piers as an offshore

FRY
D g-
FRY Dog- FRY Dog-
N,
patc COVE patch COVE p a ch COVE

Do g - 150-11111
p a t c h
FRY W9 Dog-
FRY p h FRY
COVE patc atc
P, COVE COVE

4. 5. 6.

Figure 1-1
Davisville Port Expansion Alternates
'jjjRY
COVE

feet

1-4

oil and gas exploration service base. The configuration and construction

details suggested by the consulting engineers was estimated to be much more

expensive than Alternate 2 due to the need for a deck along parts of the

bulkhead. The dredged channel would also be more exposed to wave action

and sedimentation, and present a greater likelihood of commercial operations

interfering with recreational uses in the vicinity of Allen Harbor. Recon-

struction of the existing Navy bulkhead, Alternate 5, would require the
least dredging and provide access to land adjacent to Davisville Pierst

avoiding the impact of filling parts of Fry Cove. However, a formal agree-

ment between the Navy and the State of Rhode Island would be required for

this option to be pursued further. Alternate 6, construction of a new pier

extending out from the Navy bulkhead would be contingent upon the completion

of Alternate 5 and was among the most expensive methods for increasing berths

and new land.

The environmental assessment in Part A has been prepared following the

format recommended by new regulations promulgated by the Council on Environ-

mental Quality in 1978 (43 Fed. Reg. 55994; 40 C.F.R. pt. 1502). Chapter
2 contains a discussion of the purpose and need for the proposed action,

Chapter 3 provided a summary evaluation of alternates. Chapter 4 consists

of a description of the affected environment. Chapter 5 consists of a detailed

evaluation of the consequences of alternative actions. Part B contains

I'Davisville Port Expansion Assessment, Geology" by Dr. Robert McMaster and

Stephen Greenlee, prepared in conjunction with the environmental assessment.

Part C is another technical report entitled "Effects of Port Expansion at

Davisville, Rhode Island on the Marine Environment" by Sheldon Pratt.

2-1

2. PURPOSE AND NEED FOR THE PROPOSED ACTION

SLnce 1973, when the United States Navy first announced the deactivation

of Quonset Point Naval Air Rework Facility, followed by reductions in activity

at the Construction Battalion Center at Davisville, Rhode Island state govern-

ment has actively engaged in planning for the re-use of Navy land designated

surplus to federal needs. The first proposal, made by a legislative commission

in 1973, was to create a major container port at Quonset Point with expansion

to Davisville Piers. This effort did not lead to any specific action. In

1974, following cutbacks in Navy operations, several important actions were

taken by the state to accelerate the redevelopment effort. Legislation (Citle 42,Ch.6

created the Rhode Island Port Authority and Economic Development Corporation

which became responsible for the Protection and Maintenance Agreement reached

with the Department of Defense. The Port Authority was permitted to issue

30 day cancelable leases, utilizing revenues to provide services and maintain

the property until a sales agreement was reached. The Governor's Office

prepared a general plan for re-use of surplus military lands as required

of its application to acquire the property from the General Services Admin-

istration (Governor's Office, 1974). That plan proposed that Davisville

Piers be used "for intensive industrial development of a water oriented

nature." The Dogpatch parcel, located to the south between Navy retained

land and the airp ort, "should be reserved for future industrial re-use,

perhaps related to the re-use of Area D (Davisville Piers) or to the

airport." Assuming a direct connection to Davisville Piers, "a similar

marine terminal industrial use may be indicated" for Dogpatch.

At the same time re-use planning was proceeding, the federal government

was accelerating the leasing of tracts offshore for the purpose of oil and

2-2

gas exploration. In 1975, industry nominations for tracts on Georges

Bank off the New England coast were sought by the Department of Interior,

coninciding with efforts by Rhode Island to attract oil industry intere st

to Quonset Point/Davisville. Reports by the New England River Basins Commission

(L976) raised the potential for substantial onshore economic activity in

support of oil and gas drilling and production activities. A marketing

study by Harbridge House (1976) concluded that "the development of the

offshore oil reserves on the East Coast of the United States offers a

substantial opportunity for employment in Narragansett Bay.11

A master plan for Quonset Point/Davisville was prepared by the

Department of Economic Development with the assistance of several consulting

firms during 1976 and 1977. Three development scenarios were developed and

assessed. Scenario I was based upon the assumption of a high find of

petroleum or gas on George's Bank off the New England coast. It was based

upon the assumption that Davisville would become a primary location for

industry supporting offshore oil exploration and development. Permanent

service bases,a pipe laydown and coating yard, and oil production platfor m

fabrication would all occur at Davisville. Scenario II was based on the

assumption of a medium level find on George's Bank, and a mixed land use

pattern at Davisville. Under this scenario, more service base activity

would be accommodated. However, a higher proportion of new firms at

Quonset/Davisville would not be associated with petroleum exploration.

Scenario III was based upon the assumption that no oil or gas would be

disc overed and no permanent service base activity would be located at

Davisville (Keyes Associates, 1976),

2-3

The Rhode Island Port Authority adopted Scenario II as its development

plan, which Involved the allocatIon of about 420 acres of land, Incitiditig

I)iivl.-;vlll.e I'l-ers and Dogpatch, to oil support operations. Also itic Luded

in the plan was the construction of a new bulkhead along Dogpatch Beach,

to support future expansion of oil support activity, a concept based upon

planning information developed by the New England River Basins Commission

in 1976. Service companies have been operating from Davisville since

1976 in support of test well drilling as well as exploration of the

Baltimore Canyon off the mid-Atlantic coast.

The goals of the Rhode Island Port Authority for Davisville Piers are

to provide full support for firms providing services, materials and equip-

ment to offshore oil exploration and production in the North Atlantic,

make the best use of existing and proposed facilities for oil support and

other activities, and maintain the competitive advantage of the state' for

marine transportation. Davisville is located equidistant between areas of

interest to the petroleum industry in Baltimore Canyon to the south and

George's Bank to the east, making it a convenient location for firms .

providing services to oil drilling activity in both areas. The port expansion
design prep,@tred by' C. E. Magi4ire during 1980 is based upon research

into the marine, land, utility and supporting transportation requirements

of service bases supporting outer continental shelf oil exploration. In

recognition of the need for maintaining full occupancy of new facilities,
the requirements of other users of port facilities were also investigated,

including commercial cargo and fishing.

The design preferred by the Rhode Island Port Authority, Alternate 2,

entails construction of a 675-foot long bulkhead, which contains 18 acres

'2-4

of supporting land in front of Dogpatch Beach. This was determined to be

the smallest practical increment of port expansion by C.E. Maguire, based

on an analysis of user requirements. This facility could then.be extended

southward as future needs develop.

REFERENCES

C.E. Maguire, Inc. 1980. Davisville Port Expansion. Preliminary Engineering
Report. Providence.

Coastal Resources Center. 1977. The Redevelopment of Quonset-Davisville.
An Environmental Assessment. University of Rhode Island, Kingston.

Commission to Study a Rhode Island-Connecticut Environmental City Compact.
1973. Interim Report: Quonset. State House, Providence, RI.

General Services Administration. 1978. Final Environmental Impact State-
ment. Disposal of Surplus Federal Military Properties in Rhode Island.

Harbridge House, Inc. 1976. Industrial and Commercial Marketability of
Surplus Properties in Rhode Island. Boston, Mass.

Keyes Associates. 1977. Quonset Point Technical Park Facilities Study.
Providence, RI.

New England River Basins Commission. 1976. Onshore Facilities Related to
Offshore Oil and Gas Development. Estimates for New England. Boston, MA.

New England River Basins Commission. 1976. Fact Book. Boston, MA.

Rhode Island Governor's Office. 1974. Re-use and Development of United
States Surplus Military Lands in Rhode Island. Providence, RI.

Rhode Island Department of Economic Development. 1977. Master Development
Plan Quonset Point/Davisville. Informational Booklet. Providence, RI.

3-1

3. SUMMARY EVALUATION OF ALTERNATE DESIGNS
3.1 SITE REQUIREMENTS AND ASSUMPTIONS

The Rhode Island Coastal Resources Management Council designated

Davisville Piers as the primary location in Rhode Island for service base

and other operations in support of oil and gas exploration on the outer

continental shelf (OCS). Section 540.0-2 of the Coastal Resources

Management Program adopted in 1977 states "a high priority of use of the

surplus Navy holdings at Davisville shall be commerce and industry related

and/or supportive of OCS oil and gas exploration."

The original concept of expanding Davisville Piers by constructing

a bulkhead to the south of Pier 1 along Dogpatch Beach was included in

Scenario II, the plan adopted by the Rhode Island Port Authority in 1977

in its master plan for the re-use of Quonset/Davisville. The purpose of

creating the new wharf was to provide additional marine facilities for

supporting oil industry service activities and to make the Dogpatch Beach

parcel more closely linked with oil drilling support activity at Davisville

Piers.

During the preliminary design of the bulkhead, which began in February

1980 by C.E. Maguire Inc, the user requirements for the facility were

more clearly defined and several configurations were examined for their

ability to meet user requirements and port activity needs. The basic

requirements for potential users of expanded facilities determined

by C.E. Maguire were a protected location, with a water depth of the channel

and berths of about 25 feet below mean low water, and a minimum of two

berths of 250 feet in length for OCS exploration support operation, or

feet for a one berth commercial port. Eight to ten acres of supporting

3-2

land were assumed to be needed to support each berth in the service base

operations, or 12 to 20 acres in the case of a commercial berth. The selected

design should have a low cons truction cost, and be capable of incremental ex-

pansion as demand warranted. Finally, it was assumed that the Navy control of

the land between Davisville Piers and Dogpatch Beach would preclude reconstruc-

tion of the existing Navy bulkhead or use of the Navy held land for service

base or commercial operations.

The six designs proposed by C.E. Maguire during its preliminary engineering

study are shown in Figure 3-1. This chapter provides a summary of the environ-

mental effects of these designs as well as options available to the Port Authority

which would have no impacts at Davisville. Since many of the environmental

effects of the alternate configurations are similar, the discussions of the'

designs have been consolidated in the following manner:

Section 3.2: Bulkhead construction along Dogpatch Beach (Alternate
1, 775 feet; Alternate 2, 2400 feet.

Section 3.3: Bulkhead construction north of Davisville Piers
(Alternate 4, 2,300 feet).

Section 3.4: Reconstruction of Navy Bulkhead (Alternates 5 and 6).

Section 3.5: Rejected options (Alternate 3, Fry Cove Bulkhead and
other sites).

Section 3.6: No construction option

Full discussions of each alternate design are provided in Chapter 5,

including more detailed descriptions, maps and identification of impacts. Part

C contains a thorough discussion of the impacts of dredging on marine organisms.

3.2 BULKHEAD CONSTRUCTION ALONG DOGPATCH BEACH

Description of Action

The Rhode Island Port Authority is proposing to construct a 675-foot long

bulkhead, dredge 360,000 cubic yards of material from 13 acres of Fry Cove to

FI\

-27

Dog- FRY
patc FRY Dog- FRY Dog- COVE
COVE patch COVE patch

Dog-
patch FRY Dog Dog-
patc FRY patch FRY
COVE
COVE COVE

4. 5. 6.

Figure 3-1
Davisville Port Expansion Alternates
tEEEEE

RY
CO

0 1000

feet

3-3

create a new channel 25 feet deep; and fill behind the bulkhead to create

about 18 acres of land for use as a commercial port (Figure 3-1 Alternate

2). The location of the project is the northeastern corner of the area of

Davisville known as Dogpatch Beach, just south of Davisville Piers adjacent

to land retained for use by the Navy Construction Battalion Center. Should

port activity warrant, the Port Authority would have the ability to expand

the wharf as much as 1,800 feet further south, toward the outlet of Fry

Pond, creating an additional 12 acres of land. About 160,000 cubic yards of

surplus dredged material would be stored between the State Airport and Marine

Road in Alternate 2. Maguire Alternate 1, immediate construction of the

entire 2,400 foot bulkhead involving 700,000 cubic yards of dredged material,

was rejected in favor of the incremental expansion program. Although no

construction sequence was specified by C.E. Maguire, dredged material would

probably be pumped behind the bulkhead and containment dikes. A weir would

control the flow of water back into Fry Cove, permitting settling out of

much of the suspended sediment behind the bulkhead in order to minimize the

turbitidy caused by dredging.

Im a@@.ts

The primary effect of the proposed action will be the complete altera-

tion of 31 acres of upland, shore and bottom. The principal environmental

effects of the proposed action are the permanent destruction of a two acre

salt marsh, portions of a sandy beach, and part of shallow subtidal zone

by filling 18 acres with dredged material to create a wharf. Patches of a

few square yards of oysters and soft shelled clams, and slightly larger areas

of hard clams in depths accessible to recreational shellfishing will be lost.

The new dredged channel will eliminate 13 acres of productive bottom in Fry

Cove which is a portion of the commercial hard clam fishing ground in Fry Cove.

3-4

With severe storms inflicting damage to the beach, natural processes would be

unable to restore the undeveloped portion of Dogpatch Beach because of its

isolation from sand supplies. The result probably will be an unavoidable

continuing erosion of the shore line. Later construction of an additional

12 acre wharf and 1625 foot bulkhead to achieve the full expansion proposed

in Alternate 1 would lead to the loss of another 30 acres of shore and

shallow bottom to filling, and 28 acres of productive deeper bottom due to

dredging.

The operation of the port facility will probably lower water quality

from SA (suitable for all uses) to SB (shellfishing restricted) leading to

the closure of a 1000 foot zone around the wharf to shellfishing by the

Department of Health. The temporary stockpile of surplus dredged material,

if left unprotected, will be eroded by wind and storm runoff into Fry Cove.

Mitigating Measures

Actions can be taken to lessen the impacts of dredging and bulkhead

construction. Hard clams (Mercenaria mercenaria) should be removed before

dredging. Effluent from dewatered dredged material should be released near

the existing channel to reduce surface turbidity and avoid sediment deposition

on areas where hard clams are located. The dredging sequence should permit the

longest possible retention time of water in the containment structures to

minimize the turbidity produced during construction.

Partial compensation for the loss of the beach and marsh could be

achieved by beach nourishment or marsh building nearby, for example in the

vicinity of Allen Harbor and Calf Pasture Point. However, in case of Alternate

surplus material is being reserved for future expansion. The temporary

stockptle of drodged mater-Iii.1s sliotil.d be covered or planted to redtice Oe

likelihood of erosion.

3-5

Impacts on the Dogpatch parcel could be reduced by providing road and

rail access through Navy controlled property rather than.making proposed

transportation improvements along Marine Road. C.E. Maguire estimated that

this alternate route was less expensive to construct. However, since Dogpatch

is slated for eventual industrial development, transportation improvements are

inevitable. In addition, permission would have to be secured from the Navy

for long term access through the property. A policy to confine new industrial

construction on Dogpatch south of the proposed rail line would protect the

stream and woods, as well as save the vegetated zone dividing the Navy resi-

dential compound to the north from activity at Dogpatch and the Quonset State

Airport.

3.3 BULKHEAD NORTH OF DAVISVILLE PIERS

Description of Action

Twenty-six acres of new land, and 2,300 feet of berthing would be

created by building a bulkhead linking Pier 2 to the entrance of Allen

Harbor, along land owned by the Port Authority and presently used for

offshore oil service base operations. Twenty-two acres of bottom would be

dredged to create the new berths. The 770,000 cubic yards of dredged

material would be used to fill behind the bulkhead, leaving no surplus.

Summary of Impacts

The upland portion of this site is paved with asphalt which is in

poor condition. Bulkhead development will require repavement of much of

the area. A marsh of less than 3 acres adjacent to Pier 2 would be filled

with dredged materials. This wotland is periodically overwashed by sand

because of its exposure to wave action making it less valuable wildlife

habitat. The beach leading north from the wetland to the entrance of Allen

Harbor would also be filled. FL11ing of intertidal and shallow subtidal

3-6

areas will result in the loss of an area of soft-shell clams (Mya arenaria)

and other animals. However, these areas are less productive than nearby

Allen Harbor and Calf Pasture Point.

The area to be dredged has undergone continuous disturbance from hard

clam fishing. The hard clam M. mercenaria is more resistant to the effects

of dredging than its competitors and predators, and therefore may be less

affected by disturbances caused by dredging such as siltation and burial.

Sediment suspended by dredging, and the effluent from dredged material

dewatering will add to the turbidity of the Calf Pasture Point area for the

duration of the congtruction and dredging, with sediment settling in the

deeper portions of Allen Harbor, the dredged basins and West Passage. Sand

drifts from north of the area to be dredged will probably cause filling in

the Northwestern end of the channel, at a rate more rapid than that now

occuring to the existing piers.and channel due to exposure to the north-

easterly storms. During the flood tide dredging operations may produce some

visible turbidity off Calf Pasture Point which is actively used for recre-

ational shellfishing and swimming, representing a potential aesthetic

concern.

New port activity at the mouth of Allen Harbor will increase the

likelihood of conflicts with recreational use. Shellfishing near the

wharf would likely be prohibited by the Department of Health due to a

change in water quality from SA to SB. The possibility of accidental
pollution may affect shellfishing and proposed aquaculutre activity in the

Harbor, although marina development would not be hindered.

Mitigating Measures

Release of dredging effluent near the present channel or turning

basin would reduce the biological and visual effects of suspended material

3-7

on shellfishing and swimming. Scheduling the dredging during winter months

would avoid the presence of a turbidity plume during peak recreational use.

Installation of a storm drainage system on the wharf would increase the

ability to control and cleanup spilled material before it enters the water.

The proximity to shellfishing grounds requires careful control of

operations on the wharf and by vessels to reduce the impact of pollutants

such as sewage, dock preservatives, chemicals or, petroleum products

which may enter the water directly or in storm water runoff.

3.4 IMPROVEMENTS TO PROPERTY ADJACENT TO DAVISVILLE PIERS
RETAINED BY THE UNITED STATES NAVY

Description of Action

A series of incremental actions could be taken utilizing the land

behind the presently deteriorating bulkhead which is retained by the U.S.

Navy Construction Battalion Center. These were suggested by C.E. Maguire

as Alternates 5 and 6. The first step would be to build a new 1,300

foot bulkhead seaward of the present decaying structure, and then dredge

about 10 acres of new channel producing 175,000 cubic yards of surplus

sediment requiring disposal. About 1.5 acres of new land would be created

by a small portion of the dredged material. Access might be obtained to

adjacent Navy land presently used for equipment storage. Alternate 6,

futur e expansion, would involve the construction of a new pile supported

or earth filled pier parallel to Pier 1, creating I new acres of land, and

2,300 linear feet of berthing. Fifteen acres would be dredged in addition

to that needed for bulkhead repair, yielding 370,000 cubic yards of surplus

material. The earth filled pier would reduce the volume of surplus material

to 170,000 cubic yards. The southern end of the Navy Bulkhead will be

filled and protected with stone armor.

3-8

Summary of_Impacts

Upgrading the Navy owned bulkhead will cause fewer environmental impacts

than any other construction option. Dredging and material disposal are the

primary concerns. The 10 acres of sandy bottom to be dredged contains com-

mercially valuable hard clams which will be eliminated along with other

bottom organisms serving as food for fish and ducks. If the sediment

stockpile site is located adjacent to the Dogpatch parcel, the habitat of

some small mammals will be disturbed. An alternate dredged material storage

site is located at the intersection of Marine and Davisville Roads which is

nearer to the Navy bulkhead. Any stockpile should be covered to reduce

erosion by wind or rain.

The repair work at the southern end of the bulkhead is likely to

infringe upon the cobble beach and a corner of the marsh at Dogpatch.

Some erosion of the beach at this junction would be expected. Active use

of the land adjacent to the bulkhead would produce noise and visual dis-

turbances to the Navy residential compound and birds nesting in the

nearby wetland. Pollutants in storm water runoff from the site, and

litter may also enter the marsh.
Miti The use of clamshell dredging would avoid creating a large volume of

sediment laden slurry which must be contained and settled-before release

into Fry Cove. Reuse of dredged material for landscaping or marsh building

would reduce the problem of dredged material disposal. Additional study

would be required to evaluate and plan for marsh construction. Release

of dredged effluent into existing channels will reduce the visible turbidity

and sedimentation on shallower areas which are most valuable as hard clams

and fish food habitat.

3-9

Hard clams can be removed.before channel dredging, a process already

occurring since the area was opened to shellfishing in July, 1980. Addi-

tional shore protection and land creation at the southern end of the

bulkhead could reduce the amount of surplus dredged material and protect

the marsh by improving shoreline stability. Fencing and vegetative buffers

would reduce the intrusion of waterfront activity into the residential

compound and marsh. Drainage of the site should be directed away from

the marsh.

3.5 OPTIONS CONSIDERED BUT REJECTED

Bulkhead Between Davisville Piers and the Quonset State Airport

C.E. Maguire suggested a bulkhead configuration, Alternate 3 design,

that created the greatest amount of land and berths, and offered a

potential for accommodating dredged materials from other locations in

Narragansett Bay. This proposal would create 3,200 feet of wharf, involve
filling 120 acres of Fry Cove with 4.1 million cubic yards of material,

and require 40 acres of dredging. Productive shallow and deeper bottom

would be lost, and more sediment would reach the vicinity of Allen Harbor

than in other Fry Cove options.

Several factors make this option infeasible, such as high cost, the

difficulty of obtaining and unloading two million cubic yards of fill from

elsewhere in the Bay. In addition, there is no demonstrable need for a

facility of that size.

Alternate Sites

No suitable sites compatible with the design requirements for port

operation such as offshore oil drilling service bases are available in the

vicinity of Narragansett Bay. Although Providence Harbor and state owned

property at Melville possess some potential, development plans for both

3-10

sites preclude service base development.which does not require use of the deep

berths available at both locations. New facilities could be constructed at

Melville, but development in that location would not be superior to expansion

options at Davisville Piers, since it is a considerable distance away from

the center of operations at Davisville, may not be available when needed,

and has been identified as a good site for fishing facilities (S. Sedgwick,

C. Collins, and S. Olsen. 1980 Commercial Fishing Facility Needs in Rhode

Island. Coastal Resources Center, University of Rhode Island, Kingston.

3.6 NO CONSTRUCTION

If Davisville develops as projected but no new or expanded facilities

were constructed port management problems would likely occur. Most of the

marine environmental impacts of constructing and operating the various

alternate designs discussed in sections 3.2 to 3.4 would be avoided. Firms

desiring to expand or locate at Davisville in order to be near the center

of oil support activity (;ould not be accommodated. However, upland

development at Dogpatch Beach and small scale improvements to existing

facilities would still be likely to occur due to plans for industrial

development at Davisville by the Rhode Island Port Authority.

4-1

4. DESCRIPTION OF THE AFFE CTED ENVIRONMENT
4.1 INTRODUCTION

The Davisville port expansion proposal will have impacts on both the

coastal and marine environments. Research and planning studies conducted

since 1974 (see page 2-4) have provided a great deal of information on

the upland portion of Davisville, and some data on the vicinity of Fry

Cove and Allen Harbor. Additional biological and geological field inves-

tigations were conducted during the spring and summer of 1980 in order to

obtain greater detail on the vicinity of Davisville Piers. Technical

reports describing the methodology and findings of this research are

found in Part B, Marine Geology, and Part C, Marine Biology. This chapter

begins with an overview of the entire Davisville area, followed by descrip-

tions of major terrestrial, marine geology and biological features of the

project area. The terrestrial description of the Davisville and Dogpatch

sites in Section 4.3 concentrates on the shore and upland features likely

to receive direct and indirect impacts from the proposed port expansion.

A summary of the marine geology in the vicinity of Fry Cove and Allen

Harbor, is provided in Section 4.4 including bathymetry, sediment type and

thickness, depth of bedrock and bottom surface features. The chapter

concludes in section 4.5 with a description of aquatic biology focusing

on the benthic marine organisms most likely to receive impacts. Data on

water turbidity and pollutants in the sediments and water column is also

presented.
4.2 LOCATION AND GENERAL DESCRIPTION OF DAVISVILLE AND VICINITY

Introduction

Quonset Point/Davisville is located along the West Passage of Narra-

gansett Bay in North Kingstown, Rhode Island (Figure 4-1, Inset). The

PROW"C9

WAft#M

DAVISVILLE
WICKF V6
calf 11 31

.;t.-.*'
NEWPOR.

en
Harbor
1 US Food and Drug
Administration
2 Town of North
Kingstown 2

Davisville

Piers

toad

Dogpatch

Fry

Cove
Airport

0 400 800
'F E E T N

Navy retainod

Figure 4-1 Davisville Study Area

4-2

coastline of Quonset Point/Davisville extends for approximately six miles

between the former carrier pier to the south and the boundary of Navy land

at Mount View to the north. A comparison of current with historical

National Ocean Survey Charts shows that it has been extensively modified

from the original coastal contours and characteristics. Most of these

changes occurred when the area was developed for military purposes in the

early 1940s. Construction of a second pier at Davisville, and training of

construction battalion personnel in the operation of heavy equipment have

caused additional changes to the shore.

The Rhode Island Port Authority controls two major parcels of former

Navy waterfront land slated for industrial development located between

Quonset State Airport and Allen Harbor on the West Passage of Narragansett

Bay (Figure 4-1). The more northerly parcel, Davisville Piers, incorporates

a total of 96 acres located on the south side of the entrance to Allen

Harbor. To the south, separated from Davisville Piers by a Navy retained

bulkhead and residential compound, is Dogpatch, a triangular parcel of 35

acres with the sandy beach of Fry Cove as its base, on the east. The Port

Authority land is surrounded by the Airport, and Navy controlled land

around Allen Harbor and Calf Pasture Point. The Town of North Kingstown

owns a 15 acre parcel on Allen Harbor adjacent to Davisville Piers.

The Davisville Piers and Dogpatch

The Davisville piers are now used almost exclusively as the base for

the ongoing exploratory offshore drilling. Service boats carrying drilling

muds and supplies, fuel, and gear make daily runs to the drilling sites,

some 200 miles south of Narragansett Bay in the vicinity of Baltimore

Canyon. The two piers, 250 and 600 feet wide, were built by the Navy and

extend out from the shore 1200 feet to the southeast of Allen Harbor.

4-3

The entire parcel has been heavily altered from its original state and is

almost entirely paved. Much of the Davisville Piers vicinity was created

by land filling. When dredging was undertaken by the Navy to create berths

and navigation channels, large amounts of the material were put on land.

Dredged material was also dumped into open water, linking a former island

at Spink's Neck to the remainder of the Davisville Pier parcel. Davisville

Pier is served by railroad spurs that lead to the piers. The offshore oil

drilling companies now using the area have temporary office buildings,

warehouses, pollution control equipment, drilling mud tanks and various

other equipment and supplies located throughout the site. However, the

dockside space on both piers as well as the adjacent paved areas inland of

the piers are not intensively used.

Several hundred feet to the south of the Davisville Pier area is the

Dogpatch Parcel. It was not as heavily developed and retains a diversity

of features including a beach, a small wetland, wooded areas, and largely

undisturbed soil. Several abandoned houses and extensive lawns are present

on a flat plateau above the beach.

Navy Bulkhead and Residential Compound

The 95 acres of Navy retained land separating the Davisville piers

and the Dogpatch parcel is presently used primarily for equipment storage

by the Navy. In appearance the Navy waterfront land and bulkhead is

quite similar to the adjacent Davisville Piers, consisting of flat, hard-

topped land created by filling. Rail lines, and two large warehouses, are

prominent features. The Navy bulkhead would require extensive repairs or

reconstruction and channel dredging before it could be actively reused.

Along the border between the state-owned Dogpatch parcel and the

Navy retained area there is a residential compound consisting of seven

4-4

single family homes presently occupied by Navy personnel. The area contains

several acres of lawns, trees, and ornamental plantings.

The Airport

Between the former Quonset Carrier pier and Dogpatch beach lies the

Quonset State Airport, which was formerly used almost exclusively for Navy

aircraft training and transport. Today's use is dominated by charter

flights, small aircraft training exercise,� and Air National Guard activities
recently relocated to Quonset from the Green State Airport in Warwick. Upon

declaration of a national emergency, the federal government could permanently

reactivate this airfield for military purposes in a ma tter of days.

The Quonset Point Airport required the creation of a large expanse

of land in order to make the long runways. This was accomplished in the

1940's by filling approximately 200 acres of the Bay behind a steel bulkhead.

Also filled was a major section of a small tidal estuary at the southern end

of Dogpatch Beach. Today freshwater Fry Pond flows into the Bay through a
large double culvert under the runway, which also permits tidal flushing of

the pond.

The Rhode Island Department of Transportation operates the airport

for general aviation. Future users at Dogpatch will be required to consider

such matters as communications interference, noise, height restrictions on

structures, and access route development, since the northernmost runway

extensions are directly adjacent to Dogpatch.

Allen Harbor

Allen Harbor is a large tidal embayment located directly north of the

Davisville Piers. The harbor is connected on its eastern'side to the Bay
by a large dredged channel. The harbor possesses an extensive salt marsh
and tidal flats which extend for one-third mile to the west onto privately

4-5

owned land. In addition, Allen Harbor has extensive stands of tall reed

Phragmites communis and low shrub growth and small trees including bayberry

and black cherry. On both sides of the channel entrance are extensive

stretches of sand and mud flats which attract considerable numbers of

shorebirds, particularly along the northern shore. The harbor is moderately

used by waterfowl, especially in the fall and winter months when scaup,

black ducks, and others take advantage of the protected waters for feeding

and nesting. Gulls and terns are always present at the harbor as they

are throughout most of coastal Rhode Island. Common terns have nested for

several years in the northern corner of the harbor on grounded barges along

the shore. Due largely to the past uses of Allen Harbor, water and bottom

sediment quality has declined although considerable recreational shell-

fishing does occur.

Allen Harbor is presently being used for some recreational boating,

a use which will probably increase in the future. The small Quonset Yacht

Club services the boats of Navy personnel. The town of North Kingstown

plans to utilize a parcel it has acquired on the eastern edge for marina

development, and planning for such use began in 1980. Allen Harbor has

long been regarded as a logical site for a large marina because o.f its

sheltered central Bay location, good depth and previous use as a large

marina when the base was in active use. Numerous opportunities exist at

Allen Harbor to upgrade the shoreline by covering exposed trash at the

Navy dump, establishment of attractive marina, fishing or restaurant

facilities and/or marsh or tidal flat expansion.

Calf Pasture Point

To the north of Allen Harbor lies a two-hundred acre parcel which

contains one of the largest sandy beaches on Narragansett Bay. The parcel

4-6

extends from the channel entrance to Allen Harbor north to the end of the

Navy fence bordering the Mount View neighborhood. All of this land is Navy

retained and can be used for remobilization at any time. Until this year

the beach at the northern end of the parcel has been leased from the Navy

by the Town of North Kingstown for use as a swimming beach. A large wooded

and ledge bordered hill lies in the center of the parcel on which bunkers

have been constructed for military equipment storage.

Aside from the hill, the beach at Calf Pasture Point, a red maple swamp

and a salt marsh at the northern end, most of the upland was created by the

Navy. A large cove of Allen Harbor which extended into the center of the

parcel was diked and transformed into a flat, Phragmites dominated upland.

The lack of disturbances in recent years has made Calf Pasture Point more

suitable as a wildlife habitat than during the period when it was used for

heavy equipment operator training by the Construction Battalion Center.

4-7
4.3 TERRESTRIAL ENVIRONMENT

Inttoduc tion

The land in the vicinity of Davisville Piers is a mixture of land

uses including piers, bulkheads, marshalling areas, industrial development,

commercial and military aviation, residential districts and quiet woods,

fields, and marshes. The development of Quonset Point as a N avy airbase,

and Davisville as a Construction Battalion Center during the 1940s left

the land in between the two, Dogpatch beach and its upland, relatively

undisturbed except for a cluster of single family houses which were abandoned

in 1974. This parcel is surrounded by a shoreline and topography which

bears little resemblance to its configuration prior to World War II.

Surficial Geology and Soils

Most of the surf.icial geology of the Quonset/Davisville area is domi-

nated by large expanses of glacial outwash (Figure 4-2). This includes

the entire area at Dogpatch. Outwash deposits, being the result of runoff

from a retreating or stationary glacier, consist largely of layers of silt,

sand or gravel of varying thickness. Large boulders or bedrock exposures

are usually notable absent. The outwash deposits at Davisville are extensive,

and as much as 135 feet thick in some locations (Coastal Resources Center,

1977). Glacial outwash has good water retention qualities, and as a result

some of the better performing wells are those in outwash areas.

The soils covering much of Davisville have been severely disturbed.

Only a few areas remain that have not been paved over, stripped of topsoil,

or entirely excavated leaving large exposures of the substrata. Other

areas have been filled in or covered over and now consist of made land.

The runways, the Navy and Davisville Piers (including much of the area north
of Pier #2), and the large open lands north of Allen Harbor are examples of

filled land. The Dogpatch site, consisting of about 35 acres of land

adjoining the waterfront at Fry's Cove, has not received much disturbance

to most of its original topsoils.

Qc8 sh
Qc8
s Allen&@/
Harborl
Qic7

Qem Davisville
Piers

Qc7

Qsh
Dogpatch Ea
Fry Qs Marsh
Cove Qsh Shore deposits
Q af artificial fill

w graded,undiffer-
entiated ice
contact and channel
Qgm Qem deposits
Qc Earliest
af Qc6b
Qc7
Qic7
QC8 Most recent
Qc6b Qem end moraine
Qgm ground moraine

w open water

0 2000 N
feet

Figure 4-2 Surficial Geology of Davisville
Source: J.P. Schafer, 1961. Surficial Geology of the Wickford
Quadrangle. U.S. Geological Survey, Washington D.C.

4-8

A total of six different soil types are present in the study area

according to the U.S. Department of Agriculture's Soil Conservation Service

(Soil Survey, N. Kingstown), (Figure 4-3).

From Calf Pasture Pt. to Airport bulkhead, the shore is comprised of

sandy beaches (21), rocks and steel bulkheads. Sand beaches are found

north of the ramp to just south of the Al len Harbor entrance at Dogpatch.

The beaches, consisting of lenses of coarse-medium sand with gravel admix-

ture, lie upon a coarser surface. The beaches are about 75-100 feet wide;

slope 2-4 degrees offshore; and have at times 1-2 foot cusps on their

foreshore. A small dune line borders the beach north of the ramp.

Behind the beach at Dogpatch is a small salt marsh which receives

tidal waters from a small opening through the beach, and freshwater runoff

from a culvert under Broadway draining the uplands. The salt marsh

consists largely of organic material which is mixed with sand and other

mineral sediments (Figure 4-4). The SCS classified this salt marsh soil

type as Matunuck mucky peat (20). Contiguous to and upstream of the salt

marsh is a small depression through which a small stream flows during the

wet seasons. It becomes nearly dry during the summer months. Soils in

this depression are Carlisle muck (19) and like the salt marsh are very

poorly drained as the water table remains near the surface all year. The

organic material is greater than 51 inches deep. Beaches are highly prone

to flooding, erosion, and storm damage. The salt marsh and wet upland

soils are inappropriate for most development activities due to high water

table, potential for subsidence, and susceptability to frost action. Any

Major construction activity involving the areas occupied by these soils

.should be preceeded by a program to totally excavate the area of all organic

sediments (Lester Stillson, SCS, personal communication).

Cut and fill

Land Allen
fill
Filled 20 62C Harbor
area
20 Cut an
fill

Gravel
pit

Paved

area
.Paved area

62 C DAVISVILLE
PIERS

p wa 62C
62C
Cut and *%VOGPATCH 9
fill
62A

F R Y

Paved
area C 0 V E

water

Figure 4-3. Soil types at Davisville. See text for explanation of
categories. (source: Soil Conservation Service, 1973)

Al len

Harbor

S'j Ile DAVISVILLE
00

Macsh
Do tiet
pa@CPA T C H "*-stream ou
el
Beach
N

Fry Cove
Woods

0 feet 600

,Fry Pond outlet

Figure 4-4. Location of wetlands, beaches and woods at
Davisville.

4-9

Most of the upland soils at Dogpatch are made up of two types of

Quonset gravelly sandy loam, one with a 0-3 percent slope (62A) and the

other with a 3-15 percent slope (62.C). Both consist of somewhat excess-

ively drained soils on the outwash plains and terraces composed predominately

of water sorted sands (SCS soil survey). The soils with less slope make

up the southern half of Dogpatch while the steeper area encompasses a

smaller section bordering the stream's northern shoreline. In general

the Quonset series of soils have only slight to moderate limitations for

development uses, but because of high permeability, are not suitable for

sanitary landfill or other uses which could impact aquifer recharge areas.

Quonset gravelly sandy loam soils have been designated by the Soil Con-

servation Service as soils of statewide importance for agriculture, even

though all Quonset soils tend toward droughtiness and have moderate

erosion potential. Prior to 1940, the entire area was in agricultural use.

Approximately four acres of cut and fill are present at Dogpatch,

and forms a triangular shaped zone at the most inland (northwesterly)

section near Davol Pond and Marine Road. This area was probably excavated

and regraded during the construction of the Quonset runways since it is

contiguous to them. This area has not been classified as to any individual

soil type. No cores have been taken and there is no information present as

to what is under the cut and filled area.

4-10

Hydrology

Although the entire Quonset/Davisville area is situated above the

Potowomut-Wickford aquifer, a large ground water recharge area for North

Kingstown, this aquifer will not be affected by activities at Dogpatch.

Groundwater flow under Quonset/Davisville is towards the Bay (Coastal

Resources Center, 1977, p. 82). The recharge area basins are located to

the west of the Quonset/Davisville properties.

Surface water flow at Dogpatch is limited to one small unnamed and

intermittent stream which emerges from a culvert between two buildings on

the adjacent Navy retained land (Figure 4-5). The stream follows a

natural depression on the Dogpatch parcel and empties into the small

marsh on the beach. This small stream is one of several drainage areas

on the Quonset Point/Davisville property that have been channeled and

culverted.

Vegetation
Detailed descriptions of the vegetative communities at Quonset/

Davisville are presented in earlier studies. (Coastal Resources Center,

CRC, 1977 and General Services Administration, GSA, 1979). Four plant

communities have been identified at Davisville: forested areas; shrubby

sites which are in the midst of being transformed from open fields to

woods; wetlands;.and areas where reforestation with pines has been

attempted in order to reclaim and revitalize disturbed areas. Dominant

species and other significant information has been compiled for Davis-

ville and fifty other sites at Quonset Point/Davisville including a

list of the common plant species. Both studies indicated that although

most plant communities at Quonset are typical of those found throughout
Rhode Island, they may be of more significance at Quonset/Davisville

simply because they represent pockets of relatively und isturbed areas

(off

wi 4,4-
110tv k,

0 eG

4P'
Davis
I Im

J Pier
a y

Airport
B Ikhead

to0

00
3

DOGPATCH and vicinity
Womm) kHkAGMITES
SHRUB SPARTINA N
.,.Fry Pond 0 SIRUCTURES DOGPATCH 400
outlet BOONDARY FFET

Figure 4-5 Land cover at Dogpatch parcel of study area

4-11

within a heavily modified environment and serve to provide a vegetated buffer

between heavily developed parcels and those in residential and recreational

use.

The Dogpatch area contains a mixture of typical plant communities

(late shrubs, marsh, lawn) within a small 35 acre area (Figure 4-5). No

intentional reforestation activities are known to have been undertaken at

the site although the process of succession in which larger plants replace

smaller species over time is occurring rapidly. Because of former use of

the area for Naval officer residences, a considerable amount of the Dogpatch

uplands adjacent to the houses were planted with lawns and ornamental shrubs.

These have largely been abandoned and native vegetation is slowly invading

replacing lawns and ornamental shrubs in the process.

Wildlife

A brief examination of mammal populations at Quonset/Davisville was

undertaken in 1976 (Millar and Davis, 1976). Included in this inventory

was the area adjacent to the small stream which flows through the Dogpatch

parcel. This investigation was based on the identification of various

wildlife signs including tracks, scat, browse, sightings, and animal

remains. The result of this brief survey, together with a small mammal

trapping study undertaken at the same time (Howell, 1976), and observa-

tions of birds since 1976 indicate that Davisville has an extensive and

diverse wildlife population. This is largely due to the wide variety of

land cover types on the base and the absence of man and domestic animals.

Structures and Archeological Sites

A discussion of the various buildings and other developed structures
in the Dogpatch and Davisville Pier areas and the surrounding vicinity was

4-12
presented by Harbridge House (1976, Marketability of Surplus Navy Property).

In addition to the two piers, seven buildings were identified on the Pier

property, and sixteen single family houses and a radio receiving station

located at Dogpatch. None have been identified as being of historic or

architectural significance, thereby constraining any alternative uses in

the area (General Service Administration, 1978, p. 111-7).

Likewise, no archeological features of National Register significance
exist within Dogpatch or the Davisville Piers (12/20/77 letter of Histori-

cal Preservation Commission).

Features of Special Significance in Vicinity of Proposed Development at
Dogpat
The Dogpatch area has retained most of its original topsoil which

is still vegetated to a large extent in contrast to the adjacent Airport
and Davisville parcels. The mixture of open fields, shrubs, woods and

wetlands accounts for its value as habitat for birds and other wildlife

species. Dogpatch contains four major features of special significance

in terms of development planning (Figures 4-5, 4-6).

The Beach and Dune:

Dogpatch Beach is comprised primarily of sand and extends for approx-

imately one-third mile from the bulkhead bordering the Quonset runways to
another bulkhead at the Navy retained pier to the north. The beach forms
the inland border of Fry Cove. The beach has received little recreational
use since the Navy presence was reduced in 1974. Numerous sandpipers and
plovers and similar shorebirds feed along the beach. According to Division

of Fish and Wildlife, R-hode Island Department of Environmental Management,
Dogpatch Beach has also been used as nesting habitat for a small colony
of rare least terns. However, no nesting activity was observed in 1980.

Figure 4-6
VEGETATIVE COVER, DOGPATCH PARCEL

col
@T= U
APPLE STREET

zr.'
Zo
L "AL.,
N

P
S

-A
I. Oil
Jr

WIL: ;W,

NAVY
RESIDENTIAL
COMPOUND
M
All
patch
<13

A
C3 K

Sr
X
............ .......
. .................

DOGPATCH bEACH

er
.1AR
stream open water
U-spartina marsh
n.;-phragmites marsh N
-.-woods
100

FEET

4-13

The waters of the adjacent Fry Cove are often used by large numbers of

waterfowl, especially scaup. The construction of the bulkheads at each end

of the beach years ago has trapped the beach sands within ttio'cove inter-

rupting the natural process of long shore drift. As a result sand supply

has been effectively cut off, leading to erosion of the beach face.

The southern terminus of the beach is located at two culverts which

are the outlets of Fry Pond which is to the east side of the runways.

The beach is narrow here, and is backed by a three to four foot high eroding

upland plateau. Beach width increases further to the north and sand is

plentiful, enough so that a small dune is forming and becoming vegetated

with American beachgrass. The dune is approximately 150 to 200 feet long

and appears to be slowly lengthening in a northerly direction, perhaps

from eroded material from the adjacent escarpment. However, other portions

of the beach appear to display some southerly movement of sand.

In the central portion of the beach a concrete seawall was constructed

which protects the upland plateau and several now abandoned houses from

erosion. Dune grass is gaining a foothold in front of the seawall. North

of the houses and seawall is a small tidal creek which flows through the

salt marsh into Fry Cove. Due to the unstable nature of beach sediments

the creek tends to change position slightly on each tidal cycle. The

beach width begins to narrow considerably north of the creek. A dune has

formed between the beach and marsh which is completely vegetated, mostly

with Phragmites which helps prevent washovers of sand into the marsh. The

extreme northern alignment of the beach veers gradually toward the east

to meet the Navy bulkhead. This section of beach is cobble with very

little sand present.

4-14

The Wetland:

A small, two acre wetland is located directly in back of the beach

at its extreme northerly end (Figure 4-6). This salt marsh has apparently

formed on sand accumulating after the Navy bulkhead was built. This sandy

substrate, together with the outlet of a small freshwater stream at this

location has presented ideal conditions for salt marsh formation. The

stream but not the wetland appears in nautical charts of the Narragansett

Bay prepared in 1900 by the Coast and Geodetic Survey.

The salt marsh portion of the wetland encompasses approximately

one-half acre of smooth cordgrass,_@p_@!,rtiaaL alternaflora, and open water

areas. It is surrounded almost entirely by a wide band of tall reed grass

_(Phragmites communis) which largely isolates the marsh interior from the

outside. The @@h@mL@@!@_encompasses approximately one and one half

acres. A small tidal creek through the beach connects the marsh with

Fry Cove. An inter mittent freshwater stream feeds through a culvert under

a road to enter the salt marsh's southwestern corner. The marsh and

tidal creek are used frequently by shorebirds and waders for feeding and

nesting. Use by birds is enhanced by the lack of disturbance by man and

the protective reed fringe. A pair of mallards nested successfully in

the marsh in 1980. Successful waterf owl nesting is unusual in many

marshes in Rhode Island due to high levels of human or domestic animal

disturbance.

The marsh, when viewed in relation to the entire Narragansett Bay,

is probably of little significance due to its small size and probably

minor contribution to and interaction with the Bay ecosystem. There

are numerous larger, more diverse marshes in a more rural settings which

4@15

are of higher priority to protect because of their broad values for wildlife

or as an aesthetic resource.

Woodm and Stream:

The small stream which feeds into the salt marshes emerges from a

culvert which drains Navy retained land to the north. The stream flows

through a densely wooded gully to the salt marsh. The woodland consists

largely of a tangle of shrubs and vines including wild grapes, honeysuckle,

and-bittersweet, and is approximately 10 acres in size. Dominant woody

shrubs and trees include wild black cherry, young black oak, alder, aspen

and sumac, all more indicative of a late shrub stage than a mature woodland.

Several pine trees and juniper are found on the woodland edge but the dominant

trees are hardwoods throughout the 400 to 500 foot length of the stream.

Remnants of an old orchard are present as well. Although the stream is
intermittent and'can dry up completely after several days of dry weather,

the soils within and along the sloping edges of the stream bed are highly

organic and mucky and remain wet all year. The stream bank is heavily shaded

in some sections, providing good growing conditions for numerous common

groundcover plants such as Virginia creeper, poison ivy, and sensitive fern.

Open sunlit areas, more conducive to the growth of taller shrubs contain

winterberry, bayberry, arrowwood and alder, all valuable berry producers

and attractive to birdlife. Birds observed here include the mockingbird,

robin, purple finch, redwinged blackbird as well as numerous warblers. A

brief Mammal study during 1976 found that, like the rest of Quonset/Davisville,

cottontail rabbits are numerous at Dogpatch, particularly the forest/shrubland

edge (Millar and Davis, 1976).

The major attribute of this stream and woodland, in addition to

its value to wildlife, is the important role it plays as an effective

4-16

visual buffer between the upland areas and the Navy and oil industry

operations at Davisville piers. It adds diversity to the landscape and

provides the only distinct separation between various use districts on
the Quonset/Davisville shoreline. Scientific names of species are listed

on Table 4-1.

Abandoned Lawns and Open Fields:

The central portion of the Dogpatch parcel has experienced some
changes to the native vegetative cover during the operation of the Navy

base. However, topsoils are for the most part original. The numerous

lawns and ornamental plantings associated with the abandoned housing have

now been to a large extent abandoned. Land further from the houses is
dominated by native plant species. Abandoned fields with grasses and
early shrub stage successsional areas lend a diversity to the upland envir-
onment and since present levels of disturbance are low, they are,of
particular value as wildlife feeding and nesting habitat. Large numbers

of small mammals such as whitefooted mice and meadow voles utilize this
area and birds are everywhere. Although many of the bird species'sighted

are those that have become associated with the suburban environment such

as starlings and English sparrows, the lack of use of this area by man
in recent years has made the area more attractive to "wilder" species
such as kingbirds, various warblers, and meadowlarks. The latter species
is found nesting in sizeable numbers in the abandoned fields and shrubby

areas.

4-17

TABLE 4-1

List of Common and Scientific Names of Species Observed In
Woods and Stream, Dogpatch Site

Woodland

wild grape V i t i s-
honeysuckle Lonicera
bittersweet Celastrus scandens
wild black cherry Prunus serotina
black oak Quercus velutina
alder Alnus rugosa
aspen Populus sp.
sumac Rhu s

Stream Bank

Virginia creeper Parthenocissus _qu n i@olia,
poison ivy Rhus radicans
sensitive fern Onoclea sensibilis
winterberry Ilex verticillata
bayberry Myrica ensylvanica
arrow wood Viburnum n

Wildlife

mockingbird Mimus polyglottos
robin Tu-rdus@ migratorius
bluejay Cyanocitta cristata
red winged blackbird AgelaiusplLoeniceus
warblers Parulidae
cottontail rabbit Sylvilagus sp.
Eastern meadowlark Sturnella
mallards -Inas platyrhyneas-
greater scaup marica
Shore beachgrass Amnophila brevilingulata
smooth cordgrass �partina alterniflora
reed grass P ra mites communis

4-18

References

Coastal Resources Center, University of Rhode Island. 1977. The Redevelop
ment of Quonset/Davisville: An Environmental Assessment. Marine
Technical Report #55.

General Services Administration. April 1978. Disposal of Surplus Federal
Military Properties in R.I. Draft Environmental Impact Statement
Technical Appendices.

General Services Administration. November 1978. Disposal of Surplus
Federal Military Properties in R.I. Final Environmental Impact State-
ment.

Harbridge House, Inc. 1976. Industrial and Commercial Marketability of
Surplus Properties in Rhode Island. Report to the R.I. Dept. of
Economic Development.

Howell, P. 1976. A brief small mammal survey of _Quc@nsE@_t Naval Base.
Unpublished paper presented to Zoology Department, University of Rhode
Island.

Millar, S. and A. Davis. 1976. The mammals and possible value of habitats
of Quonset Point, North Kingstown, Rhode Island. Unpublished paper
presented to Zoology Dept., University of Rhode Island.

U.S. Dept. of Agriculture. Soil Conservation Service. 1973. Interim Soil
Survey Report for North Kingstown, Rhode Island.

United States Dept. of the Interior, Geology Survey. 1968. Hydrologic
Characteristics and Sustained Yield of Principal Groundwater Units
Potowomut-Wickford area of Rhode Island. Water-Supply Paper 1775.

United States Dept. of the Interior, Geological Survey. 1961, Surficial
geology of the Wickford Quadrangle. Geologic Quadrangle maps of the
United States.

4-19

4.4 GEOLOGICAL FEATURES OF THE MARINE ENVIRONMENT

Introduction

The proposal to build a bulkhead and dredge off Dogpatch Beach raised

several concerns pertaining to the geology of the area. Since construction

of a dredged channel is enormously more expensive if blasting is involved,

it is essential to know the location of bedrock. This is also important

for bulkhead design since the foundation of the structure may have to be

anchored in bedrock. Further the environmental impacts of dredging activity

as 'well as several engineering considerations are determined in good part

by the type of sediment that must be removed. Detailed site investigations

of depth to bedrock and sediment characteristics were undertaken as part of

this environmental assessment by Dr. Robert McMaster, and are reported in

Part B. The result of the 1980 study show that bedrock in the study is

25 to 99 feet below the surface sediment and that the overburden is composed

of glacial sediments. These findings indicate no geological constraints to

project construction.

A second series of concerns relate to the behavior of the bottom. An

active bottom as determined by detailed bathymetry and observation of

ripples and waves on the bottom itself may indicate areas where in-filling

of a channel might be severe or when construction may interfere with

important natural processes. Detailed observations using side scan sonar

show that the gentle-sloping bottom off Dogpatch is almost featureless

and, therefore, largely inactive and that there are equally few signs of

activity on the slopes of the dredged channels or the deep basin off the

outlet of Pry Pond.

Adjacent to the Dogpatch shoreline, the bottom is essentially flat.

This very shallow flat bottom extends many hundredsof feet bayward. Fine

sand, light at the surface but dark below, characterizes the bottom. In

4-20

front of the Dogpatch cottages south of Pier I about 2 feet of fine sand

overlie a mud layer of 0.5 to 1 ft in thickness. The mud is composed of

85% silt, 10% clay, and 5% sand. The extent of this mud layer in the

entire nearshore bottom is unknown. An occasional boulder is also observed

in the nearshore zone. A fan-shaped deposit of sand and gravel, extending

some 200 feet outward from the shore, lies adjacent to the marsh just north

of the line of cottages. Where the airport bulkhead begins the bottom

consists of cobbles and boulders which may serve to protect the two large

culverts which permit tidal exchange with Fry's Pond.

Some insight into shoreline processes may be inferred. Evidence

of net southward beach drift is apparent from the beach accretion on the

north side of the Allen Harbor entrance, sand in-filling on the north s-4de

of the harbor channel, rip-rapping on south side of harbor entrance,

eroded shore south of Pier 1, and southward off setting of swamp channelway

south of Pier 1. However, the southward beach drift is believed to be

weak south of Allen Harbor entrance.

No evidence was uncovered during the July 1980 field inspection to

support the existence of a seasonal exchange of sand from the beach to the

nearshore bottom or from the nearshore bottom to the beach.

BathMetry
Bathymetric data are presented as a contour map (Figure 4-7). The

relief in the area is characterized by the dredged ship channel network

and a drowned stream channel adjacent to the airport bulkhead. Otherwise,

the bottom shows a gradual inclination offshore from 6 to 26 feet. Their
edges are well-defined and marked by slopes that range from 1:2.5 to 1:4.

Apparent sitimps are observed at a few locations.

-37 DAVISVILLE PIERS

Do9patch

----------

Figure 4-7
BATHYMETRY
410 (Boundinse Corrected to Mean Low Water)
-36'
Contour Intervals 1-foof
01 ---------- 01.5

N
I InGthw400 fo*t

710
214'

4-21

A drowned stream valley complex lies immediately north of the airport

bulkhead and essentially parallels the structure. This valley extends from

the vicinity of the shore eastward to a position northeast of the bulkhead

where it loses its identity. Depths within the valley reach 18 to 26 feet.

The most noteworthy aspect of this feature is that a narrow divide separates

the depression into two well-defined channelways.

Aside from these prominent features, the bottom is shallower with no

distinct relief except for two small "mounds" that occur between the piers

and airport bulkhead at depths of 17 feet.-

Bottom surface conditions (side-scan sonar)

A side-viewing sonar survey revealed a small variety of bottom features

within the area (Figure 4-8). These features include the edges of channelways;

the units of the valley complex adjacent to the airport bulkhead; the divide

within the valley complex; rake marks; three arbitrary categories of bottom

roughness (i.e. slightly rough, very slightly rough and smooth bottom);

and a number of unidentified targets. The distribution of the features

follows no pattern except that the smoothest bottom occurs only in the

channels and valley complex.

Sediment

Surface sediments range from sands to silts (Figure 4-9). These

sediment types reflect sand contents that vary from 98% sand to 4% sand.

Across the area, the bottom sediment shows dark sands composed of up to

98% sand inshore grading to dark sediment with 74-54% sand further off-

shore that contains 20-42% silt and 3-6% clay (particles less than 3.4

microns).

Rough Bottom

Very Slightly Rough Bottom

37 Smooth Bottom

Edge of Channel. Hillock. or Depression

flake Mark*

Targets Undoffillied

Chain

Dopatch

... 36-

*42

Figure 4-8
1980
SIDE-SCAN SURVEY April 16
410 (Feature Locations Based Upon Slant Ranges)

0 Q5 7.
nautical miles

I Inch.400 toot

T 1*
25' 24

76% Sand
'MMEN' -60%-75% Send

25%-60% Sand

< 26% Sand

o- Grab Samples 1-27 %sand content

a- Samples from Coastal Resources C tor
(1977) A-H %aand content

o-Core Locations: 413 i::;

t
Do9patch

00 a 06

V*4 .1
09 3M

Figure 4-9
41* SURFACE SAND DISTRIBUTION
36,

a" 9%

nautical Milos

N
I Inch 400 feet

215, 214'

4-22

The finest sediment, silt deposits, are located within the dredged

ship channel and the drowned river valley adjacent to the airport bulkhead.

In the ship channel, an unstratified silt accumulation, measured by coring

to be approximate ly 18 inches at one location, contains 75-84% silt, 6-17%

clay and 4-16% sand and overlies a sandy dredged surface. The silt within

the drowned valley shows 77% silt, 13% clay and 10% sand. Beneath the

surface silt, the bottom is composed of laminated units of fine sediment

at least to a depth of 2.3 feet.

The sand component in all sediment types is dominated by fine to very

fine sand. Shells and gravel comprise only 2-7% of the samples.

Bedrock

Bedrock depths are shown in feet (Figure 4-10). C.E. Maguire boring

sites with bedrock depths are also plotted. Compilation of bedrock depth

data is presented in Part B of this report.

The depth, attitude and shape of the bedrock surface is apparently

controlled by the down cutting of an ancient drainage system. The

dissected surface lies from 47 to 119 ft below MLW with no obvious att-t-

tude. Unfortunately, a significant portion of the surface is hidden

because of attenuation of the acoustic signals by gaseous sediments

beneath the channels and valley complex.

100
37' qNGaseous Sediment 90 8 0
110 70
Bore Hole depth to bedrock 60
50

56
42 80 90 100
49
7

,wi-4-7 "Ll.41q;IQaluilll@
70 n7O 60

Fig.4-7 BEDROCK DEPTHS
410 in feet measured from mean low
36' water. Contour interval: ten
feet.
0 Nautical Miles 0.5

LA""j
0 400
feet
710
215 241

4-23

A major bedrock valley crosses the area from NW to SE. Depths within

this valley reach more than 110 feet east of Pier 1 but shoal toward the

southeast before apparently connecting with a N-S trending channel that

lies adjacent to the study area on the east. A smaller bedrock valley,

oriented E-W, appears to join the NW-SE trending valley northeast of the

airport bulkhead. Bedrock depths within this valley are less than 90 feet.

South of Pier 1, it is uncertain as to how the bedrock depths of almost

100 feet are related to the valley segments described above.

The shallowest bedrock depthsi about 50 feet, are associated with

the western divide of the N-S trending valley that lies along the study

areals eastern side.

Overburden

Sediment thickness is plotted as an isopach map (Figure 4-11).

Calculated thickness values are based upon a sediment velocity of 5,000

ft/sec. All data on the overburden are presented in Appendix B. Sediment

thickness information from the C.E. Maguire borings and bore holes during

U.S. Navy ownership (Coastal Resources Center, 1977),is also shown.

Overburden thickness ranges from 25 to 99 feet. These values are

closely related to the configuration of the bedrock surface: the greatest

thickness occur in the bedrock valleys with lesser sediment cover lying

on the divides. Hence an overburden thickness of over 99 feet is found

immediately east of Pier 2 and more than 80 feet lies south of Pier 1.

Beneath the E-W trending valley complex, more than 50 feet of overburden

covers the bedrock.

The smallest accumulation, about 50 feet, lies above the bedrock

divide that occurs along the area's eastern side.

Gaseous Sediment

-Bore Hole-Depth (ft) of Overburden

-Bar* Hole--Depth 00 of Penetration
so so
-37, to refusal 90 90
0 -Bore M619--Dopth 00 of Penetration so 70
In Overburden 7D so
60
Is -Bore Hole--(Navy) Depth (ft)
of Penetration in Overburden 30

Dogplatch 7 0
31 4,
48

0
32
40

0
40 72

Figure 4-11
410 SEDIMENT OVERBURDEN THICKNESS
In fast
Contour Intifirvalt 10 feet

nautical miles

N
I inch - 400 feet

T1*
24'

4-24

A close inspection of the seismic records together with an inter-

pretation of C.E. Maguire's boring logs indicates that the overburden is

composed primarily of glacial outwash with a smaller amount of glacial

till.

4.5 BIOLOGICAL FEATURES OF THE MARINE ENVIRONMENT

Introduction

The primary effects of the proposed port expansion project will be to

remove several acres of shallow bottom habitat in Fry Cove by fill or

dredging and produce turbidity during dredging and dewatering of the dredged

material. For this reason, biological investigations of the project site

concentrated on characterizing the bottom communities present, assessing

the natural turbidity in the area and compiling from the literature infor-

mation on the effect of suspended sediments and burial on the organisms

present. This information is presented in greater detail in Part C. In

addition, this section contains a discussion of suspended sediments and

the levels of metals and hydrocarbons in the bottom. Finally information

on pollutants in the water column and in organisms at the site is provided

and discussed.

The additional sampling undertaken in 1980 and described in Part C.

was conducted so that comparisons could be made with the results of a 1976

survey of the Davisville site (Coastal Resources Center, 1977). Although

there has been no major change in human activities at Davisville during

the four years between studies, noticeable changes took place in both
the species composition and abundances of organisms. (Figure 4-12).

J
Q1, Ma (MARCH 5. 129 1980-
0 aoism" (MAY rN 19so)

05
& 4%.-
C 1.2!
6 %
0 -7 go
% 0:
Oil
4RIO V

Figure4-12. Grab Sample Locations for Benthic Survey
Letters A-D designate reference points along Dogpatch Beach
for each series of 0.018 m2 samples.
A pilings
B sea wall
C rocks
D navy bulkhead

4-25

Characterization of Living Communities

The bottom environments in the Davisville area can be placed into

three categories on the basis of depth. The first includes the deeper

dredged channels and basins and the natural channel in Fry Cove (sta. 1,

2, 3, 9, 10, in Figure 4-13) which are floored with semi-fluid sediments

with 80-69 percent silt and 11-21 percent clay. The second is a shallow

sand platform or terrace which extends several hundred feet offshore

below the mean low tide level from Dogpatch Beach (see Figure 4-13).

The remaining stations (4, 5, 6, 7, 83" 11) are on gently sloping bottom

grading from 95 percent sand to 31 percent sand, 69 percent silt/clay

between the beach and channel. The shells of clams, oysters, and other

bivalves provide hard substrate and shelter in this mid area. Each depth

zone/bottom type has its own temperature pattern. The shallower areas

warm faster in the spring and have higher summer temperature.

Field collections of bottom animals were made in March and May 1980

using techniques similar to those used in the October 1976 survey for

the Coastal Resources Center (Pratt, 1977). The results of both surveys

are discussed in terms of the different groups of species present and the

adequacy of the baseline data to detect impacts of development. Numbers

of individuals identified in each sample are given in Tables 2-1 and 2-2

Part C. The channel stations (1, 2, 3, 9, 10) had very low numbers

of species and individuals (1-5, 1-110). The few species present were

those adapted for life in the deeper soft bottoms of the Bay. They are

commonly found in greater densities in similar environments in the Bay.

The Dogpatch beach samples (groups A, B, C, D) contained 4-21 species

per sample and high numbers of species adapted for unstable sandy sub-

strates such as the gem clam (Gemma gemma), the telline clam (Tellina

deeper basins
terrace
0 beach

-4
V2

30
@O 04 M5 -, I
V 4 12'
3 0
0 4 06
0

Figure 4-13 Characteristics of benthic sampling stations.
(see figure 4-12 and text for explanation)

4@26

and the polychaete worms Scoloplos robustus and Spio setosa.

In the deeper beach samples on the edge of the platform (C-4) the tubes

of the large amphipod, Ampelisca verrilli, were evident. Capitella

capitata, a polychaete sometimes identified as a pollution or stress

indicator was present in this area. Only 2 hardclam (Mercenaria mercenaria).

juveniles and no softshell clams QM_V.@ arenaria.) were found.

The mid-depth samples (4, 5, 6, 7, 8, 11) contained from 21 to 31

species and 91 to 664 individuals per sample. Dominant species included

the bivalve, Tellina agillis.; the gastropods, Crepidula fornicata, and.

C. plana; the tube-dwelling amphipod crustacean,.@ @peli@sc@@ vadorum; and

the polychaete Glycera americana (bloodworm). The bivalve, Nucula-

annulata was found in the deeper, more silty samples. Hard clam juveniles

were found in all mid-depth samples. The species present in the 'mid-depth

samples were similar to those found in 1976. The numbers of individuals

and species per sample was also similar.

Samples can also be compared in terms of the relative importance of

each species within the samples by calculating a percent similarity index

(Sanders, 1960). Duplicate samples 7 and 7Q had a 59 percent similarity.

Samples from a given bottom type often show a 30 to 40 percent similarity.

The values for three stations where samples were taken both in 1976 and 1980

fall within this range:

Location Station % similarity
1976 1980

mid-depth 15 5 31.5
mid-depth 14 7 38.8
dredged channel 12 9 31.3

These comparisons indicate that the mid-depth areas have populations

of bottom animals which are stable over seasons and years. This stability

may be the result of the presence of many bivalve and polychaete species

4-27

which have a life span of a year or more, the presence of adequate oxygen

throughout the year,-and moderate wave effects and stable bottom.

The most significant finding of the survey was the large decrease of

individuals and species in the deep areas. This is illustrated by data

from matching stations:

1976 1980
Location sta. inds. species sta. inds. species

Fry Cove channel 16 420 23 10 50 3-
Dredged-channel .12 411 32 9 110 5
Dredged channel 17 460 27 -- -- --
Turning basin 11 199 22 1 16 3
Turning basin -- 2 10 2
Turning basin 3 1 1

Additional qualitative samples examined in both years substantiated this

pattern. The species which were abundant in 1976 were the bivalves Necula

annulata, Macoma tenta, and Mulinia lateralis and the polychaetes

Pectinaria gouldii and Spiochaetopterous oculatus. The bottom sediments

in all deep areas verevery incohesive and anoxic below a few millimeters.

Although the previously occurring species are all adapted for life in

relatively soft sediments, M. -lateralis is a suspension feeder and might

not be able to feed on excessively soft bottom while the polychaetes occupy

tubes and require some sediment stability. The M. -tenta population observed

in 1976 probably consisted of animals which had set and grown during the

summer. This species may not in fact be adopted for year round survival

in very soft sediments. The absence of attached shell pairs, "clappers,"

of the bivalves indicated that these had not been recent mortalities. It.

is possible that the animals in these areas were killed during a period

of low oxygen levels. An alternative explanation for bivalve reduction

in Fry Cove channel is the feeding of very large flocks of diving ducks

during the winter.

4-28

The beach area was first sampled quantitatively in 1980). These
samples (station groups A, B, C, D) show some overlap in species makeup
with the mid-depth samples (stations 4, 59 6, 7, 8, 11) but all of the
dominant species are restricted to shallow stations and are known to be
characteristic of protected beach environments. The very dense population
of the small gem clam, Gemma jger@, at one station may have resulted by
concentration by waves and current similar to that which was observed in

Charlestown Pond (Phelps, 1964). On Dogpatch Beach softshell clams are
restricted to a cove south of the Navy bulkhead and patches around boulders.
Apparently wave action and sand movement prevent establishment on the

open sand platform.
Shellfish and finfish are abundant in the waters off Quonset/Davisville.
The area supports both commercial and recreational fisheries: soft shelled
clams, quahogs, flounder, scup, striped bass, bluefish, menhaden, lobster,
conch and baitfish. North of the Davisville piers, the water is classified

SA and shellfishing is permitted. Calf Pasture Point is an important
Auaha uging ground. South of the Davisville piers in Fry Cove commercial
quahauging has been active since the area was opened by the Department of

Environmental Management in July 1980.
Data from routine Department of Natural Resources (DNR) fish trawls
northwest of the Davisville piers show that commercially important finfish
species are present. Several part-time draggers from Newport and Wickford
catch winter flounder, scup, fluke, butterfish, and baitfish in the area.
Menhaden frequently school in waters adjacent to Quonset (Ganz, 1975).
Sportfishing is extremely popular in the West Passage. Sisson (1970)
reports that Wickford based sportsfishermen spend an average of 44.6 days

4-29

a year fishing for bluefish, striped bass, flounder, tautaug, scup, mackerel,

and fluke, most of which is caught in the Quonset/Davisville vicinity.

The fisheries resources of Davisville area were inventoried by the

former R.I. DNR, Division of Fish and Wildlife (Ganz and Sisson, 1977;

summarized in CRC, 1977). They mapped concentrations of softshell clams

in the low intertidal immediately south of the Navy Bulkhead and among

rocks halfway down Dogpatch Beach. Maximum density in these patches were

similar to locations in Allen Harbor (42/m2). These areas have been used

by recreational diggers since opening of the fishery in July 1980. In

contrast shore between Allen Harbor and Davisville Pier 2 had low densities

of softshell clams (mean: 1.35/m2, n=17) despite seemingly suitable condi-

tions.

Hard clams are abundant in Fry Cove at subtidal depths. In the 1976

CRC survey all the cove was shown as having abundant clams but this was

based on only a few bullrake hauls. Since the Cove was opened in July

1980 it has been heavily fished by commercial quahaugers. As many as 30

or 40 boats have been seen in the cove at one time during periods when

preferred upper Bay areas have been closed. According to personnel of

the Department of Environmental Management Enforcement Division bullrakers

have been concentrated off the Navy "wooden" bulkhead and the airport

Itsteel" bulkhead. A high proportion of more valuable smaller clams were

reported off the steel bulkhead. Tongers working in shallower areas along

the beach appeared to be recovering higher proportions of larger clams.

A few hundred oysters are found on the rocks along Dogpatch Beach. They

are most abundant at the culvert draining Fry Pond but are limited by

availability of hard substrate and sand movement. The long double culvert

to Fry Pond may be a source of oyster larvae.

4-30

Suspended Sediments
During this project) field data on water clarity was obtained on three
occasions (March 4, May 25, and June 24, 1980). These data are compared

with the results of other studies in Narragansett Bay. Research on the

effects of suspended sediment on estuarine fauna and the effect of burial
by water deposited sediment on fauna are summarized in Part C. Winter

conditions were found on the-March 5 sampling trip. Water temperatures

were between OOC and 10C and except for a small near-bottom temperature

inversion at some stations (0.250C), there was no vertical stratification.

At the surface the clearest water was found offshore and downbay. The

most turbid water occurred on the shallow shelf off Calf Pasture Point
(Figure 4-14"). Turbidity was vertically homogeneous except at station 3

and 9 where there was a clear water layer near the bottom and at station

7 in Fry channel where the bottom layer was turbid. Light transmission
was generally high for Narragansett Bay (13-28%/m) and indicated low

concentrations of phytoplankton growth and the absence of recent storms.
On the May 28 sampling date a strong thermocline occurred at a depth
of 10-15 feet (Figure 4-14). At most stations there was a marked increase
in turbidity at the thermocline from surface values of 10-15%/m to 0-2% in
deeper layers (Figure 4-15). At station 7 in Fry Cove channel transmission/m
decreased regularly with depth from surface to bottom. At station 9 in
the dredged channel surface water was more turbid than water immediately
over the thermocline. Surface and bottom turbidities were similar throughout
the study area except in shallow water off Calf Pasture Point where turbidity
increased. Water sampled at station 4 showed an abundance of organic

detritus and copepod fecal pellets in the turbid deep layer.

ALLEN
HARSO
16
(D13 @21
16
12 21

DAVISVILLE
PIERS

21
(4E) io-
?.%25 @24
\e424 23

FRY COVE
%
020 @21 N 1022 2 8
14 25
9926

Figure4-14 Location of turbidity stations (circled numbers) and
surface/bottom values of percent light transmission
per meter obtained March 5. 1980.
ALLEN
HARSO

TEMPERATURE, OC

ALLEN HARBOR

W
W
LL. 0-
to-

C
20-
L
W STATION
a 30'

DAVISVILLE PIERS

-15

STATION 5 6
FRY COVE

STATION 9 10

Figure4-15. Temperature sections, May 28, 1980. 11:20-12:30,
Low tide 12:53 DST.

4-31

Two profiles were made on June 24 in the turning basin and in Fry

channel at Station 7 (Figure 4-17). Surface warming had continued and the

thermocline was thicker and deeper than in May. The turbidity pattern was

very different from that found in May (Figiire 4-16). The surface was

turbid, almost certainly from high concentrations of phytoplankton. Within

the thermocline the water was relatively clear, but turbidity increased

rapidly in a thermally homogeneous bottom layer.

.The results of these observations show that water was clearest in

March and that in both May and June there was a near-bottom layer of

turbid water. Since conditions were presumably calmer than in March this

layer must form as a result of impact of low density detritus from organic

production and stratified conditions leading to concentration in bottom

layers. Tidal currents rather than waves keep the particles in suspension.

'No transmissome'ter or suspended particle measurements were made in

the.study area during storms. Water along Calf Pasture Point becomes

visibly turbid when waves from the northeast erode shallow silty sand.

It seems likely that concentrations of suspended matter may then reach

levels typical of an exposed English coast (50 mg/l, Newton and Grey,

1972) or the most turbid parts of Chesapeake Bay (over 100 mg/l, Schubel,

1972). It can be assumed that estuarine animals in the-Davisville area

are exposed to such high levels of turbidity for periods of a day or two

following storms.

POLLUTANTS

Water Quality. The Rhode Island Department of Health (DH) conducted a bacterio-

logical survey of the Quonset/Davisville area between August 1975 and

November 1976 (RI DH, 1976). Surface water samples were taken at 11

stations on 6 dates. Tests were also run on samples from streams flowing

TRANSMISSION, %/METER

ALLEN HARPOR

W S
W
LL
3F 10-
20-
IL
ow 30-3 STATION 1 2 3
DAVISVILLE PIERS

STATION 6
FRY COVE

STATION 7 10

Figure 4-16. Turbidity sections, I-lay 23, 1980. 11:20-12:30, Low
Tide 12:53 DST. Wind 5-10 knots NW "S" indicates
water sampling station. Stippling indicates relatively'
turbid water.

TURNING BASIN

TEMPERATURE,*C TRANSMISSION, %/METER
21 20 19 IS 17 10 5 0
W 0 1 r 9 v
W
U.
10

(L 20
W
.. . . . . . . . .

FRY CHANNEL (STAO 7)

TEMPERATURE, OC TRANSMISSION, %/METER
W -0
W 21 20 19 18 17 10 5
U. 0 1 9
e
10-
a.
W
20

Figure 4-17 Turbidity and temperature profiles at two locations,
June 24, 1980. Dashed lines show relationship of
temperature and turbidity features.

4-32

into Fry Pond and from the Pond itself in August 1976. A summary of results

for stations near Davisville are given in Table 4-2 and.Figure 4-18. Fecal

coliform bacteria were found in very low concentrations in the Bay and Allen
Harbor samples. All samples had most probable numbers of less than 9/100 ml

(The maximum count for SA waters is 70/100 ml). A small stream entering

Fry Pond had high coliform levels which were reduced within the Pond. Fry

Cove was closed to shellfishing for a number of years because of possible

contamination from houses on the Dogpatch Beach bluff and the presence of

berthed vessels at the adjacent piers. Following a conservative policy the

RI Department of Health did not open the cove to shellfishing until July

1980, despite the abandonment,of the housing in 1974 and negat ive bacter-

iological tests in 1977.

Hydrocarbons in Sediments. There is a high to low gradient of sediment

hydrocarbons from the upper to lower Bay resulting from sewage effluents
and spills. There are additional potential sources in the Davisville area
including.effluents, spills, and dumping from both land and water based

activities. As part of the initial Quonset/Davisville impact study Brown

and Franklin (1977) obtained total hydrocarbon levels of 100-641 ug/g,
dry weight from different environments in the Davisville area (Table 473).
Additional hydrocarbon analyses were carried out during this study-

by the Graduate School of Oceanography Organic Geochemistry Laboratory.
The goals of these analyses were to allow comparison with data which the

laboratory has obtained from throughout Narragansett Bay and to gain
insight into the sources and makeup of materials which will be deposited

in the proposed dredged channels.

Duplicate analyses were carried out on a surface sample obtained from

the Davisville turning basin, June 1980. Results and preliminary di'scussion

4-33

Table 4-2. Water Quality Data for the Davisville Area.

Estuarine areas sampled on six occasions, August 10, 1975, Nov. 30, 1976.
Summarized from RIDH, 1976.

Fec
Dissolved Oxygen ColiforWOO ml
min max. median
Station mg/l % sat. mg/l % sat. mg/l %sat. min max median

5 off airport 3- 3- 3.5-
6 Fry Cove 6.4 91 12.0 118 8.85 100 3- 9 3-

7 off D.V. piers 3- 9 3-

8 off Allen H. 3.2 93 11.8 116 8.7 108 3- 9 3-

9 Allen Harbor 3- 4 3-

Fry Pond areas sampled August 4, 1976, RIDH unpublished data.

NP/100 ml
Station total coliform fecal coliform

brook to pond, Pond and Newcomb Rd. 2300 90

brook to pond, near bld. 884 2300 2300

2411 pipe to pond < 23 < 23

Fry Pond outlet 230 < 23

WATER QUALITY
2,3
13 METALS IN BIVALVES

9 0 METALS IN SEDIMENT
131.
0 HYDROCARBONS IN
4 08 SEDIMENT
:::13

024-

2T
74*,@
7 %.
0

CULVERT A6
d!
06
98

65
W,

Figure 4-18. Station locations for water and sediment quality samples.
Water quality and metals in bivalves (Rhode Island
Department of Health) metals in sediment and hydrocarbons
in sediment 27A, 27 this study). Hydrocarbons in sedi-
ments C5-9. CRC, 1977).

4-34

by Quinn, Requejo, and Pruell are given in Part C of the biological impact

report. A data summary is given in Table 4-4.

The concentration of total hydrocarbons from the turning basin was

934 ug/g dry weight, significantly higher than in fine-grained natural

sediments of surrounding areas studied by Hurtt (1978) of 359,356 and 246

ug/g. This is also an order of magnitude higher than levels in intertidal

sediments in Allen Harbor sampled in 1980 (Table 4-3). The high total

hydrocarbon level in the Piers turning basin probably represents input

of hydrocarbons from the upper bay adsorbed to fine grained organic parti-

cles and from local sources. The pres ence of benzotriazoles (BTAs) from

a source on the Pawtucket River, Warwick demonstrates transport down-Bay.

Table 4-3. Summary of sediment hydrocarbon data in study area.
(Brown and Franklin, 1977; Coastal Resources Center,
1977)

Total Hydrocarbons
Percentage
ug/g sand silt clay
Duplicate Samples

Allen Harbor 395 641 3 69 28

Channel to A.H. 196 100

Davisville Piers 294 311 8 53 39

Fry Cove Channel 103 427 8 66 26

Quinn Requejo and Pruell, unpub. Davisville turning basin,, sampled June
1980. All values Ug/g dry weight average of duplicate analysis,

identified total total
aromatics aromatics hydrocarbon&. BTA's phthalate

0-10 cm 9,769 60,0 934 0,699 1.17

4-35

The elevated levels of specific aromatic hydrocarbons and total hydro-
carbons suggest additional sources in the Davisville area. Sources may
include combustion products in used lubricating oils and weathered fuel oil.
Identified aromatics were 83 times higher in the turning basin than in
AAlen Harbor; total hydrocarbons were 12 times higher; and BTAs only 6

times higher.
The classification scheme used in Connecticut allows dredged material
with less than 5000 ug/g hexane soluble fraction (oil and grease) to be
disposed of at sea without protective measures. The total hydrocarbon
level equivalent to this is higher than the 934 ug/g found in Davisville
sediments. Davisville sediments are "clean" when compared to polluted

harbors in New England, but are "dirty" compared to immediately adjacent
parts of Narragansett Bay. Since hydrocarbons are strongly adsorbed to
particulate matter, a dredging and disposal technique which controls

release of sediment would also contain hydrocarbon pollutants.

Metals in Sediments. Elutriate tests were carried out on six samples to
provide data for future permit applications and to provide baseline infor-
mation. In these tests (reported in Part C) sediment is shaken with Bay

water and the water tested for released metals. The test gives a more

realistic measure of the impact of hydraulic dredging effluent rele ase

than bulk sediment analysis does.

For five metals (barium, cadmium, chromium, mercury, and lead) all

test concentrations were below the limit of detectability of the analytic

method used. These results illustrate the low solubility of most metals

in sea water: chromium in mid-bay sediments is 50-400 ppm (Olsen and

4-36

Lee, 1979), but was less than 0.2 ppm in the tests; lead in mid-bay sediments

is about 100 ppm (Olson and Lee, 1979), but less than 1.6 ppm in the tests.

Copper was detectable in all the elutriate tests. Concentrations

ranged from 0.114-0.182 ppm. The absence of a relationship between concen-

tration and sediment type or sample location may indicate an unexplained

analytic problem. The EPA pollution standard for copper is 0.005 ppm.

Metals in Clams. It has been suggested that there could be high concentra-

tions of heavy metals in sediments and organisms in the Quonset/Davisville

area as a result of discharge of metal plating solutions (Eisler et al.
1977, 1978) or of dumping of metal scrap at Allen Harbor (CRC, 1977).

Eisler et al. found elevated metal levels in the widgeon clam (Pitar

morrhuana) near the former Naval Air Rework Facility outfalls at Quonset

Point.

The State Department of Health carried out a special study of metals

in clams in the Davisville area between December 1976 -and June 1977.

Soft-shell clams were collected at four stations. In Figure 4-19-metal

levels of clams are shown for the stations in order of distance from the

Allen Harbor dump. There is no trend for any metal. Except for one Fry

Cove sample, all metals are below the U.S. Food and Drug Administration

alert levels. Alert levels have no direct relation to safety of consumption,

but relate to regional norms (FDA would advise the local management agency
of a potential concern, however, there are no legal standards for levels
of metals). For most metals similar levels were found in both soft-shell

and hard clams and levels did not vary from environment to environment.
This constancy suggests that metals are being regulated by physiological

mechanisms.

Refere nces

A complete bibliography can be found in Part C, section 5.

M YA ARENARIA

5 - - - - - 5 0.5
Pb Cr Cd
4- 4- 0.4-

3- 3- 0.3-

0
0
2- 2- .0.2- 0 0
a- 0 0 0 0
0- 0 0 0 0 0 0 0 0.1- 0 0 0
z 8 a 0
0 0 .0 0 . - 1 0
1 4 2 6. 1 4 2 6 1 4 2 6
< - I I I I I I I I
x 60 W 50-
0
Cu Zn I- NEAR
z 0 DUMP
W 40- 40-
L) 2- YACHT
z 30 CLUB ALLEN
0 30- HARBOR
0 - - - - - - - - - -- 0 4-NORTH
20- .0 0 20- 0 0 0 COVE
0
10- 0 10- 0 0 0 6- D.R BEACH
--- FDA ALERT LEVEL
0 ---------I-----------0
1 2 4 6 1 2 4 6'

Figure 4-1-9. Metal levels in soft shell clams (Ilya arenari a)(dry weight) at
four locations. (R.I. Dept. of Pealth, Dec. 19, 1976-June 1977).
0

5-1

5, ENVIRONMENTAL CONSEQUENCES OF ALTERNATIVE ACTIONS

5.1 INTRODUCTION
Several alternate development plans were prepared during the prelim-
inary engineering phase of the Davisville Pier extension project. Although
all were technically possible, the designs vary considerably in environmental
impact, cost feasibility, and compatibility with Port Authority needs and
plans. Considerations of cost and feasibility are covered in depth in the
Preliminary Engineering Report by C.E. Maguire. This chapter provides a
detailed discussion of the environmental effects of the alternate designs

as well as a consideration of alternate sites and a no-construction option,

in the following manner:

Section 5.2: Bulkhead Construction Along Dogpatch Beach (Alternates
1 and 2) -

Section 5.3: Bulkhead Between Davisville Piers and the Quonset State
Airport (Alternate 3)

Section 5.4: Bulkhead North of Davisville Piers (Alternate 4)

Section 5.5: Improvements to Property Adjacent to Davisville Piers
Retained by the United States Navy (Alternates 5 and
6)

Section 5.6: Actions with No Impact on the Davisville Site

Each Section begins with a description of a design proposal by the

consulting engineers, followed by the identification of terrestrial and

marine environmental impacts of the option, and recommendations for

mitigating measures. The impact assessments include the direct effects

caused by the construction of a wharf and associated transportation linkages

and indirect effects which are the result of facility operations. Many of

the effects of the development will occur during construction, lasting only

5 @-2

a short time before disappearing and causing no permanent damage. Some

effects from construction and operation, however, will make lasting, irre-

.versible changes to the site. Measures which should be taken to reduce

adverse temporary and permanent effects are identified in the concluding

portion of each section.

5.2 BULKHEAD CONSTRUCTION ALONG DOGPATCH BEACH

Description of Action

Two designs were developed by C.E. Maguire for dredging portions of

Fry Cove and constructing a bulkhead on the eastern edge of Rhode Island

Port Authority controlled land north of the Quonset State Airport. Alter-

nate 2, the design selected for implementation would create a 665-foot

steel bulkhead immediately to the south of Navy owned wooden bulkhead,

with the option to extend it further south to a maximum length of 2,400

feet. The northern most portion of proposed development overlaps land

presently owned by the Navy. Alternative 2 would create 18 acres of land

with the potential for creating an additional 28 acres at a later date

(Figure 5-1). Alternate 1 would create the entire 46 acres of new land

all at once (Figure 5-2).

The proposed action, Alternate 2, will involve dredging about 13

acres to a depth of 25 feet and removing 350,000 cubic yards of material.

Approximately 190,000 cubic yards will be used to fill behind a 675-foot

long sheet-pile bulkhead, creating 18 acres of land part of which is

presently open water and the remainder a beach and marsh. The channel

would begin at the south side of Pier 1, gradually narrowing from 700

to 250 feet at the southern end of the new bulkhead. The southern

termintis of the new wharf will be protected by a 700-foot long wall. of

F-1

_v-

D
a 0 0DPAT

ARNMOR SLOPC

NWKMEAD

L------ NEW CKANKL

R PIER a

a U a N S I I- PORT
IN

Figure 5-1 Selected Port Expansion Plan

A i I V

R 11 (IR

I L
o a F A T c

Kw cHANNEL
1-41 r#r's covE

I --ILL

Figure 5-2 Full Development Port Expansion Plan

5-3

stone armor. The dredged material which is not used to create the wharf,

about 160,000 cubic yards, would be stockpiled on roughly 15 acres adjacent
to Dogpatch either for re-use if the bulkhead is extended, sold or used as
fill elsewhere by RIPA (Fig. 5-1). For the most part road access would

follow Marine Road, cutting along Greenwich Avenue to the back of the

wharf. A rail line would originate at the intersection of Pond and Marine

Roads, run parallel to the improved Marine Road about 400 feet to the

north until just past the Airport communication buildings where it would
then rejoin the new road out onto the wharf. An alternate route for both

road and rail connections would originate from the vicinity of the Navy

bulkhead.

The proposed action would permit extending the bulkhead further

south as needed, as much as 1,800 feet. The stockpiled dredged material

as well as newly dredged sediment would be used to fill behind the bulkhead

to create a wharf similar in size to that proposed in C.E. Maguire Alternate

1. If the entire wharf were constructed at once, approximately 700,000

cubic yards would be removed from the 28 acres of new channel to create a

total of 46 acres of new land. The southern end of the wharf would terminate

just north of the outlet of Fry Pond. Road and rail access would be provided

by extendind the alignments south along the back of the wharf. The dredged

channel along the additional bulkhead segment would be 250 feet wide.

Terrestrial Impacts

The construction of a new bulkhead at Dogpatch Beach with back filling

of dredged materials will result in major permanent alterations to the

existing sand beach, dunes and marsh, to several of the presently abandoned

houses above the beach, and to the old fields on the uplands to the rear

of the property (Figure 5-3).

D 0 G P A C H

Broadway

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

NAVY BULKHEAD

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

F R Y

C 0 V E

Figure 5-3 Changes to Dogpatch from Design 2,Incremental Development
Le_y to symbo I s
Doypatch boundary Marsh to be fillod +f-+
Existing shorcline @7
New shoreline Water to be filled N
New road
New rail

5-4

Bulkhead development and back fill (both Alternatives 1 and 2) will
i

cause the complete elimination of the small marsh. In order to properly

level the new land in back of the bulkhead, dredged materials will have

to be placed over the top of the marsh, and elevated up to the existing
road (Broadway) in back of the marsh. This would cover the marsh with
approximately 4-6 feet of material and bury the culvert which is presently
supplying freshwater to the marsh. In order to allow continued freshwater
discharge, a culvert would be installed, through the existing marsh prior
to covering it with fill. This would permit stream drainage to continue
through the new bulkhead wall and out into the Bay. The elimination of the
salt marsh will result in a decreage in habitat for those species which
require the salt marsh environment for feeding and shelter. Sessile
animals such as bivalves, crustaceans, and tube worms present in the

wetland at the time of burial will be killed. Adult birds will escape but

will have to go elsewhere for feeding and nesting grounds.
Both Alternatives 1 and 2 will heavily impact the sandy portion of
Dogpatch Beach, with Alternative 2 burying the northern half and Alternative
I totally eliminating all beach frontage. Dunes will be covered up to:the
upland plateau elevation. The existing concrete seawall in front of the
cottages will also be buried. The loss of the sandy beach, whether partial
as in Alternative 2 or total as in Alternative 1, will bring a reduction in
the avai lable sand beach area within Narragansett Bay. However, Dogpatch

Beach has not been accessible to the public for more than forty years, and
is slated by the Port Authority for industrial and commercial develo pment

that would preclude general public access to the site.

5-5
C. E. Maguire proposed that rail and highway access to the newly con-

structed wharf in Alternative 1 or.2 be provided from the west through the

Dogpatch parcel. However, they noted that extending the road bed and rail

line from the Navy retained property just north of the bulkhead would be

less expensive. Removal or demolition of several unoccupied houses will

be required to construct a new road under the proposal for Alternate 2.

Site preparation prior to any development of Dogpatch would involve removal

of most, if not all existing unoccupied residential structures. The con-

struction of a rail line across the upland through the open fields and

shrubby areas at the southern edge of the woods will require removal of

vegetative cover and top soils along its entire length. A berm would be

constructed across low spots on Dogpatch in order to construct the rail

line. If hydraulic dredging is used, a dike about 10 feet high may be

needed to contain surplus dredged materials on about 15 acres of land.

The pile should be landscaped to prevent erosion'by wind and rain,

Acting nesting areas for numerous pairs of Eastern Meadowlarks in

the upland meadow along with other birds and small mammals which presently

live in Dogpatch will be displaced or disturbed by a renewal of active

use of the site.

Aquatic IE!pacts_

The two plans for dredging and bulkheading in front of Dogpatch Beach

Alternates 1 and 2 will have similar effects. Portions of a shallow sandy

platform at the foot of the beach will be permanently eliminated. This

area has small patches of soft-shell clams Q@ya arenaria), a few oysters

as well as several species of bottom animals eaten by fish and wading birds

compared to elsewhere in Narragansett Bay. If development is not carried

the full length of the beach, there will be little change in the remaining

5-6

area, although the harvest of bivalves will be restricted by the Department

of Health within 1000 feet of the wharf. Oysters on rocky bottom near the
'Fry Pond culvert would be killed by shallow burial only if effluent sediments
accumulated there. Bulkhead construction will also eliminate a small area

with depths of 2-5 feet which has quantities of hard clams available to

recreational diggers with rakes or tongs.

The areas which would be dredged to channel depth would eliminate

either 13 (Alternate 2) or 41 (Alternate 1) acres of estuarine bottom with

present depths of 9 to 10 feet. The area is presently used for the harvest

of hard clams. In addition other bottom animals which are major food of

bottom fish and diving ducks will be killed by dredging. As a result, other

species less valuable to man or bottom feeding animals will colonize the

soft sediments that will accumulate bottom of the dredged channel.

An important factor in the determination of specific aquatic impacts,

is the construction sequence, which is not specified in the preliminary

engineering report. Individual contractors will have different approaches

to dredging and bulkhead construction. The major concern is the manner

in which the slurry of water and sediment created by hydraulic dredging

is dewatered and released to the Cove. The longer the slurry is retained

behind a dike or weir, the clearer the effluent released to the Cove will

be. The placement of the weir close to the existing channel will cause

sediment to settle in the channel, which already is a poor habitat for

many of the bottom organism desired by man and bottom feeding birds and

fish. Bottom animals on the edge of the dredged channel will be subject

to burial slumping of the banks. During dredging, organisms will be
subject to turbidity from the effluent. Suspended sediment concentration,
however,'is expected to be below lethal levels for fish and bottom animals

5-7

even at the effluent outlet. In much of the Cove, suspended sediment will

be at levels which will temporarily inhibit feeding of shellfish and zoo-
plankton and reduce growth and survival of shellfish larvae for the duration
of dredging. Motile animals will be able to recover from shallow burial

(inches) by material settling from the effluent.

A small increase in the silt/clay component of sediments in the mid-

depth area of Fry Cove will not-cause a radical change in the species

presently found there; the bottom fauna will remain similar where the

silt/clay percent ranges from 5 to 39 percent. The combination of mechan-

ical disturbance and change to finer sediments could induce setting of the

flopportunistic" species, Mulinea lateralis (coot clam) and AT2@@,lisca,

abdita (an amphipod crustacean).

Deeper areas (20-30 feet deep) surround Fry Cove to the north, east,

and south. These are floored with fine grained sediments and when sampled

in March 1980, had an "impoverished" bottom fauna. Fine grained sediment

from dredging effluent will be deposited in these areas depending on the

outlet location. Raising the elevation of the closed basin in Fry Cove

channel and lowering the concentration of organic matter on any of the

deep bottoms through dredging induced sedLmentation, could cause estab-

lishment of faunal communities in these areas.

Available evidence suggests that fish movements will be unaffected

by moderate turbidity in Fry Cove (see Part C). Fish may actually be

attracted to the disturbed bottom. Following completion of dredging, winter

flounder will be seasonally concentrated along the slopes of the new channel.

The limited volume of organic sediments which will be dredged will

release a small amount of oxygen-consuming and toxic compounds. These

might be detectable in oxygen-poor bottom water.

5-8

Suspended sediments and dissolved substances released into Fry Cove

will be reduced in volume and significantly diluted before reaching the

area north of the Davisville Piers and will have no measurable effects on

hard clams or finfish there.

Mitigating Measures

Terrestrial Impacts: Although bulkhead construction and dredge and fill

activities will have severe impacts on the beach and marsh system at Dog-

patch, steps can be taken which can help to lessen consequences of these

impacts. Any dredged materials stored temporarily at an upland location
should be quickly covered or planted so as to lessen the potential for

erosion from wind or storm water runoff. In order to further decrease

erosion potential following.final implementation of site development at
Dogpatch, a sediment erosion control plan should be undertaken for the
upland area following the guidelines of the Soil Conservation Service.
Although it would be impossible to entirely compensate for the loss

of the beach and marsh system at Dogpatch, it may be possible to provide

similar habitat elsewhere near the site through beach nourishment and

marsh construction. This would be viable only if the surplus dredged

material was not stockpiled for future use. It would appear that the

area in and around Allen Harbor has potential, particularly for building

a marsh of similar size. This possibility should be examined during the
final design phase of the port expansion proposal, prior to construction.

Use of the alternate road and rail route across retained Navy

property examined by C.E. Maguire would avoid upland disturbances as a
direct result of port expansion. However, the site is already slated for
industrial re-use regardless of port development at Davisville, making

5-9

road improvements necessary. A vegetative buffer and and fencing would help

reduce the visual and noise impacts of expanded service base operations to

the adjacent Navy residential compound. Fencing along the proposed upland

rail line would maintain a separation between commercial activity to the

south and the woods and Navy residences to the north. The growth of

general aviation at Quonset State Airport, and the recent relocation of

the Rhode Island Air National Guard to Quonset constitutes a major source

of noise to the area greatly overshadowing that produced by the trucks,

equipment and vessels engaged in port activities at Davisville.

Aquatic Impacts: Although several acres of shellfish habitat will be lost,

the remaining stock of hard clams could be removed before dredging begins,

to reduce the economic loss. A hydraulic dredge should be considered for

complete removal of clams including sub-legal sizes, which could be.

transplanted elsewhere.

Both summer and winter dredging has advantages and disadvantages.

Summer dredging may reduce mortality of animals by burial and allow better

control of all aspects of the dredging and monitoring program, and avoid

interaction with spawning winter flounder. Winter dredging reduces possible

effects of oxygen consumption in deep water, increases dispersion of sedi-

ment and dissolved substances, avoids interaction with planktonic larvae,

and avoids interference with recreational uses.

Release of dredging effluent near the present dredged channel which

already has a soft bottom of low productivity, will reduce surface turbidity

and prevent deposition of sediment in mid-depth areas where hard clams are

present. The slowest rate of dredging consistent with economic operation

will result in an increased retention time of the dredged effluent, helping

5-10

to reduce the suspended matter levels released in effluent. A review of

the dredging sequence at the time of construction should be made to insure

that a reasonable effort is made to control turbidity.

IEven with full development of the Fry Cove Shore, the central portion

of the cove should be able to continue to be used for shell fishing and

shpport finfish and migrating waterfowl. The present circulation of water

into the Cove from the West Passage and the removal of find grained sediment

by wave action will continue to maintain the productivity of the bottom.

The installation of a storm drainage system to collect wharf runoff in a

central location should be considered as a means of aiding the clean up

of accidental land spills, particularly if large amounts of petroleum or

other potential pollutants will be handled at the site.

5.3 BULKHEAD BETWEEN DAVISVILLE PIERS AND THE QUONSET STATE
AIRPORT

Description of Action

C.E. Maguire Design 3 proposes a maximum berth and land filling design.

A bulkhead would be constructed from the corner of the present Navy bulkhead

3,100 feet to the southeast, connecting with the steel bulkhead that forms
the northern edge of the Airport, close to its northeast corner (Figure 5-4).

A 25-foot channel would be created by dredging 40 acres of Fry Cove. About

120 acres of new land would be created by placing 4.1 million cubic yards

of material behind the bulkhead. Only 1.2 million cubic yards of material

would be provided by dredging the channel. The remaining 2.9 million cubic

yards would have to be borrowed, perhaps from other dredging projects in
Narragansett Bay as an alternative to ocean disposal. The Fry Pond outlet

would be channeled through a 2,200 foot long culvert extension. No land

use scheme for this alternate was prepared. Aside from technical problems

V.
?

ji t'

OJIL j
DOOPATCH

. . . . . . . . . .

No.

VIEW a
NEW CHANNEL

@X-

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Ir FORT
QUONSET Al
PI,

WON 0

Figure 5-4 Maximum Expansion Design

5-11

in creating the large land area, information developed by C.E. Maguire does

not substantiate any need for a facility of this size.

Terrestrial Impacts

The impacts resulting from the implementation of C.E. Maguire Design

3 would be similar to those expected in designs 1 and 2 (Section 5.2).

Dogpatch Beach and its wetland would be eliminated through burial by dredged

material. Land uses and transportation access in the upland Dogpatch area

adjacent to Marine Road and the wooded stream would be similar to designs

1 and 2.

Aquatic Impacts

Construction of a bulkhead across Fry Cove will eliminate both the

shallow areas described in Section 5.2 and the productive bottom in the

center of the cove which has commercially harvestable quantities of hard

clams as well as bottom animals useful as food for fish and waterfowl.

The remaining undisturbed bottom will be subject to a larger volume

of suspended matter over a longer period than with the other options.

More suspended matter and dissolved substances would reach Allen Harbor

and Calf Pasture Beach because of the larger size of project and its

location further out in the Cove.

The best established techniques for filling a disposal area with

spoil from a distant area is bucket dredging into scows, transport to

the disposal area, dumping into deep water next to the disposal site, and

hydraulic dredging into the containment area. The additional material

handling will produce more suspended sediment than the aquatic disturbances

described in Section 5.2.

5-12

5.4 BULKHEAD NORTH OF DAVISVILLE PIERS

Description of Action

An increase in berthing and supporting land at Davisville could be
achieved by dredging a channel and constructing a wharf from the mouth of

Allen Harbor southeast to the northeast corner of Pier 2 (Figure 5-5).

This option, presented by C.E. Maguire as Alternate 4, would expand the
land area of the portion of Davisville controlled by the Rhode Island

Port Authority and presently leased to various firms supporting the
petroleum industry's outer continental shelf exploration program in the

North Atlantic. A mixture of bulkhead and pile supported deck structures

would be required to create 2,300 feet of berthing. Incremental imple-
mentation of this scheme was not examined. About 22 areas of bottom would

be dredged, producing 710,000 cubic yards of material which would be com-
pletely used in creating 26 acres of new land. The bulkhead would be
protected on its northwest end at the entrance to Allen Harbor by a 400
foot sloping wall of stone. The adjacent Davisville Piers area is already

largely paved and served by rail spurs.

Terrestrial Impacts
C.E. Maguire Alternate 4 would avoid the terrestrial impacts to the
Dogpatch area likely to occur from designs 1, 2 and 3 since it involves
construction of pier and bulkhead in a totally different location north
of existing pier 2. Likewise, the existing open water area at Fry Cove

will be unaffected with the implementation of Alternate 4.

Most of the land adjacent to the newly constructed pier in Alternate
4 is already paved. It is used as supplementary storage of equipment by
offshore drilling companies located on Davisville Piers. The immediate

L 2@:@,

AIWOR SLOPE

006PATCH

jF40

Sma"Em
r..a
VC,
W'@
FRY'S COVE r

LI@W
Z

V
PIER a

QUONSET PONT

Figure 5-5. Bulkhead North of Davisville Piers

5-13

shoreline consists of marsh and sandy beach, but an extensive parking and

work area begins just a few feet back from the shore. The.Davisville Piers

site is predominately filled land, created by the Navy using material

obtained from channel dredging along with soil trucked in from outside the

site. The area was graded with a slight slope towards the Bay for surface

drainage, and then paved with asphalt. A lack of maintenance of the

pavement is evident by the effects of weathering and cracking in many

areas, which has allowed plants to grow and increase the rate of pavement

breakup. The adoption of Alternate 4 would result in greatly increased use

of the area and would probably require repaving prior to a heavy increase

in use.

Adjacent to the north side of Pier 2 is a marsh of less than 3 acres,

which has formed between the pier and a small stone groin. This marsh

would be covered with dredged material if design 4 is adopted. This marsh

is already highly exposed and is prone to damage from periodic overwash

by sand.

North of the stone groin and extending northwesterly towards Allen

Harbor entrance channel a sandy beach has formed. The sand probably comes

from the extensive beach at Calf Pasture Point. Unless attempts were made

to recover the sand prior to bulkhead and pier construction, this small

beach would also be covered with dredged material.

Aq.!AE@tic Impacts

The proposal to dredge a channel north of Davisville Piers and con-

struct a bulkheaded containment area partially in shallow water will have

effects similar to those discussed for alternatives 1, 2 and 3 in Fry

Cove. The shallow area north of the piers has been considerably modified

5-14

by construction and dredging and may not have reached equilibrium with wave

currents, indicating that rapid sedimentation would occur in the dredged

channel. A low density of soft-shell clams and other bottom animals, by

comparison to Allen Harbor, will be eliminated by construction in intertidal

and shallow subtidal areas.

The area in which dredging will take place is similar in depth and

sediment type to the central portion of Fry Cove with the exception that

it has undergone continuous disturbance from hard clam fishing. Fishing

effort has probably reduced the average size of hard clams and changed

the makeup of bottom communities by favoring faster growing "opportunistic"

species. Disturbance of the bottom by dredging may actually favor hard

clams by inducing setting and reducing the number of competitors and

predators.

Suspended sediment from dredging effluents and resuspended dredge

material will add to the turbitity of Calf Pasture Point area. Suspended

sediment will be deposited in the deep parts of Allen Harbor, in the dredged

basin, and the deeper parts of the West Passage. During the incoming tide

turbidity may be visable along Cal.f Pasture Beach where recreational shell-

fishing and swimming takes place. Estuarine sediment (material deposited

since glaciation) is probably deeper north of the piers than the thin venier

at Fry Cove. Therefore more oxygen consuming compounds, nutrients, and

possible more fine grained sediment would be released from this sediment

than from sandy glacial outwash. Some pollutants are present in surface

sediment at the mouth of Allen Harbor. These do not reach toxic levels,

will be largely retained through adsorption to sediment in the bulkheaded

area,

5-15

Dredging would probably not affect the-movements of winter flounder

into Allen Harbor. However, industrial development north of the piers

could interfere with commercial and recreational shellfishing if grounds

are closed by the state. The potential of pollution entering Allen

Harbor from an oil or chemical spill during operations at Davisville

may lead to contamination affecting the future value of Allen Harbor for

shellfishing and aquaculture. Industrial development is compatible with

use of the harbor for marina operation, however, since channel improvements

north of the piers would replace a portion of the present shallow and

narrow entrance. Department of Environmental Management Policy will create

a closure zone for shellfishing roughly 1000 feet bayward of the new

wharf.

Mitigating Measures

Release of dredging effluent near or into the present turning basin

would reduce the effects of suspended material on shellfishing and swimming

as well as the visibility of the sediment plume. Winter dredging would

avoid interaction with recreational use of the area. Clams could be removed

from the areas to be dredged. Control of all land and vessel discharges

and release of preservatives from dock structures is, more important north

of the Piers than in Fry Cove because of the extensive use of the area for

shellfishing, and the need to avoid additional pollution.
5.5 IMPROVEMENTS TO PROPERTY ADJACENT TO DAVISVILLE PIERS
RETAINED BY THE UNITED STATES NAVY

Description of Action

Expansion of the capacity of Davisville Piers to accommodate increased

offshore oil service or related shipping activity could be achieved by im-

proving the Navy owned wharf immediately adjacent to Pier 1, and then

5-16

expanding the berth and operating area by building a parallel earth or
pile supported pier. These variations are presented as Alternates 5, 6,
and 6A in the Preliminary Engineering, Davisville Pier report and supple-
mentary progress report (Figure 5-6 and 5-7). Alternate 5 would create
a new bulkhead 1,300 feet long in front of the existing decayed wharf,
and provide for a 25-foot dredge depth. A stone armored slope would be
built at the southern end, creating 1.5 acres of land. A surplus of
approximately 175,000 yards of sediment would be dredged from the 10-acre
new channel and require stockpiling. A part of the upland portion of the
Navy controlled site, which consists of more than 40 acres of open land,
would be required for structures, storage and movement of vehicles and

equipment.
Expansion of the capacity of this new bulkhead could be accomplished
by constructing a pier parallel to the existing piers I and 2. C.E.
Maguire suggested an earth or pile supported pier 300 feet wide and 1000
feet long creating 7 acres of new area and 2,300 feet of berthing. The
dredged channel would be expanded an additional 15 acres to provide access
to both sides of the pier, creating an additional 370,000 yards of surplus
material for the piling supported pier (Alternate 6) or only 170,000
additional yards for the earth filled pier (Alternate 6A).

Terrestrial Impacts
Alternatives 5, 6 and 6A will result in surplus amounts of dredged
material being produced as a result of dredging in front of the Navy Pier
because only limited amounts of dredged material will be necessary as
fill material. Design 5 will produce 175,000 cubic yards and design 6
370,000 cubic yards of material which would have to be stored off site.

1, AI

L
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COOPATCH

rar's cove
P Til.

ARNOOR SLO
DULKK!AD-,,
New CHAMN

QUON31T Al PONT

601

Figure 5-6. Reconstruction of Navy Bulkhead.

1, O-p a
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F A.y

For's COVE ARMOR SLOPE
P$

MIW_.RUL HEAD-

NEW PIER--r-
NEW CHARMEL-j- plan 2

L ---- J,

ANNE L

QUONSET AtOPORT

I-J
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Figure 5-7. Expansion of Navy Bulkhead.

5-17

An earth pier, 6A, would reduce the storage requirement to 170,000 cubic

yards. Several problems would be created if the surplus material is moved

to an upland storage area nearby. The use of hydraulic dredging will

produce a slurry of sediment and water. A 16 acre containment area for

dewatering must be constructed at the storage site. If a nearshore disposal

site at Dogpatch is selected (Figure 5-6, letter D) some adverse effects

on wildlife will occur (particularly small mammals and songbirds) since

there is moderate wildlife useage presently at this site. Disposal at

Site M near Marine Road (largely an old asphalt parking lot) will have

little potential impact on wildlife or Fry Cove but could impact Davol

Pond if the material is not properly contained during dewatering. The use

of a clamshell dredge would mean that little or no containment would be

required at either site.

A potential problem with both sites and dredging techniques will be

the blowing of surface sediments once they have dried, creating a nuisance

for workers and equipment nearby. Dredged material will present little

threat to groundwater resources through the natural leaching of salts or

contaminants because groundwater flows at both potential disposal areas

are towards Narragansett Bay, and not inland towards the Potowomut aqui-

fer (Coastal Resources Center, 1977).

Small amounts of the dredged material will be utilized as fill

beside the existing Navy bulkhead causing shoreline modifications. This

fill will bury the small cobble beach area which is utilized infrequently

by feeding shorebirds. This fill will be retained by the construction of

an armor slope on the south side. Depending on the height of the armor

slope and the fill behind it, some filling or infringement on the beach

5-18

or marsh is probable. After construction, it is likely that some beach

erosion will occur where the armor slope meets the sandy beach. This

could result in a change to flow patterns into and from the marsh which

can easily be avoided.

Active use of the Navy pier areas will result in some disturbance to

the adjacent Navy housing just inland of the piers. The greatest effect

will occur in the form of noise, but some impacts on air quality from

engine exhausts or particulate matter could occur depending on the range

and intensity of uses. The present privacy of the Navy housing area

will likely be somewhat disrupted by active use of the pier.

There could be some indirect effects on the small salt marsh from

runoff or drainage from the paved surface of the pier. Runoff into the

marsh could have some negative impact, particularly due to the contami-

nants present in surface runoff from such areas (oils, toxic wastes, etc.).

Some disturbance to wildlife usage of the marsh will occur and may diminish

its value to nesting birds.

Aquatic Impacts

Dredging in front of the Navy Pier will deepen a sandy bottom which

slopes from depths of 3 to 12 feet to the edge of the present dredged

channel. Commercially harvestable densities of hard clams found throughout

this area will be eliminated and will not recolonize the dredged channel.

Bottom organisms used by fish and ducks for food will also be eliminated

in the newly dredged area . The location of concentrations of winter

flounder will move from the present channel edge to the new edge.

Dredge effluent from bulkhead and stockpile areas will temporarily

create turbidity which will not cause mortality of bottom animals or

fish, but which may for the duration of dredging slow the rate of growth

5-19

of planktonic larvae and zooplankton in the immediate area.

Shallow burial (less than a few inahes) from effluent

sedimentation or leakage from the bulkhead will kill attached barnacles

and a few oysters and mussels, but will not be severe enough to prevent

most species from reaching the surface. Organisms such as hard clams

buried more deeply by slope failure will not survive. (A discussion of

the ability of various marine organisms to recover from burial is provided

in Part C.) Mechanical disturbance of the bottom and sedimentation from

dredging effluent in Fry Cove may result in an increase in bottom species

adapted for rapid growth in the absence of competition. These could

include species with value to man (hard clams) those having the ability to

stabilize the bottom (tube building polychaetes and amphipods), and species

valuable for fish and duck food (amphipods, coot clams, rut clam).

Sedimentation from dredging effluent will further result in a temporary

increase of the silt clay fraction at all depths in Fry Cove. At shallow

and mid-depths this may result in small changes in the relative abundance

of the present fauna. Fine sediments deposited in natural and dredged

channels will remain there. Species of low economic evalue will colonize

these sediments.

While organic sediments at the edge of the present channel are being

dredged there will be release of oxygen-consuming compounds as well as

hydrogen sulfide and ammonia into the water. The released volumes of these

substances would have little effect on marine organisms except within the

containment areas and possibly in bottom waters which are isolated by

vertical temperature stratification in the summer.

The presence of shipping, industrial development, and use of toxic

preservatives on structures will lower or threaten to lower the water

5-20

quality in Fry Cove. Department of Environmental Management policy will
create a closure zone for shellfishing roughly 1000 feet bayward of the

wharf.

Mitigating Measures
Terrestrial: Problems associated with runoff of dredged material into the@

Bay, pond or any lower elevated area could be largely corrected by proper
initial placement and useage of dredged material and if clamshell dredges
were used instead of pumping the material hydraulically. If dredged

material were used to construct a landscaped playing field or marsh, this

would help solve the problem of dried sediments being blown around or
washed away. Careful consideration of marsh sites should occur during

the final design phase of the project.
By extending and curving the armor slope around towards the pier it
may permit additional amounts of dredged materials to be contained and
lessen the potential for direct intrusion onto or into the marsh surface.
However, some long term beach erosion adjacent to the armor slop may

still occur.
Although retention of complete privacy at the residential area is
impossible with renewed pier use, it is feasible to provide additional
buffering by the use of vegetative barriers, particularly rapidly growing
conifers. The marsh might be given added protection by fencing along the
northern edge prior to construction activity at the pier, and also by
strict drainage control that could direct all surface runoff away from

the marsh.
Aquat Hard clams can be removed before dredging is carried out.
Intensive fishing since Fry Cove was opened in June 1980 have already
reduced the population. Dredging in the winter will reduce potential

5-21

effects on planktonic larvae, increase dispersion of suspended sediment

and dissolved substances from spoil effluent, and avoid possible low

oxygen values in deep water. Summer dredging will reduce mortality to

bottom animals by burial since many are more,active at temperatures greater

than 100C. If containment area effluent is released near channels there

will be a reduction in both visible turbidity and the deposition of sediment

on the shallower areas that are most valuable for hard clams and fish food

organi sms*

5.6 ACTIONS WITH NO IMPACT ON THE DAVISVILLE SITE

Description.of Action

There are two courses of action which would have no effect on the

vicinity of Davisville Piers. First the Rhode Island Port Authority

could construct facilities for expanded petroleum exploration service

operations at another site in Rhode Island waters which it either controls

or could acquire an interest. The remaining choice available to the Port

Authority is not to make any new investments in port activity in support

of petroleum exploration.

Alternate Sites. There are few waterfront locations in Narragansett Bay

which have enough developable land adjacent to at least 20 feet of pro-

tected water to be of value to companies supporting offshore oil
development. Much of Narragansett Bay is navigable by supply boat. A

channel with a depth of 40 feet follows the East Passage of Narragansett

Bay up to the Providence River. The West Passage of the Bay has a

natural navigable depth greater than 20 feet and a 30 foot or greater

dredged channel serving Quonset/Davisville. The channel to Fall River

has a depth of 35 feet. Smaller coves and harbors are served by shallow

channels suitable for recreational craft. However, waterfront along these

5@-22@

navigational channels which possesses a potential for accommodating additional
marine transportation use and could meet the requirements of the project is

confined to Providence Harbor, and the former Navy fueling piers at Melville,

in Portsmouth. Other sites such as Coddington Cove, the Quonset Carrier

Pier, the Tiverton shipping area, Newport and Jamestown Harbors are occupied

by active uses, have little land available, and are in many instances
already experiencing overcrowding from competing marine interests (Figure 5-8).

Providence Harbor does have potential for increasing its neobulk and

containerized cargo handling an activity similar to that conducted at bases

which serve offshore oil exploration and development (New England River

Basins Commission, 1980, Ports and Harbors Study, Draft, Boston MA). For

example, the Municipal Wharf, owned by the City of Providence, has six
deep berths used for export of scrap steel and import of lumber, fuels,
steel automobiles, liquids, and chemicals. Other privately operated

terminals handle petroleum and some other cargo. Due to the presence of

the 40 foot channel, terminal operators and related port users have con-

centrated on increasing shipping activity by building berths to accommodate

larger vessels, attracting new cargoes, and developing the export trade.

The shallow draft of the offshore drilling service vessels and the volume

of materials handled relative to the needs of other port users makes a

service base operation an inefficient use of the Providence Harbor water-

front. The lack of interest in attracting service base operations to

Providence reflects this fact.

The Melville Industrial Area, owned by the Rhode Island Port Authority,

is an irregular strip of land of some 50 acres located on the western

shore of Portsmouth. It was formerly used as a fueling and maintenance

PROVIDENCE

0 5 io km

Figure 5-8 Alternate Port Expansion Sites in Narragansett Bay
1. Port of Providence 2. Davisville
3. Melville 4%. Coddington Cove

5-23

pier and boat basin by the Navy. To the north is Navy retained land and
docking facilities, and a large privately operated marina. The Melville

site includes two piers 25 and 50 wide respectively which are 1000 feet
long, and served by 35 foot deep channels. Neither pier is suitable for

service base operations since there is very little room on the piers

for vehicle movements. A shorefront wharf, of which the State owns 600

feet, has less than 16 feet of water.

The Rhode Island Port Authority has slated the entire Melville site

for industrial development and is in the process of considering a variety

of proposed uses. These include a grain shipment and milling operation,

commercial fishing offloading and a home port for a portion of the Rhode

Island fishing fleet. It is conceivable that a wharf of good depth and

useful size could be created by bulkheading and dredging the shoreline

to the south of the piers. Some 20 to 25 acres of land, most of it

existing, could be allocated to service base operations.

Development of Melville is proceeding concurrently with Davisville

Piers. Use of Melville as an offshore oil service base, however, would

conflict with established Port Authority policies. Based on extensive

planning studies the Port Authority has already decided that offshore

oil'service companies should be concentrated at Davisville and that other

marine industry firms would best be located at Melville. In addition

several drawbacks exist to the location of oil service facilities at

Melville, including its limited land area, exposure to prevailing south-

westerly winds, distance from major highways, and isolation from the

existing service base operations at Davisville.

No Construction. The Rhode Island Port Authority could decide that it

will not construct the 675 foot bulkhead proposed as C,E. Maguire Alter-,

nate 2, with its provision for incremental expansion up to 2,300 feet,

5-24

or undertake any work to increase facilities for use by the companies

servicing offshore oil exploration and production platforms. By doing

so, the marine and shoreline impacts of dredging and bulkhead construction

described in sections 5.2 to 5.5 would not occur. Although marine envir-

onment impacts to Davisville and Dogpatch would be avoided, the use of
the Dogpatch Beach parcel for any other industrial or commercial development
is likely to have some effects on the woods and stream which feed the

small salt marsh, as described in Section 5.3, including demolition, site

preparation, road improvements, and construction of buildings and parking

lots.

PART B

DAVISVILLE PORT EXPANSION

ASSESSMENT

GEOLOGY

Prepared by R. L. McMaster and

S.M. Greenlee

The preparation of this report was financed in part by funds from the Office
of Coastal Zone Management, National Oceanic and Atmospheric Administration.
U.S. Department of Commerce, administered by the ENERGY OFFICE, EXECUTIVE
DEPARTMENT, GOVERNOR"S OFFICE, STATE OF RHODE ISLAND.

Part B Page
Introduction . . . . . . . . . . . . . . . . . . . .. . . . . . . . 1

Scope and Significance . . . . . . . . . . . . . . . . . . . . . . 1

Procedures . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2

Field Operations

Laboratory Techniques

Results . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Shoreline . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Bathymetry . . . . . . . . . . . . . . . . . . . . . . . . . 4

Bottom Surface . . . . . . . . . . . . . . . . . . . . . . . 5

Sediment . . . . . . . . . . . . . . . . . . . . . . . . . . 5

Bedrock . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Overburden . .. . . . . . . . . . . . . . . . . . . . . . . . 6

References . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Appendix A . . . . . . . . . . . . . . . . . . . . . . . . . . . 9

List of Figures

1. Tracklines, Seismic Reflection Survey

2. Tracklines, Bathymetric and Side Scan Survey

3. Bathymetry

4. Bottom Character Based on Side Scan Sonar Interpretation

5. Surface Sand Distribution

6. Bedrock Depths in Time Un its

7. Bedrock Depths in Feet

8. Sediment Overburden Thickness

Introduction

A geological survey was conducted on the beaches and adjacent near-
shore bottom within the general area defined by Calf Pasture Pt. and the
airport bulkhead (Fig. 1). In the offshore zone, the investigation was
limited to the bottom between the 6 and 26 foot contours but including the
dredged channels.

Scope and Significance

The purpose of the surveywas to (a) describe the general beach conditions;
(b) determine the character of the nearshore bottom surface and overlying
suspended sediment based upon soundings, side viewing sonar, bottom samples,
and transmissometer readings; (c) describe the morphology and position of the
bedrock surface; (d) ascertain the thickness and general composition of the
overburden above the bedrock; and (e) assess the geologic environmental impact
to the area relative to bulkhead installation and bottom dredging.

The findings are used in the following manner. For the shoreline, beach
accretion and erosion sites are identified and sand transport, longshore and
onshore-offshore, is inferred. In the nearshore, the bottom relief is mapped
as well as the general distribution of sand, mud and suspended sediment. These
results permit the evaluation of processes responsible for sediment erosion,
transportation,and deposition under present environmental conditions and the
prediction of sediment responses after dredging and pier construction.

The bedrock surface is mapped so that its attitude, shape and relief
are determined. These.data are correlated with the borings made by C.E. Maguire,

Inc.

Finally, these results are assessed relative to the geologic impact on the

nearshore environment due to bulkhead installation, a dredging operation and
deepening of the bottom.

-2-

Procedures

.1. Field operations: R/V Schock was used to obtain sounding profiles,
sub-bottom profiles, side-scan sonographs and bottom sampling. Navigational
fixes were made with Loran C. Tracklines for the sub-bottom, soundings
and side-scan sonar surveys are shown in Figs. 1 and 2.

The following pieces of equipment were utilized. The bathymetric survey
was made with a Raytheon depth system composed of a narrow beam transducer
and a 719 Recorder. Continuous depth profiles of the bottom were recorded.
For the sub-bottom investigation, a continuous seismic reflection profiler
consisting of a E.C,&..G.,Uniboom sound source, a 10 element hydrophone, a
filter unit and an EPC Recorder, was used. In this operation, sound signals
were directed into the bottom at one second intervals. These pulses were
reflected from various sub-bottom features and the returning signals were
picked up by the hydrophone array. In turn, the pulses were filtered at a
band width of 600-1100 Rz and then printed at a sweep rate of either 1/4 or 1/8
sec.as a continuous sub-bottom profile.

A Klein Associates, Inc., side-scan sonar composed of a towfish and
two channel wet paper recorder was used to view the bottom conditions. Opera-
tionally, the fish was towed about 3 feet below the water surface. Sound signals,
emanating from both sides of the fish were beamed perpindicular to the direction
at which the fish was moving. These signals were reflected back from various
bottom targets on either side of the fish and recorded. The system was adjusted
to survey a 248 ft.wide strip on each side of the fish. The navigation was
fixed so that the dual strips of one trackline juxtaposed or overlapped the
dual strips of each succeeding line.
In the sediment sampling, grab samples were retrieved from the bottom Sur-
face with a Smith-McIntyre sampler and a 5 fo ot gravity corer was used to
collect a vertical section of the bottom.
2. Laboratory techniques: The data generated from bathymetric, sub-bottom
and side-scan surveys were processed as follows. Depth measurements were
sampled from the record at 12 sec,intervals, corrected to mean low water (MLW)
and plotted. For the sub-bottom data, the seismic profiles were sampled at

30 sec.intervals.

Wits 624

,412

Trackline March 26, 1980
37' .122
Trackline from Coastal
Resources Center (1977)

woo

.725
406

.650
1726
14"

1w.

1432 1.50 Sol '100
@120

600
...2 t
.651
-63S

1556

1640
,30 1.2
M4
-552 1342 .63 1
.4130 1436 'IQ

SX5 ".1154
W" MS
SN

FIG. I TRACKLINES
41* Seismic Reflection Survey

9 1214
0 nautical miles 0.5 1

I InCh=400 feet

711
25' 24 1

CALF PASTURE POINT

ALLEN HARBOR
ENTRANCE 09"
09M

0 0050

0604

"ll COM
0"

0634
7
U M4 090.

0920

090 0416
09011
101 ow ow

Q 'o. 0"o 922
A,
Q7 W3 09" 0259
C.1
M2 we
'000

*26 1014
033

@50

1035 34

0034 0@
100.9 1006 1044
1030 1028 20 lom 1005 09M
low .034
1004 O@2
1 0932
AIRPORT BULKHEAD J002
FIG.2 TRACKLINES
41* Bothymetric and Side-scan Surveys
36' April 16, 1980 4 1000

0 05
nautical miles Oise
.49

I incha,110 feet

71*
25' 24'
1

-3-

Measurements, in time units, were determined for the bottom surface and
bedrock interface. These time units were converted to feet by using a velocity
of 4800 ft/sec for water and 5,000 ft/sec for overburden (Birch and Dietz, 1962).
Unfortunately none of the C.E. Maquire boring sites that reached bedrock
were within the draft limitations of R/V Schock. Hence the sediment velocity
value was taken from a determination that was made previously at a nearby
location in Narragansett Bay. Plots of bedrock depths were made in both time
units and feet and a plot of the overburden thickness was prepared in feet.
Side-scan bonographs were analyzed for distinctive bottom characteristics and
these features were plotted on a map to provide a mosaic of the bottom.

Sediments were analyzed by methods used in sedimentary geology. Sands
were washed, dried, weighed, sieved through a nest of screens consisting of
openings of 2, 1, 0.5, 0.25, o.125 and 0.063 mm..and weighed. The resulting
data were used to calculate the proportions of sand and grayel as well as
the type of sand present.

Samples composed primarily of silt-clAy components were washed, screened
through.a 2 mm.sieve and semi-dried. A test sub-sample was taken from which
one weighed fraction was used for moisture content determination and the other
weighed fraction was used to measure the amount of sand, silt and clay present.
For the latter fraction, a hydrometer analysis method as described in the
American Society for Testing Materials boo k of standards, was followed. However
only the 250 and 1440 minute settling times were recorded. After the analysis,
the contents in the hydrometer cylinder were passed through a 0.062 mm screen
and the sand fraction was weighed and seived. The data was then utilized in
calculating the percentages of sand., silt, and clay. In this analysis,
clay is defined as particles that are less than .0034 mm (3.4 micron)
rather than the conventional 3.9 micron.
Results
1. Shoreline: From Calf Pasture Pt. to Airport bulkhead, the shore is
comprised of sandy beaches, rocks and steel bulkheads. Sand beaches are
found north of the ramp to just south of the Allen Harbor entrance at Dogpatch
(Fig-2). The beaches, consisting of lenses of coarse-medium sand with
gravel admixture, lie upon a coarser surface. T .he beaches are about 75-100
feet wide; slope 2-4 degrees offshore; and have at times 1-2 foot cusps on
their foreshore. A small dune line borders the bench north of the ramp.

-4-

On other sections of the shoreline, beaches are poorly developed or
absent. These include the south side of Allen Harbor entrance, around the
ramp, between the ramp and Pier 2 - where the eroded edge of marsh deposits
forms the shoreand south of Pier 2 immediately west of bulkhead terminus.

Adjacent to the shoreline, the bottom is essentially flat. This very
shallow flat bottom extends many hundreds of feet seaward. Fine sand, light
at the surface but dark below, characterizes the bottom. In front of the
cottages south of Pier 1 (Dogpatch), about 2 feet of fine sand overlie a
mud layer of 0.5 to I ft in thickness. The mud is composed of 85% silt,
)D%clay, and 5% sand. The extent of this mud layer in the entire nearshore
bottom is unknown. Moreover an occasional boulder is also observed in the
nearshore zone. A fan-shaped deposit of sand and gravel, extending some 200
ft outward from the shore, lies adjacent to a swamp that is located just north
of the line of shore cottages. This. swamD is drained by a well-developed channel
that is offset toward the south on the beach face before turning seaward on
the fan. Where the bulkhead begins the bottom consists of cobbles and
boulders. which may serve to protect the two large bulkhead culverts which
connect with Fry's Pond.

Some insight into shoreline -processes may be inferred from these observa-
tions. Evidence of a net southward bea ch drift is apparent from the beach
accretion on the north side of the Allen Harbor entrance, sand infilling on the
north side of the harbor channel, rip-rapping on south side of harbor entrance,
eroded shore south of Pier 1, and southward off setting of swamp channelway
south of Pier 1. However, the southward beach drift is believed to be weak
south of Allen Harbor entrance.

No evidence was uticoveredduring the July field inspection to support the
existence of a seasonal exchange of sand from the beach to the nearshore bottom

or from the nearshore bottom to the beach.

2. Bathymetry- Bathymetric data are presented as a contour map (Fig. 3).
The relief in the area is characterized by the dredged ship channel net-
work and a drowned stream channel adjacent to the airport bulkhead (Fig. 3).
Otherwise,the bottom shows a gradual inclination offshore from 6 to 26 feet.

-37'

-----------------

FIG. 3 BATHYMETRY
416 (Soundings Corrected to Moan Low Water)
36'
Contour Intervals I foot

0 0.5
nautical miles

I Inch-400 feet

716
24
I

-5-

Their edges are well-defined and marked by slopes that range from 1:2.5
1:4. Apparent slumps are observed at a few locations.

A drowned stream valley complex lies immediately north of the airport
bulkhead and essentially parallels. the structure. This valley extends from
the vicinity of the shore eastward to a position northeast of the bulkhead
where it loses its identity. Depths within the valley reach 18 to 26 feet.
The most noteworthy aspect of this feature is that a harrow divide separates
the depression into two well-defined channelways.

Away from these prominent features, the bottom is shallower with no
distinct relief except for two small "mounds" that occur between the piers and
airport bulkhead at depths of 17 feet.

3. Bottom. surface conditions (side-scan sonar): The side-viewing sonar
survey reveals a small variety of bottom features within the area (Fig. 4).
These features include the edges of channelways; the units of the valley complex
adjacent to the airport bulkhead; the divide within the valley complex; rake
marks; three arbitrary categories of bottom roughness (i.e. slightly rough,
very slightly rough and smooth bottom); and a number of U'nideritified targets.
The distribution of the features follows no pattern except that the smoothest
bottom occurs only in the channels and'valley complex.

4. Sediment
Surface sediments range from sands to silts (Fig. 5) (Appendix A).
These sediment types reflect sand contents that vary from 98% sand to
4% sand. Across the area, the bottom sediment shows dark sands composed of
up to 98% sand inshore grading to dark sediment with 74-54% sand further off-
shore that contains 20-42% silt and 346% clay(particles less than 3.4 microns).

The finest sediment, silt deposits, are located within the dredged ship
channel and the drowned river valley adjacent to the airport bulkhead. In the
ship channel, an unstratified silt accumulation, measured by coring to be
approximately 18 inches at one location, contains 75-84% silt, 6-:17% clay
and 4-16% sand and overlies a sandy dredged surface. The si.ir within the
drowned valley shows 77% silt, 13% clay and 10/0Q" sand. Beneath the surface silt,
the bottom is composed of laminated units of fine sediment at least to a
depth of 2.3 feet.

aso
Slightly Rough Bottom

.:-Very Slightly Rough Bottom

Smooth Bottom

Edge of Channel, Hillock. or Depression

Rake Marks

L on
-Targets Undefined

Chain

trim

Ion 01 111.

100 9).4

FIG. 4
SIDE-SCAN SURVEY April 16, 1980
41* (Feature Locations Based Upon Slant Ranges)
36,

0 nouticet miies 0.5

1 Inch-400 feet

25' 71*
214'

0211
75% Sand
,\MMMM\@ - 50%-75% Sand

25%-50% Sand
57'
RE- < 25% Sand

o- Grab Samples 1-27 %sand content

0- Samples trom Coastal Resources C ter
(1977) A-H %sandcontont
@,?Lv -a@ J4jj j:
-0- Core Locations:

.... .............
4 ......... ... ..........
r: r:: j t-,! ot I

P
.............

1:7

0031%,

Im'
q

FIG. 5

SURFACE SAND DISTRIBUTION
41*
-36'

nautical miles

I inch 400 foot

:vIx

710
25' 24'

The sand component in all sediment types is dominated by fine to very
fine sand (Appendix A). Shells and gravel comprise only 2-7% of the samples.

5. Bedrock
Bedrock depths are shown in time units (Fig. 6) and feet (Fig. 7)
based upon a speed in water of 4800 ft/sec and a sediment velocity of 5,000
ft/sec (Birch and Dietz, 1962). C.E. Maguire boring sites with bedrock
depths are also plotted on Figure 7. Compilation of bedrock depth data is
presented in Appendix B.

The depth, attitude and shape of the bedrock surface is apparently con-
trolled by the down cutting of an ancient drainage system. The dissected sur-
face lies from 47 to 119 ft below MLW with no obvious attitude. Unfortunately,
a'significant portion of the surface is hidden because of attenuation of the
acoustic signals by gaseous sediments beneath the channels and valley complex.

A major bedrock valley crosses the area from NW to SE. Depths within this
valley reach more than 110 feet east of Pier I but shoal toward the southeast
before apparently connecting with a N-S trending channel that lies adjacent to the
study area on the east. A smaller bedrock valley, oriented E-W, appears to join
the NW-SE trending valley northeast of the airport bulkhead. Bedrock depths
within this valley are less than 90 feet. South of Pier 1, it is uncertain as
to how the bedrock depths of almost 100 feet are related to the valley segments
described above.

The shallowest bedrock dephts, about 50 feet, are associated with the
western divide of the N-S trending valley that lies along the study area s eastern
side.

6. Overburden: Sediment thickness is plotted as an iso@ach map (Fig. 8).
Calculated thickness values are based upon a sediment velocity of 5,000 ft/sec.
All data on the overburden are presented in Appendix B. Sediment thickness
information from he C.E. Maguire borings and bore holes during U.S. Navy
ownership (Coastal Resources Center, 1977) is also shown on Figure 8.

Overburden thickness ranges from 25 to 99 feet. These values are closely
kelated to the configuration of the bedrock surface: the greatest thickness
occur in the bedrock valleys with lesser sediment cover lying on the divides.
Hence an overburden thickness of over 99 feet is found immediately east of
Pier 2 and more than 80 feet lies south of Pier 1.

Alf)
37' 2

20---

FIG. 6 BEDROCK DEPTHS
4 In tirno units (milliseconds)
-36 Contour interval, 5 rnsec

0 0.5
nautical miles

I inch 400 feet

710
25' 24'
L

37' IgGaseous Sediment 100 90
Bore Hole depth to bedrock 100 110 80 70

70
80

lilt ]lilt]

;7
11 lilt

90
80 1
49

70 n7O 60

Fig.. 8 BEDROCK DEPTHS
-410 in feet measured from mean low
A 36' water.Contour interval: ten
feet.
0 Nautical Miles 0.5

0 400
feet
710
25' 241

so
40 r
,,o

Gaseous Sediment

-Bore Hole--Depth (it) of Overburden

-Bore Hole--Depth (it) of Pehetration 90
-37' to refusal 90 90
0 -Bore Hole--Depth (it) of Penetration 70
In Overburden 70 60
1.60
11 -Bore Hole--(Navy) Depth (it) 50
of Penetration in Overburden 40 30

0
84 50

5qr 0
52
39 7
47 0

0
52
a
41 0
44 32
? 40
2
70

0
0 32
48 72
V4

%-,Go
50
60

FIG. 8
SEDIMENT OVERBURDEN THICKNESS
41' In foot
-36'
Contour Intervol: 10 feet

nautical miles

1 inch m 400 feet

25' 24'

-7-

Beoeath the E-W trending valley complex, more than 50 feet of overburden
covers the bedrock.

The smallest accumulation, about 50 feet, lies above the bedrock divide
that occurs along the area's eastern side.

A close inspection of the seismic records together with an interpretation
of C.E. Maguire's boring logs indicates that the overburden is composed
primarily of glacial outwash with a smaller amount of glacial till.

-8-

References

American Society for Testing and Materials, 1968, Book of ASTM Standards.
Standa rd Method for Grain Size Analysis of Soils, p. 205-216, Phila, Pa.

Birch, W.B., and F.T. Dietz, 1962. Seismic refraction investigations in
selected areas of Narragansett Bay, RI. J. Geophys. Res. 67: 2813-2821.

Coastal Resources Center, 1977. The Redevelopment of Quonset/Davisville, An
Environmental Assessment. Kingston, Univ. of Rhode Island.

APPENDIX A

Sediment Data*

Table I

@@TpLe %Sand %Silt %Clay
1 + 14 69 17

2 + 11 69 20

3 + 6 81 13

4 93 7 -

5 95 5 -

6 + 77 18 5

7 84 16 -

8 + 31 48 21

9 + 9 80 11

10 + 10 77 13

11 + 37 55 8

21 93 7 -

22 95 5

22A 93 7 -

23 + 55 39 6

24 + 74 23 3

25 98 2 -

26 + 93 4 3

27 + 16 76 7

+ hydrometer analysis performed
Sand greater than .063 mm.
Silt greater than .0034 mm., less than .063 mm.
Clay less than .0034 mm

SAND SIZE DISTRIBUTIONS

TABLE 2.

Sampie 2 mm -L.-rm ..5 nm .25 .125 .062

1.8 32.1 32.1 32.1

2 7.4 7.4 25.9 25.9 33.3

4 - A 7.4 16.3 56.4 9.3

5 4.9 11.6 22.0 25.1 24.0 6.5

6 .2 2.0 11.8 39.8 25.2 22.0

7 .6 2.4 4.5 16.0 28.6 22.0

8 1.0 4.9 4.9 9.8 48.0 30.4

9 - 4.8 4.8 7.3 29.3 58.5

10 - 6.5 6.5 9.7 19.4 54.8

11 .3 1.2 2.3 2.3 26.3 68.4

21- .1 .6 1.0 3.0 43.4 50.0

22 .1 .8 1.3 5.9 67.3 23.5

22A .1 .5 .9 1.6 61.5 33.6

23 .2 1.1 2.5 5.7 42.2 48.2

24 - .5 1.9 15.7 37.0 45.4

25 .1 2.3 10.4 14.3 63.8 9.1

26 - .4 .7 12.1 49.3 37.3

27 - .9 1.9 3.7 18.5 74.1

APPENDIX B

SUB-BOTTOM DATA

(a) (b) (c) (d)
Time to btm Btm depth Time to Bdrk Time Diff Sed Thick Depth to Bdrk
Position m sec 4800 ft/sec (m sec) c-s (m sec) (ft) (b+d)(ft)

1540 5.5 26.4 19 13.5 67.5 93.9

1540.5 5.75 27.6 18.5 12.7 63.5 91.1

7.5 36

1542 5.5 26.4 18.5 13.0 65 91.4

5.2 25 19.0 13.8 69 94

5.2 25 18.5 13.3 66.5 91.5

5.0 24 18.5 13.5 67.5 91.5

1544 5.0 24 19.5 14.5 72.5 96.5

4.5 21.6 18.0 13.5 67.5 89.1

4.0 19.2 17.0 13 65 84.2

5.0 24 16.5 11.5 57.5 81.5

1546 4.75 22.8 16.5 11.7 58.5 81.3

3.5 16.8 16 12.5 62.5 79.3

3.5 16.8 15.5 12 60 76.8

3.0 14.4 16 13 65 79.4

1548 3.2 15.4 15.5 12.3 61.5 76.9

3.0 14.4 14.5 11.5 57.5 71.9

3.5 16.8 14 10.5 52.5 69.3

3.5 16.8 -13.5 10 50 66.8

1550 4.0 19.2 13 9 45 64.2

3.5 16.8 13 9.5 47.5 64.3

2.5 12 12.5 10 50 62

4.0 19.2 13 9 45 64.2

G* denotes gaseous sediment

-2-

Appendix B (con 't)

S"UB-BOTTOM DATA
(a) (b) (c) (d)
Position Time to btm Btm depth Time to Bdrk Time Diff Sed Thick Depth to Bdrk
m sec 4800 ft/sec (m sec) c-s (m sec) (ft) (b+d) (ft)

1552 4.5 21.6 G

5.0 24.0 G*

1553 4.5 21.6 G

5.0 24 G

1554 4.5 21.6 G

3.5 16.8 11.5 8 40 56.8

3.5 16.8 12.5 9 45 61.8

4.0 19.2 13.0 9 45 64.2

1556 3.5 16.8 13.0 9.5 47.5 64.3

3.5 16.8 15.0 11.5 57.5 74.3

4.0 19.2 15.0 11 55 74.2

4.0 19.2 16.0 12 60 79.2

1558 4.0 19.2 16.5 12.5 62.5 81.7

4.2 20.2 18.5 14.3 71.5 91.7

4.2 20.2 21.0 16.8 84 104.2

6.5 31.2 G - - -

1600 6.5 31.2 G - --

7.0 33.6 21.0 14 70 103.6

7.0 33.6

1602 7.0 33.6

7.2 34.6 G - - -

5.0 24 12.0 7.0 35 59

6.5 31.2 13.5 7 35 66.2

denotes gaseous sediment

-3-

Appendix B (con't)

SUB-BOTTOM DATA

(a) (b) (c) (d)
Time to btm Btm depth Time to Bdrk Time Diff Sed Thick Depth to Bdrk
Position m sec 4800 ft/sec (m sec) C-a (m sec) (ft) (b+d) (ft)

1604 6.5 31.2 14.5 8 40 71.2

5.5 26.4 15.0 9.5 47.5 73.9

5.5 26.4 15.5 10 so 76.4

5.5 26.4 15.5 10 50 76.4

-4-

Appendix B (con't)

SUB-BOTTOM DATA

.(a) (b) (a) (d)
Position Time to btm Btm depth Time to Bdrk Time Diff Sed Thick Depth to Bdrk
m see 4800 ft/sec (m see) c-a m see) (ft) b+d (ft)

1606 5.5 26.4 16.0 10.5 52.5 78.9

5.5. 26.4 16.0 10.5 52.5 78.9

5.2 25 13.0 7.8 39 64

5.0 24 15.0 10 50 74

1608 5.0 24 16.0 11 55 79

4.5 21.6 18.0 13.5 67.5 89.1

3.5 16.8 19.0 15.5 77.5 94.3

3.5 16.8 19.5 16 80 96.8

1610 4.0 19.2 22.0 18 90 109.2

3.5 16.8 23.0 19.5 97.5 114.3

3.0 14.4 22.5 19.5 97.5 111.9

1612 3.0 14.4 21.5 18.5 92.5 116.9

3.3 16.8 22.0 18.5 92.5 109.3

3.2 15.4 22.0 18.8 94 109.4

1614 3.5 16.8 19.0 15.5 77.5 94.3

3.5 16.8 17.5 14 70 86.8

3.5 16.8 16.0 12.5 @62.5 79.3

3.7 17.8 15.5 11.8 59 76.8

1616 4.2 20.2 15 10.8 54 64.2

1616.5 4.7 22.6 14.5 9.8 49 71.6
1617 5.0 24 15.0 10 50 74
1617.5 5.0 24 14.5 9.5 47.5 71.5
1618, 5.0 24 15:5 10.5 52.5 76.5
? 6.2 29.8 18.0 11.8 59 88.8
1619 5.0 2.4 13.0 13 65 89

-5-
Appendix B (con't).

SUB-BOTTOM DATA
(a) (b) (c) (d)
Position Time to btm Btm depth Time to Bdrk Time Diff Sed Thick Depth to Bdrk
m sec 4800 ft/sec (m sec) c-a m sec) (ft) @b+d (ft)

1619.5 5.0 24 17.0 12 60 84

1620 4.7 22.6 15.5 10.8 54 76.6

4.0 19.2 13.0 9.0 45 64.2

3.5 16.8 12-.5 9 45 61.8

3.5 15.4 17.0 13.8 69 84.4

1622 3.5 16.8 17.5 14 70 86.8

3.2 15.4 19.0 15.8 79 94.4

3.5 16.8 18.5 15 75 91.8

3.5 16.8 19.0 15.5 77.5 94.3

1624 3.5 16.8 20.0 16.5 82.5 99.3

3.5 16.8 21.0 17.5 87.5 104.3

3.5 16.8 20.0 16.5 82.5 99.3

1626 3.5 16.8 19.0 15.5 77.5 94.3

6.0 28.8 G

7.0 33.6 G

1628 7.0 33.6 C
7.5 36 G*

6.7 32.2 G

1630 7.0 33.6 G* -

4.'-0 19.2 16.5 12.5 62.5 81.7

1631 4.0 19.2 16.5 12.5 62.5 81.7

3.5 16.8 16.0 12.5 62.5 79.3

denotes gaseous sediment

-6-
Appendix B (con't)

SUB-BOTTOM DATA
(a) (b) (c) (d)
Position Time to btm Btm depth Time to Bdrk Time Diff Sed Thick Depth to Bdrk
m sec 4800 ft/sec (m sec) c-a (m sec) (ft) b+d (ft)

1632 3.5 16.8 15 11.5 57.5 74.3

3.5 16.8 14 10.5 52.5 [email protected]

3.5 16.8 13.5 10 50 66.8

3.5 16.8 13 9.5 47.5 64.3
1634 3..5 16.8 13 9.5 47.5 64.3
3.5 16.8 13 9.5 47.5 64.3

3.5 16.8 12.5 9.0 45 61.8

5.0 24 G

1636 5.0 24 G

- - 12.0 - - -

4.2 20.2 12.5 8.3 41.5 61.7

5.0 24 G * - - -

1639 5.0 24 G*
5.0 24 G * - - - 1

1640 5.2 25 11.5 6.3 31.5 56.5

3.5 16.8 12.0 8.5 42.3 59.3

3.5 16.8 11.5 8 40 56.8

3.5 16.8 12.0 8.5 42.5 59.3

1642 3.2 15.4 12.0 8.8 44 59.4

3.2 15.4 12.0 8.8 44 59.4

3.5 16.8 17 13.5 67.5 84.3

3.2 15.4 18.5 15.3 76.5 91.9

1644 3.0 14.4 18.5 15.5 77.5 91.9

3.0 14.4 19 16 80 94.4

denotes gaseous sediment

-7-
Appendix B (con't)

SUB-BOTTOM DATA
(a) (b) (C) (d)
Position Time to btm Btm depth Time to Bdrk Time Diff Sed Thick DeDth to Bdrk
m sec 4800 ft/sec (m sec) (.c-a m sec) (.ft) b+d (ft)

1645., 3.2 15.4 19.5 16.3 81.5 96.9

3.2 15.4 20 16.8 84 99.4

1646 3.2 15.4 20 16.8 84 99.4

7.5 36 G* - - -

7.7 G* - - -

7.5 36 G* - - -

1648 6.5 31.2 G* - - -

6.7 32.2

6.5 31.2

6.5 31.2 G*

1650 6.7 32.2

6.7 32.2

7.0 33.6

1652 7.0 33.6 21.5 14.5 72.5+ 106.1

7.2 34.6 21.0 13.8 69 103.6

7.5 36

1654 7.5 36 15 ? 6.5 32.5 68.5

7.0 33.6 14.5 7.5 37.5 71.1

7.0 33.6 15.0 8 40 73.6

7.0 33.6 14.5 7.5 37.5 71.1

1656 7.0 33.6 14.5 7.5 37.5 71.1

7.5 36 15.5 8 40 76

7.5 36 15.0 7.5 37.5 73.5

6.5 31.2 15.5 8 40 71.2

denotes gaseous sediment

-8-
Appendix R (con't)

SUB-BOTTOM DATA
(a) (b) (c) (d)
Position Time to Btm Btm depth Time to Bdrk Time Diff Sed Thick Depth to Bdrk
m sec 4800 ft/sec (m sec) (c-a m sec) .(ft) b+d (ft)

1658 6.0 28.8 15.0 9 45 73.8

6A 28.8 16 .0 10 50 78.8

5.5 26.4 16.0 10.5 52.5 78.9

5.5 26.4 16.5 11 55 81.4

1700 5.5 26.4 16.0 10.5 52.5 78.9

5.7 27.4 16.5 10.8 54 81.4

6.0 28.8 16.0 10 50 78.8

6.0 28.8 16.5 10.5 52.5 81.3

1702 6.0 28.8 16.0 10.0 50 78.8

6.0 28.8 16.0 10.0 50 78.8

5.5 26.4 17.0 11.5 57.5 83.9

6,0 28.8 17.0 11.0 55 83.8

1704 5.7 27.4 16.0 10.3 51.5 78.9

5.7 27.4 16.0 10.3 51.5 78.9

5.7 27.4 16.5 10.8 54 81.4

1706 5.7 27.4 17.0 11.3 56.5 83.9

5.5 26.4 15.5 id 50 76.4

5.5 26.4 15.5 10 50 76.4

5.5 26.4 19.0 13.5 67.5 93.9

1708 5.7 27.4 21.0 15.3 76.5 103.9

5.5 26.4 21.0 15.5 77.5 103.9

5.5 26.4 22.0 16.5 82.5 108.9

5.5 26.4 21.0 15.5 77.5 103.9

1710 5.5 26.4 20.5 15.0 75 101.4

5.0 24 19.5 14.5 72.5 96.5

-9-

Appendix B (con't)
SUB-BOTTOM DATA
(a) (b) (c) (d)
Position Time to btz Btm depth Time to Bdrk Time Diff Sed Thick Depth to Bdrk
m sec 4800 ft/sec (m sec) (c-a sec) (ft) b+d (ft)

1711 5.2 25 19.5 14.3 713 96.5

5.2 25 19.5 14.3 71.5 96.5

1712 5.2 25 19.0 13.8 69 94

5.0 24 19.0 14 70 94

5.5 26.4 18.5 13 65 91.4

5.5, 26.4 19.0 13.5 67.5 93.9

1714 5.7 27.4 19.0 13.3 66.5 93.9

6.5 31.2 18.5 12 60 91.2

6.0 28.8 18.0 12 60 88.8

6.0 28.8 13.0 7 35 63.8

1716 4.0 19.2 12.0 8 40 59.2

4.0 19.2 12.0 8 40 59.2

3.7 17.8 13.0 9.3 46.5 64.3

1718 4.0 19.2 13.0 9 45 64.2

4.0 19.2 13.5 9.5 47.5 66.7

4.0 19.2 13.0 9 45 64.2

4.2 20.2 15.0 10.8 54 74.2

1720 4.5 21.6 17.5 13 65 86.6

4.5 21.6 18.5 14 70 91.6

4.5 21.6 18.0 13.5 89.1

1722 4.2 20.2 18.5 14.3 71.5 91.7

4.0 19.2 20.5 16.5 82.5 i0l.7

4.0 19.2 21.0 @17 85 104.1.

4.0 19.2 22.5 718.5 92.5 '-111.7

-10-

Appendix B kcan't)

SUB-BOTTOM DATA
(a) (b) (c) (d)
Time to btm Btm depth Time to Bdrk Time Diff Sed Thick Depth to Bdrk
Position m sec 4800 ft/sec (m sec) c-a (m sec) (ft) b+d (ft)

1724 4.2 20.2 24 19.8 99 119.2

7.0 33.6

7.2 34.6

7.0 33.6 G*

1726 7.0 33.6 G

7.0 33.6 G

6.5 31.2 G

1728 4.5 21.6 18.5 14 70 91.6

4.2 20.2 18 13.8 69 89.2

4.2 20.2 17.5 13.3 66.5 86.7

4.2 20.2 17 12.8 64 84.2

1730 4.2 20.2 16.5 12.3 61.5 81.7

1730,5 3.2 15.4 G* - - -

1731 3.5 16.8 G* - - -

3.7 17.8 15.5 11.8 59 76.8

1732 3.5 16.8 16 12.5 62.5 79.3

3.7 17.8 16 12.3 61.5 79.3

1733 4.0 19.2 15.5 11.5 57.5 76.7

5.0 24 G

1734 5.0 24 G

5.0 24 G

1735 3.7 17.8 13 9.3 46.5 54.3

3.5 16.8 14.5 11.0 55 71.8

denotes gaseous sediment

Appendix B (con't)

SUB-BOTTOM DATA
(a) (b) (c) (d)
Position Time to btm Btm depth Time to Bdrk Time Diff Sed Thick Depth to Bdrk
m sec 4800 ft/sec (M sec) c-a (m sec) (ft) (b+d) (ft)

1736 3.5 16.8 14.5 11 55 71.8

5.2 2.5 15.5 10.3 51.5 76.5

4.5 21.6 16.5 12 60 81.6

5.0 24 16.5 11.5 57.5 81.5

1738 5.0 24 18.0 13 65 89

5.0 24 18.0 13 65 89

5.0 24 18.5 13.5 67.5 91.5

5.5 26.4 19 13.5 67.5 93.9

1740 7.5 36 C* - - -

7.5 36 C* - - -

7.5 36 19.5 12.0 60 96

6.0 28.8 19.0 13 65 93.8

1742 6.0 28.8 19.5 13.5 13.5 96.3

denotes gaseous sediment

12-

Appendix C
SUB-BOTTOM DATA (Profile from Coastal Resources Center, 1977)
(a) (b) .(c) (d)
Time to btm Btm depth Time to Bdrk Time Diff Sed Thick Depth to Bdrk
Position m sec (4800 ft/sec) (m sec) c-a (m sec) (ft) b+d (ft)

1200 4.6 22.1 16.0 11.4 57 79.1

4.6 22.1 14.5 9.9 49.5 71.6

Al 4.6 22.1 14.5 9.9 49.5 71.6

4.6 22.1 14 9.4 47 69.1

02 4.7 22.6 15 10.4 52 74.6

4.7 22.6 14 9.3 46.5 69.1

03 4.7 22.6 12.0 7.3 36.5 59.1

4.7 22.6 10 5.3 26.5 49.1

04 5.0 24 10.5 5.5 .27.5 51.5

5.0 24 11.5 6.5 32.5 56.5

5.0 24 12.5 7.5 37.5

4.7 22.6 11 6.3 31.5 54.1

06 4.5 21.6 9.5 5.0 25 46.6

4.5 21.6 11.0 6.5 @32.5 54.1

07 4.5 21.6 95 5.0 145 46.6

5.0 24 11 6.0 30 54

08 6.0 28.8 11.5 5.5 27.5 56.3

6.0 28.8 12.0 6,0 30 58.8

09 6.5 31.2 13 6.5 32.5 63.7

6.5 31.2 11 4.5 22.5 53.7

1210 6.5 31.2 12.0 5.5 V.5 58.7

6.5 31.2 11.5 5.0 25 56.2

11 7.5 36 13.5 6.0 30 66

7.0 33.6 14.0 7.0 35 68.6

Appendix C
SUB-BOTTOM DATA (Profile from Coadtal Resources Center, 1977)
(a) (b) (c) (d)
Position Time to Btm Btm depth Time to Bdrk Time Diff Sed Thick Depth
m sec 4800 ft/sec m sec c-a (m sec) (ft) b+d (ft)

1212 6.5 31.2 15.0 8.5 42.5 73.7

6.5 31.2 15.5 9.0 45 76.2

13 6.5 31.2 15.5 9.0 45 76.2

6.5 31.2 17.0 10.5 52.5 83.7

14 6.7 32.2 15.5 8.8 44 76.2

6.7 32.2 16.5 9.8 49 81.2

1215 6.5 31.2 19.0 12.5 62.5 93.7

6.5 31.2 19.0 12.5 62.5 93.7

16 6.5 31.2 19.0 12.5 62.5 93.7

6.5 31.2 19.0 12.5 62.5 93.7

17 6.5 31.2 19.0 12.5 62.5 93.7

6.5 31.2 17.0 10.5 52.5 83.7

18 6.5 31.2 18.0 11.5 57.5 88.7

6.5 31.2 17.0 10.5 52.5 83.7

19 6.5 31.2 16.0 9.5 47.5 78.7

6.5 31.2 16.0 9.5 47.5 78.7

1220 6.5 31.2 15.5 9.0 45 76.2

PART C

EFFECTS OF DEVELOPMENT AT DAVISVILLE,

RHODE ISLAND ON THE MARINE ENVIRONMENT

Prepared For

The Rhode Island Department of Economic Development

Sheldon D. Pratt
Graduate School of Oceanography
University of Rhode Island

1980

TABLE OF CONTENTS

Page

1. Introduction . . . . . . . . . . . . . . . . . . . . . .

2. Aquatic Biology
2.1 Introduction . . . . . . . . . . . . . . . . . . . 2-1
2.2 Field Collections . . . . . . . . . . . . . . . . 2-1

Methods . . . . . . . . . . . . . . . . . . . . . . 2-1
Results . . . . . . . . . . . . . . . . . . . . . . 2-3
,)_9
Discussion of Field Data . . . . . . . . . . . . . Z-

2.3 Fisheries Resources . . . . . . . . . . . . . . . . 2-14
2.4 Effects of Development on Organisms 2-16

Burial . . . ... . . . . . . . . . . . . . . . . . 2-16
Bivalves . . . . . . . . . . . . . . . . . . . . . 2-16
Crustaceans . . . . . . . . . . . . . . . . . . . . 2-17
Suspended Sediment . . . . . . . . . . . . . . . . 2-18

3. Suspended Sediment

3.1 Introduction . . . . . . . . . . . . . . . . . . . 3-1
3.2 Field Collections . . . . . . . . . . . . . . . . . 3-1

Methods . . . . . . . . . . . . . . . . . . . . . . 3-1
Results . . . . . . . . . . . . . . . . . . . . . . 3-2

3.3 Discussion . . . . . . . . . . . . . . . . . . . . 3-4

Seasonal and Spatial Pattern . . . . . . . . . . . 3-4
Particle Concentration . . . . . . . . . . . . . . 3-5
Turbidity Produced by Dredging . . . . . . . . . . 3-5)
Effects of Alternate Designs . . . . . . . . . . . 3-7

4. Pollutants

4.1 Introduction . . . . . . . . . . . 4-1
4.2 Pollutant Data . . . . . . . . . . 4-1

Water Quality . . . . . . . . . . . . . . . . . . . 4-1
Hydrocarbons in Sediment . . . . . . . . . . . . . 4-4
Metals in Sediments . . . . . . . . . . . . . . . . 4-7
Hydrocarbons in Clams . . . . ... . . . . . . . . . 4-9
Neoplasia in Soft Shell Clams . . . . . . . . . . . 4-11
Metals in Clams . . . . . . . . . . . . . . . . . . 4-12

5. References

LIST OF FIGURES

2-1. Grab sample locations from benthic survey
3-1. Location of turbidity structures and surface/bottom values of
percent light transmission per meter obtained, March 5, 1980.

3-2. Temperature sections May 28, 1980.

3-3. Turbidity sections May 28, 1980.
3-4. Turbidity and temperature profiles at two locations, June 24,
1980.

4-1. Station locations for water and sediment quality samples.

4-2. Allen Harbor stratigraphy and location of samples.

4-3. Metal levels in soft shell clams.

4-4. Metal levels in hard clams Mercenaria mercenaria in Allen Harbor.

LIST OF TABLES

2-1. Davisville Benthic Survey. Number of individuals recovered from
.1 M2 grab samples.

2-2. Davisville Benthic Survey. Number of individuals recovered from
.018 m2 grab samples.

2-3. Response of marine fauna to suspended sediment.

3-1. Transmission and temperature of surface and bottom water in the
Davisville area.
4-l'. Water quality data for the Davisville area.

4-2. Sediment hydrocarbon concentration in the Davisville area.

4-3. Hydrocarbon concentration of soft shell clams.

4-4. Clam analyses, RIDH, Allen Harbor project..

4-5. Hard clam analyses station 9 of Mount View, North Kingstown.

1. INTRODUCTION

This repor t was prepared in support of environmental assessment work for

the Rhode Island Department of Economic Development by the Coastal Resources

Center (CRC) in order to evaluate designs for port expansion at Davisville

Piers proposed by C.E. Maguire, Inc.

Baseline data were collected and some potential biological effects
of development were identified in a 1977 report on redevelopment of Quonset/

Davisvil le by CRC. In response to the issues raised in 1977 for the

Davisville project area, both from special field observations and from recent

studies by other agencies.

Field collections and baseline data are presented in three subsections

(Aquatic Biology, Suspended Sediments, Pollutants) with some discussion of

the effects of alternative plans. The major conclusions of this report

as they pertain to specific designs are summarized in the Environmental

Assessment of Davisville Port expansion.

2 AQUATIC BIOLOGY

2.1 Introduction

Development in the Davisville area will affect all elements of the
estuarine ecosystem including planktonic plants and animals and free-swimming
fish and crustaceans. Only the bottom-dwelling animals (benthos) are con-
sidered in detail in this report. Bottom animals will be directly effected
byremoval or burial and by changes in bottom type and pollutant concentration.
They can be sampled quantitatively because they are mainly small in size and
have limited mobility. They include commercially important species and species

which indicate stress or changed bottom conditions.

Field collections of bottom animals were made in March and May 1980
using techniques similar to those used in the October 1976 survey (Pratt,
1977). The results of both surveys are discussed in terms of the different
groups of species present and the adequacy of the baseline to detect impacts

of development.

Recent literature on the effects of suspended sediment and burial on

estuarine animals is reviewed to identify the potential impact of dredging

alternatives.

2.2 Field Collections
Methods.. The study area for benthic biology included the area between
the airbase bulkhead and the Davisville piers as far out as the dredged

turning basin and approach channel. Quantitative grab samples were taken

by two methods.
In depths of more than 6 feet bottom samples were taken with a 0.1 m2
Smith-McIntyre grab with weight adjusted for bottom hardness. A subsample
was mmoved for grain size analysis. Stations were located near those sampled
for the 1976 Quonset-Davisville study where practical (Fig. 2. 1). A single

0 CO M' (MARCH 5,12, 1980)
O.OISMP- (MAY 6, 1980)

05 30
120
cv@ %
'7
6 9
00 0',
010

Figure 2-1. Grab Sample Locations for Benthic Survey
Letters A-D designate reference points along Dogpatch Beach
for each series of 0.018 m2 oaicples.
A pilings
B sea wall
C rocks
D navy bulkhead

2-2
sample was taken at 11 stations. Three partially full grabs were combined
in 7Q to provide a qualitative sample.
The shallow flat at the foot of Dogpatch beach was sampled by hand with
a "gas can" sampler which collects a deep sample (40 cm) 0.018 m2 in area.
Single samples were taken along 4 transects perpendicular to the beach.
All samples were sieved on a 1.0 mm screen as in the 1976 study. The
residue was preserved and stained in rosebengal-formaldehyde. Animals were
separated from debris and identified to species. Shell lengths of mollusks
were measured and sample residues such as animal tubes and shells were

recorded.

2-3

Results. The bottom environments in the Davisville area can be placed into

three categories on the basis of depth. rhe dredged channels and b.-isl n I-Ind

the natural. channe-I in Fry Cove (sta. 1, 2, 3, 9, tO) are floored wtth sowL-

fluid sediments with 80-69 percent silt and 11-21 percent clay. Along Dog-

patch Beach a sand platform extends several hundred feet offshore below

the mean low tide level. This area was sampled by "gascan" stations. The

remaining stations (6, 5, 4, 7, 11, 8) are on gently sloping bottom

grading from 95 percent sand to 31 percent sand, 69 percent silt/clay

between the beach and channel. The shells of clams, oysters, and "deckers"

(Crepidula) and live "deckers" provide hard substrate and shelter in this

mid area.

Each depth zone/bottom type has its own temperature pattern. The

shallower areas warm faster in the spring and have higher summer temperature.

The deep samples were taken in March when water temperature was 10C through-

out the water column. The shallow "gascan" samples were taken on a sunny

day in May with water temperature about 150C.

Numbers of individuals identified in each sample are given in Tables 2-1
and 2-2. The 0.018 m samples are 5.5 smaller than 0.1 m2samples. Parameters

for 1976 and 1980 samples from similar locations are given in Table 2-3.

The channel stations (1, 2, 3, 9, 10) had very low numbers of species

and individuals (1-5, 1-110). The few species present were those adapted

for life in the deeper soft bottoms of the Bay, but are usually found in

greater densities (Table 2-1).

The Dogpatch Beach samples contained 4-21 species per sample and high

numbers of species adapted for unstable sandy substrates such as the gem

clam (Gemma gemma), the tellin clam (Tellina agillis) and the polychaete

2-4
Table 2-1

DavisvilleBenthic Survey. Number of individuals recovered from
0.1 m2 grab samples (March 5,12, 1980).

SPECIES STATIONS
1 2 3 4 5 6 7 Q7 8 9 10 11

Polychaeta
Glycera americana 7 3 15 7 18 3 12
Pectinaria gouldii 2 2 8
Nephtys incisa 4 9
Mediomastus ambyseta 1 13 36 20
Maldonopsis elongata 12 1 6 7 1
Clymenella torquata 2 1 1
Spiochaetopterus oculatus 2 1
Tharyx sp. 1 28 1
Pholoe minuta 1
Scoloplos robustus 1
Capitella capitata 1 2 5 5
Sabellaria-@-ulgaris 3 10 8
Harmothoe extenuata 1 1 1 2
Nereis succinea 3 1 4
Strebiospio benedicti 3 9 3 1 3 6
inoe nigripes 6 1 6
Phyllodoce drenae 1 1 1
Polydora ligni 2 1 1
Glycinde solitaria I
Lumbrinereis fragilis I
Paraornis fulgens 2
Goniadella gracillis 1 2
Amphitrite ornata 2
Amphitrite cerrata 1
Polydora sp. 1 1
lumbrinereid sp. 1
Paranaitis sp. 1 4 3
Syllid sp. 1 1
Notomastus?
Micropthalmus?
Polycirrus,? 2
Scoloplos? 2 2
Oligochaeta 1

Nemertines 2 10 1

Anthozoa
Edwardsia sipunculoides I

2-5

Table 2-1 (cont'd

SPECIES STATIONS
1 2 3 4 5 6 7 Q7 8 9 10 11

Mollusca
Nucula annulata 13 1 1 87 95
Tellina 9 13 2 24 16 41 2 4
-!@ f @11 k! @ 10 11 1 2 13
mulinea lateralis 3 9 2 1 1 11 3
Yoldia limatula
Pitar morrhuana 3 1 4
Mercenaria mercenaria 1 7 7 1 3 3
Mya arenaria 2 2 1 11 1
Pandora gouldiaria 1
Lyonsia hyalina 15 19 10 1
Acteon caniculata
Tc-teon punctostriatus 5 2
Nassarius trivittatus 1 22 13 2
Crepidula fornicata 120 86 19 14 224
Crepidula plana 74 95 23 6 175
Anomia simplex 1 2 4 1 10 12

Crustacea
Ampelisca vadorum/abdita 52 364 488 4 7 46 108
Ampelisca verrilli 1 2 8 1 3 1
Unciola irrorata 3 3
Batea catharinesis 1 3
Upogebia affinis 1
Microdeutopus gryllotaloa 1 10 2
Elasmopus levis 2 1
Paraphons spinosus 12 1 2
Corophium SPP.
Rhithropanopeus harrisi 4 4 2 1 5
Pagurus longicarpus

Table 2-2
Davisville Benthic Survey- number of individuals recovered from 0.018 M2 grab s.amples (May 6, 1980).

A (pilings) B (wall) C (rocks) D (bulkhead)
2 3 4 1 2 3 4 2 3 4 1 2

Polychaeta
Glycera americana 1 3 1- 4 3 1
Te`diomas@us imbyseta 4 1 7 1 15
Capitella capitata 13 2 25 15 10 1 3
Notomastus luridus 1
Goniadella qracillis 1
Clymenella torquata 1 2 4 2
Spiochaetopterus oculatus 2 2 2 2
Tharyx sp. 1 1 2 2 7
Scoloplos. robustus 16 9 10 15 4 7 4 3 15 27
Streblospio, benedicti 1 3 3 3 4 4 1
Polydora ligni 9 3 2 1
Spio, setosa 10 82 14 19 18 26 15 37
Pygospio, Sp. 7 1 3 13 9 63 1
Dispio sp. 4 5 2 2 7 1 1 2 1 3
Nereis arenaceodonta 1 2 2
Podarke obscura I
Eteone heteropoda 6 6 1 9 4 1
Eteone longa 1 3
Drilonereis tenuls 1 5
Diopatra cuprea 1 1
Parapionosyllis lonqicerrata 8
Syllis #1 1 1 1
Exogene
Oligocheate 1 11 10 14 3 6 1 3
25 2
I
Nemertines 2 1 .1 1

Table 2-2. (cont'd

A (pilings) B (wall) C (rocks)_ D (bulkhead)
2 3 4 1 2 3 4 2 3 4 1 2

Mol I usca
Nucula annulata 1 2 10 2 2
Tellina agilis 4 1 20 1 6 1

Gemma gemma 357 87 2369 2 6 6 8 13
Mercenaria mercenaria I
Crepidula fornicata 1 2 2
Acteon caniculata 2 17
Mysella sp.? 1

Crustacea
Ampelisca verrilli 14 1
Ovalipes ocellatus
Number of Species 16 16 19 14 17 4 13 21 10 20

2,8

worms (Scoloplos robustus) and �Ri:o setosa. In the deeper beach samples

on the edge of the platform (C-4) the tubes of the large amphipod, @_Mk@_1_iscq,

verrilli, were evident. q4Rjtelja SApLtat@@, a polychaete sometimes identi-

fied as a pollution or stress indicator was present in this area. Only 2

hardclam juveniles and no sof tshell clams were found (Table 2-2).

The mid-depth samples contained from 21 to 31 species and 91 to 664

individuals per sample. Dominant species included the bivalve, Tellina

the gastropods, Crepidula fornicata, and C. pLana,; the tube-dwelling

amphipod crustacean, 3mpeli:.sca vadorum; and the polychaete americana

(bloodworm). The bivalve, Nucula annulata was found in the deeper, more

silty samples. Hard clam juveniles were found in all mid-depth samples.

-Di-scussion of Field Data.. The species present in the mid-depth samples were

similar to those found in 1976. The numbers of individuals and species

per sample was also similar as shown below for matched samples.

1976 1980
Location & depth sta. inds. species sta. inds. species

Fry Cove 10' 15 609 37 6 664 31
Fry Cove 10' 5 647 25
Fry Cove 8' 4 333 25
Fry Cove 12' 14 289 19 7 91 21
Fry Cove 15' 11 261 17
Fry Cove 15', 18' 13 333 26 8 510 28
North of piers 10 473 32

Samples can al:3o be, compared in terms of the relative importance of each
species within the samples by calculating a percent similarity index. This
is calculated by summing the smaller percent abundance in which each species
is found in the pair. Dtipticate samples often show a 70 percent simi.larity
(Sanders, 1960). Duplicate samples 7 and 7Q had a 59 percent similarity.

2-9

Samples from a given bottom type often show a 30 to 40 percent similarity.

The values for three sample pairs taken in 1976 and 1980 fall within this

range.

Location Station % similarity
1976 1980

mid-depth 15 5 31.5
mid-depth 14 7 38.8
dredged channel 12 9 31.3

All of preceeding comparisons indicate that the mid-depth areas have

populations of bottom animals which are stable over seasons and years. This

stability may be the result of the presence of many bivalve and polychaete

species which live a year or more, the presence of adequate oxygen through-

out the year, and moderate wave effects. Heavy colonization by amphipods

of the species 3mpelis@ could occur at these depths as at the 1976 stations

off Allen Harbor. This would change relative abundances but

not species makeup.

Any large change in the makeup of species or species numbers caused by

dredging could probably be detected in the mid-water areas. One problem

which exists is the unknown effects of the extensive hard clam fishery now

taking place there. It is likely that soft bodied tube dwelling polychaetes

will be at a disadvantage and that fast growing "opportunistic" species

such as the "coot clam" Mulinea lateralis will increase. Removal of competi-

tors and disturbance of the bottom may also increase setting of hard clams.

The mo st significant finding of the survey was the large decrease of

individuals and species in the deep areas. This is illustrated by data

from matching stations.

2-11

1976 1980

Location sta. inds. species sta. inds. species

Fry Cove channel 16 420 23 10 50 3
Dredged channel 12 411 32 9 110 5
Dredged channel 17 460 27
Turning basin 11 199 22 1 16 3
Turning basin 2 10 2
Turning basin 3 1 1

Additional qualitative samples examined in both years substantiated this

pattern.

The species which were abundant in 1976 were the bivales Nticula annulata,

Macoma tenta, and Mulinia lateralis and the polychaetes Pectinaria _&2.uldi@i_

and Spiochaetopterous oculatus. In 1980 moderate numbers of N. annulata and A.

abdita were found at stations 9 and 10 respectively, but only a few individuals

were found in the turning basin samples.

The bottom sediments in all deep areas was very incohesive and anoxic

below a few millimeters. Although the previously occurring species are

all adopted for life in relatively soft sediments, M.' lateralis.is a suspen-
sion feeder and might not be able to feed on excessively soft bottom while

the polychaetes occupy tubes and require some sediment stability.

The M. tenta population observed in 1976 probably consisted of animals

which had set and grown during the summer. This species may not in fact

be adapted for year round survival in very soft sediments.

The absence of attached shell pairs, "clappers", of the bivalves

indicated that these had not been recent mortalities. It is possible that

the animals in these areas were killed during a period of low oxygen levels

in a previous summer. The absence of animal activity would allow the

sediment to remain anoxic below the surface throughout the year.

2-11

An alternative explanation for bivalve reduction in Fry Cove channel

is the feeding of very large flocks of diving ducks during the winter.

Scaup species are abundant in the cove. They have a diverse diet which

varies with the availability of food species. In a Long Island Sound study

Cronan (1957) found that important animal food of scaups included the nut

clam, N. annulata the coot clam M. lateralis; the barrel bubble, Retusa

canaliculata; and the blue mussel, @4yt@[email protected]. All these species are

present in Fry Cove. The small size and thin shell of M. tenera would

also make it a likely duck food. Scoters, which are usually found on the

open coast, sometimes enter the Bay where they feed on mollusks including

juvenile hard clams (Cronan and Halla,- 1968). Whether or not ducks are respon-

sible for the improverishment of the Fry Cove channel, they must have e ffects

on bottom animals throughout the cove.

The beach area was first sampled quantitatively in 1980. These sample s

show some overlap in species makeup with the mid-depth samples but all of

the dominant species are restricted to shallow stations and are known to

be characteristic of protected beach environments. The very dense popula-

tion of the small gem clam, -Geama-&eE@ja,, at one station may have resulted from

concentration by waves and currents similar to that which was observed in

Charlestown Pond (Phelps, 1964). On Dogpatch Beach softshell clams are

restricted to a cove south of the Navy bulkhead and patches around boulders.

Apparently wave action and sand movement prevent establishment on the

open sand platform.

2-12

The shallow, sandy platform, mid-depth area, and deep channel will

be affected differently by proposed development and respond to the changes

indLfferent ways. The shallow sandy platform off Dogpatch Beach has a

relatively high density of infaunal species, including some which are eaten

by winter flounder and wading birds. Wave action prevents development of

clam beds here. T his area would be eliminated by bulkheading and filling

in Fry Cove. Shallow bottom adjacent to developed

areas will be subject to mechanical disturbance and turbidity during

construction, but wave action will return the topography and grain size

to that existing previously.

The mid-depth area (much of it 10 feet deep) had the largest number

of species and individuals. The species present and their.densities
remained similar between the 1976 and 1980 sampling periods. Abundant crustaceans and

small bivalves provide potential sources of food for winter flounder,

and other fish and diving ducks. Significant populations of hard clams are

found at these depths both north and south of the Davisville Pier.

Portions of this area would be permanently lost by dredging. Mid-depth

areas adjacent to a dredged channel would be subject to burial by slumping

and sedimentation, to turbidity during construction, and to changes in

sediment grain size and water quality following construction.

The deep areas (20-30 feet) with soft, organic bottoms have the lowest

value to man in that harvestable bivalves and bottom animals eaten by fish

are nearly absent. Infaunal populations were much lower in these areas in

1980 than in 1976. Deep areas will receive fine grained sedimentation

from dredging activities. Newly dredged channels will fill with soft sedi-

ments and develop benthic populations similar to those found in the present

dredged areas.

2.3 Fisheries Resources 2-13

Shellfish and finfish are abundant in the waters off Quonset/Davisville.

The area supports both commercial and recreational fisheries: soft shelled

clams, quahogs, flounder, scup,striped bass,.bluefish, menhaden, lobster,

conch and baitfish, North of the Davisville piers, the water is classified

SA and shellfishing is permitted. Calf Pasture Point is an important quahoging

ground. South of the Davisville piers in Fry Cove commercial quahogging has

been active since the area was opened by the Department of Environmental

Management in July 1980.

Data from routine Department of Natural Resources fish trawls northwest

of the Davisville piers show that commercially important finfish species

are present. Several part-time draggers from Newport and Wickford catch

winter flounder, scup, fluke, butterfish, and baitfish in the area. Menhaden

frequently school in waters adjacent to Quonset (Ganz, 1975). Sportfishing

is extremely popular in the West Passage. Sisson (1970) reports that Wickford

based sportsfishermen spend an average of 44.6 days a year fishing for blue-

fish, striped bass, flounder, tautaug, scup, mackerel, and fluke, most of

which is caught in the Quonset/Davisville vicinity.

The fisheries resources of Davisville area were inventoried by the R.I.

DNR, Division of Fish and Wildlife (Ganz and Sisson, 1977; summarized in

CRC, 1977). They mapped concentrations of softshell clams in the low inter-

tidal immediately south of the Navy Bulkhead and among rocks halfway down

Dogpatch Beach. Maximum density in these patches were similar to locations
in Allen Harbor ( 42/m2). These areas have been used by recreational diggers

since opening of the fishery in July 1980. The shore between Allen Harbor

2
and Davisville Pier 2 had low densities of softshell clams (mean: 1.35/m ,n=17)

despite seemingly suitable conditions.

2-14

Hard clams are abundant in Fry Cove at subtidal depths. In the previous

CRC report (1977) all the cove was shown as having abundant clams but this

was based on only a few bullrake hauls. Since the cove has been opened it

has been heavily fished by commercial quahogers. As many as 30 or 40 boats

have been seen in the cove at one time during periods when preferred upper

Bay areas have been closed. According to personnel of the RIDEM Enforcement

Division, bullrakers have been concentrated off the Navy "wooden" bulkhead

and the airport "steel" bulkhead. A high proportion of more valuable smaller

clams (Mercenaria mercenaria) were reported off the steel bulkhead. Tongers

working in shallower areas along the beach appeared to be recovering a

higher proportion of larger clams. A few oysters are found on the rocks along

Dogpatch Beach. They are most abundant where the Fry Pond culvert empties but

are limited by availability of hard substrate and sand movement. At this loca-

tion harvestable individuals were 90-110 mm in length and most had smooth

eroded shells from the action of sand. About 15 percent had patches of sand

within the inner shell resulting from sand being forced in by waves and

covered by new shell. Near the bulkhead shells were heavily rust stained

but the tissue appeared normal. The long double culvert to Fry Pond may be

a source of oyster larvae. Fry Pond itself has little hard substrate for

oysters.

2-15

2.4 Effects of Development on Organisms

A long list of "potential" effects of development could be prepared.. It

is believed that only removal, burial, and exposure to suspended sediments

will measurably effect biota during construction. Pollutants are not present

in the glacia 1 outwashed sediments which make up most of the volume to be

dredged, and moderate pollutant levels in the sediments flooring the present

dredged channels are not readily available to organisms. Deepening will

change a number of sediment and water variables and will permanently change

the makeup of the bottom community in the dredged area.

Burial. The fauna transported to bulkheaded disposal areas and the fauna

within the bulkhead will be killed by deep burial and drying. Fauna around

the dredging effluent and adjacent to unstable slopes may be subject to

shallow burial,

Maurer et al. (1978) reviewed the literature on the ability of fauna to

recover from burial and,report the results of their own experiments with

estuarine species. They concluded that "many of the species tested ... showed

a surprising ability to vertically migrate and survi ve remarkably well in

relatively thick depths of native and exotic sediments under laboratory

conditions."

The results of short-term burial experiments with characteristic estuarine

species are summarized below. For each taxonomic group larger species are

given first.

Bivalves

Mercenaria mercenaria (hard clam, juveniles, 1.5-2 cm) recover from 32 cm of
sand at summer temp. Less recovery in silt/clay in summer, but no difference

due to sediment type in winter (Maurer et al., 1978).

2-16

Mya arenaria (soft shell clam) recover from 10 cm sand in 2-10 hours.

(Glude, 1954).

Nucula proxima (nut clam I cm) 90 percent and 32 percent reach the

surface in 8 cm and 16 cm of silt/clay in one day (Maurer et al., 1978).

Gemma gemma (gem clam 0.8 cm) recovers from 23 cm sand, 5.7 cm silt

(Shulenberger, 1970).

Polychaetes

_R122Atra_@;Epre@@ (tube dweller, 10 cm) recovers from 30 cm of sand

(Myers, 1972).

Nereis succinea (burrower, 8 cm) rapidly recovers from up to 85 cm

Maurer et al., 1978).

.@f2hty,@ Ancisa (burrower, 6 cm) rapidly recovers from at least 21 cm

silt/clay (Saila et al., 1972).

Scol2plo@@[email protected]_. (tube dweller, 4 cm) recovers in up to 30 cm of sand but

have low recovery in 8 cm silt/clay (Maurer et al., 1978).

Strell @os jo benedicti (tube dweller, 1 cm) can recover from up to 6 cm

silt/clay (Saila et al, 1972).

Crustaceans

Crangon sp.. (shrimp) swims through and above sediment slurry

(Peddicord et al., 1975).

Neopanope sayi (xanthid crab, 2.3 cm) moves upward through unconsolidated

sediment but become trapped if migration is delayed (Maurer, et al. 1978).

In summary recovery from burial is greater in larger species. Poly-

chaetes seem to be particularly well adopted for recovery while some crus-

tacea may become trapped by moderate burial. Species adapted for either silt/

clay or sand have difficulty moving through the other sediment type.

2-17

These results indicate that most motile benthic species in the

Davisville area will attain the surface after burial at the rate of a few

cm a day such as might occur from effluent release. Attached species

would be affected by shallow burial,but these are restricted to intertidal

rocks and bulkhead and a few subtidal boulders. In the intertidal areas

wave motion will tend to prevent permanent deposition of fine sediment.

Burial by sediment slumps and flows at the construction site to a depth

of 1-10 cm would kill some small species but some larger worms and bivalves

including hard and softshell clams would reach the surface.

S.uspended Sediment. Suspended sediment could potentially cause mortality by

clogging the gills of aquatic animals, it could also reduce the efficiency

of filter feeding, and cause avoidance by swimming fish. The following

table summarizes the results of laboratory exposure experiments with species

and genera present in the Davisville area. In general very high sediment

concentrations are necessary to cause mortality, even in static tests which

introduce additional stress. The larvae and juveniles of open water fish

were much more sensitive than adults of species occupying shallow

channels. The Bay scallop was the most sensitive of the commercially impor-

tant bivalves tested (Table 2-4).

Pumping rates of bivalves and ingestion rates of planktonic copepods

are reduced by suspended sediment concentrations of around 100 ug/l.

Recovery of adults will take place when turbidity is reduced, but larvae

may have decreased survival and settling success if growth is retarded.

2-18

Table 2-3. Response of marine fauna to suspended sediment.

Bioassays

Sherk et al. (1973) 24 hr. static test, percent survival

1. Fundulus majalis (striped killifish) 90% in 47,000 mg/l silt

2. Fundulus heteroclitus (mummichog) 90% in 24,470 mg/l silt
3. Tautogolabrus adspersus (cunner) 90% in 10,000 mg/l fullers
earth

4. Morone americana (white perch larvae) 50% in 3,750 mg/l natural
sediment

5. Morone saxatilis (striped bass larvae) 50% in 4,850 mg/l natural
sediment

6. Menidia meni dia (Atl. silversides) 90% in 580 mg/l fullers earth
7. Pomatomus saltatrix (bluefish juv.) 90% in 800 mg/l fuller's earth

Peddicord and McFarland (1978) 91 day flowing water test, percent survival.

1. Mytilus edulis (blue mussel) 80% in 15,500 mg/l clean silt

2. Crangon niqricauda (shrimp) 85% in 19,700 mg/l clean silt
3. Cancer magister (Dungeness crab) 62% in 9,200 mg/l contaminated
sand/silt (mortality during
molting)

Raytheon Co. (1974) 96 hour static test, no mortality observed at the
given concentrations of fine fraction of natural sediments.

1. Mercenaria mercenaria (quahog) 83,200 mg/l

2. Mercenaria mercenaria larvae 10,200 mg/l

3. Mlya arenaria (soft shell clam) 83,200 mg/l

4. Crassostrea virginica (oyster) 83,200 mg/l
5. Crassostrea vir inica larvae 9,600 Mg/I

2-19

Table 2-3. (cont'd. )

6. Pecten irradians (bay scallop) 500 (50% survival at 96 hrs.
1,760 mg/1)

7. Pecten irradians larvae 10,000 mg/l

8. Homarus americanus (lobster) 20,400 mg/1

9, Pseudopleuronectes americanus (winter flounder) 20,000 mg/l

Sublethal Effects

Davis (1960) and Davis and Hindu (1969) growth and survival of clam
and oyster eggs and larvae reduced at 125 mg/l suspended matter.

Loosanoff (1961) pumping rate of oyster reduced at 100 mg/l suspended matter

Sherk et al. (1976) reduction in ingestion rates of algae by estuarine
copepods.

1. Eurytemora affinis 55% in 250 mg/1 silt but
stimul ated at 100 mg/l

2. Acartia tonsa 50% in 100 mg/1 silt

3-1

3 SUSPENDED SEDIMENTS

1.1 Introduction

Hydraulic dredging will be used to transport sediments from the channels

to bulkhead and stockpile areas. Available equipment produces a slurry with

about 13% solids. Without confinement much of the fine grained fraction would

return to the estuary in runoff. Containment within dikes with long retention

times and with shallow "skimming" type outlet weirs will provide retention

of all but clay size particles. The degree of attention placed on control of

suspended sediments will depend on the grain size and pollutant level of the

dredged material and on the sensitivity of the aquatic environment in the

effluent area.

Suspe*nded sediments are usually asource of concern where hydraulic

dredging is being carried out. While this is to some extent the result of

the visability of turbid water plumes, there are many ways in which

suspended sediments would potentially effect marine life. Natural turbidity
levels and patterns of resuspension must be known in order to project the

impact of dredging on the environment and to determine whether dredge-

produced turbidity will be detectable. During this project field data on

water clarity was obtained on three occasions. These data are compared with

the results of other studies in Narragansett Bay. Research on the effects

of suspended sediment on estuarine fauna and the effect of burial by water

deposited sediment on fauna are summarized in the previous section.

3.2 Field Collections
On March 4, May 28, and June 24, 1980 water clarity was measured at 10

stations along three transects extending approximately one mile from Fry

Pond outlet, Davisvill e Pier 1, and Allen Harbor entrance (Fig. 3-@. The

ALLEN
HARSO 16
13 (016 21
12 021

DAVISVILLE
18'
PIERS I

2
04) io-
@24
W24 23

SO
FRY COVE

21 -W2
1(9 @ k,'-'
WE 5 26

Figure 3-1. Location of turbidity stations (circled numbers) and
surface/bottom values of percent light transmission
per meter obtained March 5, 1980.

3-2

instrument used was a Martek XMS transmissometer with a one meter path length

and white light. Depth and temperature sensors were attached to the trans-

missometer. Percent transmission versus depth and temperature versus depth

were recorded on a portable X-Y recorder during lowering and raising of the

instrument package. On May 28 surface and subsurface water samples were
taken through a tube attached to the transmissometer into an evacuated flask.

Particles were collected on 8 Pm nucleopore and 0.45 = millipore filters

for microscopic examination.

Results

Winter conditions were found on the March 5 sampling trip. Water

temperatures were between O'C and I'C and except for a small near-bottom

temperature inversion at some stations ( 0.25'C), there was no vertical

stratification. At the surface the clearest water was found offshore and down-

bay. The most turbid water occurred on the shallow shelf off Calf Pasture

Point (Fig. 3-1). Turbidity was vertically homogeneous except at station

3 and 9 where there was a clear water layer near the bottom and at station

7 in Fry channel where the bottom layer was turbid. Light transmission was

generally high for Narragansett Bay (13-28%/m) and indicated a low level of

phytoplankton and the absence of recent storms.

On the May 28 sampling date a strong thermocline occurred at a depth of

10-15 feet (Fig.3-2). At most stations there was a marked increase in

turbidity at the ther mocline from surface values of 10-15%/m to 0-2% in deeper lay-_

er.s (Fig, 3-3, Table 3"1). At station 7 in Fry Cove channel transmission/m decreased

regularly with depth from surface to bottom. At station 9 in the dredged

channel surface water was more turbid than water immediately over the thermo-

cline. Surface and bottom turbidities were similar throughout the study

area except in shallow water off Calf Pasture Point where turbidity increased.

TEMPERATURE, OC

ALLEN HARBOR

W
W
U- 15

CL 20-
19 3-01 STATION 2
DWISVILLE PIERS

STATION 5 6
FRY COVE

STATION 8 10

Figure 3-2. Temperature sections, May 28, 1980. 11:20-12:30,
Low tide 12:53 DST.

TRANSMISSION, %/METER

ALLEN HARBOR

W S
W 0-
U.
.10
10-
20-
L
CW 301 STATION 1 2 3
DAVISVILLE PIERS

:kj-

STATION 6
FRY COVE

STATION 7 8 10

Figure 3-3. Turbidity sections, may 28, 1980. 11:20-12;30, Low
Tide 12:53 DST. Wind 5-10 knots NW "S" indicates
water sampling station. Stippling indicates relatively
turbid water.
-15-

IEIE@m M M @ @ M mm M @ @ M = M M M @

Table 3-1 Transmission (%/m) and temperature (*C) of surface and bottom water in the Davisville area.

MARCH 5 MAY 28 JUNE 24
Trans Temp Trans Temp Trans Temp
Station Depth (Ft.) Surf Bot Surf Bot Surf Bot Surf- Bot Surf Bot Surf Bot

1 Off Allen H. 6 13 12 0.5 0.5 6 3 16 13.4

2 18 16 16 0.5 0.8 8 0.5 15.1 12.6

3 27 21 21 0.7 1.0 11.5 1.5 14.7 12.5
4 Off DV Dock 29 21 20 0.5 0.5 15.5 0 15.5 12.2 9 0 19.8 16.5

5 29 25 24 0.2 0.5 14 2 14.9 12.5

25 1 15.2 12.7
6 24 23 0.2 0.5 15
7 Fry Cove 20 20 14 0.5 0.5 13 0 15.3 12.2 9 0 19.3 18.2
8 10 21 21 0.5 0.5 10 0 15.7 13.0
9 30 22 25 0.0 0.0 8.5 1.5 15.2 12.5

10 25 28 26 0.0 0.0 14 1 15.1 12.6

3-4

Water sampled at station 4 showed an abundance of organic detritus and copepod

fecal pellets in the turbid deep layer.

Two profiles were made on June 24 in the turning basin and in Fry

channel (station 7). Surface warming had continued and the thermocline

was thicker and deeper than in May. The turbidity pattern was very different

from that found in May (Fig. 3-@. The surface was turbid, almost certainly

from high concentrations of phytoplankton. Within the thermocline the water

was relatively clear, but turbidity increased rapidly in a thermally homo-

geneous bottom layer.

3.3 Discussion

Seasonal and spatial pattern. At the study site the water was clearest in
March despite the frequency of winter storms. The surface values of 13-28%
transmission/m compares well with values of 17-22% recorded at the Graduate
School of Oceanography dock during calm periods in January and February
(Pratt and Heavers, 1975). In the G50 dock study, storms reduced trans-
mission to zero, but recovery was complete within 3-4 days. Oviatt and
Nixon (1975) measured sedimentation in Narragansett Bay with traps collected
at weekly intervals. They concluded that forces responsible for sediment
resuspension and deposition operated over shorter time periods. The shortness
of episodes of sediment transport suggest that most particles have settling
rates faster than clays. Oviatt and Nixon, and Collins (1974) both fou nd that

most suspended particles in the Bay were silt size.
In both the May and June records there was a near-bottom layer of
turbid water. Since conditions were presumably calmer than in March this
layer must form as a result of input of low density detritus from.organic
production,and stratified conditions leading to concentration in bottom
layers. Tidal currents rather than waves keep the particles in suspension.

TURNING BASIN

TEMPERATURE,OC TRANSMISSION, %/METER
21 20 19 18 17 10 5 0
W 0
W
It 10
x
I-- - . -R::
(L 20.
L

FRY CHANNEL (STA.7)

TEMPERATUREv OC TRANSMISSION, %/METER
W
W 21 20 1.9 18- 17 10 5 0
U. 0
e
10-
a.
W
20

Figure 3-4. Turbidity and temperature profiles at two locations,
June 24, 1980. Dashed lines show relationship of
temperature and turbidity features.

3-5

Particle concentration. Concentration of suspended matter was not

measured in this study. It is only possible to-convert light transmission

values to dry weight concentrations if the makeup of particles does not

change. Changing proportions of small particles and organic matter (with

large light stopping area relative to weight) complicates the relations-hip.

Measurements in Narragansett Bay and Rhode Island Sound by Pratt and Heavers

(1975) suggest the following approximate transmission-concentration conver-

sions: 20%jm=1-2 mg1l; 10%/m = 3.5 mg/l; 5%/m=4.5 mg/l; and 2%/m=5 mg/l.

Concentrations in the Davisville area derived in this way range from 1-5 mg/l.

These levels,are comparable to Morton's (1972 winter) Baywide mean of 3.7 mg/1

and Collins', (1974) Baywide surface and bottom means of 1.1 and 3.2 mg/l.
(both authors removed some organic matter from the samples). Tur bid bottom

water from the upper Bay with less than 1%/m transmission contained 21.6 mg/l

of suspended matter (Pratt and Bisagni, 1976).

No transmissometer or suspended particle measurements were made in the

study area during storms. Water along Calf Pasture Point becomes visibly

turbid when waves from the northeast erode shallow silty sand. It seems

likely that concentrations of suspended matter may reach levels typical of

an exposed English coast (50 mg/l, Newton and Grey, 1972) or the most turbid

parts of Chesapeake Bay (over 100 mg/l, Schubel, 1972). It can be assumed

that estuarine animals in the Davisville area are exposed to such high levels

of turbidity for periods of a day or two following storms.

Turbidity produced by dredging. Hydraulic cutterhead dredges creates

suspended solid levels below "a few hundred mg/1" only in the immediate

vicinity of the dredging site according to Peddicord and McFarland (1978).

Much more suspended matter is released in the dredge effluent. Palermo et al.
(1978) analyse the design, operation, and management of spoil containment

areas. They state that a well designed containment area can reduce suspended

matter from 145 g/l (13% sediment) to 1-2 g/l in effl uent from

3-6

silt/clay spoil. The rate of release of effluent depends on dredge size,

pipeline length, dredging depth, and hours per day of operation. For a

medium size cutterhead dredge with 18" outlet pipe roughly 5,000 cubic
yards of effluent are produced per hour. If 2000 mg/l of sediment in the
effluent remained in suspension it would be necess ary to dilute it 43 times
with 5 mg/l water to achieve a concentration of 50 mg/l, a "high natural"

level. Each hour 44 acres of water 9' deep would be needed for dilution.

The actual concentration of spoil-derived sediments in Bay waters will

depend on distance from the discharge, mixing rate, and settling rate of
particles. No field observations of water circulation have been made in the

Davisville area. The circulation model of the area.-prepared by Isaji

(1977) shows no-Kth and s.outh.tidal flows entering Fry Cove and the

Allen Harbor entrance cove, but at a reduced velocity. Small gyres flowing

contrary to tidal flow formed in the southwest corner of Fry Cove. When the
model was run with dredged depths similar to development alternative 1,

current velocities were further reduced in the deepened area.

Reduced velocities and partially closed circulation would allow suspended

sediment to settle within the coves. Containment seems to be best developed

in Fry Cove. It appears from the model that during flood tide water and
suspended sediment from Fry Cove would enter the main west passage flow and

not be carried directly into the Allen Harbor entrance cove.
When hydraulic dredging effluent is discharged into water without
containment, a fluid mud may be formed on the bottom with up to 20 g/1 sediment.
Ponded deposits of this material will kill sessel animals and will not support
larger motilespecies (Peddicord and McFarland, 1978). It is possible that a
limited volume of fluid mud could collect in the Fry Cove channel and the
dredged channels and basins from either containment area effluent or sediment

released by the cutterhead.

3-7
In summary it may be concluded that the maximum concentrations of suspended

sediments to which organisms. will be exposed are 1-2 g/l (1000-2000 mg/1) in

the immediate area of the containment area effluent. Suspended sediment

levels within the coves would be an order of magnitude higher than background

under calm conditions and similar to storm conditions.

Effects of alternative designs. Most of the material which would be

dredged in any of the suggested designs would consist of water-deposited

glacial sediments containing no organic matter or chemical pollutants. Small

volumes of estuarine sediments and recent channel-bottom fillings contain

moderate levels of pollutants which tend to remain adsorbed to particles.

We are not concerned with toxic pollutants but with the visual quality of the

water and the effects of suspended sediment and changes in bottom sediment

type on organisms.

It is most likely that effluent will be released into Fry Cove (designs

1,2,3,5,6). There will be a tendency for suspended particles to remain within

the cove. Fine material deposited on shallow sandy bottom (less than 10'

depth) will be subject to resuspension. It is unlikely that there would be

a permanent change in grain size in these areas. Ultimately, fine sediments

will be deposited in natural deep areas and dredged channels where they will

contribute to the softness of the bottom. Layers of dredge derived material

might be identifiable from absence of organic matter. Clay size particles

will be transported the greatest distance and may be deposited in silt/clay

bottom within the bay or be carried outside the bay. From April to October

water density stratification will inhibit upward mixing of sediments in near-.

bottom water. Locating discharge points near deeper areas might speed the
deposition of sediment in natural settling basins and reduce effects on

3-8
organisms in shallow water. It is unlikely that high concentrations of
suspended matter could reach Allen Harbor or Calf Pasture Point beach from

Fry Cove.

Release of effluent from a bulkhead north of the Davisville Piers

(design 4) would create temporary turbidity in the Allen Harbor entrance
cove and off Calf Pasture Point. Some sedimentation within Allen Harbor is
likely. Release into the turning basin or newly dredged channel would induce
settling in deeper water and also aid dispersion by north-south tidal currents.

11. POLL2JTION

4.1. Introduction

in this scetion data is giveti oii the pollunints prosent W Lhe sedillivilt

which may be dredged and on the likelihood of pollutant release from sediments

during dredging. The levels of pollutants in sediment and fauna of areas

adjacent to the proposed dredged area are tabulated as a basis for moni-

toring future development. The pollutant status within the present dredged

channels and developed area is used to-project conditions which will be

found in future dredged channels.

The Quonset/Davisville environmental assessment (CRC, 1977) directed

concern toward the possible effects of a large industrial dump on the

environment of Allen Harbor. A number of studies on pollutants and the condi-

tion of fauna in the Harbor have been carried out since that report was

released. Data from those studies are summarized here as baseline data for

monitoring during development outside the Harbor and to guide future

management of the Harbor itself.

Pollutant data is presented by subject and then discussed in terms of

alternative development plans.

4.2. Pollutant Data

Yater ality. The Rhode Island Department of Health conducted a bacterio-

logical survey of the Quonset/Davisville area between August 1975 and
November 1976 (RIDH 1976). Surface water samples were taken at 11 stations

on 6 dates. Tests were also run on samples from streams flowing into

Fry Pond and from the pond outlet in August 1976. A summary of results

for stations near Davisville are given inTable 4-1.

4-2

Table 4-1. Water quality data for the Davisville area.
(See Figure 4-1 for station locations).

Estuarine areas sampled on six occasions, August 19, 1975, Nov. 30, 1976.
Summarized from RIDH, 1976.

Dissolved Oxygen Fecal Coliform/100-ml
min max median
Station mg/l % sat. mg/l % sat. mg/l % sat. min max median

5 off airport 3- 3- 3.5-
6 Fry Cove 6.4 91 12.0 118 8.85 100 3- 9 3-
7 off D.V. piers 3- 9 3-
8 off Allen H., 3.2 93 11.8 116 8.7 108 3- 9 3-
9Allen Harbor 3- 4 3-

Fry Pond areas sampled August 4, 1976, RIDH unpublished data.

MPN /100 ml
Station total coliform fecal coliform

brook to pond, Pond and Newcomb Rd. 2300 90
brook to pond, near bld. 884 2300 2300
24" pipe to pond < 23 < 23
Fry Pond outlet 230 < 23

WATER QUALITY
2,3
0 METALS IN BIVALVES
9
OV. i6.9 0 METALS IN SEDIMENT
0 HYDROCARBONS IN
Ae
-4 08 SEDIMENT
:-:13

024

27
7
7 4:`
0
27A

06
2 rc 025
@0

%%
CULVERT
9
06

:5
10:
(A5 _j

Figure 4-1. Station locations for water and sediment quality samples.
Water quality and metals in bivalves (Rhode island
Department of Health) metals in sediment and hydrocarbons
in sediment (27A, 27 this study). Hydrocarbons in sedi-
ments (5-9. CRC, 1977).

4-3

Oxygen concentrations were high on all dates as expected for that

portion of the Bay. Concentrations may have been lower in bottom water.

however. Olsen and Lee (1979) show July (1972) bottom values of 3-4 mg/I

beneath surface water with 6-8 mg/l. During the summer vertical stratifica-

tion.partially isolates bottom water and oyxgen may be consumed by degrada-

tion of organic matter in bottom water and on the bottom. Sensitive animals

are affected by oxygen levels of less than 2 ml/l.

Fecal coliform bacteria were found in ve ry low concentrations in the

Bay and Allen Harbor samples. All samples had most probable numbers of

less than 9/100/ml/l. The maximum count for SA waters is 70/100 ml/l. A

small stream entering Fry Pond had high coliform levels which were reduced

within the Pond.

Fry Cove was closed to shellfishing for a number of years because of

possible contamination from houses on the Dogpatch Beach bluff and the

presence of berthed vessels at the adjacent piers. Following a conserva-

tive policy the RIDH did not open the cove to shellfishing until July

1980, despite the abandonment of the housing in 1974 and negative

bacteriological tests in 1977.

Coliform bacteria were uniformly low in hard clams from Narragansett

Bay north of Allen Harbor (Mount View, Table 4-5). Levels in both hard

clams and soft-shell clams from Allen Harbor in 1976-1977 are clearly

higher (Table 4-4). Sources of bacteria at that time may have included

buildings in the vicinity of the harbor and in its watershed and vessel

discharge. The intestinal bacteria of seabirds also gave positive coliform

tests.

4-4

Hydrocarbons in Sediments. High sediment hydrocarbon levels in the upper
Bay resulting from sewage effluents and oil spills decrease gradually down-
Bay. There are additional potential sources in the Davisville area including
effluents, spills, and dumping from both land and water based activities.
.As part of the initial Quonset/Davisville impact study Brown and Franklin
(1977) obtained total hydrocarbon levels of 100-641 ug/g dry weight from

different environments in the Davisville area (Table 4-2).
1Additional hydrocarbon analyses were carried out during this study by
the Graduate School of Oceanography Organic Geochemistry Laboratory. The
goals of these analyses were to allow comparison with data which the labora-
tory has obtained from throughout Narragansett Bay and to gain insight into
the sources and makeup of materials which will be deposited in the proposed

dredged channels.
Duplicate analyses were carried out on a surface sample obtained from
the Davisville turning basin, June 1980. Results and preliminary discussion
by Quinn, Requejo, and Pruell are given in Appendix 3. A data summary is

given in Table 4-2.
The concentration of total hydrocarbons from the turning basin was 934
ug/g dry weight, significantly higher than in fine-grained natural sediments
of surrounding areas studied by Hurtt (1978) of 359,356 and 246 ug/g. This
is also an order of magnitude higher than levels in intertidal sediments in
Allen Harbor sampled in 1980 (Table 4-2). The high total hydrocarbon level
in the turning basin probably results from deposition of fine grained organic

4@5

particles with adsorbed hydrocarbons from both upper Bay and local sources.

The presence of benzotriazoles (BTAs) from a source on the Pawtucket River,

Warwick demonstrates down-Bay transport.

The eleveted levels of specific aromatic hydrocarbons and total hydro-

carbons suggest additional sources in the Davisville area. Sources may

include compustion products in used lubricating oils and weathered fuel

oil. Identified aromatics were 83 times higher in the turning basin than

in Allen Harbor; total hydrocarbons were 12 times higher; and BTAs only 6

times higher.

The classification scheme used in Connecticut allows dredged material

with less than 500 ug/g hexane soluble fraction (oil and grease) to be dis-

posed of at sea without protective measures. Total hydrocarbon level

equivalent to this is higher than the 934 ug/g found in Davisville sediments.

Davisville sediments are "clean" when compared to polluted harbors in New

England, but are "dirty" compared to immediately adjacent parts of Narragansett

Bay. Since hydrocarbons are strongly adsorbed to particulate matter, a

dredging and disposal technique which controls release of sediment would

also contain hydrocarbon pollutants.

Baseline data from Allen Harbor is of interest because of the use of the

harbor for shellfishing and the potential for pollutant introduction from the

former dump on its shores.

4-6

Table 4-2.. Sediment hydrocarbon concentration in the Davisville area

Brown and Franklin, 1977. rep licate subtidal samples, 0--3", October 1976
ug/g THC % sand, silt, clay (CRC, 1977)

Allen Harbor 395 641 3 69 28
Channel to A.H. 196 100
Davisville Piers 294 311 8 53 39
Fry Cove Channel 103 427 8 66 26
Brown et al., 1979. samples from Allen Harbor intertidal flat

ug/g THC
4/6/77 a b c composite
0-3't 107 186* 65 286
3/6t' 228 272 101

*Franklin, unpublished.

4/77 (from Fig. 2)

0-311 205
3-611 100
6-9t' 60
9-12"
Appledorn et al, 1979. Allen Harbor flat (ug/g THC)
10/77 67 101 sampled April 1980. All values
ug/g dry weight

Quinn and Pruell, unpub. Allen Harbor flat

identified total total
aromatics aromatics hydrocarbons BTA's phthalate
0-2 cm 0.117 4.7 75.2 0.124 0.114
18-20 cm 0.129 2.6 46.9 -- 0.036
26-28 cm 0.541 9.4 50.1 1.192
Quinn, Requejo and Pruell, unpub. Davisville turning basin, sampled June 1980.
All values ug/g dry weight average of duplicate analysis.

identified total total
aromatics aromatics hydrocarbons BTA's phthalate

0-10 cm 9.769 60.0 934 0.699 1.17

ALLEN HARBOR

D.Y M.P.-
SECTION

oFLAT

100

'0100*01*000,000 0* 0 0000 *04),0610800,016 WkSILI
000 00 0

ORGANIC
SILT- CLAY SAND. TILL
4
??

Figu::e 4-2. Allen Harbor stiatigraphy and location of sammp@ss, a
granular silt layer, 1--riought to be deDosited fr07. '-ydraulic
dredging overflow, overlies estuarine sil---clay. Analyses
were taken at the top and botto-c. of the silt layer (0-2 cm.,
0004?00 0100 0.-
000t
...TILL

18-20 c:a) and at the top of the silt-clay layer (26-28 cT.).

4-7

An intertidal flat in Allen Harbor (Figure 4-2) has been studied exten-

sively in conjunction with a study of neoplastic disease in clams. Bro%'M

et al. (1979) and Appeldoorn (1979) report total sediment hydrocarbon values

ranging from 65-286 ug/g dry weight. Pratt (1977) noted that the flat

appeared to be made up of hydraulically dredged sediment overlaying normal

subtidal estuarine sediments, As part of this study samples were taken

at three depths at two locations on the flat and analysed for hydrocarbons

in an attempt to contrast conditions before and after the harbor was used

for disposal. Results obtained by Quinn and Pruell are given in Appendix

1 and are summarized in Table 4-2.

Benzotriazoles (BTAs) which have been produced since 1963, were found

only in surface sediment. Total hydrocarbons and aromatic fraction of

surface sediments were relatively low. The mid level sample was taken in

the hydraulic fill, but below the level of animal activity; BTA's were

absent, proving a pre-1963 data of deposition. The deepest sample contains

total hydrocarbons levels similar to the surface but aromatic hydrocarbons

and phthalate are relatively high. Apparently these pollutants had been

deposited in the harbor in the early years of development and then buried

by dredged material. Pre-development sediments were not sampled.

Brown and Franklin (1977) measured higher levels of phthalates outside

Allen Harbor than within it. The removal or burial of sediments over the

past 30 years may explain this distribution. The complex pattern of

dredging and filling in the Davisville area will make any further under-

standing of pollutant dynamics difficult to obtain.

Metals in Sediments. There has been concern about metals entering the

Davisville area through discharge of plating solutions at Quonset Point

and dumping at the Allen Harbor dump. Eisler (1977) found elevated levels

4-8

of metals around Quonset Point and in deeper areas of adjacent West Passage.
It is likely that some metals from this source can be found in the dredged
channels at Davisville. Sediment samples from an intertidal area immediately
adjacent to the dump at Allen Harbor did not have high metal levels (EPA,
Narragansett analysis for CRC, 1977). Metal analyses of clams from Allen
Harbor suggest that there is higher than normal copper available in the
water column but that other metals are normal. Continued sedimentation,
dredging, and spoil deposition in Allen Harbor make interpretation of sedi-
ment contamination difficult (see discussion of hydrocarbons in sediments).
The proposed Fry Cove and dredging area consists of a thin layer of
reworked sand over sandy sediments deposited during glacial retreat. The
layer of estuarine sediment is thicker north of the piers. There is no
evidence of release of toxic effluents or dumping toxic solids in either

of these areas. It is very likely that these sediments contain high

levels of metals. Nevertheless a'small program of analyses of metals in

sediment has been conducted to provide data for future permitting processes,

to demonstrate any enhancement of metal deposition in dredted channels, and
to provide background information on this portion of the Bay. Sample

locations are shown in Fig. 4-1.

Elutriate tests were carried out on six samples to provide data for

future permit applications and to provide baseline informati-on. In these
tests sediment is shaken with Bay water and the water tested for released

metals. The test gives a more realistic measure of the impact of hydraulic

dredging effluent release than bulk sediment analysis does.
For five metals (barium, cadmium, chromium, mercury, and lead) all

test concentrations were below the limit of detectability of the analytic
method used. These results illustrate the low solubility of most metals

4-9

in water: chromium in mid-bay sediments is 50-400 ppm (Olsen and Lee,

1979), but was less than 0.2 ppm in the tests; lead in mid-bay sediments

is about 1.00 ppm (Olson and Lee, 1979), but less than 1.6 ppm in the

tests.

Copper was detectable in all the elutriate tests.. Concentrations

ranged from 0.114-0.182 ppm. The absence of a relationship between con-

centrati on and sediment type or sample location may indicate an unexplained

analytic problem. The EPA pollution standard for copper is 0.005 ppm.

drocarbons in clams. A single value for concentration of hydrocarbons in

soft-shell clams in the Davisville area was available at the time of the

previous report. Additional values obtained by Brown et al. (1979) and

Appledoorn et al. (1980) (Table 4-3) indicate that Allen Harbor levels are

higher than those found in a southern Rhode Island barrier beach lagoon

(Winnapaug Pond (30 vs 5 ug/g wet weight).

Quinn and Pruell analysed hydrocarbons in softshell clams from the

same flat in Allen Harbor as part of this study (Appendix 2). -

They found levels similar to those previously reported (37.9 and 30.2 ug/g

wet weight). These levels can be compared with those of hard clams in the

polluted Providence River measured by Boehm and Quinn (42 ug/g).

The pattern of abundance of specific aromatic hydrocarbons in Allen

Harbor clams reported by Quinn and Pruell and by the U.S. Public Health

Service is similar to that found in the sediments throughout the Bay.

The major aromatic hydrocarbons phenanthrene, fluoranthene, and pyrene

probably originate from the combustion of coal and,petroleum products

(Quinn and Pruell, appendix 2

4-10

Table 4-3. Hydrocarbon concentration of soft-shell clams (Mya arenaria) from
Allen Harbor

CRC, 1977. Total hydrocarbons: 59.2 ug/g wet weight

Brown et al., 1979.
Total hydrocarbons of clams transplanted to and from Winnapaug Pond
(Table VIII) sampled in October 1977

approx.
ug/g dry weight ug/g wet weight

Win. to Win. 32 4
A.H. to Win. 60 7
Win. to A.H. 215 26
A.H. to A.H. 271 33

Appeldoorn et al., 1980

Total hydrocarbons of clams adjacent to transplant experiment.

approx.
ug/g dry weight ug/g wet weight

July 125 15
October 315 38

Quinn and Pruell, unpub. Sampled April 1980, 15-20 clams/analysis,
concentrations ug/g wet weight

Identified Total Total
aromatics aromatics hydrocarbons Benzotriazoles

mid cove 0.345 7.7 37.9 0.036
near navy 0.230 6.7 30.2 0.049
dump

4-11

Appledoorn et al. (1980) found that Allen Harbor clams suffering from

neoplastic disease had a hydrocarbon makeup similar to the sediment. Met-

abolic dysfunction or stress appeared to have prevented these individuals

from metabolizing or depurating hydrocarbons.

Neoplasia in soft-shell clams. There is a high prevalence of neoplastic

disease in soft-shell clams in Allen Harbor. This disease consists of a

proliferation of abnormal blood cells and is often fatal to the clam.

Cooper (1979) described techniques of diagnosis and the stages of

neoplasia in soft-shell clams and monitored disease levels in Allen Harbor

at monthly intervals from July 1977 to March 1979. They found that adult

clams were more susceptible than juveniles (Ist year)., During the study

period incidence of neoplasia varied over a range of 19-43% with the

highest levels in October and May and the lowest level in the summer.

Neoplasm severity and clam mortality was highest in late winter.

Cooper found that the disease could be transmitted through the water

and transplanted by injection. Other bivalves in Allen Harbor including

hard clams did not have neoplasia. A virally induced disease specific

to soft-shell clams would best fit these facts.

It has been suggested that pollution stress could have some effect on

clam susceptability, but there was no clear cut relation of disease and

environments studied by Brown et al. 1979. Polluted areas such as the

Providence River had low incidences. It is possible that the high density

of clams in Allen Harbor contributes to a high level of this transmitted

disease. Since hydrocarbon pollutants in the surface sediments and metal

levels in clams are not unusually high, it seems necessary to deemphasize

pollutants and consider natural stress and disease transmission.

4-12
Appledoorn et al (1980) estimate that soft-clam production at Allen

Harbor was reduced by as much as one-fifth due to neoplasia. Soft-shell

clams have only been examined within Allen Harbor. Brown (1977) con-

ducted a histopathological examination of hard clams from south of Quonset

Point, Fry Cove, and Calf Pasture Point. These clams had no neoplasia

but did have unusual accumulations of lipofuscia pigment. Brown discussed

as possible causes of this accumulation ingestion and storage of

unsaturated hydrocarbons from natural sources or petroleum pollution and

metabolic disorders caused by pollutants. The equal incidence of this

condition at all locations would argue against the effect of a pollutant

from a point source.

Metals in Clams. It has been suggested that there could be high concen-

trations of heavy metals in sediments and organisms in the Quonset/

Davisville area as a result of discharge of metal plating solutions

(Eisler et al (1977, 1978) or of dumping of metal scrap at Allen Harbor

(CRC, 1977).

Eisler et al. found elevated metal levels in the widgeon clam (Pitar

morrhuana) near the former Naval Air Rework Facility outfalls at Quonset

Point. Metals which showed clear increased near the outfalls w ere found

at normal concentrations in the Davisville area.

The Rhode Island Department of Health carried out a special study of

metals in clams in the Davisville area between December 1976 and June

1977. Station locations and a summary of data are shown in Figure 4-1

and Table 4-4.

Soft-shell clams were collected at four stations. In Fig. 4-3 metal

levels of clams are shown for the stations in order of distance from the

Allen Harbor dump. There is no trend for any metal. Except for one Fry

4-13

Table 4-4. Clam analyses, RIDH Allen Harbor Project

Coliform bacteria metals,ppm dry wt.
Date Sta. Species MPN/100 ul Ph Cd Cr Cu Zn

12/20/76 1 softshell 220 1.7 0.18 18.2 0.82 21.3
12/20/76 4 softshell 140
2.2 0.20 19.3 1.17 26.8
12/20/76 6 softshell 230 2.5 0.21 48.2 0.87 40.8

3/21/77 2 hard 0 1.17 0.25 10.3 1.16 17.4
3/21/77 2 softshell 110 -- -- -- -- --
3/21/77 4 softshell ? 1.62 0.16 -- 0.62 18.0

3/?/77 6 softshell 790 1.0 0.14 14.1 0.56 8.5
3/?/77 4 softshell 330 1.1 0.09 11.4 0.52 12.5

4/18/77 2 softshell 490 -- -- -- -- --
4/18/77 3 hard 490 -- --
4/18/77 2 softshell 0 0.31 0.16 -- 0.42

5/23/77 2 hard ? 0.65 0.13 7.1 0.88 10.4
5/23/77 1 softshell 330 1.3 0.11 17.5 0.76 11.5

6/13/77 3 hard 90 0.74 0.08 12.7 0.31 11.2
6/13/77 2 softshell 490 1.2 0.10 20.4 1.2 21.0

M YA AffNARIA

5 5 0. 5
Pb Cr Cd
4- 4- . 0.4-

3- 3- . 0.3-

2. 0 2- Q2 - 0 0 0
CL 0 0 0 0 0
a. 0 0 0 0 0 0 0 0.1- 0 0 0
ob 8
z 8 0 0
0 01 .0 L-j 0A I A- 0- a I
2 6 1 4 2 6 1 4 2 6

Cr 50- 50-
Cu 0 Zn I - NEAR
z 0 DUMP
W 40- 40-
u 2- YACHT
z CLUB ALLE N
0 30- 30 HARBOR
- - - - - - - - - -- 0 4- NORTH
20- 0 0 20- 0 0 COVE..O
8 0 0
0 6- D.R BEACH
10- 10- 0 0
--- FDA ALERT LEVEL
0 0 1 t I I
1 2 4 6 1 2 4 6

Figure 4-3. Metal levels in soft shell clams (Ilya arenaria)(dry weight at
four locations. (R.I. Dept. of Hea@ft-h-,, -Dec. -19, 1976-June. 1977).

4-14

Cove sample, all metals are below FDA alert levels. Alert levels have fio

relation to safety of consumption, but relate to regional norms.
Hard clams were sampled from one location in Allen Harbor. A baseline
for assessing Allen Harbor values is provided by data from a location north
of the Harbor monitored regularly by the RIDH. Data from January 1978 to

March 1980-is available from that station (Table 4-5). Hard clams within
Allen Harbor had metal levels similar to those from the reference station
with the exception of copper which was higher (Fig. 4-4). Chromium and
copper in Allen Harbor and chromium at the reference stations are at

the FDA alert levels.
The copper increase in Allen Harbor is probably real since copper and
co pper alloys can be seen in the former dump and copper bottom point is

used on vessels moored in the harbor.
Phelps and Myers (1977) measured heavy metals in hard clams from clean
and polluted locations in Narragansett Bay. They found that zinc levels
remained the same in both areas, but that copper and chromium increased
by about 3 times and cadmium and lead increased by about 0.7 times in the
polluted area. For the Davisville samples it would appear that the con-
stancy of zinc levels is due to physiological regulation by the clams and
that zinc could not be a hazard to man or useful as a bioindication of
pollution. The similarity of lead, chromium and cadmium in Allen Harbor
and control clams indicate that the Harbor is not polluted with these

metals. The elevated levels of copper in Allen Harbor clams is consistant
with the presence of the metal in the dump and the ability of the clams

to concentrate it.

4-15

Table 4-3. Hard clam analyses, RIDH, Station 9 of Mount View, North Kingstown

Coliform bacteria metals, ppm dry wt.
Date MPN/100 ml Pb Cd Cr Cu Zn

1978 Jan. 0 1.18 0.08 6.1 19.7
March 0 0.72 0.03 2.6 7.3
April 20 0.46 0.50 16.9 10.0
November 20 -- 0 2.18 19.04

1979 May 20 0.45 0.06 1.09 27.4
June 20 0.62 0,29 4.5 27.3
July 20 0.55 1.89 0.18 17.3
Aug. 20 0.91 0.10 4.9 18.4
Oct. 20 0.54 0.16 3.56 17.3
Nov. 20 0.47 0.12 3.8 23.7

1980 March 20 0.68 0.09 0.11 2.5 10.7
@March 20 0.59 0.11 0.13 0.71 13.44

FDA Alert levels, northern

hard clams 4.0 0.5 1.0 10 65
softshell clams 5.0 0.5 5.0 25 30

MERCENARIA MERCIENARIA

5 Pb' 25 -Cr 05 r Cd
4 2.o - 04.

0
3 1.5- 0.3-
0 0
0 0
0
a- 2- 1.0 -0- 0.2-
CL 0
0 0 0 0
0.5- 0.1- 0 0
z 0 0
0 0 ......... 0 0 a 0
2r3 MV 2,3 Mv 2,3 MV
Cr 25 - 65
CU
z Zn
w 20 - 40
0 2,3 ALLEN
z 0 HARBOR
0 15 - 30-.
0 MV MOUNT
0 0 VIEW
10 - 20 - 41 ---FDA ALERT
0 0 0 LEVEL
5 - lo- 8 @-
t 0
01 0. OR IL -1
2,3 MV 2*3 MV

Figure 4-4. Metal levels in hard clams (Mercenaria mercenari-a)
in Allen Harbor (Stations 2,3 north cove, December 1976-
June 1977); north of harbor (January 1978-March 1980).

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5-2

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U.S. Waterways Exp. Sta., Vicksburg, Miss. DMRP Tech. Rept. DS-78-10.
89 pp.
Peddicord,'R.K. et al. 1975. Effects of suspended solids on San Francisco
Bay organisms. Appendix G. Dredge disposal study San Francisco Bay
and estuary. U.S. Army Corps of Engineers, San Francisco District.

Peddicord, R.K. and V.A. McFarland. 1978. Effects of suspended dredged
material on aquatic animals. U.S. Waterways Exp. Sta., Vicksburg,
Miss. DMRP Tech. Rept. D-78-29. 102 pp.

Phelps, D.K. 1964. Functional relationships of benthos in a coastal lagoon.
Ph.D. Thesis, Univ. of Rhode Island.

Phelps, D.K. and A.C. Myers. 1977. Ecological considerations in site
assessment for dredging and spoiling activities. In Proceed. 2nd
U.S.-Japan meeting on management of bottom sediments containing toxic
substances, Oct. 1977. EPA. Ecol. Res. Series, EPA-600-3-77-083.

Pratt, S.D. 1977. Benthic biology of areas adjacent to Quonset Point/
Davisville. Tech. App. The Redevelopment of Quonset/Davisville: An
Environmental Assessment. Coastal Resources Center, Univ. of R.I.

Pratt, S.D. and J.J. Bisagni. 1976. Monitoring results -- Providence River
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Pratt, S.D. and R.M. Heavers. 1975. Background turbidity conditions of
Rhode Island Sound and Buzzards Bay. Rept. to N.E. Div., U.S. Army
Corps of Engineers. Grad. Sch. Oceanogr., Univ. R.I. Kingston, R.I.
69 pp.

5-4

Raytheon Company. 1974. A Study of the effect of marine sediments on the
survival of selected commercially important fish and shellfish of
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Rhode Island Department of Health, Division of Water Pollution Control.
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Saila, S.B., S.D. Pratt, and T.T. Polgar. 1972. Dredge spoil disposal in
Rhode Island Sound. Mar. Tech. Rept. 2 Univ. of R.I. 48 pp.

Sanders, H.L. 1960. Benthic studies in Buzzards Bay, III. The structure
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Schenck, H. Jr. and A. Davis. 1973. A turbidity survey of Narragansett
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Shulenberger, E. 1970. Responses of Gemma @gemmi!@ to a catastrophic burial.
The Veliger- 13: 163-170.
Sisson, R.T., 1970. A preliminary evaluation of the magnitude of the sport
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St. Austell and Managissy Bay. J. Mar. Biol. Ass. U.K. 56: 769-7180.

APPENDIX 1

Allen Harbor Sediment Analysis
September 10,1980
J.G.Quinn and R.J.Pruell

Our interpretation of the*data (enclosed) is as follows:

0-2 cm section
Based on the presence of di-2-ethyl hexyl phthalate, (DEHP),, this
section was deposited after 1945.' Based on the presence of Benzotriazole B,
this section of the core was deposited after 1963. The f (.saturated)
and f 2(aromatic) hydrocarbons are relatively low in compIrison with other
areas of the bay. The major so'Urce of these hydrocarbons is probably a
combination of petroleum products and fossil fuel combustion products.

18-20 cm section
Based on the absence of Benzotriazole B and low value of DEHP this
@ection was probably deposited close to 1945. The hydrocarbon disiri'bution
is in agreement with this observation.

26-28 cm section
Based on the absence of Benzotriazole B and the high value of DEHP,
this'section was probably deposited between 1945.and 1963. The high
concentration of DEHP and the increased level of f2 hydrocarbons suggest
considerable industrial or defense related activities during this time.
One possible explanation of these trends would be the input of
dredged material containing organic pollutants (phthalate and f 2 hydro-
carbons) deposited between 1945 and 1963, followed by 'cleaner, material
deposited close to 1945. These materials may have been deposited in the
early to m*id-60's or over a longer time period (e,g. 1950-60). They
have since been covered by recently accumulated s diment (1963 to present).

/d
Enc.

Allen Harbor Sediment Analysis a

Mid-cove core
(4/14/80)

0-2 cm 18-20 cm 26-28 cm

(ng/g)
Naphthalene __b 1.7 5.0
2-methyl naphthalene 1.5 2.4
1-methyl naphthalene. 0.6 1.5
Biphenyl 0.6 1.7
C2 naphthalene 0.5 1.2
Fluorene 2.4 2.3 16.8
Dibenzothiophene 6.5 2.2 12.3
Phenanthrene 18.7 12.4 115.1
Fluoranthene 43.8 43.5 183.8
Pyrene 28.9 45.6 132.9
B[alanthracene 8.1 6.0 30.8
Chrysene 'a triphenylene 8.6 12.5 37.3

Total identified aromatics (12) 117.0 129.4 540.8
(ug/g)
Total f 1 hydrocarbons 70.5 44.3 40.7
Total f 2 hydrocarbons 4.7 2.6 9.4
Total f I + f 2 hydrocarbons 75.2 46.9 50.1
(ng/g)
Benzotriazole A c 51*.7
d
Benzotriazole B 72.2
Di-2-ethyl hexyl phthalate 114.0 36.4 1192.5

aAll concentrations on a dry wt. basis.
b<1 ng/g.
cBenzotriazole A- 2-(2'-Hydroxy-3',5-di-t-amylphenyl)-2H-benzotriazole.
dBenzotriazole B '= 2-(2'-Hydroxy-3',5'-di-butylphenyl)-5-chloro-
2H-benzotriazole.

APPENDIX 2

Analysis of Mya Arenaria collected from Allen Harbor on April 14,1980
November 12, 1980
J.G. Quinn and R.J. Pruell

Attached are the results of our analysis of clam samples from
Allen Harbor. Our interpretation of the data is as follows:

Aromatic Hydrocarbons: We have identified at least fourteen
specifTc -aromatic hydrocarbons in these samples. The most abundant
hydrocarbons were phenanthrene, fluoranthene and pyrene. These three
compounds are the major hydrocarbons found in sediments from Allen
Harbor and throughout Narragansett Bay, and probably originate from
the combustion of coal or petroleum products. Our values for fluoran-
thene (104-151 ng/g), and pyrene (44-69 ng/g) are in fair agreement
with those reported by the FDA for a sample of Mya collected from Allen
Harbor on 12/20/76 (fluoranthene: 75 ng/g, and pyrene: 48 n/g/).
Total fl (saturated) and f2 (unsaturated) Hydrocarbons: These
values for total hydrocarbo-ns(30-38 pg/g) are in general agreement with
values reported by the*CRr in 1977 (59 pg/g). The sample collected from
the mid-cove area shows slightly highe.r levels of total hydrocarbons
(and aromatic hydrocarbons) but lower levels of benzotriazoles. These
differences are probably not significant.

JGQ/d
Att.

Hydrocarbons and selected organic compounds in

softshell clams (M a arenaria) from Allen Harbor.
@2@4/14/KT
Mid-Cove Near dump
Aromatic Hydrocarbons

Naphthalene -- --
2-methyl naphthalene 3.9 3.2
1-methyl naphthalene 1.9 1.1
Biphenyl 2.0 1.4
C2 naphthalene 1.8 0.9
1,4 + 2,3 dimethyl naphthalene 3.2 1.6
Acenaphthalene 7.6 4.5
2,3,5 trimethy1naphthalene 7.6 2.7
Fluorene 8.4 4.6
Dibenzothiophene 8.6 5.9
Phenanthrene 68.2 44.3
Fluoranthene 151.1 104.2
Pyrene 69.2 44.4
B[alanthracene 4.2 4.7
Chrysene and triphenylene 8.1 6.7
Total identified aromatics 345.8 230.2
Benzotriazole Ac 34.1 46.3
Benzotriazole B d 2.3 2.9
(AII)b
Total f 1 hydrocarbons 30.2 23.5
Total f 2 hydrocarbons 7.7 6.7
Total f I + f2 hydrocarbons 37.9 30.2

aanalysis done on an aliquot of homogenate produced using 15-20
clams.
All concentrations on a wet wt. basis.
cBenzotriazole A = 2-(2'-Hydroxy-3',5'-di-t-amylphenyl)-2H-
benzotriazole.
dSenzotriazole B = 2-(2'-Hydroxy-3',5'-di-t-butylphenyl)-5-chloro-
2H-benzotriazole.

APPENDIX 3

Analysis of surface sediment collected on June 24,1980 from the dredged
basin off Davisville
November 10, 1980
J.G.Quinn, A.G.Requejo, and R.J.Pruell

Attached are the results of our analysis of this sample. Our
interpretation of the data is as follows:

Aromatic Hydrocarbons: We have identified at least twelve specific
aromatic hydrocarbons in s sample. The high concentrations of
phenanthrene, fluoranthene and pyrene suggest a combustion source for
these hydrocarbons (e.g. burning of coal or petroleum products).

Benzotriazoles and Di-2-ethylhexylphthalate: These compounds
are somewhat higher than expected based on our previous analyses of
sediments from the West Passage of Narragansett Bay. The organic
carbon values are also slightly higher than expected. The data suggest
that some particulate organic material (containing benzotriazoles,
phthalate, and hydrocarbons) from the Providence River may be trans-
ported to the mid-bay area via tidal currents, and eventually settle
out and accumulate in the dredged basin off Davisville.
Total fl (saturated) and f2 (unsaturated) Hydrocarbons:
These 7a-lues-are about three times higher than expected based on our
previous analyses of sediments from the West Passage of Narragansett Bay.
The data suggest a second source (other than the Providence River) of
petroleum hydrocarbons in the vicinity of the Davisville area.

Our conclusions are:

1) The slightly elevated levels of benzotriazoles, phthalate
and organic carbon are probably due to transport, deposition and
accumulation of particulate organic material from the Providence River.

2) The high levels of three specific aromatic hydrocarbons and
total hydrocarbons suggest an additional source in the vicinity of the
Davisville area. This source includes polycyclic aromatic hydrocarbons
from the combustion of fossil fuels as well as a complex mixture of
hydrocarbons from petroleum products.
3) The concentration of aromatic hydrocarbons, total hydrocarbons,
benzotriazoles and phthalate is significantly higher in Davisville
surface sediment compared to Allen Harbor surface sediment (see enclosed
report of September 10, 1980).

JGQ/d
Enc.
cc: S. Pratt

Davisville Sediment AnalL@Llsa
Subsample 1 Subsamole 2
Aromatic hydrocarbons
ng/g
naphthalene --b 33.0 33.0
2-methyl naphthalene 31.6 31.6
1-methyl naphthalene 22.9 22.9
biphenyl 20.3 20.3
C2 naphthalene -- 12.3 12.3
fluorene 500.5 367.5 434.0
dibenzothiophene 222.2 173.8 198.0
phenanthrene 1947.5 1482.4 1714.9
fluoranthene 4862.0 4104.1 4483.0
@pyrene 2541.2 2141.2 2341.2
B[alanthracene 172.0 248.7 210.3
chrysene & triphenylene 270.2 -- 270.2

Total f, hydrocarbons 929.4 818.9 874.1
Total f2 hydrocarbons 68.5 51.5 60.0
Total fl + f 2 hydrocarbons 997.9 870.4 934.1

ng/g
Benzotriazole A 626.9 432.1 531.0
Benzotriazole B d 190.7 145.3 168.0

]Ig/g
Di-2 ethylhexylphthalate 1.34 1.00 1.17
Cycloalkene M.W. 344 3.97 3.33 3.65
Organic carbon 24.0 � 0.5 mg/ge

aAll values reported on a dry weight basis.
bnot analyzed.
CBenzotriazole A = 2-(2'-hydroxy-31,51-di-t-amylphenyl)-2H-benzotriazole.
dBenzotriazole 8 = 2-(2'-hydroxy-3',51-di-t-butylphenyl)-5-chloro-2H-
benzotriazole.
etriplicate analysis.

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