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Proceedings
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Dredging Workshop
Point Lookout, New York
September 10-11, 1985
Sponsored by the New York State Department of State
Coastal Management Program with assistance from:
New York District Corps of Engineers
New York State Department of Environmental Conservation
New York State Sea Grant Extension Program
Mario M. Cuomo
Governor
Gail S. Shaffer
Secretary of Slate
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DREDGING WORKSHOP PROCEEDINGS
Point Lookout, NY
Septemher 10-11 1985
Table of Contents
Welcoming Remarks
Thomas Doheney, Town of
Paqe
Hempstead. . .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .1
Opening Remarks
Janes Morton, New York State Departnent of State.......3
.TC'~r_ ZarlJ'lit, P.S. Army COr-f'R of Engineers,
Session r
A.
Session
A.
Session
A.
N.. Y.. DiEt.t. ict.. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .... .. .. .. .. .. .. .. .. .. .... .. .... .. 5
Technical Considerations in the Design ~f a Dredging
Project - IHIJiam F. Slezak, U.S. Arm~' Corps of
Engineers IN.. Y.. District.................................................... 7
B.
Technical Considerations in the Design of ~ Dredginq
Project or l,hi:t !"lrecqing Cor-tractors l"ished EVery
Regulator Knel'! About Dredging: Private Dredging
Projects - Brion Lindholm, Great r,akes Dredge,.
Cind Dock Compc.r..y...................................................... ~-:~. 10 .. .. .11
C.
Questions and Answers. IO.......... . . IO..... . IO............... .15
II
Overview of Potential Impacts
of Dredged Material - Richard
Engineer Waterways Experiment
of Open Water Disposal
Peddicord, U.S. Ar~y
Station.............17
B.
Effects of Disposal of Fine Grained Sediments on
Benthos - John D. Lunz and Douglas G. Clarke, U.S.
Army Engineer Waterways Experiment Station........21
C.
Questions and Answers................................. 27
III
Corps' Requlatory Application of Test Results -
John Tavolaro, U.S. Army Corps of Engineers,
N. Y. Di!=;trict..................................... 29
B. Questions and Answers.............................33
Session
A.
IV
Introduction:
tVindows: Are
James Morton,
Panel Discussion on Dredging
They an Effective Tool -
New York State Department
of State................................. . . . . . . . . .35
B. Contractor's Perspective - Charles Pound,
Aqua Dredge, Inc.................................. 37
C. Municipal Perspective - Jeffrey Kassner,
Town 0 f Brookhaven................................ 39
D.
Session V
A.
Session
A.
State Perspective - David Fallon,
New York State Department of Environmental
Conservation. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .43
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E.
State Perspectiv~ - James W. Morton and
~'hc""'r:c: P.art, NE'v Yc-rk Std'LL DeF'a.rt!tle;J~ c.; State...f:5
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Seasonal restrictions on Bucket Dredginq
Operations - John D. Lunz, Douglas G. Clarke,
and Thomas J. Fredette, U.S. Army Engineer
Waterways Experiment Station......................47
G.
Questions and Ans\-1ers.............................49
Introduction: Drceging and Disposal in Low-Energy
Environment!' (Protect~(i Bays, Canals, Harinasl-
Aram Terct,unian, Nev' York State Department of
State. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .51
B. Dredging Impacts on Benthic Intertidal. COJ1'.l!'l1nities,
Shellfisl1 and Habitats - Carmela CUC'ffiO, Marine
Sciences Pese~rch Center, SUNY at Stony Rrook.....53
C.
New York State Department of EnvironmAntal
Conservation Perspective on Dredqinq in
Ne~! York's Tidal Wetlands - Charle s E<.mil ton,
New York State Department of
Environmental Conservation........................57
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D. Consultant's Perspective- Charles Bowman,
Land Use Company..................... .0........... .61
E.
Questions and Answer.............................. 63
VI
Introduction: Dredging and Disposal in Moderate
and High Energy Environment!' - Jay Tanski, New York
State Sec_ Grant E::tc::r,sion Prograrr................. (5
B.
Coastal Procpsses to be Considered For Dredging
Design At Tidal Inlets - Gary A. Zarillo,
Marine Sciences Research Center...................67
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C. Problems and Comments for Small Dredging Projects -
John R. GuIdi, Suffolk County Department of Public
works, Waterways Division................~........73
D. Dredging Jones Inlet: Municipal Perspective -
Thomas Doheney, Town of Hempstead, Department of
Conservation and waterways..................:.....75
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E.
Coast.al ~!anagement Issues in Inlet Dredging -
Ararn Terchunian, New York State Department of
State.. .. .. ~ .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. .. 71
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F. rLnsideratlor~ Tn the Dp~ign of Large ~ale,
Corps Dr~cglng Proje~ts - Gilbert. K. Nersesi~n,
U.S. CorpE o~ Engineer~, New York District........81
G. Questions And Answers.............................89
H. ~orkshop Atter~dance Li~~..........................91
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WELCOMING REMARKS by T. Doheney
Good morning ladies and gentlemen, on behalf of the
presiding Supervisor Tom Gulotta, and Commissioner Gino Aiello, I
would like tQ welcome you to our Town and our Depart~ent for this
most important workshop on dredging. Commissioner Aiello regrets
that he cannot attend today's session since today is also Town
Board Day and his attendance there is both necessary and
mandatory. He will however be with us tomorrow.
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Before we begin, I would like to offer, if I may, a few
comments on having such a workshop as this since there can be a
tremendous amount of good and knowledge to come out of it for
everyone. We should approach each session with an open mind,~
attempt to examine. and learn each others problems, try to be '
practical, and examine the issues of dredging relative to each.,
project area as that area exists today, in order to make a
determin2tion whether dredgi~g i~ cood, bad or necessa.y. Above
all let's try to ke8~ things light since it is one of those rare
occasions when all parties to dredging are represented in the
same rocw together.
I would like to express my personal appreciation to Jim
Morte:. of the Department of State for organizing thi!' Iwrkshop
and choosing us tc host it.
Thank you.
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OPENING RE~mRKS by James Morton
New York State Department of State
'Coastal Management Program
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Thank you Tom for your kind introduction and very valuable
assistance in providing this meeting room. Before getting into
my remarks I woUld also like to extend my thanks to members of
the Planning Group who worked with me in organizing this
workshop. They include Bill Slezak, Jim Mansky, John Tavalaro
and Debbie Freeman from the New York District Corps Office; Ken
Koetzner, Barbara Rinaldi and Joe Pane from New York State
Department of Environmental Conservation; Jay Tanski from New'
York State Sea Grant and Aram Terchunian from the New York State
Coastal Management Program.
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I bec~~ve We hav~ ar. impre5~iv~ cast of speakers, panelists
and workshop participan~s. We have representatives from dredging
contractors, co~s~ltants, ane the scientific community as well as
federal, state and municipal regulatory agencies. All of you
have considerable understanding about dredging. Some of you have
known differences of opinion on the subject of dredging, In
fact, when I was telling John GuIdi who ~le were inviting to the
workshop, he asked if we would be setting up a gun check at the
door. 1 answ~red no, but we purposely invited represen~dLives
from both sides of the issue. {
One of the basic premises of this Workshop is tha~-there is
not one of us here toda~l \\'ho fully understands all the _.
complexi ties of the dredsing issue. ~\ore than oncE' we've heard
dredging contractors exclaim, "Why don't you regulators get
yourself out on a dredge and see the real world?" Or a regulator
complain I "Why don't those dredgers realize that their project
will knock out an important shellfif,h bed?"
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Through my invol Ver.lent with New York's Coastal Management
Program I I've had the opportnni ty to wi ~ness much of t.his
crossfire. WE' in fact have made a few shots as well. It's time
that we sat down in a room together, shut the door, roll up our
shirtsleeves, listen to one another's concerns, and then start
developing guidelines for designing a dredging project that not
only reduces env1ronmental risks but also is economically and
technically practical. Collectively, there is much wisdom and
e:{perience in this room. We are the experts. But we each only
have a piece of the answer and we must share our information.
Yes, we expect some heat in our discussions over the next two
days; that is one of the reasons many of you were invited. Rut
we cannot let this opportunity to share ideas degenerate intc
simply a gripe session.
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There is a second prerase to this ~Iorkshop upon which I hope
we can all agree, and t~at iM: dredging is not in and of itself
a bad thing. Dredging is integral to harbor management, the
marina industry and public access. Tte challenge we face is
designing our dredging projects so they do not encroach on other
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user groups such as the commercial fish~rman, or on the
environment.
However, we must also realize that when wp dredge, we are,
in a very real sense, tinkering with Mother Nature. And ",hen we
make a mistake, she can punish us cruelly. We need the
scientists here today to help us better understand how dredging
and disposal of dredged material does, and does not affect the
environment.
Our agenda is full and we need to get started. But first I
would like to introduce John Zammit, Director of the Operations
Division for the New York District Army Corps of Engineers.
Without the help of John and others, we would not be having this
workshop. Since nearly everyone in this room knows John, he
needs no further introduction, so won't you please welcome John
ZaJT1r.'.it. .
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OPENING RE~~RKS by John ZamMit
Chief, Operations Division
U.S. Army Corps of Engineers, New York District Office
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Thank you, Jim. I just want to share a few words of
welcome. I am very pleased we are having this workshop today ann
that we have a chance for those of us with differing views to
exchange our ideas. We in the Corps are concerned about some of
the special conditions being placed on dredging projects. We
need to determine if the anticipated benefits of these .special
conditions are worth the extra cost of their being implemented.
We h2ve a mission to accomp]i~h: to keep our channels open to
allow for safe navigation and access to our ports while in
compli2nce with Federal environmental regulations anc laws. ~t
is time that wa all started werking together and sharing in tha
eff<,'r~ to ge: tt.:r r.issie:". 6.cconplishl'c.
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And now I wculd like to 1ntroduce the first speaker for this
Session: Bill Slezak, Chief of the Navigation Branch of the
Corps will discuss t~chnical considerations that must h~ taken
into account when ae~igning a dredging project.
"'hank you.
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TECHNICAL CONSIDERATIONS IN THE DESIGN OF A DREDGING PROJECT
by
William F. Slezak, Chief, Navigation Branch
U.S. Army Corps of Engineers, New York District '
INTRODUCTION - What I plan to do during thiE talk is to
discuss: a) where, why, what, and how we dredger b) the
environmental considerations that enter into planning for a
federal projectr and c) present Corps policies regarding the
maintenance of federal projects. Following my talk, Mr. Brian
Lindholm will be discussing some of the technical and economic
aspects of dredging from a dredging contractor's perspective. .
The New York District's area of jurisdiction extends over
the drainage basins of Lake Champlain, the Hudson River, the
Hackensack Riv~r, the FaES[ic Fiver, the Raritan piver and all of
Long Island. Within this jurisdiction there are some 550 miles
of Federally authorized navigation channels. The ty~e5 of
navigation projects we are responsible for include:
~) the deer draft navigation channels in and around the
Port of Ne\~ York which vary from 14 to 45 ft. in depth.
Sediments in these channels are generally fine-grained and the
dredged materials have historically been disposed in the ocean.
The sediments generally are contaMinated as a result 0; their
location in a highly industrialized area. Nevertheless, the
sediments in general d~ not appear to be toxic to marine life.
The Matter of seciMent toxicity will be addressed in g!"_eater
detail 10 the next two sessions. .
b) the Hudson River tc 1'.lbany and Lake Champlain ~'hich
includes a 32 ft. channel to the Port of Albany and 12 ft.
through the Barge Canal and the Narrows to Lake Champlain.
Sediments vary frOM coarse grained to fine grained. Sediments
are relatively uncontaminated excep~ for occasional minor levelE
of PCR's in the Hudson River.
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c) shallow draft
harbors in New Jersey,
in these locations are
commercial allo recreational channels and
Long Island and Lake Champlain. Sediments
generally not contaminated.
As to why we dredge, the obvious answer is to allO\~ the safe
movement of vessel traffic.
Dredging is accomplished either mechanically or
hydraulically. The most common mechanical device used in the
Harbor is a bucket or clamshell dredge which essentially scoops
up the shoaled material and places it into a scow which is
subsequently towed to the designated dumpsite.
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Hydraulic dredges include cutterhead or pipeline dred9~s
which have suction lines extending to the bottom. The shoaled
sediment is then pumped in a slurry through a pipeline to the
disposal site. The ADCO, owned by American Dredging Company, is
a 27 inch diameter pipeline dredge, which is presently working in
Jones Inlet and is pumping the dredge material onto Point Lookout
Beach. There it is serving to restore that beach which has been
eroded.
Another type of hydraulic dredge is the hopper dredge, in
which the material dredged is pumped into hoppers aboard the
vessel. The hopper dredge, NORTHERLY ISLAND, owned by the North
Atlantic Trailing Co., is presently working in Fire Island Inlet.
One of the advantages of using a hopper dredge, as opposed
to a hydraulic dredqe, is tha+ this dredge is mobile and can work
in rough seas, such as those experienced i~ inlets and entrance
channels.
EN\:~ONMENTAL CONSIDERATIONS THA'f E!;'!'ER INTO PLAK!\ING A
FEDERAL DREDGING PROJECT. We in the Corps are in a unique
position in 'Il\~t \~e not 0nly do dredging either with our mm
equipl'1ent or by contract, but also regula t.e dredginq by others.
Rather than constituting a conflict of interest, I believe this
dual respnnsibility has worked out well. As dredgers we are
subject to the same env:;'rcr.mental review process as .....ould be flny
private d~edging operators.
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This responsibility includes sa.ds=ying the criteria and
guidelines established by EFA pursunn~ to the Clean ~aters Act,
and the Ocean Dumping Act, as wlol] [. S satis fying other related
environmental laws and executive orders such as NEPA, the
Endangered Species Act, the Fish S Wildlife Coordination Act and
the Coastal Zone Mpnagement Act.
In addition, a considerable research effort has taken place
and is continuing to take place which h~s investioated all facets
of disposal alternatives for dredged material, including
beneficial uses and state-of-the-art evaluative procedures for
contaminated sediments. Particularly noteworthy among these
research efforts was the 5-year $33 million Dredaed Material
Research Program (DMRP) which was managed by the-Corps of
Engineers Waterways Experiment Station (WES).
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We are fortunate in having here two gentlemen from WE E who
were involved in the DMRP, which was essentially conpleted in
1979, and who are now involved in a successor program known as
the Dre~ging Operations Technology Support Program or DOTS.
Through this program, Corps Districts are provided technical
support in dealing wi~h dredging problems.
We in the New York District have been actively involvF.d in a
Dredged Material Management Program in which various d1sposal
alternatives are being investigated for possihle implementation.
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CORPS OF ENGINEERS POLICIES REGARDING MAINTENANCE DREDGING.
I "l'Oula now like to discuss current Corps policies regarding "-
dredging projects.
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It is the Corps of Engineers' policy to regulate the
discharge of dredged material from its projects to assure that
dredged material disposal occurs in the least costly, most
environmentally acceptable manner, consistent with engineering
constraints established for the project.
The EA or EIS for the project, in conjunction with the 404
(bl (1) Guidelines and the public notice coordination process,
are utili7ed in formulating environmentally acceptable
alternatives. The-least costly, environmentally acceptable
alternative or alternatives selected through this information _,
process is the Federal Standard for the project. In other words,
the Federal Standard is the IFast costly disposal alternative,
among those which satisfy all applicable Federal laws and
regulations.
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The policy further states that Corps Districts will
cooperate to the maximum extent practicable to comply \Ii th State
Water Quality Standards, and CZM Programs, and to minimize
impacts on fish and wildlife resources.
However, if a Federal or state agency imposes beneficial
uses as a special condition, any additional expense associated
with such provisions will not be a Corps responsibility_.unless
specifically authorized by Congress.
1/\ SUM~1\RY:
1) Considerable knowledae has heen gained during the past
10 years regarding the impacts of dredging and disposal through
research efforts such as the Dredged Material Research Program
and successor research programs carried out at WES.
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2) We in the Corps are very sensitive to the environmental
issues associated \lith dredging and disposal, and are also
required to abide by federal environmental laws and regulations.
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3) We will also cooperate to the maximum extent practicable
to comply with State Water Quality Standards, and CZM programs,
and to minimize impacts on fish and wildlife resources.
4)
special
expense
If, however, a state agency imposes beneficial uses as a
condition, the Corps may not pick-up the additional
unless specifically authorized by Congress.
5) Similarly if agency imposed testing or monitoring
exceeds that needed to meet the Federal standard, that agency or
the local sponsor ~ill be asked to pay the increased costs.
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TECHNICAL CONSIDERATIONS IN THE DEITGN
OF A DREDGING PROJECT OR WHAT DREDGING CONTRACTORS
WISHED EVERY REGULATOR KNEW ABOUT DREDGING:
PRIVATE DREDGING PROJECTS
by
Brion Lindholm
Great Lakes Dredge and Dock Company
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I have been asked to le~ you know what we, as dredging
contractors, wish every regulator would understand about
dredging. Our greatest wish would be that every regulator would
be more familiar with the actual dredging process from an .
operational viewpoint. With this in mind, I will first run
through some slides that show typical dredging equipmcnt and
techniques.
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Some of you may anticipatE: that, bei.r.g a typiCal cor.tractor,
I will tell you about the ineptness of Government officials in
regulatory capdcitie~, and about the inequities and ahsurdities
of many environmental regulations. I am not here fo:- this
purpos~, nor do I believe such to be the truth. I would like,
however, to talk about some regulations and environmental
concerns that we, as contractors, have difficulties
understaLcing, and that maybe are not in the overall public
benefit. ·
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We all understand that some of us here are professjonal
people ",ith the pr:;.mary funct iOll to protect the enviror.ment.
Others here are professional people mandated to mail1tain
channels, waterways, beaches, etc. as well as having
responsibility for environmental considerations. Those of us who
are contracto:-s do what We are told without always understanding
or appreciating the reasons why. The amount of difficulty placed
on the dredging process by environmental regulations is reflected
in the dredging cost. The onus of responsibility is on you, the
regulators, to determine what any given regulation is worth.
l'lork shops like this should be more co=on. We must not waste
public mone~' vlhile performing a necessary, and oft..n desirable
public service and at the same time we must assure this service
is carried out in a manner compatible with our environment.
The opening of the Western Long Island Sound disposal area
will save the marina industry and its users a lot of money as th..
distance to the disposal area is in direct proportion to the cost
of dispcsal. While this move was unpopular with some of the
public, the recreational use of boats is very popular and this
necessitates dredging.
The first subject I would like to ~alk about may not be
considered, by strict interpretation, to be an environmental
regulation at all. For many years the upland disposal of dredqed
materials h8s been mandated as the most desirable method of
disposal, with few exceptions. Upland disposal provides ~ 5ense
of s6cur:.ty. We knm' ",here the material is, vlE' can look at it,
we car. manage it.
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The strings attached to upland disposal are getting
difficult tc live with. Land, especially waterfront property, is
at a premium in many metropolitan areas; setting aside hundreds
of acres to contain a sea of mud is not very attractive. The
media, often mislabeling dredged materials, force local citizen
groups into an "anywhere but here coalition".
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We must build more facilities such as Craney Island and Hart
Miller Island for dredged materials that are unsuitable for ocean
disposal and we must ocean dispose all materials suitable for
such. We also must use more dredged materials to nourish our
beaches and to supply sand to our building materials inQustry.
The word "turbidity" is always associated with dredging in a
contrary manner. It's probably true, however, that a vessel
moving through shoaled water creates more turbidity than the
dredging proces5 required to remove the shoal. The fear of
turbidity manifests itself in several environmental restrictions.
Effluent cont~ol in upland disposal areas, overflow restrictions
on hopper and bucket operations, al1d turbidity curtains e:re a
few.
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Some of these restrictions work much better in design than
they do in practice and their utilization is very costly. For
example, as yeu may kno\o.', a turbidity curtain consists of a
f10atino tUDe that SUppOTts a curtain, weighted at the bottom.
This configuration attempts to cr~ate an underwater dam in the
hope of ha-ltino turbidity. This may work fine in a lab,tenl: ~lith
negligible current, but on mest projects with any current, the
curtains are usually destroyed \lithin da;'s of placement. What's
probably ~lorse, m.,ar:inc::r1ess <.r.6 ineffective restrictions-;
stubbornly maintained as these turMidity curtains often are, have
the effect of eroding credibility between the owner, contractor
and regulatory bodies. Let us be sure that industry has input in
the regulations needed to meet certa~n parameters. Maybe it
would be best to set the criteria and let owners and contractors
decide the best way to meet these criteria.
One of the important factors in determining dredging cost is
the timing of the project. Are environmental ,...indows worth the
costs, and do they perform their designed function well enough to
compensate for hundreds of thousands of dollars in downtime for
weather and the increased risk of sinking of equipment? These
costs are passed on to the owner and in most cases, the taxpayer.
Let's be sure about the relative value of environmental windows
before assigning them to contract5.
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Most dredging contractors and owners will tell you the
permit process is an infuriating, t~dious and potentially
expensive nuisance. One essential ingredient in improving this
necessary process is to have the Corps of Engineers and other
State and Local ac::rEncies get together and work out a timEtRhle
for o~ting on permits, and to allow private parties to
"piggy-back" when adjace~t to federal projects.
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There is much knowledge regarding the regulation of dredging
and the environmental effects of dredging. We believe these
regulations and effects should be closely evaluated as to actual
effectiveness and cost. The moving of materials from one place
to another place will always be a reality. Whether or not
certain regulations in this process are effective or cost
effective is something that we must not overlook as responsive
users of public monies. Our company, and I believe, most others
in the dredging industry, is willing to assist at any time those
who have the burden of this responsibility. I believe that if we
all work together, we ~7ill more easily achieve the best results
with the least cost and effort.
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SESSION 1
Questions and Answers
Question 1 David Fallon, (DEC) : Would you please expand your
thoughts on turbidity and silt curtains?
Response: Bill Slezak, (COE): Regarding silt curtains, I think
Brion Lindholm spoke accurately about their poor performance in
open waters. If there are currents of more than 1 or 2 knots,
silt curtains become useless.
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Dick Peddicord, (vffiS): Silt curtains are not filtersl they
are barriers. They do not extend to the bottom of the water and
so water passes under the silt curtain. This process
concentrates turbidity near the bottom where benthic communities
exist. without the curtains, the turbity would spread out,
become dilutec to concentrations less biologically significant.
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Question 2 Jeff Kassner, (Town of Brookhaven): Which creates
more of a regulatory he2dache, dredging or disposal?
Response: Bill Slezak, (COE): Environmental laws are generally
geared more to disposal than dredging.
Question 3 Aram Terchunian, (DOS): What levels of turbidity
sh0uld we be concerned abcut?
Response: John Lunz,(WES): In the lab, turbidity levels of 1,000
mg/l have been shown to caDse adverse impacts although biological
co~munities in the mid and north Atlantic are more tolerant of
turbidity. Onp exception 1E shellfish larvae.
Comment 4 Frank Januzzi, (Weeks Dredging): Recently a zilt
curtain was requ1red and adc80 $250,000 to the project cost and
it accomplished nothing.
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Comment 5 Charles Pound, (Aqua Dredge): We were recertly
prohibited from completing a dredging project unless we used a
silt curtain. Meanwhile the Corps was doing a sidecasting
dredgins project nearby.
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Question 6 Roberta Weisbrod, (DEC): Are containment Islands
hurricane resistant?
Response: Bill Slezak, (COE): Hurricanes would be taken into
account while designing the island.
Brion Lindholm (GLD & D Ce.): The island in BaltiMore was
designed to withstand weather conditions that have occurred over
the past 100 years.
Question 7 Al Bauder, (OGS): Would users pav to use the
containment isltif,d in on'er to offset the cost?- WhRt :5 "the
future use of the land?
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Response Brion Lindholm (GLD & D Co.): The states have to
provide disposal area~ for federally maintained channels.
Baltimore charges $2/cubic yard for private dredgers. Hart
Miller now has a private beach; when it is filled it will be
a state park and half a wildlife refuge.
Question 8 Chris Zeppie,(PA): The Corps is looking at the
most economical disposal options. How does this objective
dovetail with current policy of ocean disposal being th~ option
of last resort?
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Res~onse Bill SlezakICOE): Most economical is not a formal
POllCY yet; it may be in the future. In the future, ocean
disposal may be changed to be considered on an equal footing with
other options.
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Question 9
relaxir.g its
Larry Pen~y. (Town cf East Hampton) :
regulil-::io;l.s on 6umping on wetlal1ds?
Is th~ Corps
Responses Bill Slezak(COE): No. Sensitive environmental areas
are safe. If there is a beneficial use like beach nourishment,
the local sponsor must pay the increased costs of placing the
materia 1 on thE" beach rather than shipping it to ar. offshore
site.
Comment 10 Norm Rubinsteln, (EPA) :
dredged material as a resource, nOt a
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We should consider clean
nuisance.
Responses Jim Morton, (DOS): Clean sand dredged from navigation
channels should be placed on a beach. But to do so would cost
extra noney and this money must be provided by a cooperating
agency. New York State has no established fund to provide this
money.
Jean Gilman, (DEC): DEC is not authorized to provide this
money.
Bill Slezak, (COE): Every pro4ect is required by la~1 to have
a local sponsor. For example NYS DOT i~ the sponsor for the
Hudson River Navigation Project.
.
Comment 11 Dan Natchez, (Consultant): You as regulators will
tell applicants to spend more for a preferred environmental
reason, while the Corps goes for the cheapest alternative. This
is very hypocritical.
Bill Slezak,leOE): Remember, it's not just the cheapest
alternative, but the cheapest and environmentally acceptable
alternative we try to use.
- 17 -
OVERVIEW OF POTENTIAL IMPACTS OF OPEN WATER
DISPOSAL OF DREDGED MATERIAL
by
Richard Peddicord
Environmental Laboratory
U.S. Army Engineer Waterways Experiment Station
,.
The Environmental Laboratory of the U.S. Army Engineer
Waterways Experiment Station (WES) has been involved in research
on environmental impacts of dredged material disposal for
approximately 10 years. This effort began with the five-year, 32
million dollar Dredged Material Research Program in 1975 and has
continued with several multi-million dollar research programs
since that time. We al~o have the Dredging Operation Technical
Support (DOTS) Program which provides the scientific e~pertise of
~FS to Corps Dlstrict! or a short-term response basis to address
immediate specific problems. This effort has kept us very much
in touch with the needs of the Corps Districts and those with
whom they work. We have also conducted a variety of jointly
funded researct, efforts with the Environmental Protection Agency
and other Federal envi ronmental groups, some of which ha"e been
supported in part or in whole by the New York District.
"
A perspect.ive on the volume of oceiin-dumped dredged materiCtl
is provided by the fact that from 1973 through 1981 a low of 41.3
million cubic yards and a high of 99.7 million cubic yards of
dredged material were dispused annual17 in the oceiin. The
average ocean disposal volun~ per year is approximately-65
million cubic yards around th~ country. The New York District
annually disposes something in the neighborhood of 10 million
cubic yards depending on the amount of sediment deposition and
dredging during a particular year.
Dredged material consists of a soil fraction which is the
mineral constituents eroded from the lane plus interstitial water
surrounding those particles in the sediment, a few percent of
or~anic matter and anv contaminants which mav be associated with
that organic matter or the soil fraction. Contaminants can be
associated with dredged material in five major kinds of
geochemical association. It is the nature of the geochemical
association of the contaminant with the dredged material that
determines the environmental activity of the contaminant and,
therefore, the potential impact of the dredged ~aterial. In
order of increasing tightness of association and, there~ore,
decreasing potential for environmental impact, contaminants may
be associated with the dredged material as: II) dissolved in the
interstitial water between sediment particles; (2) ionically or
exchangeably bound to the surface of the individual mineral
particles; (3) in a reducible coatina around those !\",ineral
particlR~; (4) in associa~ion with organic matter in the
seoiment; and (5) metal may b~ part of the crystallin~ G~trix of
the mineral particles themselves. Although biological and
environmental activity decreases in the iibove order, the
- 18 -
abundance of contaminants in each of the fractions increases_in
the above order. That is, the most available fractions contain
the smallest percentages of the contaminants and the greatest
percentages of the conta~inants are in the lesser available
fractions. ContaMinants can shift between fractions depending
upon geochemical conditions at the disposal site. This becomes
very important because it means that a sediment which might cause
acceptahly low environmental iMpacts if disposed Oil land, could
pose a risk if disposed in the water: and conversely, some
sediMents which may pose little environmental concern at an
aquatic disposal site may pose serious problems at an upland
site. For instance, in aquatic sites the dredged material will
remain water saturated, anoxic, reduced, and near neutral in pH.
In upland sites as the material dries, it oxidizes and may become
highly acidic. These differences in conditions greatly influence
the availability of conta~inants from the dredged material. It
is for this reaS0n that most scientists familiar with dredged
materi~l believE th~t it must bE evaluat~d on a case-bv-case
basis in order to select and identify the disposal alternative
that poses the least environmental threat. Therefore, the
Environmental Laboratory has developed a management strategy
which suggests that both aquatic disposal and upland disposal be
considered on an equal basis when disposal alternatives are being
evaluated. Comprehensive environmental protection cannot be
achieved unless the environment is viewed as an entity and it is
recognized that disposal on land may influence the water.
Environmental impacts are not necessarily avoided by simply
avoiding aquatic disposal, but rather the impacts may si~ply be
shifted, and perhaps in a more adverse form, to a different
portion of the environment. Thcl'"efore, a comprehensive~look at
all alternatives is necess~ry for real environmental protection.
When dredged mate~i~l is discharged in ~he open water, most
of it goes to the bottom, and in depositional environments,
remains there. Both field and laborator~' experience in this
country, Japan, and the Netherlands over the past l'leveral years
have demonstrated that under cer~ain conditions it is possible to
cover or cap the deposi~ of contaminated sediMent with a cle.aner
sediment, thereby isolating it from the aquatic environment.
This is proving to be an acceptable management technique for
contaminated sediments in aquatic disposal sites.
When looking at the potential for environmental impacts
around an aquatic disposal site, one must consider not only the
biological activity of contaminants but also the
time-concentration relationships under which animals will be
exposed to those contaminants. For instance, around open water
discharges of dredged material, suspended solids concentrations
tend to return to background levels within 1000 to 2000 yards of
the discharge point. When hopper dredge discharges take place
eleva~ions may reach perhaps 1000 to 2000 mg/l suspended solids
at the point of discharge and return to background ccncentrations
within approximately lODe yards of the site and within 10 to 30
min. Therefore, both the concentration of suspended solids and
the time during which organisms May be exposed to them must be
"
,"
'.,
.
r
. .
<
r
," , .
.
- 19 -
considered in evaluating the potential for environmental impact.
One must also recognize the variability inherent in sampling data
in order to assess impacts.
The influences of geochemical conditions on con~aminant
availability are such that contaminant mobility tends to be
greater at acid pH and oxidized conditions. This holds true for
a variety of contaminants associated with dredged materials in
several different geochemical fractions. Rather weak statistical
correlations exist between total or bulk chemical concentrations
of any individual contaminant in sediment, and toxicity of that
sediment. This has been shown in a number of cases and holds
true for both toxicity and bio-accumulation. Techniques have
been developed and are continually being refined for biological
examination of individual sediments on a case-by-case basis to
predict th~ actual potential for environmental impact of both
upland and anu~tic discharges of that particular sediment. Using
these techniques and recognizing the time/space concentration
distribution relationships of the contaminants from the
discharge, it is possible to make accurate genera~ statements
about potential for impacts at a particular site and to identify
the disposal environ~ent which poses the least potential for
overall impact ~ith a giverl sediment.
. .
"
. .
. .
- 21 -
EFFECTS OF DISPOSAL OF FINE GRAINED SEDIMENTS ON BENTHOS
A Point of View
John D. Lunz*, and Douqlas G. Clarke**
U.S. Army Engineer Waterways Experiment Station
A clearer understanding of the potential biological effects,
or if you prefer, the impacts, of disposal of fine grained
sediments is possible if one considers impacts in the following
framework:
Activity In this instance the activity is the placement
of fine textured sediments (mud) into the aquatic environment. A
better definition of the activity would include information about
the type of dredge and disposal equipment used during the
projec~. A mechanical bucket or clamshell dredge will pick-up
sediment from the bottom in nearly the same consister,cy as the
material occurs on the bG'c'coD r.aturally. to/hen this material is
transferred to a barge or scow, which transports it and dumps it
at the disposal site, the material consists of a relatively large
percentage of solids and small percentage of water mixed with it
1n comparison with material handled using other dredging and
disposal methcc5. Hydraulic hopper or cutterhead pipeline
dredges tend to mix the material on the bottom with water. This
causes the dredaed n'i:terial to be lower in solids and hiqher in
liquid content.' The solid:liquid ratio influences the w~v
material descends to the bOttOffi anc affects the thickness' and
spread of the deposit on the bottOM.
Alteration This refers to the physical or chemical
alteration of the environment that is affected by the activitv.
Environmental alterations can be described in Qualitative or in
quantitative terms. For examplb, the frequently heard statement
that the aauatic disposal of dred9cd material increases the
turbidity of the water is a qualitative statement. A
qliantitative statement would include information about the levels
of turbidity without the disposal activity and the levels with
the disposal activity.
Effect In biological language, the effect or impact is
the result of the biological response to the environmental
alteration. The effect is not always undesirable or "bad". A
determination about whether an effect is desirable or undesirable
must be made in relation to society's goals for a particular
waterbody. For example, hard clams and scallops are nct
typically harvested from the same Long Island embayments. While
hard clams are the most important commercial shellfish resource
in the Great South Bay, bay scallops are the most important
shellfish harvested in the Great Peconic Bay. These two types of
shellfish have different environmental requirements. If it were
possible to devise a scheme that modified environmental
conditions in the Great South Bay which led to the displacement
of hard clams by bay scallops, that effect would probably be
"bad" in the minds of persons who preferred clams to scallops.
* Research Mari~e Biolcqi~t
** Oceano9rapher
- 22 -
Systems of Biological Classification Used for
Studying Disposal Impacts
Biological science is loaded with technical terminology and
different classification systems. Aquatio organisms are often
classified according to where they live in the vertical dimension
between the water surface and the bottom sediment. Interwoven in
this classification are terms that describe an organism's
mobility. Terms of particular relevance to this discussion are:
plankton, which are organisms or life stages of organisms with
very weak swimming ability whose movements are influenced to a
greater degree by the direction of water currents than by their
ability to swim across or ag&inst a current; nekton, which are
organisms capable of swimning against or across a current and;.
benthos, ~lhich means bottom and refers to organisms that live at
or below the '~ater-H:)cliInent boundary.
"
Dredged material disposal operations in aquatic environments
tend to alter bottom sedi~er.t conditions more than any other
aquatic environmental conditions. Because of this, studies about
the bioloqicul effects of disposal operations frequently
emphasize the henthos. There are other reasons for focusin~ on
the benthos: they do not move around as much as plankton and
nekton; they are relatively long-lived, especially wher; compared
,~ith plankccn and; a lot of informat~on is known about the~r
biology.
,
Benthic biological responses, ie. responses of the benthos,
are usually measured at one or more of three different -levels of
biological organization. The individual organism represents one
level. When the individual is the focus of attention, responses
observed include altered patterns of feedinq, respiration, and
chemical composition. Other observations are sometimes made on
individual organisms, but the three mentioned above are the most
common. A second level of organization is the population. A
population is a collection of individuals of the same species.
The striped bass population of the Hudson River is an example.
Population measures include observations of growth in numbers and
growth in the average size of population members which provide
information on reproductive health and general condition.
Population studies are more coronon than individual organism
studies and probably more meaningful because the condition of a
population is the long term basis for knowing the impact of a
fishery on that population. A third level of biological
organization is the community. Different species living together
comprise a community. A relevant example is a shallow-water
mud-bottom benthic community dominated by a variety of different
species of marine worms and clams. Community studies of benthos
are most common among types of benthic impact investigations.
Characteristics examined include total number of different
species, total number of individuals, total weight (biomass),
relative propor~ions of different species, feed ins types and
others. The value of some species comprising a benthic community
is obvious when those species are commercially or recreationally
- 23 -
important like hard clams, scallops, mussels, blue crabs,
lobsters or blood worms. But for each commercially or
recreationally important species there are literally hundreds of
species of clams, worms, shrimp-like animals and other benthos
that have no commercial or recreational value. These are,
however, important for various ecological reasons. For example,
they provide food for fish.
Benthic Responses to the Disposal of Fine Grained Sediments
.
Individual organisms, populations and communities persist at
a particular location because they are adapted to physical and
chemical environmental conditions at that location. If an animal
is capable of efficiently feeding, respiring, etc. within a
particular range of environmental conditions, then its long-term
survival, or the survival of other individuals of the same
species is threatened when conditions extend outside of that
range. A larq~ number 0: physical ane chemical environment~l
conditions involving water and sediment o.uality are important to
survival of benthos. This discussion will concern itself with
those conditions most likely to be influenced by dredqed material
disposal activities.
,'.
,
Let us begin the discussion by constructing a realistic
scenario involving the disposal of fine-grained (muddy) sediments
over the bottom of an estuarine or coastal marine disposal site
located in the \Iaters of the State of Ne,,' York. The project
would most likely involve the USe of a bucket or clamsh~ll
dredge. The dredge would transfer the material at the dredging
site into ~ barge or scow which wo~ld then be towed or pushee to
the disposal site. At the disposal site, doors located at the
botton of the barge would be opened. The fine-grained dredged
sediments would descend through the water column, impact the
bottom and be distributed in the form of a mound. The areal
dimensions of the mound, and its height or thickness will
obviously be affected by the volume of the material. These
characteristics and the slope of the material between the tOp of
the mound and its eages will also be influenced by the location
of the barges over the site during disposal operations, the water
current regime at the site, and the specific properties of the
material that would cause it to behave more as a liquid and flow
over the bottom or, more as a cohesive and plastic material with
a resistance to flow and a tendency to mound higher on the
bottom. .
Next let us: (a) describe what happens to the estuarine or
coastal marine benthos that live on or in the bottom within the
boundary of the designated disposal site; and (b) dis~uss the
conditions that seEm to influence the kind of benthos that
recolonize the disposal site and the rate at which colonization
proceeas.
- 24 -
Animals occurring within t.he area impacted by the dredged
material immediately following its descent to the bottom are
probably killed. Survival by animals covered by the dredged
material as it spreads over the bottom from the impact area
depends on the thickness of the blanket of matp.rial together with
the physical similarity between the dredged material anc the
sediments occurring naturally at the disposal site. Animals
usually found in mud seem better adapted to survive burial when
covered with mud than animals usually found in sand. The
converse seems valid as well: animals usually found in sand seem
to survive burial in sand better than mud animals. There are at
least two reasonable explanations for this observation. First,
animals whose bodies have evolved for burrowing in sediments of a
particular physical character are to an extent specialized and
unable to cope with too great a change in sediment type. Second,
anatomical respiratory and feeding structures have evolved to
allow efficient oxygen transfer and food gathering in a
particular sedimentary environment. Of course this point does . '.
not apply tee. animals whicr. have no bnn:owing ability. If an
animal spends its life attached to a piece of broken shell or
other firm substrate and feeds by filtering water (like a mussel)
or trapping particles suspended in the water flowing over it
(like a barnacle) I it is not. adapted to survive burial.
The kinds of benthos that recolonize a dredged material
deposit and the rate of recolonizati0n seem to be determined hy
(a) the character of the dredged material relative to the
character of th~ natural bottom sediments, (b) what I shall call
the disturbance climate which refers to the magnitude, frequency
and seasonality of physical or chemical d~sturbance to ~hich the
benthic cOIlUllunit~' of an area is adapted ane'! (c) the availability
of mobile propagules, ie. juvenil E: c.r adult forms of benthos
capable of moving onto the dredged material deposit, in the
vicinity of the dredged material deposit. If the drednpe
material is similar in character to material occurring on the
bottom naturally, if the general area is disturbancE adapted such
as a shallow muddy-bottomed estuary stirred up by seasonal
prevailing winds and, if the general area around the disposal
site is characterized by benthic communities containing species
that produce a nearly continuous supply of mobile juveniles and
adults capable of drifting as plankton at night, possibly in
search of more food-rich, recently disturbed bottoms, then
colonization of the dredged material deposit will be very rapid.
Under these circumstances it is also very likely that there would
be only small differences between the benthos invading a new
deposit and the natural bottom cOIlUllunity of the general area. A
change in sediment type and/or a change to the natural
disturbance climate will at least temporarily, and possibly
permanently, alter the character of the benthos of an area. A
fine sand bottom populated by an abundance of small shrimp-like
animals living at or above the surface of the sediment might be
displaced by a muddy bottom containing large numbers of marine
worms and small clams living at and beneath the sediment surface.
If the disposal site receives dredged material at a time that is
incompatible with the seasonal reproduction cycles of some
henthos or if the dredgE~ material deposit is isolated from a
r
- 25 -
.
source of propagules by distance, or by local water circulat_ion
patterns, the period of recolonization will be prolonged. .
Depositional environments, i.e. bottoms of estuaries and coastal
waters which are relatively deep or protected in other ways from'
bottom turbulence caused by wind-generated waves, tend to be
inhabited by benthic communities that require extended periods of
bottom stability for their establishment and persistence. When
those areas are disturbed by dredged material disposal, the
community that first develops on the bottom is usually different
than the original community. This occurs even when the dredged
material is similar to the original bottom material. With time
the community condition changes, becomes more similar to the
pre-disposal conditions, and may eventually be indistinguishable
fron the conditions that preceded disposal.
a-
An important resource management auestion is: Has the
estuarine, or coastal ~'ater botton area used for dredged material
disposal ~eEn reduce6 in value by that disposal? Mnre
specifically the ques~~on becomes: Do the benthos that first
colonize dredged mater~al placed on a depositional botton, or the
benthos that live on the dredged material during the period it is
changing biologically and becoming more like the ore-disposal
benthos, have the same fish-food value as the original bottom?
The answer appears to depend on the type of fish and the size of
fish whose food supply is involved, because even among
bottom-feeding fishes, different types (species) of sinilar
looking fishes eat different things and different sizedJagec'! fish
of the same type (species) commonly eat different things. Fish
feeding behavior is a complicated subject but the follQ~ing
generalizations arc oefensible: (a) many estuarine anCtnearshore
coastal marine fishes with recreational or cornrnelcialimportnnce
are opportunistic or plastic in their feeding habits. Their
survival and gro~th isn't deFendent on a single or several
species of benthos, (b) the efficiency with which these
opportunistic predators feed not only affects how long it takes
them to fill their stomachs, but how hard they have to work to
fill their stomachs, and influences how much food energy is used
for bare maintenance of life and how much food energy IS
,. available for qrowth and reproduction; (c) feeding efficiency is
determined by the anount and the distribution of available food.
Food concentrated in patches is consumed more easily than the
same amount of food that is more uniformly distributed over the
bottom, and (d) the availability of food depends on the size of
the potential food item in relation to the ability of the fish to
capture and eat ~hat potential food item as well as on how deeply
in the sediment the available sized food items are located.
"
'0
.- II
These qeneralizations lead us to the conclusion that the
fi~h-food value of a bottom affected by dredged material disposal
depends on: (a) the total weight (amount) of benthos occurring on
the bottom, (b) the area over which the total weight is
distributed, (c) the sizes of the benthos comprising that ".eight;
a~d (dl the way in wh~ch the individual sizes and w~ichts of the
benthos are distributed both horizontally and vertically on and
below the sediment surface. Different species of fishes and
- 26 -
sizes of fishes vary in their abilitv to efficiently detect,
capture and eat certain sized food i~ems located at varions
depths below the sediment surface.
Eenthic communities naturally occurring on depositional
bottoms are characterized by numbers, weights, sizes and
distributions of benthos that are different when compared with
communities of recently disturbed or recovering bottoms. The
desirability of these altered fish-food conditions depends on the
types of fisheries local resource managers wish to preserve or
enhance. I stated above that many recreationally and
commercially important fish species are opportunistic or plastic
in their feeding habits. The intentional implication is that not
all fishes feed this way. Some appear much more selective than
others. Some flatfishes seem to prefer to feed upon the
shrimp-like benthos living at or just above sandy bottoms. It
would not be easy to aefend a statement that changing the bottOM
from saD~to mud would have no effect on the food value of the
bottom fo, these fishes.
,
Conclusion
We obviously lack information about all the effects of fine
grained sediments on benthos. Eut biologists specializina i~ the
study of the benthvs and the interactions between the benthos and
the sediment envircnment lhcnthic ecologists) have gathered an
impressive and very useful information base. Eenthic ecologists
working together viU. fishery biologists can educate one another
to achieve a quantitative understanding about the influence that
changes in the benthos have upon the fish-food value of an
estuarine or nearshore marine bottom. This kind of knowledge is
available and could be uSEful fer making d~edged material
mangement deoision~.
r
- 27 -
SESSION 2
Questions and Answers
'-
Question 1 Dave Fallon, (DEC): Is there a problem with
dissolved contaminants migrating away from the aquatic disposal
site?
Responses: Richard Peddicord, (WES) : In an aquatic disposal
site, movement of contaminants from the disposal site is measured
in millimeters per year! Contaminant movement through-
interstitial water is so small as to be negligible. However, the
weight of the overlying sediment cap can induce some contamina~t
movement, but we cannot measure this movement with precision. ~
"
At the dredging site, suspended sediments dilute to
acc~ptable levels within 1,000 meters of the dredge operation.
Contaminant mobility is a function of the concentration of
suspend~~ solids an~ duration of ~y.posur~. However the amount of
suspended sed1ment induced by dr~dging is less than that caused
by a working shrimF boat.
Question 2 Hank Smith, (DEC): Can't you add colloids (e.g.
lime) to the dredge slurry stored in a diked upland disposal site
to lessen the potential for metals to leach from the disposal
area?
Response: Richard Peddicord, (WES): Yes, this process is usable
but there ~s a question of cost. By physically manipulating the
dredge materials during disposal, it may be possihle to achieve
the same objective at a lesser cost.
Question:3 Bob Teeters, (Connecticut): Does our knowledge of
geoohemistry help us predict the uptake of arsenic by plants?
Response: Richard Peddicord, (WES) : We could not predict the
magnitude of uptake but we could have predicted that there would
be a problem.
'i
Question 4 Art Miller, (DEC) : Is the Corps consid~ring using
EPA's acid ,soluahle techniques in elutriale tests for metals?
Response: Norm Rubinstein, (EPA): This is one of the methods
being considered, but it is not routinely being used for testing
dredged materials.
Question 5 Jeff Kasner, (To\o.'n of Brookhaven): Hav~ VOD
considered integrating the results of biological comrr~nity and
water quality impact assessments in order to determine overall
impacts of a project?
Responses:
particularly
are invclved
John Lunz, (HES) :
when people with a
in the assessment.
Yes, this is possible,
good deqree of local knowledge
- 28 -
Comment 6 Ron Abrams,(DEC): Do not assume that because fish can
shift th~ir diets when their feeding area is altered by dredge
material disposal that there won't be other negative ecological
consequences of changing their diet.
Response: John Lunz,(WES): Some fish change their diets
seaso~ally~ other cannot. If a particular fish species feeds on
only epifauna of one type and we eliminate these, then we lose
those fish. In other cases, some fish species can do well on a
variety of foods and feed on whatever is most easily available.
.
- 29 -
CORPS' REGULATORY APPLICATION OF TE 1T RE SJLTS
by
John Tavolaro
U. S. Army Corps of Engineers, New York District
"
The previous speakers have discussed impacts in the field
and the technical aspects of dredging and disposal projects. My
focus will be on how we use this information as regulators. The
two basic questions are: (1) What tests are required.and why?
and (2) How do we interpret the results?
.
"
Originally I was going to describe the regulations but that
began to get very complicated and almost exclusively a legal
briefing. Regardless of the applicable regulation, testing is
required to address the environmental concerns that are the basis
:or the rEC:l:iaticllb, 'I'h' crm: of the mat.ter here is the
environmental concern, rather than the regulations per se that
dictated the recuire6 testillg. Regulations give an agency the
legal authority to consider environmental aspects of dredging and
disposal projects. So, in this discussion we will assume that
the legal authorit:' is a given and not address applicable
regulations.
We as regulators must first look at the specifics for each
project. Thcr~ is a biq difference in potential impac~s
depending upon type of drecging, method of disposal, etc. Then
~le must determine ",hat thE, questions are (which aspect of
project, if any, shows environmental concernsl. Finally we must
determine the means to answer these questior,s. This does not
always mean that testing is required. Existing information
should be used \'lhenever pos sible. 'I'f'sting should bs speci fj c to
the project and should only be used to fill in the gaps in our
knowledge.
"
I will now discuss what ~esting is re~uired and why, in a
very general way. Just as all dredging and disposal projects can
be classifif'c by their potential impacts (physical, chemical and
biOlogical, and the interactions among them), s1m11arly,
environmental testing is also divided into
physical/chemical/biological types. Physical t~sts are basically
grain size analyses. Chemical tests include bulk chemical
analysis, elutriate analysis and special tests designed for
contained dredged material disposal facilities, i.e., the
modified elutriate test. Biological tests consist of the
bioassay test (liquid, suspended particulate and solid phase) and
the bioaccumulation test. Each type of test tells a limited
story and is designed to address specific elJVironmental
questions.
'.
The grain size test tells you a lot immediately ahout
overall pollutionpotent1al ana physical impact potential, The
coarser the sediment grain size, the lower the potential for the
sediment to be contaminated.
- 30 -
The bulk chemical test has a very limited usefulness by
itself. It does not address mobility or bioavailability of
contaminants and should never be used that way. It can be used
if the degree of pollution is unknown, or in order to look for
"hot spots" of a given contaminant.
'-
The elutriate test should be used if there is
water quality impacts during dredging or disposal.
address bioavailability of contaminants.
Regarding the bioassays, the liquid and suspended
particulate phase could be used if there is concern for water
quality impacts causing mortality of water column organisms. the
solid phase could be used if there is concern for mort~lity of
benthic organisms at the disposal site.
a concern for
It does not
The bioaccumulation test is usually done in conjunction with
the solid pha~r tioassay. :t could be used if ther~ is concern
for bioaccumulation of contaminants at the disposal site.
Testing methods are relatively straightforward and are the
responsibility of local Corps Districts, the EPA and local
agencies. The trickier aspect is how we interpret the results of
the testing. A lot of what follows is the result of the Corps
expenditure for the Ocean Disposal program.
The grain size anc bulk chemical analysis are used merely as
inventories 1 environmental impacts cannot and should not'be
int~rpreted with confidence from there tests.
ThE elutriate enalysis should be done in triplicate to
determine a mean and standard deviation. The site water test
should also be done in triplicate. If you detect elevated
contaminant levels in the elutriate and they are statistically
significantly diffcr~nt from the site water, then you have to
calculate the mixing zone to see what impact dredging will have
on thp ~Iater qualJ. ty at the dredging site.
Most of the methods for bioassays has been developed in
response to Ocean Disposal requirements. Dredged material is
prepared in a liquid form and in a suspended particulate form for
testing purposes. Various concentrations are run for various
water column species. We then calculate the LC 50, the Limiting
Permissible Concentration (LPC) (1% of LC 50 as safety factor)
and the mixing zone (modeling) to determine size of mixing zone
once LPC is achieved. The material that settles out after mixing
is the solid phase. Three species are exposed to the solid phase
dredged material for 10 days and the percentage of mortality is
determilled statistically. If there is a statistically
significant difference in mortality and the difference is) 10%
for anyone species or for the com~unity as a whole, then no
ocean disposal is allowed.
.
- 31 -
Bioaccumulation testing is done in conjunction with the
solid phase bioassay. A tissue analysis of the survivors is done
in triplicate and statistically compared to a reference sediment
(clean sand). If there is statistically significant difference
and the test value is greater than Interpretive Guidance Matrix
Value, there is cause for concern.
"
The Interpretive Guidance b<latrix is similar to a "Water
Quality Standard" for the area around the disposal site only in
this case it is a "Bioaccumulation Standard" in the New York
Bight. Bioaccumulation values below "ambient" levels of
bioaccumulation in the disposal environment are not cause for
concern. The matrix sets maximum ppm values for each species in
the test, based upon analysis of organisms. The matrix has been
agreed upon by all ocean disposal regulatory agencies; it is
dynamic and can change as ambient conditions chang€.
. .
That in a nutshell is hov we determ10e what testinq is
required and how we irt~rpret results. I want to emphasize that
it is important to look at the specifics of dredging and disposal
projects in order to define the appropriate environmental
questions. Always keep in mind that specific tests were designed
to address specific questions; no more and no less. If testing
is needed, the proper test must be used; otherwise, any analysis
of the data is misleaei~s. rinally, data interpretation o. the
proper test is essential. Tests are not definitive; they are
open to 1nterpretaticn an6 ob scientists, 88 well as regulators,
our interpretation must be based on fact not on bias.
. . \'
<r
.'" I;
- 33 -
SESSION 3
Questions and Answers
'-
Question 1 Holly Haff, (NYC Dept of Planning): How does the
Corps interpret ,the sediment data? What percent of the permit
applications received include test results showing unacceptable
contaminant level?
r
Response: John Tavolaro,(COE) Guidelines for interpreting
sediment test results are not laid out as precise as those for,
conducting the test. The standards used for judging the relative
acceptability of sediment to be dredged were derived from years
of arguing and law suits. A 10% difference between reference and
test data is generally considered a large enough difference to
trigger the Corp's copcern.
Question 2
whether the
cap or Id th
Jim Morton, (DO ~: How does the Corps
materinl coula b~ placed at the Mud Dump
a cap.
decide
without a
Response John Tavolaro, (COFl: Matrix values exist for some
contaminants such as mercury, PCB's, cadmium and zinc. We do not
have a matrix value for P~HS. When test results SDOW ,
contamination levels 10% greater than the matrix level, 'then we
require capping.
Question 3 Unkno,,,n Participant..: Are bioassays required only
for projects involving more tJ'lan ~5,000 cubic yards of dredged
seediment?
o'
Response John Tavolaro, (COE): It depends cn the location of the
dredging project. If the project calls for disposal in Long
Island Sound, then bioassays are required for projects involving
25,000 cu yds or more. When leesser amounts are involved, we
still require bulk chemical analysis. If test results show a
high degree of contamination, we would then require bioassays.
..
Question 4 Unknown Part~cipant: Are the Corps and EPA
phasing out acute toxicity tests?
Response: Norman Rubinstein, (EPA): We're not phasing out any
tests: we'll use a hierarchy of tests. Early tiers are cheap
and simple, using predictive models. The new procedure will
eliminate routine bioassay testing and the automatic $10,000
charge that goes with it. We may have to move to more complex
tests, depending on the scope of the project and the effect on
substrate colonization.
Richard Peddicord, (UESl: All projects warrar.t some looking
at. l'lith some it's readily evident that there's not a lot of
problems. Grey areas take'more investigation than black or
white. Only a few projects need the full array of testing.
- 34 -
Question 5 Unknown Participant: On mixing zone models: how
do you determine what's an appropriate size of the mixing zone?
Response John Tavolaro, (COE): There are two ways to establish
mixing zones. In a narrow channel the mixing zone cannot exceed
a set size. In the ocean you calculate what the mixing zone will
be without constraints, and then determine if the size of the
calculated impact area is acceptable.
Question 6 Dave Fallon, (DEC) When I see the approval of
ocean disposal of sediments dredged from the Arthur Kill, which
is a pretty stressed area, I have to question the value of the
bioassay test.
Response Norm Rubinstein, (EPA): The test works in terms of the
end points we have selected. Contaminants associated with
sediment t~rn cut ta be l~s~ toxic than pure contaminants
dissolved in water becau~E they are less biologically available.
Sediments suck up the contaminants, functioning like a sink. In
a cleaner environment, se6i~ents serve as a source of
contaminants.
Question 7 Dave Fallon (DEe): Isn't it easy to manipulate
bioassay tests so as to obtain desired results?
Responses:
procedures
agencies.
Norman Rubinst;E~1l (EFA): No. ThE tEsting
prescribed reflect a consensus of federal regulatory
Jim Mansky, (COE): A lahoratory must go thro~ah a rigorous
QA/QC before we'll allow them to conduct tests. The COL and EFA
inspect all labs.
eill Slezak, (COE): The Arthur Kill ~sn't pristine but the
sediment is so coarse grained that it doesn't absorb much.
Que~t ion B Larr'! Penny, ('rown of East Hampton): Hm.1 many
project~ fail ocean disposal criteria?
Response John Tavolaro, (COE): About 5% of the projects have
failed the solid phase bioassay.
- 35 -
INTRODUCTION: PANEL DISCUSSION ON DREDGING WINDOWS:.
ARE THEY AN EFFECTIVE TOOL
by
James Morton
NYS Department of State
,
This afternoon's panel topic is dredging windows. It is our
intent to take a candid view of this commonly used strategy to
mitigate adverse environmental impacts of dredging projects.
. .
Very simply, dredging windows are time limits imposed by
regula~ors within which a dredqing project must be completed in
order to avoid interfering with some other important use of the
project area such as fish spawning, waterfowl nesting or human
recreational activities.
Intuitively appealing, dr~dging windows set by different
regulatory agencies sOfubtimes create an untenable situation:
overlapping time restrictions can limit the allowable time for
dredging such tDat there is insufficient time to complete a
project.
We have invited panelists representing both sides of the
issue. I_trust we will have a lively discussion.
Our first panelist is Charles Pound, of Aqua Dredge, Inc.,
and an articulate spokesman fer the cOIT~unity of dredgi~q
contractors. .
"
- 37 -
CONTRACTOR'S PERSPECTIVE
by
Charles Pond
Aqua Dredge, Inc.
Regulators are making it difficult for dredging firms to do
their job. Some contractor concerns are:
(1) Redundancy in forms and regulations. There should be a
mechanism for adjusting the standards for reviewing a project to
the size of a project. A project of 100 cubic yards should not
undergo the same scrutiny as one for 1,000,000 cubic yards.
. .
(2) There should be a standard review process for small
projects so that regulators can concentrate on important ones.
(3) Re0u1ators ne~d to do a better job of screening
objections t8 ~rniects tv ~~ke sure thc~ Bre valid.
(4) CorrJrol' sense must be useci \lhen applying dredging
windows. For instance, in Long'Island Sound once bad weather
months and dredgina restriction months are subtracted frOM the
year only three months are left for getting the work done.
(5) Is there really an environMental basis for settinq
dreeigi:,g \iindows QUI-' t.'"' turLJ.d,-t:., especi"lly for small projects?
(6) When setting dredging windows regulators should take
into account th~ specific type of equipment to be used as SOIT1e
dredges produce little, if any. turbidity.
'. r
<T
." "
- 39 -
DREDGING WINDOWS-MUNICIPAL PERSPECTIVE
by
Jeffrey Kassner
Town of Brookhaven
Division of Environmental Protection
INTRODUCTION
Intuitively, dredging windows, the restriction of dredging
to certain periods of the year, appear to be good environmental
policy. Ecological theory holds that most organisms and
ecosystems are more sensitive to environmental perturbations at
certain times ("critical periods") than at others. In the marine
environment, the critical period is thought to be durin~ the
summer months when reproductiOIl anc" production are at their
pe~ks. For this r6ason, dredging has been prohibited by many
regulatory agencies during the warmer months of the year,
typically ~i."ing a "dredg ir.g window" from September to May.
The Town of Brookhaven is the largest of Long Island's 13
townships and has had a seasonal dredging window for over five,
years. In considering dredging windows from a municipal
perspective, using the Town of Brookhaven as an example, two
questiolls_cre pertinent.. First, what is the jurisdictional basis
that er.ab1es the TCt:n to establish a dredging window and by
extension, why does the Town choose to exercise the option?
Second, what is the ratior.ale for the dredging window? -.'
THE TO\~"N OF BR00KHAVEh' S BASIS Fer. ;. DREDGING v;INDOlv
..
The Tmm of Brookhaven was established in the
mid-seventeenth century hy the Dongan Patent issued by the then
colonial Governor of New York. It is the basis of the Town's
regulatory authority and at the same time mandates that the Town
trustees protect and preserve the environ~ent of the Town for the
good of its citizens. Furthermore, most. underwater lands and
wetlands were to b~ held in common by the Town, giving it a
property interest as well.
,"
Brookhaven's trustees and subsequently the Tovm Board,
Brookhaven's legislative bodies, have regulated usage and
development of wetlands and waterways since the inception of the
Town. Initially, this was done by Town resolution on a
case-by-case basis. In 1976, the Tow~ formalrzcd its wetlands
regulatory procedures with the adoption of it's wetlands
ordinance. The regulations therein cover waterways, wetlands and
adjacent areas.
The Town has chosen to regulate wetlands, which includes the
establishment of a dredging window, because it feels t.hat the
Town carl be much more sensitive and responsive to local needs,
concerns, and conditions. There is certainly adequate
justification for this position. While some may argue that this
- 40 -
creates additional bureaucra~ic delays, with coordinated review
with other regulatory agencies, it actually gives a flexibility
to the regulatory process and better protects the environment
because the Town is mor~ aware of the local nuances of a project.
THE BAUS FOR THE DREDGING WINDOW
Originally, the Town's position was that no dredging should
be permitted from May to September. This was based on the
concern that increasing the suspended sediment load during this
period of the year would interfere with the reproduction and
feeding of commercially and recreationally valuable fish and
shellfish. A wide variety of laboratory studies confirm the
lethal and sublethal effects of elevated suspended sediment
concentrations.
If one locks at ~he natural concentration of suspended
sedim~nts, how~~pr, it is ouite apparent that meterological
events (i.e. storms) routinely suspend considerable quantities of
sediments which marine organisms are obviously able to withstand.
For this reason, if the concentration of suspended sediments
induced by dredging is of the same magnitude and length of time
as storm generated concentrations, then dredging would, in
effect, mimic a natural event. Therefore, the ecosvste~ should
respond to th~ dredging as if it were a storm, permitting the
dredging wincC\v to be rela::ed in certain instances.
In the Great South Bay, for example, the average
concentration of suspended sediments is about 10 mg/l. During
storm events, susp~nded sedirn~nt concentrations routinely exceed
30 mg/l and can go as high 130 mg/l. The concentration of
suspended sediments increases rapidly but returns to background
levels in about a week. Although the information is l~rgely
lacking, it is likely that most small scale dredging operations
produce suspended sediments profiles similar to storms.
Thus, under certain conditions, it appears that there may
not be a need for a dredging window and'the Town has become more
flexible in requiring a window. Unfortunately, predictive models
that could provide suspended sediment concentration contours
surrounding dredging operations have not yet been developed.
Decision making therefore is based on available geophysical, and
hydrological information, as well as the characteristics of
adjacent areas. These are assessed for each application, tc
determine if there is sufficient justification to waive the
summer restriction.
The creneral ~own policy is that when the impact cf the
dredging is not clear cut, a window will be invoked with projects
that take longer than two or three days to complete. The
seasonal restriction is not required for coarse materials since
they generate little suspended sediment. With medium to fine
sediments, the \.]indow may be waived if the area iE' ~1f,11 flushea
and no important natural resources will be impacted. Suspended
sed~ment mitigation measures are usually required when the window
is waived.
- 41 -
In addition to adverse suspended sediment impacts on the.
ecosystem, there is concern that dredging operations will cause a
significant decrease in dissolved oxygen, which is a particular
problem in the warmer months. Where the sediments are highly
organic or the area to be dredged is poorly flushed, this is a
legitimate concern, and a seasonal dredging requirement is always
applied to the project.
'-
..
There is one additional case in which a time requirement
will be placed on a dredging project but is not necessarily
seasonal. In many instances, an area will be used by wildlife or
for recreation for a well defined time period. In these cases, a
time restriction will be required, consistent with the usage.
THE THIING OF DF-EDGING WINDOWS
..
Give~ th2t seascnLl dredg1n~ restrictions are justified and
necessary, the next ~uestiDn is wlilit are the appropriate time
limits? In a few limit~d instances, the timing is obvious but in
most cases, it is not. Further confusing the issue, the critical
period is not the same for all organisms.
It has also been accepted as fact that the marine
environment is most sensitive to dredging in the summer months.
This necds to be crit1cally evaluated. A case could be mace that
dredging should not be permi~ted in winter because the ~ow water
temperature slows biological processes such that organisms are
less able to respond to the dre~ging stress.
One thing that is certain in setting a dredgincr window, is
that the timing must be consistent among the regulators. This
has not always been the caSE. A difference of one or two weeks
in setting the starting and ending dates is not likely to have a
serious environmental imryact but will cause serious oonfusion
with the public and hardship to contractors. This is an unfair
burden to impose, particularly since the value of dredqing
windows has net been conclusively proved or disap"roved. It is
clear that regulators must become consistent.
Dredging windows tend to be more qualitative than
quantitative. They are also based on laboratory studies that may
not be applicable to real world situations. The benefits derived
from dredging windows are not likely to be insignificant, but one
must keep in mind the scientific limitations behind dredging
windows in setting and maintaining policy.
FUTURE NEEDS
Additional research into dredging windows is certainly
justified and needed to validate and refine the dredging window
concept. From a regulators perspective, it would be most useful
if the distribution of suspendeel sediments around a dredcring
project could be predicted. When the distribut~on shows a~
impingement upon valuable natural resources, then a dredginq
window could be set.
- 42 -
Work is also needed to better define the timing of the
dredging window. What is good for one organism may be harmful to
another. It is clear that the objectives of dredging windows
need to be better clarified. ,
In conclusion, the use of dredging windows is probably
warranted. Their implementation needs to be refined, however, to
ensure both environmental protection and the realization of other
societal needs.
- 43 -
DREDGING WINDOWS: STATE PERSPECTIVE
by
David Fallon
NYS Department of Environmental Conservation
. .
The Division of Marine Resources, New York State Department
of Environmental Conservation, is of the opinion that dredging
windows do have a value but they must be implemented on a case by
case basis and that blanket prohibitions against dredging in any
particular time period are not necessary at this point in time.
In the future, if generic EIS's demonstrate that there would be
some value in placing dredging windows on specific areas to
protect specific species this could be accomplished. But to do
this at present would bp. premature. It is our opinion that the
ma;or concern with drec~ing in enclosed environments is a
possible prublem with lower disso~ved oxygen (DOl levels. I
think a reasonable approach to the problem of 10~ler dissolved
oxygen levels is to have the appropriate government agency
generate a list of areAS based on their experience where they
believe dissolved ol:ygen problems might result from credging
activities. ThE NYSDEC has produced such a list for Suffolk
County. Even in these cases it might not be necessary to
prohibit the dredginc at this time but rather it would be
advisable to have dissolved oxygen monitoring with perm~t
restrictions that would a~tomatically stop dredging should the DO
readings go below a certain point, for example 4 milligrams per
liter for ten to twenty minutes. Generically, we advis~ that
large dredging operations shculd be scheduled to occur between
October 15th and ~ay 15th.
~
However, once a credging project has been initiated it
should be allowed to go to completion even if it goes into this
window. The reason for the time period chosen has to do not only
with biology but with social and economic factors. In the New
York areas most of the marine recreational and corr~ercial
activities occur during the May 15 to October 15 period. This is
~ also the peak time for spawning activity of most but not all
commercially and recreationally important species in New York
waters. To summarize, the Division of Marine Resources in New
York State has an advisory on the conduct of dredging activities
in specifically identified areas in the warmer months when lower
dissolved oxygen levels might occur. We do not have blanket
prohibitions against dredging at any time. Such prohibitions may
prove beneficial after the completion of generic environmental
impact statements for specific areas.
. .
.. 4'
- 45 -
DREDGING WINDOWS PANEL DISCUSSION
STATE COASTAL MANAGEMENT PROGRAM PERSPECTIVE
by
James W. Morton and Thomas Hart
NYS Departnent of State
. .
I am pinch-hitting for Tom Hart, our Habitats biologist on
the Coastal Management Program Staff who was unable to make it to
this Workshop. Torn has been directly involved in developing our
Significant Coastal Fish and wildlife Habitats Program. He has
asked me to briefly describe this Program, and to explain how we
think it will prove useful in establishing appropriate dredging
windo~ls .
New York's Waterfrc~t Revitalization and Coastal Resources
Act authorizer tIll: Secretary of State to designate discrete arNlS
along our State's cOast that are vital to the survival of our
coastal fish and ~lild~~fe resources. The Department of State has
worked closely with the Department of Environmental Conservation
in an effort to identify, describe and map each of these hahitat
areas. In addition an attempt was made to identify the types of
uses and activities likely to create an adverse impact on each
habitat. This sitp specific information provided in the habitat
narratives has already prc~en usefu: in our project reviews for
federal consistency.
. .
As an illustration of to~ we have used the habitat
narratives in our federal consistency reviews of dredgfrc
projects, I will briefly discuss tre Fire Island Inlet Dredqing
Project. One of the proposed disposal areas was to be a spit of
land n~ar the Inlet known locally as the Sore Thumb. According
to our habitat narrative a least tern colony had become
established on the Sore Thumb. In order to avoid interfering
with the least tern nesting activity, man-induced physical
disturba~ces of this area should not occur between June 1 and
August 1. The dredging project, however, had been scheduled to
commence 011 July 15.
. .
Perceiving a problem, I decided to contact one of the
biologists with first hand knowledge of the site, who was listed
in the habitat narrative. I learned that the most critical
period for the terns ended once the eggs hatched and that usually
occurred the second or third week in July. I also learned that
if the location of the proposed disposal could bc shifted far
enough away from the least tern colony so there would be a 500'
buffer area between the disposal site and nesting site, then the
comnation caused by the disposal operation would"not create a
problem for the terns.
With this information, I contacted Bill Slezak in the Corps
and learne6 that the ti~ing and location of the dredging project
could be adjusted without unduly interfering with the dredging
project. \'ie would be able to dredge the Inlet and not cEsturb
the least tern nesting activity.
- 46 -
Such fine tuning of a project to mitigate adverse
environmel,tal impacts is not possible without site specific
information. We feel that the habitat narratives will serve as a
useful tool for regulators and dredging contractors to obtain the
specific information needed to identify effective mitigation
techniques that will also allow a project to go forward. We feel
that broad brush, regional dredging windows are not always
sufficiently precise and may unnecessarily preempt a dredging
project. We offer regulators in other state and federal agencies
ready access to the habitat narratives for use in the permit
process. We will also be trying to maintain a high degree of
communication with other regulatory agencies and permit
applicants so as to reach an agreement on an acceptable and
effective dredging window for a given project.
Thank you.
- 47 -
SBASONAL RESTRICTIONS ON BUCKET DREDGING OPERATIONS
by
John D. Lunz,* Douglas G. Clarke,** and Thomas J. Fredette+'
U.S. Army Engineer Waterways Experiment Station
Abstract
"
Seasonal restrictions are sometimes imposed on bucket
dredging operations in response to concerns for potential impacts
of sediment resuspension on various biological resources. Five
broad categories of biological concern are identifiable: (I)
survival and development of egg and larval stages of fishes;
(II) survival and development of egg and larval stages of
shellfishes; (III) survival and movements of juvenile fishes and
shellfishes; ITV) survival and movements of sub-adult and adult
shellfishes and, (V) survival and movements of sub-adult and
adult fishes, The available published and unpublished literature
relevant to these ccr,cerns is often contradictory, not always
directly applicable to actual dredging operation conditions, and
generally inadequate to either confirm or refute significant
dredge-induced impacts. Resource managers, handicapped by
inconsistencies within the technical data base, often resort to
establishment of rigid dredging windows. Sufficient evidence
exi~t~, however, to suggest that most life history stages of
target biological resources are very tolerant of elevated
suspended sediment concentrations, and that the logic which leads
to n.gid dred9ing windows is contra-indicated. In place of
dredging windows the suggest~0r. is offered for the use of a
standardized list of questions to solicit specific information
about the project and location. This information would be used
to guide discussions and consequently decisions about the need
for restrictions. The questions require information about
contaminant and physical properties of the sediment at the
dredging location, the size and shape of the water body to be
dredged, prevalent local hydrodynamic conditions, the occurrence
of nearby important benthic un~ planktonic resources, proximity
to a natural or dredqed channel, and the natur~l turbidity
characteristics of the water body.
. ,
.,
*Research Marine Biologist
**Oceanographer
+Marine Ecologist
- 49 -
SESSION 4
Questions and Answers
Comment 1 Rob Green, (DEC): There are nine sewer outfalls in
Westchpster county. Since pathogenic organisms reside in
Westchester County Harbor sediments, dredging these areas has
been restricted during the swimming season.
Questl.on 2
turbidity they
regulated?
Response: John Lunz, (WES): There exist unregulated activities
which may be creating impacts that are more adverse than
dredging.
Ed parthe, (Shoreline Consulting Corp): Given the
generate, shouldn't shrimp trawlers in the Gulf be
Question 3 Euge~iu Flatow: When it is necessary to halt a
dre6g1ng project 2~ler it is s~arted tc avoid harming a resource,
who suffers the ll~bi11ty7
Response: Charles Pound, (Aqua Dredge): The dredging contractor
absorbs the loss.
Question 4 Unknown Particlpant: Is there any monitcring
going on to see if dredging windows are working?
Response: Charles Pound, (Aqua Dredge):
inspection. But if we aren't ~llowed to
measurements.
I've never had an
dredge, we canout
take
Comment 5 Dan Natchez, (Ccnst;lu,:'.U: DB.ve Fallon suggests thi.it
private industry prepare ~he Generic EIS. I thihk government
agencies have expertl.se. The New York District should consider
doing a harbor characterl.za~ion s~udy. This study should be a
cooperative effort.
. . \'
cr
. "
- 51 -
Introduction
Dredging and Disposal in Low-Energy Enviror.ments -
(Protected Bays, Canals, Marinas)
by
Aran Terchunian
NYS Coastal Management Program
"
"
In this morning's session we will examine small dredging
projects that individually may seem insignificant, but
cummulatively may be quite important. As a reviewer of. projects,
I examine hundreds of minor dredging ((100 cubic yards) projects
annuc.lly. I have noticed that a standard approach to project
review can decreasf' processing time and increase protection of :
coastal resourc~s,
This n0rning we Kill hear fron several noted speakers
representing academia, regulatory agencies and consultants. Thf'
object of this session is tr. determine what are the most
important parameters; how can they be best addressed in project
review; and ho~ can applicants/consultants/contractors design and
implement pro~ects to protect these inportant coastal resources.
"
"
- 53 -
DREDGING IMPACTS ON BENTHIC INTERTIDAL
COMMUNITIES, SHELLFISH AND HABITATS
by
Dr. Carmela Cuomo
Marine Sciences Research Center
SUNY at Stony Brook
Benthic intertidal communities are located, as their name
implies, in areas of the marine environment subjected to tidal
fluctuations, wave action, and sediment reworking. In a sense,
they are "d1sturbance" communities. The effects of dredging - an
artifical disturbance - ona natural disturbance community must
be evaluated by examining the changes which are wrought by the
dredging on the physical, chemical and biological components of
the system. Th~ IcllOl,,'bc discussion ~.'ill center on the physical
and chemical components of benthic intert1dal communitiGs and
will only briefly allude to the biological components. The
effects which dredging (both the area dredged and the area
receiving the dredge spoil) would have on the physical, chemical
and biolog1cal components of a seagrass community (Zostera
marina) will bE presented as a case example.
ThE EPdime~t type of an area is determined primarily hy the
current re9ime of the region, the location of the region relative
to wave action, and the prox1rnity of a sediment source.
Sediments may vary from coarse clastics to extremely fine silt
and clay part1cles. In general, for non-carbonate sediments, the
finer the grain size the greater the organic content of the
sediments. The amount of organic matter present in sediments is
a main factor which affects the sediment pore water chemistry,
which, in turn, "ffects the biclogical corr.position of the regie,n.
The geochemistry of non-conservative constituents of the
pore waters in marine soft sediments can be quite complex and
vary temporarily and spatially. As mentioned above, the main
compositional component of fine-grained. sediments influenced by
'. both physical and biological factors is organic matter, This
pool may consist of dead phytoplankton and zooplankton, dead
benthos, vascular plant t1ssue, anthropogenic material, and fecal
" pellets. For the purposes of this discussion, the simplified
formula CH~O will be used to refer to this reservoir of organic
matter. L.
Organic matter falling through the water column or exposed
at the sediment-water interface may be degraded aerobically
through the actions of aerobic decomposing organisms provided the
water is oxic.
This reaction, assuming complete m:idation, is represented as:
CH20 + O2 -+ CO2 + H20.
- 54 -
As dissolved oxygen is usually available only to those
sediments directly in contact with the overlying oxic water
column, aerobic decomposition is generally restricted to a zone
near the sediment surface. Organic material not fully deco~posed
aerobically by the time it is buried is subject to a
decompositional regime dependent on the pore water redox
conditions of the enclosing sediments. Organic matter associated
with anoxic pore waters in fine-grained sediments in areas of
minimal bioturbation, such as is normally found in disturbed
regions, will undergo a sequential decomposition (nitrate
reduction, manganese oxide reduction, iron oxide reduction,
sulphate reduction, and methanogenesis) which represents the
preferential utilization of electron acceptors by facultative and
obligate anaerobic bacteria according to the maximum energy gains
derivable. Of these reactions, the dominant one occurring in
marine sediments is sulphate reduction:
-. C" 0 + S()~ ~
~ r 2 . 4
H2S + HCO 3'
The dominant chemical species present in pore waters of
reduced sediments, therefore, is sulphide. Thus, organisms
prespnt in fine-grained sediments rich in organic matter must be
able, in some manner, to tolerate the presence of H~S.
..
Whether or not sulphl.de and other end-products of anaerobic
organic matter decomposii.ion enter the water column deptmds er.
both the amount of disturbance an area receives and whether or
not a deeply bioturbating in fauna is present. Areas suhjected to
much physical disturbance (eg. intertidal areas) usually contain
an abundance of snaIl, oppor~unistic species (polychaetes and
bivalves) which do not biot.urbate to a large exter.t (< 3 em): the
RPD' in such sediments is located very near the sediment-water
interface. Areas containing deeply hioturbating (>3cm) infauna
have an RPD located several cm down in the sediments. The
presence of deeply bioturbating infauna serve to continually
bring oxygenated water in contact with reduced sediments, thus
oxidizing the sediments. Communities o~ this type are generally
located in shallow to deep subtidal regions: they may
occasionally, however, be present nearshore. Should such
communities experience a disturbance, the upper oxygenated layer
of sediment would be removed, exposing the underlying
organic-rich sediments and reduced pore waters to the
sediment-water interface. Such changes would exert a strong
influence on the benthos of an area.
From the above discussion of sediment type and geochemistry
it is possible to see the difficulties inherent in any attempt to
eValuate the effects of dredging on an intertidal (disturbance!
communi ty. The remainder of the paper ,.ill focus on an example
of one shallow subtidal to intertidal benthic community - the
~05tera marina community - and the effects which dredginq might
have on it.
Eelgrass beds (Zostera marina) thrive in protected shallovl
waters, especially along salt marsh creeks and channels, in are?s
- 55 -
where sandy sediments predol".inate. They are an important
communit~' for sev~ral r~a30ns: (1) a substantial ~mount of .
nutrients (eg. NO , PO ) are bound in the stand~ng crop of
seagrasses; (2) m~ny sp~cies (eg. clams, scallops, lobsters) use,
them as nursery grounds or as predator protection areas; and (3)
organic-rich fine sediment particles are trapped by them,
reducing turbidity in the local area. The sediments underlying
eelgrass beds are generally reduced and rich in organics. The
RPD, in these sediments, however, rises near to the
sediment-water interface in some areas and is depressed in
others, owing, among other things, to the presence of
fine-grained sediments, of infauna (e.g. clams, juvenile
lobsters), and of the plants themselves. The sediment chemistry
underlying an eelgrass bed is even more complex than the simple
end-members described in the preceding paragraphs.
..
The dredgir,g of a seagrass community results in both
physical and cheMical change~ ~hich, in turn, exert a strong
influence on the b~vlogy of the area. If dredging occurred
within or adjacent to an eelgrass community, the following
alterations could be expected. First, Zostera marina itself and
its accompanying benthos would be physically removed.
Additionally, species which commonly live among the seagrass
blades for protecticn would be exposed to predation. Secondly,
the removal of sediment would alter the hydrography of the area,
which could result in increased erosior, of underlyinc or adjacent
sediments. This sediment erosion would manifest itself as
increased water column turbidity which would liMit light ever
adjacent eelqrass beds and affect their productivity. Increased
turbidity also has, in general, a negative effect on
filter-feeC!ers, such as clams, thus reducing the produc1:ivity of
the benthos as .,ell. FurtJ.ermore, the removal of ~ostera _ 3
el!minates a large sink for many nutrients (e.g. NO 1 PO 4 '
NH 4); the area then becomes more susceptible to eutrothica~ion.
Finally, the underlying reduced, organic-rich sediments ann their
pore waters which are not USUally in contact with the water
colul".n are now exposed at t.hE sediment-water interface.
Colonization of these sediments is more likely to occur by small,
pioneering, opportunistic polychaetes and bivalves, rather than
V by the commercially import.ant species which previously occupied
the eelgrass beds. Again, the benthic productivity, as well as
the plant productivity of the area dredged, is reduced.
<f"
,_ (I
Areas receiving dredge spoil material would undergo similar
alterations. The severity of these effects, however, would be
mediated by the initial location of the site, the types of
organisms present, the organic content of both the naturally
occurring sediments at the site and the dredge spoil sediments,
and the depth of the RPD in the site sediments. Ideally, the
deposition of dredge materials in a region which normally
contains a "d~sturbance" corrIDunity would be less severe than one
which contains a deeply-bioturbating infauna. Dredge spoil
deposition in such an area (ie. intertidal regions), however,
would present the .difficult problems of containment and increased
turbidity.
- 56 -
It is obvious that the location of the dredging operation is
an extremely important condition which affects the long-term ,
recovery of a site. Generally, nearshore areas contain
assemblages of organisms adapted to disturbances, and contain
highly reduced sediments. Shallow subtidal sediments and
sediments underlying eelgrass communities mayor may not possess
physical, chemical, and biological components of disturbance
systems. The degree to which they do not will have a strong
determining effect on their ability to withstand and/or recover
from the effects of dredging.
.
\
\
,
1 RPD (Redox Potential Discontinuity) - the chemical boundary
laver above which oxidation reactions dominate and below which
reduction reactions predominate. In sediments it often is
manifested as a change in color from lighter colored oxidized
sediments to dark gray to black reduced sediments.
- 57 -
NEW YORK STATE DEPARTMENT OF ENVIRONMENTAL CONSERVATION
PERSPECTIVE ON DREDGING IN NEW YORK'S TIDAL WETLANDS
hy
Charles Hamilton
Department of Environmental Conservation
Division of Regulatory Affairs
INTRODUCTION
. .
Dredging Permits are required under two Environmental
Conservation Laws: Art. 15, Protection of Waters and Art. 25,
Tidal Wetlands Act. The magnitude of the project, location of
the dredge project, and placement of dredge material will
determine whether or not the project is a minor or major project
in accordance with the Uniform Procedures Act regulations. If
the project is considered minor, it is reviewed by the department
only and a permit issued without public notice. All major
projects are reviewed by the Department and public notice is
issued at the commencement of the review period.
Dredging projerts for Art. 25, Tidal ~letlands Act (TWA) are
reviewed pursuant to 6 NYCRR Part 661 Tidal Wetlands-Land Vse
Regulatior.~ (TWLURI. ~hey are received by The Division of
Regulatory Affa~rs (DRA) and sent for technical review to Bureau
of Marine Habitats Protection (BP.HP), Fisr. and wildlife (F&W) and
Coastal Engineering. Dredging of Intertidal Marsh (IM~; High
Marsh (HN) formerly connected (FC), coastal fresh (FM) shoals and
mudflats (SM) are presumptively incompatible (PIP) with the
regulation which ~ean5 the burden of proof is upon the applicant
to prove the dredge project will not adversely impact the
benefits associated with the tide'] ",'etlands. Placement of
dredged material on 1M, HM, FC, CF is incompatible (I), and PIP
on SM, and LZ.
VOLmlE OF APPLICAT:rONS AND STANDARDS
..
In Nassau and Suffolk County, we currently receive 1500-2000
Tidal Wetland permit requests on an annual basis; 100-300 majur
Tidal Wetlands dredging projects ranging from dredging of
Intra-Coastal waterways, entrance to harbors and creeks, channels
inside harbors, marinas, new docking areas, and,associated docks;
and, 300-500 minor dredging projects for maintenance dredging,
placement of dredge material on upland areas, and dredging less
than 500 cubic yards.
Dredging in small harbors such as Gull Pond which are mainly
used by small outboard vessels (vessels less than 20'), has .
usually been limited to maintenance of existing channels in their
e::isting locations, or new dredging for new dock areas. In these
small boat harbors we have issued per~its for dredging depths of
4' with a one foot overcut, channels 50' - 100' in width with 1:3
side slope and with no dredging within 25' of vegetated wetlands
to minimize impacts of boat wakes, and sloughing off of wetlands
- 58 -
banks. Dredged material has been deposited in approved dredge
spoil locations (upland), utilized for beach nourishment
depending on sediment compositions, and placed in borrow areas.
Outside channels found in the water of Great South Bay, Gardiners
Bay, Little and Big Peconic Bays, South Oyster Bay, etc. are
limited to 6' depths with an I' overcut and 100' width. :pcil is
commonly utilized for beach nourishment on public bay beaches.
'-
The largest problem facing these major type of projects is
locating acceptable spoil sites and means for placement of
dredged material. Many of our dredge spoil areas on Great South
Bay and Moriches Bay have been developed for residential use.
Three to five hundred individual applications are received
annually for dredging of canals. Most of these dredging requests
accompany requests to construct bulkheads and docks, or
reconstruct failed pocks or bulkheads. Dredging to depths of ~,
to 6' is generally approved provided the area to he dredged does
not include vegetated tidal wetlands such as 1M or significant 1M
areas. Many landowners replacing or reconstructing their
bulkheads require backfill for their new structures and since
most of thc areas are fully developed as pool decks it is often
impossible to bring in upland fill. Therefore, the canals are
dredged wherever these bulkh~ads are replaced.
Many new dock applications are submitted with dredge
requests =or the area of the dock or for dredging of navigational
channels to the docking are~. In most cases the Dep~rtment
requests modification to lengths of docks so as to eliMinate need
for dredging or mininize the area to dredged.
In regards to Marina request~ for dredging it is COIT~Cr. to
see up to three requests for small amounts of dredging at a
marina in a given year. We are discouraging this type of
application and are now requesting Master Plan dredging for the
entire marina. The advantage of this policy is that it
eliminates the need for the applicant to see the Department on a
seasonal basis and allows the marina owner to schedule dredge
projects well in advance. We will also know in advance the
limitation of our dredge spoil location in certain harbors and
creeks. The Department has issued approximately a dozen permits
of this type and we hope in the future to issue them to all
marinas for a minimum of 5 years and maximum of 10 years.
Similar to the concept of one marina: one application, the
Department is concerned that locating spoil sites will become
more difficult. The DEe recommends using Master Dredging Plans
by townships and/or counties, Generic Environmental Impact
ttatements (GElS), and/or improved communication between
regulators, interest groups, applicants consultants, contractors,
and the public to solve this problem.
- 59 -
Mitiqation Factor Utilized
Often a project will be modified to reduce the impact on
tidal wetlands. In some projects, the Department will request
that additional wetlands be created to replace wetlands lost
during development. These measures and techniques are commonly
referred to as "mitigation", and some of them are explained
below.
1. Minimize area to be dredged: Alter length, width, depth
of projects in sensitive areas, and construct docks in such a
length so as to reach navigable depths.
2. Create buffer zoneR from dredge area and tidal wetlands:
1:3 slopes, no dredging within 25' of vegetated 1M.
3. Relocate area to be dredged from productive shellfish
breas, t~dt} ~etlands, aL6 gras~ b~d~. Also, relocat~ areas
where spuil is to be placed to lim~t impacts.
4. Transplant shellf~sh resource and tidal wetland
vegetation when iI<pacted. A 2:1 replacement ratio is usually
used in m~~or and minor projects.
5. Alter dredging techniques in areas adjace~t to tidal
wetlands - (dragl~ne in canals, and mari~ns, hydraulic dredges ih
small boat channels and in harbors and creeks).
6. Create Least Tern Nes~ing Habitat utilizing clean dredge
spoil - Accabonac Harbor - (EP. Tmm, SeDT'''!, NYSDEC!F [--1'1)
Summary
"
In conclusio~ all our decisions are made on a case by case
basis. The Department attempts to balance the type and magnitude
of the project, the public need and the impacts likely to occur
with the benefits associated with preserving tidal wetlands
values. Through permit condit~ons and m~tigation techniques we
can minimize many of the associated adverse impacts of dredaing
and still achieve the objectives of the project. However, the
success of this permit system is dependent upon communication and
cooperation between the regulators, the applicants, and the
contractors.
"
~
'. \
e
r
" ,
- 61 -
CONSULTANT'S PERSPECTIVE
by
Charles Bowman
The Land Use Company
,
There are numerous ways in which consultants are helping
prepare projects which are environmentally sensitive to the
coastal environment.
to
(1) Bulkheading is not always the most effective way to
control erosion. A fringe marsh can be very useful in erosion"
control a~ a substantial savings. A properly designed slope w~th
riprap can also be "an effective alternative.
(2) Clean dredged material may be used for dune creation ~r
to establish Least Tern habi~ats. Erosion control blankets can
be used to keep the reaterial in place.
(3) Specific plants can be used to establish vegetation in
marsh enviror~ents. Weeping Alkali grass will grew under very
salty conditions. Spartina patens will usually follow with time.
(4) Most concerns are site specific. The consultant must
balanc~ an applicant's objectives with the unique conditions uf
the project site in order to develop an environmentally
acceptable plan.
- 63 -
SESSION 5
Questions and Answers
Question I Chris Zeppi, (PA): When dredge materials are to
be placed upland, must the applicant apply for a N.Y. Solid Waste
Permit?
Response: Charles Hamitlon, (DEC):
a wetland, a solid waste perMit is
course, the sediments are clean.
When it is placed adjacent to
not needed, assuming, of
Question 2 Roy Haje, (En-Consultants): One of the standard
allowable water depths for dredging is four feet. Shouldn't the
allowable depths be increased to six feet so as to avoid adverse
environmental impacts by lessening the frequency of dredging?
Responses:
effects of
parameters
Aram Terchunian, (DOS): We would need to look at the
increasing allm'Table depths considering such
as hydrology, siltation rates, and light penetration.
Dr. Cuomo, (MSRC): One of the scientists at MSRC, Bill
Dennison has been studying this question. The degree of
biological impact caused by dredging deeper varies ac~ording to
the type of benthic community present. Some communities are more
vulnerable than others. Impacts must be judged on a case by case
basis.
Question 3 John Lunz, (~IE $: Is the effect of dredging on
depth of light penetration an issue in New York? Since fine
grain material is being placed in upland sites, turbity becomes
less of an issue.
..
Response: Dr. Cuomo(MSRC): Turbidity may affect eel grass beds.
A 10% redurtion in light penetratior. could affect an eel grass
bed. More iMportantly, changes in circulation patterns induced
by dredging could have a greater effect'on eel gross bens.
.'
Comment 4 Ed Parthe, (Shoreline Consultants): By dredging deeper
channels we reduce the potential for chronic increased turbidity
caused by boat wake.
Question 5 Al Bauder, (OGS):
plans involving local governments
disposal sit.es?
Does DEC or DOS have any future
to develop new, regional
Response: Charles Hamilton, (DEC): We have no programs with
towns. We have worked with counties. DEC will not 00 out and
prepare a generic EIS for dredging but we are willing to work
with local governments.
Question 6 Bill Slezak, (COE): I wish to again raise a
question that has not been answered: is it better to dredge
deeper less often or to dredge shallow more often?
- 64 -
Response: Charles Hamilton, (DEC): It depends on how close you
are to a tidal wetland. If you dredge a deep cut too close to
the wetland, you cause the face of the wetland to sl~p and
erode. Maybe it would be better to dredge deeper in open waters
but less deep in small harbors and creeks. This must be decided
on a case by case basis.
Question 7 Chris Zeppi, (PA): Why doesn't the State require
all communities preparing local waterfront revitalization
programs to set aside disposal sites?
Response: Aram Terchunian, (DOS): We have not mandated local
governments to do this but we'd be willing to help them do so.
Question 8 Eugenia Flatow: Where should the responsibility
lie for preparing dredging master plans.
Respon~e: John GuIdi, (Suffolk County DPW): Dredging plan~ arc
unrealistic since we do not know until spring what the previous
winter storms have done in filling our channels or eroding our
beaches. Also, there are very few new projects planned for
Suffolk County so long range planning is not needed.
- 65 -
New York State
MODERATE AND HIGH ENERGY ENVIRONMENTS
by
Jay Tanski
Sea Grant Extension Program
'-
DREDGING AND DISPOSAL IN
"
In most dredging projects a great deal of attention is given
to predicting and preventing possible adverse biological and
chemical impacts. These considerations are especially .important
in low energy environments characterized by fine-grain sediments
and high biological productivity. However, in many higher energy
environments, such as tidal inlets or open ocean sites, sediments
are generally contaminant-free: and biological productivity is .'
relatively low. Fere, the effects of dredging on the physical
processes take on more importance. Dredging and dispos?l .
operations in high energy l<INironme:-,t~ can significantly alter
hydrodynamic processes which in turn can adversely affect
sediment erosion and deposi1:ion patterns and water quality
characteristics both at the s~te and in adjacent areas. Proper
consideration of possible adverse physical impacts early in the
planning stages is crucial to the success of most dredging
projects.
. .
Ur.fcrtunatt'~Y, dred9ing in high energy areas is often done
on a crisis basis. This is especially true of tidal in1ets where
public safety and economic concerns necessitate the need for
quick action. In many cases, the potential impacts of_a dredging
project can not be adequately assessed in time because the
necessary information is out-dated or non-existent. This lack of
information frequently results in costly delays and mistakes
despite the fact that modeling techniques and other methods have
been developed that can provide managers with the information
needed to more: accurately assess possible impacts associated with
the various dredging options before the work is done.
'.
Presently, few dredging operations in high energy areas are
based on long term management strategies. To effectively and
efficiently manage these projects decision makers need a
framework that will provide timely answers to questions regarding
physical impacts on shoreline stability, sedimentation ann water
quality. Comprehensive, integrated management plans that
incorporate availahle historical information and predictive
modeling methods that can be used to evaluate the effects of
dredging and d~sposal options are needed. Development and use of
such management plans can help decision makers maximize
environmental, economic, and social benefits of dredging while
minimizing adverse impacts.
- 67 -
COASTAL PROCESSES TO BE CONSIDERED FOR
DREDGING DESIGN AT TIDAL INLETS
by
Gary A. Zarillo
Marine Sciences Research Center
Introduction
The need for understanding the dynamics of tidal inlets can
be traced back to early inlet stabilization projects in the late
19th and early 20th Centuries. Some of these projects were
monumental in scale, such as the stabilization of Charleston
Harbor, South Carolina, and Grays Harbor, Washington, and
resulted in dramatic changes in configuration of the inlet and
adjacent shoreline. Numerouz other stabilization and navigation
improvement projects too}; place at other inlets during this time
period and all resulted in significant changes to inlet dynamics
and shoreline stability. The results of many of these early
projects were unpredictable and undesirable. Nevertheless,
modif1cation of natural inlets has continued with economic growth
and population 9rowth in coastal areas. Inlets promote
commercial and recreational navigation between sheltered waters
and the open ocean, provide for tidal flushing to enhance water
quality, reduce flooding due to storm surge, and provide avenues
for fish migration as well as serving many other r,eeds;--
"
Modificat10ns to natural inlets span the range from dredging
at the inlet entrance to complete stabilization with structures
(jetties) designed to minimize the amount of sediment transported
into the inlet and to control tidal currents. Even where natural
inlets have not been significantly altered, understanding their
influence on tidal flushing, shoreline stability and overall
environmental and economic impact of a coastal region is no less
important.
\
,
.
,
r
Hydraulios and Sedimentary Processes at Tidal Inlets
In any inlet/bay system, the inlet hydrodynamics, bay
response and sediment transport patterns depend on a number of
internal and external factors. These factors i~clude geometry of
the inlet and bay, freshwater inflow, ocean-tide characteristics,
---- the local and nonlocal wind and atmospheric pressure fields,
hydraulic resistance characteristics and the wave field at the
inlet entrance. The exchange of relatively large volumes of
water (tidal prism) between bay and ocean through an inlet can
have a significant effect on the stability of the inlet and
adjacent shorelines, as well as the water quality of the bay.
c
In their natural state, most inlets are shaped into an
idealized form of a nozzle. Therefore, the ebb-flow patterns at
an inlet are similar to those of a turhulent ;et of water issuinq
from the n07.zle, whereas flood-flow patterns are similar to a -
more streamlined flow into the bell-shaped entrance of the
- 68 -
nozzle. Sand transport patterns and the distribution of shoals
around an inlet are a direct function of these flow patterns as
modified by wave action and any man-made changes to the inlet.
On ebb flow, the momentum of the existing water is confined to
the deeper portions of the outer shoals (ebb-tidal delta) due to
a lower water level. This forms a seaward-directed jet. High
velocities in the central core of the jet can carry sand a
considerable distance seaward. Lateral transfer of the jet's
momentum causes an entrainment of adjacent waters and a
consequent eddy formation. On flood tide, water converges
towards an inlet from all sides, particularly in the lateral
swash channels (or flood channels), which have a greater depth at
this time. This idealized form leads to alongshore currents on
both sides of the inlet, carrying, sand towards the inlet at all
times where it can be distributed to the flood-tidal and
ebb-tidal shoals. Navigational and beach erosion problems in the
vicinity of inletE are closely related to this kind of
circulation pat"ern and sedi~ent trapping mechanism.
wav~\action and wave-driven circulation patterns in the
vicinity of inlets can aggravate both beach erosion and shoaling
problems. ~o~e refraction-diffraction patterns around the outer
bar (ebb-tidal delta) can result in longshore currents directed
toward the inlet on both sides of the inlet, thus working in
concert with tid~l circulation patterns that cause 1nlet-directed
sand transport. Again, sediment trapping at the inlet and
build-up of flood-tidal and ebr.-tidal shoals is enhanced. In
addition to supplying sediment for build-up of inlet shoals, wave
action also plays a role in limiting maximum shoal volume. In
areas of relatively high wave energy compared with tidal energy
(such as Long Island's south shore), sand transported to the
outer ebb-tidal delta will in part be returned onshore by waves.
The result is that the outer shoal volume will tend to be
relatively small and largely suotidal. In this case the inner
shoal system (flood-tidal delta) will tend to be better developed
and partly intertidal. Along the microtidal shoreline of Long
Island, the pattern of inlet shoal development fits this model
very well. Flood-tidal deltas associated with Shinnecock and
Moriches Inlet are volumetrically larger than corresponding
ebb-tidal deltas.
Inlet migration is a significant process along
wave-dominated microtidal shorelines, such as Long Island, where
net longshore drift is particularly strong. As sand accumulates
on the updrift side of an inlet, the inlet channel tends to
become s~aller than the equilibrium size required by the ocean
tidal range and tidal prism of the bay. Therefore, erosion of
the inlet throat occurs on the downdrift side as sand accumulates
on the updrift side. Before st~bilization, both Shinnecock and
Moriches Inlets migrated westward and reworked several mile of
barrier island.
Some inlets tend to be quasi-stable and do not migratE cver
large distances, but are subject to frequent shifting of their
- 69 -
outer channels. This tends to occur when ebb-tidal shoals extend
far enough seaward that the existing main inlet channel becomes
hydraulically "in~fficient". At this point, a storm or extremely
high spring tide may break a new, shorter and more efficient
channel through the inlet shoals. The older channel tends to
fill in and the new channel becomes the dominant conduit of tidal
flow. All of Long Island's stabilized larger inlets are subject
to this kind of configuration change. ~aller inlets (such as
Hecox Inlet) that can undergo only limited alongshore migration,
because of the small size of their landward bays, are also
subject to abrupt and frequent changes in outer-channel
configuration.
"
All of the major inlets along the south shore of Long Island
have been stabilized, and sections of shoreline formerly subject
. to breaching in the migration zone have now become the sites of
significant real estate development. Inlet stabilization,
however, has resultec in a new set of problems related to
shoreline changes. An example is the rapid growth cf flood-tidal
shoals to relatively large volumes on the landward side of both
Shinnecock and Moriches Inlets. This indicates effective
trapping of sand from the littoral sediment supply, which
nourishes south shore beaches. Possible evidence for this is the
accelerated rate of erosion along the Westhampton barrier island
that began in the early 1950's after Shinnecock Inlet was
reopened and stcbilized. Another common problem associated with
stabilized inlet& is severe erosion of the beach adjacent to the
downdrift jetty. Wave refraction patterns around inlets
stabilized with jetties commonly result in seaward-flowing
rip-like currents that remuve sand fro~ the downdrift beach.
Beach erosion problems just to the west of Shinnecock Inlet are
probably related to this kind of process. .
State-of-the-Art Methods for Studying Inlet Dvnarnic~
.'
Much of the information that is available concerning the
geomorphic variability of inlets, inlet-beach interaction and
sediment transport patterns associated with inlets has been
developed from observational and historical studies. Results of
these studies clearly illustrate the complex nature of tidal
inlet systems, but have not provided the quantitative predictive
tools needed to plan effective management of inlets. In recent
years physical and mathematical models have been used as
predictive tools for assessing the response of inlets to proposed
man-made modifications. Observational data from proto-type
situations (real inlets) are generally used to calibrate these
models.
Models of natural phenomena are used primarily for gatherinCl
essential data sets in greater numbers and at lower cost than
would be possible in a prototype situation. Generally, this
means a great acceleration of the time scale in associa~ion with
an increased density in space. Models of tidal inlets have been
constructed primarily for predicting tidal curents und
water-level fluctuations in the vicinity of inlets. A model can
lead to accurate predict10ns of the prototype situation if the
- 70 -
physical laws that govern both model and prototype are identical.
One of the great strengths of modeling techniques is that models
governed by simpler laws than the prototype can provide useful
predictions if these laws are nearly identical to those governing
the dominating processes. In many cases, processes of secondary
importance can be eliminated without significantly changing
predictions.
In the case of tidal inlets, some modeling techniques
eliminate several important terms that are not important in
describing the overall hydrodynamics of an inlet, but can be of
great significance in determining sediment transport patterns.
For example, simple analytical models that provide an exact
solution to simplified mathematical equations describing inlet
dynamics do not account for harmonic overtides (shallow water
tides) responsible for tidal asymmetries. Such asymmetries give
rise to dominance of ebb or flood bedload transport in many inlet
systems.
Physical models of tidal inlets have the advantage of
allowing the modeling of flow boundaries as accurately as desired
without significantly increasing operating costs. Physical
models of tidal flows are small-scale, geometrically similar
repl~cas of prototype systems. As such, some terms in the
equations of motion that govern hydrodynamics of inlets cannot be
scaled in the laboratory (gravity, for instance). Other ter~s,
such as Coriolis and wind shear, can be modeled, but only with
difficulty and added expense. In addition to difficultIes in
modeling techniques, physical models require space and
significant cost for construction.
Numerical modeling is the only technique that can be used to
model complex hydrodynamics at inlets at reasonable cost. The
ability to electronically or magnetically store a numerical Model
gives it a distinct advantage over physical models in that it may
be rapidly inexpensively applied to a number of prototype
situations at low cost after initial development. Numerical
models of tidal flows arE constructed by representing physical
boundaries, free surface elevation, velocity vectors and other
variables by their numerical values at a discrete set of
computational points at discrete times. Accounting for the
Coriolis effect, atmospheric pressure gradients and wind stress
does not cause a great computational difficulty as in physical
models.
AppropriateObiectives for Tidal Inlet Studies
Prior to a dredging project or other engineering activities
at tidal inlets, predictive tools should be developed to ~eet the
following goals: 1) assess the response of inlet navigational
channels to natural forces, dredging activities and stabilization
structures, (2) assess the influence of waves on inlet dynamics,
(3) define mechanism~ of natural sand by-passing, (4) assess the
effects of inlets on adjacent beaches, and (5) determine th~
impact of inlet modifications on the tidal range of associated
- 71 -
bays and lagoons. Most of these goals can be met using a
combination of both observational studies and modeling studies.
In addition to these specific objectives, which are geared toward
engineering applications at stabilized inlets, it is particularly,
important to develop study methods that reflect the present level
of knowledge of the physical processes that operate at tidal
inlets. Therefore, each new study conducted should be useful in
identifying and weighing the need for further research on inlet
processes and should ultimately advance the state-of-the art.
p
:
- 73 -
DREDGING WORKSHOP
Problems and Comments for Small Dredging Projects
by
John R. Guldi
Suffolk County Dept. of Public Works waterways Division
. Suffolk County mai~tains approX..i.matelY two hU~~;Lq~~*~~
wh1ch are mostl v small~.r:!Jets~~nd chilJID.~s JrOM t.he_l.IUlt: .
harbors and natural or man-made canals. The work is px~wari~v
one of removingshoal~~g which occurs at the entrance inlets due
to deposit of granular material from the adjacent beaches which
is moved by littoral drift or storm action into the inlet. Since
the frequency and severity of storm action is unpredictable, it
is necessary for the COl;nty to have maintenance permits on hand
and current so as to be able to respond with a minimum of delay.
For this reason, seasonal restrictions on permits is undesirable
and prevents us from reacting to a problem in a timely fashion.
There are times when that anq other permit restrictions ~
preclud~JJ.;(....timely__~esEonse. and result in a loss ot t~e use of a
particular inlet for -an enfire boating season. We believe that
there exists no evig~n~~."~.~ i~~C3!~S a~v la~~petrimen~l
.e.f.fa~5.-due__to_our!;mall_ hydra_ul.ic~...r.s~ging pr.qj~ and
therefora time restrictions are unnecessary.
.,.
A major problem in our opinion is the duplication and
multiplicity of required permits. Too many agencies and groups
are involved which causes long delays in the permit process. We
have found that it is difficult to obtain agreement on certain
technical aspects between different sections of the same
regulatory agency, much less between agencies. Many of the
people making decisions are not familiar with the site and cannot
find the time to make field inspections. It is felt that a
majority of the questions asked and problems perceived would and
should be resolved by a site inspection with the applicant.
i Another problem which plagues us is that even after certain
; policies are set, they seem to change with every change of
regulatory personnel. We cannot plan our projects when there
exists no long term policies. It is further compounded when the
different regulatory agencies overreact to every individual
complaint from a citizen. If the policies were ,clean-cut,
individual inquiries could be answered by indicating the
provisions of pre-set and agreed-to policies.
,
c
There must also be an understanding on the part of the
regulators as to some of the real-world considerations which we
have to live by as pertains to funding, scheduling, contractual
legalities with contractors, homeowners legal releases, weather,
pumping distances, equipment availability, local political
considerations, and a myriad of public and individual
considerations and opinions - ell of which we have to cope with
in order to perform our task. Many times, unilateral and
- 74 -
arbitrary restrictions by the regulators make our job impossible
due to all of the considerations not being compatible and
therefore compromises must be made. We feel the regulators could
help us by eliminating unnecessary "niceties" and assuming a
posture of compromise when it will help us perform our work.
In summary, it is believed that the regulatory permit system
should be consolidated under one agency, and a more practical
approach along with site visits with the applicant should be
initiated. A positive approach with the idea of aiding us in
obtaining permits rather than an attitude which seems to indicate
that every obstacle to permit issuance should be utilized, would
go a long way in solving the problem of keeping our waterways
viable with a minimum of disturbance to the environment.
,
,
.
- 75 -
DREDGING JONES INLET: MUNICIPAL PERSPECTIVE
by
Thomas Dohenev ,
Town of Hempstead Department of Conservation and Waterways
Since authorized by Congress in the early 1950's,
maintenance dredging of Jones Inlet has taken place over time by
a number of methods: bucket dredge, sidecasting, hopper dredge
and hydraulic dredging. It was 14 years ago that a cooperative
agreement between the Town of Hempstead and the Army Corps of
Engineers was made for the purpose of dredge spoil disposal and
nourishment on a portion of the beach front designated as a feeder
beach West of the Inlet.
We in the Town considpr ourselves fortunate for the working
relationship we have had, and continue to have, with the Corps
and for the resultant beach nourishment from the navigational
maintenance projects over the years. Without such projects, cur
Town's beachfront would cease to be available to so many who
enjoy its use over the summer season.
Since the mid 1970's the realization that the Jones Inlet
Jetty was filled to its capacity with sand became apparent to all
of us. Sand was no longer trapped but was coming around through
and over the jetty causing rapid shoaling in the designated
navigation channel, and requiring repeated dredging projects. A
recently completed study of the Jones Inlet channel maintenance
alternatives indicated that frequent dredging projects.to
maintain navigation could be reduced by widening the channel from
its present authorized width of 250 ft to 750 ft based upon
exhaustive benefit-cost determinations. While I may not agree in
principle with the findings the economics cannot be argued when
justifying the overriding need to provide navigation at the least
cost and most benefit.
,
Although the study calls for the placement of the dredge
spoil from the project on the beachfront west of the Inlet,
yesterday's talk by Mr. William Slezak of the Corps, which
highlighted that agency's new posture of selecting the least
expensive, environmentally sound, disposal plan, is cause for
concern on my part.
We need the sand from these inlet projects desperately,
since the very cause of our accelerated erosion stems from the
migration of the navigational channel westerly, as a function of
the sand by-passing the inlet jetty. In addition, no
municipality could afford to nourish its beachfront as often as
its necessary, nor could it make up the difference between
hydraulic dredging and the least expensive and environmentally
sound dredging operation, if the Corps selected that alternative
through the bidding process. There is only one ent~ty which can
afford hydraulic dredging of the magnitude required for Jones
- 76 -
Inlet and that entity is the Federal Government. What a local
entity can do and, may well be required to do, is to demonstrate
its appreciation for beach nourishment by doing everything in its
power to preserve, protect and enhance that resource to the best
of its ability for as long as possible.
Since the first cubic yard of sand was placed on our
beach front we in the Town of Hempstead have tried to protect it
from loss and abuse through fencing and planting together with
restriction on vehicle access and man made alterations.
Our entire Beach Preservation Law which was adopted in 1976
was an out-growth of the beach nourishment projects by the Corps.
Since that time we have built nearly two miles of new sand dunes
for shoreline protection, established more than 20 acres of beach
grass nursery areas, and each fall we erect more than 10 miles of
sand fences on a 4 mile oceanfront to hold this precious resource
until the next season.
A demonstration such as this I hope would carry enough
weight so that future consideration for beach nourishment from
inlet dredginq projects could fill the economic void between the
least economical type of dredge contract and hydraulic dredging
contracts for Jones Inlet.
The following slides will demonstrate severul aspects of the
dredging of Jones Inlet past and present, especially the disposal
of dredge spoil on downdrift beach fronts, and the management
effort which annually is put forth by the Town to hold, ..protect,
and enhance the fill placed on our beach.
-77-
COASTAL MANAGEMENT ISSUES IN INLET DREDGING
by
Aram Terchunian
New York State Department of State
'-
INTRODUCTION
The preceeding talks have highlighted some of the-technical,
and social considerations of dredging in high energy
environments. It is the job of the coastal manager to meld these
considerations into a well balanced project.
The objectives of an effective management program are:
(1) adequate depth for safe navigation: (2) minimize channel
maintenance, maximize flush1ng; (3) minimize erosion on
adjacent shorelines; (4) minimize changes in tidal prism (i.e.
salinity) and mixing; and, (5) minimize sand trapping on the bay
side on inlets.
In order to achieve these objectives, an understanding of
natural and stabilized tidal inlets is necessary.
Natural tidal inlets breach barrier islands, forming an
unrestricted connection between the previously separated ocean
and the bay. Most inlets are formed as the result of a storm cr
other imbalance in the natural hydraulic flow of the bay or
ocean. Inlets migrate in the direction of littoral tral1sport,
and thus follow domina::t. wave direct ion. Inlets usually rr_1grate
in the direction of net sediment transport until they close or
stabilize. Often, an inlet will migrate thousands of feet, shoal
up and close, and then breach again at the original location of
breaching. This cyclical nature is common to Long Island south
shore inlets.
..
Tidal inlets are critical to the ffiaintenance of high water
quality in the bays located landward of them. Tidal inlets
provide for a mixing of fresh and salt water to create the unique
estuarine conditions that produce exceptionally high biological
productivity. Inlets also flush polluted water out of the bay,
further improving water quality. A natural inlet balances these
flushing and mixing benefits so that the highest water quality
and biological productivity are maintained.
Tidal inlets also provide significant flooding and erosion
benefits in their role of helping to maintain the barrier island
system. Barrier islands, which front most of New York's Atlantic
Coast, provide flooding and erosion benefits to the bays and
mainland located landward of them by absorbing the energy from
elevated tides and waves associated with storms. An inlet
maintains the barripr island's width in the face of constant
erosion, by trapping sand on the bay side of the island after it
flows through the inlet on an incoming tide. Therefore the
breachinq and migration associated with natural tidal inlets is
- 78 -
necessary to maintain the natural protection which barrier
islands provide.
Tidal inlets also provide important navigation benefits.
However, the meandering path of a natural inlet channel is not
always amenable to high volume and high safety boat traffic. In
order to improve an inlet's navigability for commercial and
recreational craft, man has stabilized many inlets with one or
two parallel stone jetties. This construction is usually
accompanied by initial and maintenance dredging to maintain a
navigation channel. Inlet stabilization creates an imbalance in
the natural inlet function of estuarine mixing/flushing and the
barrier island maintenance. Typically, stabilization has three
principal impacts. First, the sand naturally moving along the
beach is dammed up by the stone jetties. This causes the area
up-current or updrift of the inlet to accrete and the area
downdrift to erode. :econd, because the inlet no longer migrates "
with the direction ct net sediment transport, large tidal deltas
accrete on the ocean and bayside of the inlet. These ebb and
flood tidal shoals, as they are called, are no longer ephemeral
features moving with the inlet, but rather grow into large
semi-perQanent features. This not only increases navigation
hazards, but also limits the amount of sand available to
downdrift beaches, causing more erosion. The third effect of
stabilization is to change the natural balance of mixing and
flushing. An increase of ocean water int.o the bay could change
the biological diversity of the estuarine syst.em. More oceanic
species would be able to survive, especially predatory species.
Conversely, limiting the amount of ocean water could cause the
bays to stagnate, and decrease water quality.
Long term tidal inlet management involves the complex
process of balancing navigation, flooding and erosion protection,
and estuarine productivity benefits. Fortunately, the way that
an inlet reacts to change offers unique opportunities to provide
the needed balance. Navigation channels can be designed to
minimize changes in the tidal prism, and thus changes in the
natural mixing/flushing actions. The sand from dredging can be
used to maintain the high level of natural flooding and erosion '.
protection. The challenge of tidal inlet management is to
maximize the economic, environmental, and social benefits
associated with tidal inlets, while minimizing the adverse
impacts on the barrier islands, bays, mainland. Effective tidal
inlet management requires an historical perspective, a definitive
model of the inlet's natural functions, operational procedures,
and periodic review.
REQUIREMENTS OF A LONG TER~~ INLET MANAGEMENT PROGRAM
Historical Perspective
Bathymetric and topographic surveys of Long Island's south
shore have been undertaken since 1838. The data from these
surveys detail the movement of the tidal inlets, and give
enormous input into how the sediment load is partitioned at the
,-
"
"
"
- 79 -
inlets. Viewing the charts in time order sequence can point out
the "before jetties" and "after jetties" hydrographic portrait of
the inlets. From these time sequential charts, a hypothetical '
model of inlet dynamics can be developed. Of special
significance are the longer term trends that are found in the
historical charts. Measurements of the ebb and flood tidal
deltas, the adjacent beaches, and the inlet channel and throat
area can lead to. quantification of sand motion over an almost 150
year period. Results should be displayed in tabular or graphical
form.
Definitive Model of Inlet Hydrodynamics and Sand Flow
A state-of-the-art computer-based hydrodynamic model is
considered an integral part of any major inlet management
program. A field verified model allows the various alternatives
to be tested at mininal cost. A computer model for a tidal inlet
could be based on the model that was used at Oregon Inlet, North
Carolina. The model should cover sufficient geographic area to
allow simulation several miles up and downdrift of the Inlet.
Such a model should be coupled with existing models for south
shore bays developed by Marine Science Research Center at Stony
Brook, and the Long Island Regional Planning Board. These
definitive models will be able to simulate the effects of changes
in tidal inlets.
Operational Procedures
Standard operating procedures (SOP) for both short and long
term actions at the inlets should be developed. These-procedures
should reflect the informatioll gained from the historical charts,
the predictive modeling, and dredging and disposal records, and
observations.
c
c
Variables, including bathymetry, salinity, wave data, and
current data, should be monitored periodically to be used in the
computer model of shoaling and erosion. In addition to before
and after surveys of the dredging operation, periodic surveys
\ should be taken every quarter.
Special attention should be directed to the
the dredge material. If deposited on the beach,
these operations should be stabilized with beach
fencing. If deposited offshore, profiles should
determine the movement of the material.
of
ultimate fate
the sand from
grass and sand
be taken to
Periodic Review of Operations
An Inlet Committee consisting of appropriate federal, state
and local officials, as well as Inlet user groups, scientists,
and parties of interest should be formed to periodically review
the state of Fire Island Inlet.
- 80 -
Projects in the coastal environmental must be able to adapt
to ever changing littoral conditions. Periodic review of the SOP
is one method of addressing this issue. Personal experience of
the Inlet users is another excellent source of information on
Inlet changes. The information collected during the surveys
should also be examined.
SUMMARY
The objectives of long term management of tidal inlets are:
1. Maximize navigational access and safety;
2. Maximize conservation of estuarine resources (salinity
level, finfish, shellfish, vegetation, and wildlife) ;
.
3. faximize conservation of sand sources (i.e., minimize
losses of littoral material) ;
\
4. Maximize public access to shoreline; and,
I
5. Remain responsive to changes in the physical
environment, or social use, or environmental stress.
To achieve these objectives, lor.g lerm management of tical
inlets require~ in-depth knowledge of the past and present inlet
processes, an interactive model to determine the impact-of
various options, and identification and periodic review of
standard operating procedures. Periodic synthesis and
distribution of this information is also critical to effective
inlet management.
The following information sources may be helpful in
producing such a report:
-- FitzGerald, Duncan M., 19B1, Patterns of shorel~ne change
along Atlantic City (New Jersey) beach caused by Absecon Inlet
processe~, Technical Report *6, Department of Geology, Boston
University, 02215 (see page 57 for hypothetical model of inlet
processes) .
-- FitzGerald, D. M., D. K. Hubbard, D. Nummendal, 1978,
Shoreline changes associated with tidal inlets along the South
Carolina coast, in Coastal Zone '78, pp. 1973-1974 (mechanisms
of sand bypassing on page 1978 and use of historical charts).
.
-- Everts, Craig H., 1979(?), Perdido Pas dredged material
disposal study, U.S. Army Corps of Engineers, Coastal Engineering
Research Center.
.- 81 -
CONSIDERATIONS IN THE DESIGN
OF
LARGE SCALE, CORPS DREDGING PROJECTS
by Gilbert K. Nersesian
District Coastal Engineer,
U.S. Army Corps of Engineers, New York District
,
The design of large scale navigation projects involving
dredging requires an understanding of the problems, assembly and
evaluation of all pertinent facts, and development of rational.
plans which meet the needs of navigation interests and users ~n
the most economical and efficient manner.
,
The development and improvement of design considerations for
a waterway include the amount and type of traffic that will be
using the waterway, the commodities moved, safety, efficiency,
reliability, and cost. Safety and efficiency should receive
primary consideration before the project is optimized with
respect to cost. Safety of the project will depend on the size
and maneuverability of the vessels using the waterway, size anc
type of channel and navigation aids provided, effects of current
and wind, and experience and judgment of navigators. tince this
judgment factor is involved and is, oftentimes, so diverse that
it is difficult to evaluate, poteDtially harzardous conditions
should be eliminated insofar as practicable. Therefore, optimum
design of a specific waterway will require an evaluation of the
physical environment, currents, weather conditions, and judgment
of factors of safety depending OD navigator's response.
Corps of Engineers projects in the New York Bight and Long
Island shore areas which have exposure to high energy wave
environments, include the Ambrose Channel entrance to New York
Harbor and entrance channels at Rockaway Inlet, East Rockaway
Inlet, Jones Inlet, Fire Island Inlet, Moriches Inlet and
Shinnecock Inlet, all along the south shore of Long Island.
Elsewhere on Long Island navigation channel entrances at Port
Jefferson Harbor, Mattituck Inlet, Greenport Harbor and Lake
Montauk Harbor are located in shore areas having a moderate wave
energy environment. Typically, the navigation projects which
provide these entrance channels also feature jetties which
provide obstructions to littoral drift, control entrance
currents, prevent or reduce shoaling in the entrance channel,
maintain channel alignment, and/or provide protection from wind
and waves. Interior channels connect the entrance with other
channels, marinas, piers or docks. These channels are usually
semiprotected in a bay, estuary or river. Some projects provide
anchorage areas for vessels to stand by, moor, load or unload.
In addition, turning basins may be provided for radical change of
vessel direction. They are usually located at or near the upper
end of the interior channel and possibly at one or more
intermediate points.
- 82 -
PRELIMINARY PLANNING
,
Prior to undertaking design of a navigation project, there
is an extensive preliminary planning effort which needs to be
accomplished. During the preliminary planning, the amount and
type of traffic that would be using the waterway should be
considered. Info~ation on the type of traffic is used to select
the design vessel. The amount of traffic could determine whether
one-way or two-way traffic should be provided. Layouts.should be
prepared using various channel alignments and dimensions and each
layout should be evaluated on the basis of the number of trips,
trip time, commodities transported, safety, environmental and
social impacts, and construction and maintenance cost.
Comparisons of project costs with benefits indicate the most
economically feasible layout for the specific project. Planning
for the project will require an understanding of the problems
that can be encountered, anc the assembly and evaluation of all
pertinent information that could affect development and operation
of the facilities. The U. ~ Coast Guard should be consulted in
both the preliminary and final design process. Their views on
channels and bridges, vessel maneuverability, traffic management,
operational restrictions, and optimum aids to naviga~ion should
be incorporated in the d~sign and presented in appropriate
reports and design memoranda. It is important, therefore, that
the following steps be undertaken during the early planning
stage:
,
Review appropriate planning and design publicati~ns.
Consult with local authorities, gover~ent agencie&, and
select and list ~he design cQnditions that have to be met.
data.
Collect and analyze pertinent physical and environmental
Determine amount and type of traffic and largest vessel
to be accomodated.
Determine type of commodities that will be moved.
Select layout and alternatives that should be considered
and determine advantages and disadvantages of each with annual
cost.
.
Assess any adverse environmental and other impact~.
Determine amount, type, and frequency of harzardous cargo
(LNG, ammunition, etc.) movement and evaluate any special
provisions or requirements.
DATA EVALUATION AND ANALYSIS
Physical data to be evaluated for design of a navigation
project will require an analysis and evaluation of information on
the following factors:
- 83 -
Design Vessel and Other Vessels Using Waterways
Dimensions (length, beam, draft).
Maneuverability and speed.
Number and frequency of use (congestion).
Type of cargo handled.
Other Traffic Using Waterway
Types of smaller vessels and congestion.
Cross traffic.
Weather
Wind (velocity, direction and duration).
Waves (heights, period, direction and duration).
Visibility (rain, smog, fog and snow).
Ice (frequency, dur~tion and thickness).
Abnormal waters levels (high and low).
Characteristics of Channel
Curreuts, tidal anc / or ri '!er (velocity, direction and
duration) .
Sediment sizes and areal distribution, movement, and
serious scour and shoal areas.
Type of bed and bank (soft or hard).
.
Alignment and configuration.
~
Freshwater inflow.
Tides.
Salinity.
Dredge disposal areas.
Water quality.
Biological population (type, density, distribution, and
migration) .
Obstruction (sunken vessels, abandoned structures, etc.)
- 84 -
Existing bridge and powerline crossings (location, type
and clearances).
The aforementioned factors will have to be evaluated in
order to determine the requirements to be met with each
alternative layout. This evaluation should indicate traffic
pattern, weather conditions, and channel characteristics that
will affect navigation. The channel design should permit safe
passage of the design vessel under most weather conditions with a
competent navigator. Extreme weather and/or flow conditions
should be analyzed for their effects on the design vessel and
smaller vessels, and the frequency of occurrence of unsafe
periods should be indicated. The probability of unsafe
conditions for a design vessel that might use the channel only a
few times a year could have some effect on channel design.
Weather conditions that exceed those which produce unsafe
conditions at sea should not be considered. For example,
hurricane winds and waves would not normally be selected as the
design conditions for a navigation channel.
.
ENGINEERING STUDIES
A number of engineerinq studies will have to be conducted to
establish project design. The following studies are normal for
navigation project design:
Design vessel.
Water levels.
Waves (naturally occurring and vessel generated).
Currents.
Sedimentation (sediment budget and channel shoaling).
Channel depth.
Channel width.
Channel alignment.
Dredging and disposal.
Turning basins.
Jetty and entrance channel layout.
Jetty type.
Environmental iMpacts.
Accident record (channel enlargement study) .
Interviews with navigators and Coast Guard views.
- 85 -
Model study.
Datum.
,
Operation and maintenance plan.
PLAN FORMULATION
:
Selection of the final dimensions of any navigation project
is made only after undertaking a vast number of engineering,
environmental and economic studies. These studies initially may
result in consideration and development of several plan
alternatives, each of which may have particular attributes such
as being the least costly, the most economical, the one which has
the least possible-impact on environmental resources or the one
which is most desired by users of the waterway. The selected
plan generally will be the one which be~t satisfies the concerns
of economics, rninimize< eDvironmental impacts and meets the
navigation needs.
CHANNEL DREDGING
Channel dredging is performed for initial construction of
navigable waterways and for subsequent maintenance after
construction. The initial construction provides the design depth
witq provlsions for adva~ce mainteuance dredging and dr~dging
tolerance. Maintenance dredging provides for removal of
sediments deposited on the channel bottom. The type of material
to be dredged and the location of disposal areas are important
factors that influence channel cost estimates. Also, cost
estimates should be prepared for various channel alignments and
dimensions for project optimization. Deep-draft channel
locations which are exposed to wave action or where disposal is
in exposed areas, are usually dredged by hopper dredges. Where
channels are in protected or semiprotected areas, pipeline
dredges usually are more economical with greater production.
c
<
\ DREDGING METHODS
Dredging methods employed by the Corps vary considerably
based on the channels and materials to be dredged. The principal
types of dredges in the New York Bight and Long Island area
include hydraulic pipeline types (cutterhead, plain suction and
sidecaster), hopper dredges, and clamshell dredges. Other
dredges include dipper and special purpose dredges. There are
basically only three mechanisms by which dredging is actually
accomplished:
.
~
Suction Dredging. Removal of loose materials by
dustpans, hoppers, hydraulic pipeline, plain suction, and
sidecaster dredges, usually for maintenance dredging projects.
Mechanical Dredging. Removal of loose or hard cCffipacted
materials by clamshell or dipper dredges, either for maintenance
or new work projects.
- 86 ..
Combination of Suction and Mechanical Dredqinq. Removal
of loose or hard, compacted materials by cutterhead, either for
maintenance or new projects.
'-
SELECTION OF DREDGING EQUPIMENT
Selection of dredging equipment and methods used to perform
the dredging will. depend on the following factors:
Physical characteristics of material to be dredged.
Quantities of material to be dredged.
Dredging depth.
.
Distance to disposal area.
.
- Physical environment of and between the dredging and
disposal ,reas.
Cont~ination level of sediments.
\
Method of disposal.
Production required.
Type of dredges available.
DISPOSAL SITES
Disposal sites can be located in the ocean, an estuary,
intertidal strea~s, a lake, or on upland areas. Ocean disposal
remote from the channel assures that the material will not
reenter the channel; however, costs will generally be higher.
Disposal in estuaries should be in areas where tidal currents
will not move the material into the channel being developed or
adversely affect the environment. Intertidal disposal (between
low-tide and high-tide levels) might be feasible where creation
of marshes for fish and ~ildlife habitat or beach restoration is
desired. Upland disposal will usually require dikes and weirs to
control the solids content of runoff water returning to the
waterway and temporary restraining structures might be required
for marsh creation. The effects of disposal in streams on
channel maintenance and development and the environment must be
considered.
USE OF DREDGED MATERIAL
A study of beneficial use of the dredged material might
indicate an increase to project benefits. Some beneficial uses
of dredged material would be:
Landfill for industrial or park development.
Construction materials.
- 87 -
TOp soil.
Marsh creation.
Beach restoration or nourishment.
ENVIRONMENTAL EFFECTS
Studies must consider all positive and negative
environmental effects of the alternative plans considered. Some
of the environmental effects may be changes in:
Water levels.
Erosion.
Shoaling patterns.
Water circulation.
Flushing rates.
Salinity intrusion.
~
Any plan recommended must have an environmental assessment.
This assessment will indicate whether a Statem~nt of Findings or
an Environmental Impact Statement will be required, including a
comprehensive mitigation plan with cost for any adverse effects.
In the development or improvement of deep-draft navigation
projects, the effects of dredging and dredge disposal on fish and
wildlife resources and possible productive use of dredged
material have to be considered. Special consideration will be
re~uired for both dredging method and disposal wh~n dealing with
contaminated materials. The possible impact of erosion and/or
accretion that may result along shores on either side of an
improvement of the entrance at the mouth of any river or inlet,
ha~ to be carefully assessed. Project limits sho~ld be extended
beyond the project features to allow future mitigation work, if
needed. Model studies should be used to predict project-caused
changes in salinity, shoaling patterns, current velocities, tidal
flushing, and dispersion rates. Project limits should be
extended beyond the project features to allow future miti~ation
work, if needed. Model studies should be used to predict
project-caused changes in salinity, shoaling patterns, current
velocities, tidal flushing, and dispersion rateS. Prototype
verification data for mod~l studies are essential and should
cover a wide range of conditions. Quantitative biological
85sessment of project impact to the aquotic life is needed to
plan mitigation measures.
89
SESSION 6
Questions anc Answers
'-
Question 1 Chris Zeppie, (PA): Should the Dept. of State be
playing a lead role in developing inlet management plans?
Response: Aram Terchunian, (DOS): Florida has a successful plan
at the state level being done by their Coastal Management
Program. We at DOS need to consider this futher.
Question
permanent
Larry Tuthill, (Southold): Have you considered a
by-pass system at the Inlet?
Response: Gil Nersesian, (COE): That's come up on
shore. Fire Island is the only project where this
it combines naviaation and beach erosion control.
part of Jones Beach need& nourishment there's
natural hypassing there.
the south ,
is built in:
The western.,
net sufficient
Question 2 Carol Coch, (COE):
regional dispGsal sites, have you
or a large-s~ale wetland project?
Since Suffolk County needs
considered a containment island
Response: John GulcilSC row): We'rr aware of the prohlerr bet
most of our jobs are maintenance dredging and are disposed of
with beach nourishment, so a regional disposal site isn!t that
important to us. The land simply isn't there and islands are too
expensive.
Comment 3 Ed Parthe (fuoreline Consultants): If channels aren't
deep enough, we'll have to truck goods in and thus pollute the
air. If you close marinas, condominiums will he built in their
place. There's no legislative mandate for comprehensive
planning, but you should keep in mind the balance.
Response: Aram Terchunian, (DOS): If you want a deeper dredging
depth, tell us why and how. We're willing to listen.
,
.,
Question 4
permits has
coordil1ated
Eugenia Flatow: An applicant needing three
to deal with three levels of governments. Has
these, perhaps with computers?
anyone
Responses: John Guldi(SC DPW):
joint permit proce&sing, they ~o
judgment.
When the COE and the state have
for the most conservative
Jay Tansky, (Se~ Grant): There is no formal agreement for
joint permit processing.
Jim ~orton, (DOS): Sequential review of permits is a
problem but we didn't address the issue of h0\" to improve
re<;ulatory procedures at this workshop. Coordination has heen
done in Buffalo District that I would like to duplicate in NYC.
- 90 -
Comment 5 Janet Dietrich, (Town of Huntington): People go to the
federal government and the state, and no one comes to us. How
could we get the word out to the public that they have to see us
too?
,
.
.
.
- 91 ~
DREDGING WORKSHOP ATTENDANCE LIST
Mr. Ronald Abrams
NY5 Department of Environwental Conservation
Region 2
2 World Trade Center
New York, New York 10047
.
Mr. Vichit Aramsombatdee
NYS Department of Environmental Conservation
Region 2
2 World Trade Center
New York, New York 10047
Mr. William Atlas
New York District, US Army Corps of Engineers
26 Federal Plaza, 19th Floor
New York, NY 10278
Mr. Ranc~ll Austin
NYS Department of Environmental Conservation
Region 2
2 World Trade Center
New York, NY 10047
,
Mr. Alan Bauder
Division of Land Utilization
NYS Office of General Services
\TOWer Building
Empire State Plaza
Albany, NY 12242
<
r
Mr. William Barton
NYS Coastal Management Proqram
Mr. Norman Berger
Director of Navigation Projects
NYC Department of Ports & Terminals
Battery Maritime Building
New York, NY 10004
- 92 -
Mr. Charles Bowman
The Land Use COMpany
P.O. Box 361
Wading River, NY 11792
"
Dr. Henry Bokuniewicz
Marine Sciences Research Center
SUNY @ Stony Brook Building H
Stony Brook, NY 11794
Mr. Robert Bowne
Sidney B. Bowne & Son
235 E. Jericho Turnpike
PO Box 189
Mineola, N~ 11501
\
.
.
.
Paul Buzash
NYS Office of General
Tower B\1ildina
Empire State Plaza
Albar.y, NY 12242
"
Services
Ms. Karen Chytalo
Division of Regulatory Affairs
N.Y.S. Department of Environmental Conservation
State University of New York ~ Stony Brook
Building 40
Stony Brook, NY 11790
Ms. Carol Coch
Water Quality Compliance Section
New York District, US Army Corps of Engineers
26 Federal Plaza, 19th Floor
New York, New York 10278
,
.
~1r. Dennis Cole
Division of Requlatorv Affairs
NYS Department-of Environmental Conservation
State l1niversity of New York @ Stony Brook
Building 40
Stony Brook, NY 1179C
- 93 -
Ms. Mindy Berger
52 Derby Place
Smithtown, NY 11787
Mr. Brian Zitani
Environmental Control
Town of Babylon
190 Farmer's Avenue
Lindenhurst, NY 11757
.
~
..
- 94 -
MICHAEL COREY
N.Y.S. COASTAL MGMT PROGRAH
Dr. Carmela Cuomo
Marine Sciences Research Center, South Campus,
Building H
SUNY @ Stony Brook
Stony Brook, NY 11794
Mr. Dewitt Davies
Regional Marine Resource Council
Veterans Memorial Highway
Hauppauge, NY 11788
~
.
Mr. Robert DeBruin
Civil Engineer & Land Surveyor
2468 North Jerusalem Road
North Bellevore, ~Y 11710-1198
Mr. Gregor~ DeBruin
Civil Engineer & Land Surveyor
2468 North Jerusalem Road
North Bellevore, NY 11710-1198
Ms. Janet Deiterich
Department of Environmental Control
Town of Huntington
100 Main St.
Huntington, NY 11743
,
Mr. Charles De Quil1feldt
NYS Department of Environmental Conservation
State University of New York @ Stony Brook
Building 40
Stony Brook, NY 11790
Mr. Thomas Dohenev
Director of Conservation
Town of Hempstead
Department of Conservation and Waterways
Lida Boulevard, P.O. Box J
Point Lookout, NY 11569
- 95 -
SALVATORE ERVOLINA
N.Y.S. D.E.C.
'-
Mr. David Fallon
New York State Department of Environmental
Conservation
Bureau of Marine Habitats
Building 1140
SUNY @ Stony Brook
Stony Brook, NY 11794
.
.
.
Mr. Thomas Farrell
Director
Planning & Deve1opme~t
Village of Fort Chester
Port Chester, NY 10513
Mr. Jeffrey Rabkir.
NYS Department of Environmental Conservation
Region 2
2 World Trade Center
New York, NY 1004,
Mr. Kenneth Feustel
Environmental Control
Town of Bahy10n
190 Farmer's Avenue
Lindenhurst, NY 11757
,
Ms. Eugenia Flatow
456 Riverside Drive
New York, NY 10027
Mr. Allen E. Francis
Recording - Corresponding Secretary
I.U.O.E., Local 25 M.D.
675 Fourth Aver.ue
Brooklyn, NY 11232
- 96 -
Ms. Deborah Freeman
Water Quality Compliance
New York District, US Army Corp of Engineers
26 Federal Plaza, 19th Floor
New York, NY 10278
'-
Dr. Joseph Germano
Marine Surveys, Inc.
5 Science Park
New Haven, CT 06511
.
Mr. George Gaige
Nassau County Department of Health
240 Old Country Road
Mineola, NY 11501
.
.
Ms. Edwina Gilbert
NYS. Office of Parks, Recreation
and Historic Preservation
Empire State Plaza
Agency Bui~ding #1
Albar.y, NY 12235
Ms. Karen Gustina
U.S. Army Corps of Engineers, NY District
Environmental Branch
26 Federal Plaza, 19th Floor
New York, NY 10278
Mr. Rob Greene
Regional Permit Administrator
NYS Department of Environmental Conservation
State University of New York @ Stony Brook
Building 40
Stony Brook, NY 11790
>
.
.'
Mr. John Guildi, P.E., L.S.
Principal Engineer
Division of Waterways
Suffolk County Department of Public Works
Yaphank Avenue
Yaphank, NY 11980
- 97 -
Ms. Holly B. Haff
Deputy Director
Environmental Management Division
NYC Department of City Planning
Two Lafayette Street, Room 2208
New York, NY 10007
Mr. Roy Haje
En-Consultants, Inc.
64 North Main Street
Southampton, NY 11968
.
.
Mr. Charles Hamilton
NYS Department of Environmental Conservation
Region 1, Division of Regulatory Affairs
SUNY @ Stony Brook, BuildinG ICO
Stony Brook, NY 11794
"
Ms. Louise Harrison
NYS Department of Environmental Conservation
State University of New York @ Stony Brook
Buildin<; 4C
Stony Brook, NY 11790
Mr. F. L. Jannuzzi
Contracts Manager
Weeks Dredging & Contracting, Inc.
216 N. Avenue, East
Cranford, NY 07016
..
Mr. Edward Johannemann
\~/o Sidney B. Bowne & Son
'235 E. Jericho Turnpike
Mineola, NY 11501
<
c
:
Ns. Eileen Jones
National Resources Management Specialist
Division of Professional Services
US Department of Interior
Gateway National Recreation Area
Headquarters Building 9
Floyd Bennett Field
Brooklyn, NY 11234
- 98 -
Mr. John Kahabuka
NYS Power Authority
123 Main St.
White Plains, NY 10601
Mr. Jeffrey Kassner
Department of Environmental Protection
Town of Brookhaven
205 S. Ocean Avenue
Patchogue, NY 11772
.
Mr. Kenneth Kimidy
New York District, US Army Ccrps of Engineers
26 Federa\ Plaza, 19th Floor
New York, ~Y 10-278
.
.
Mr. J. Glynn Kinq
King Terra Marine Contracting
10 Burn Road
Shelter Island, Nl 11964
Ms. Susan King
Nassau County Department of Health
240 Old Country Road
Mineo1a, NY 11501
Mr. Ken Koetzner
Bureau of Marine Habitats
NYS Department of Environmental Conservation
State University of New York @ Stony Brook
Building 40
Stony Brook, NY 11790
. .
.
.
Mr. Richard Krauser
Water Quality Compliance Section
New York District, U.S. Army Corps of Engineers
26 Federal Plaza, 19th Floor
New York, NY 10278
- 99 -
Ms. Ellen Larsen
Costallo Marine Contracting Corp.
Box AK
Greenport, NY 11944
"
Ms. Marion G. Latham
Costello Marine Contracting Corp.
Box AK
Greenport, NY 11944
.
Ms. Kathy Lester
Town of Easthampton
159 pantigo Road
East Hampton, NY 11937
.
.
Mr. Brion Lindhol~
Great Lakes Dredge & Dock Co.
PO Dra\\"er K
Staten Island, NY 10303
Mr. Simon Litten
Research Scientist
Division of Water
NYS Department of Environmental Conservation
50 Wolf Road
Albany, NY 12233
-'-.
*
Mr. Michael Litwa
NYS Department of Environmental Conservation
State University of New York @ Stony Brook
Building 40
Stony Brook, NY 11790
.
.
Mr. John Lunz
U.S. Army Corps 0= Engineers
Waterways Experiment Station
Vicksburg, MS 39108
- 100 -
Mr. Soon Loo
New York District, US Army Corps of Engineers
26 Federal Plaza, 19th Floor
New York, NY 10278
"
Mr. Dennis Lynch
Commissioner
Environmental Control
Town of Babylon
190 Farmer's AVenue
Lindenhurst, NY 11757
.
.
Mr. James ~ansky, Chief
Permits Branch
New York District, US Army Corps of Engineers
26 Federal Pla?a, 19th Floor
New York, NY 10278
Mr. Joseph Martino
Civil Engineers I Hand Surveyor
2468 North Jerusalem Road
North Eel1evore, NY 11710-11ge
JAMES MORTON
N.Y.S. COASTAL MGMT. PROGRAM
Mr. Fred Mushacke
NYS Department of Environmental Conservation
State University of New York @ Stony Brook
Building 40
Stony Brook, NY 11790
.. .
.
.
Mr. Daniel Natchez
Daniel S. Natchez & Associates
555 AIda Road
Mamaroneck, NY 10543
Mr. Gilbert Nersesian
NY District, US ArMY Corps 0= Engineers
26 Federal Plaza
New York, NY 10278
- 101 -
Mr. Arthur Newell
Bureau of Environmental Protection
New York District, US Army Corps of Engineers
26 Federal Plaza, 19th Floor
New York, NY 10278
.
,
Ms. Linda O'Leary
NY!NJ Port Authority
1 World Trade Center
Room 74 E
New York, NY 10048
.
.
Mr. Thomas Ouellett~
State of Connecticut
Department of Environmental Protection
Water Resources Unit
165 Capital Avenue
Hart:orc, CT 061n6
l>"r. ,"Joseph Pane
NYS !)E~lll"':::r"L.:.~ G..... LL'._~nr.rr.€:-~'_,
Region 2
2 World Trade Center
New York, NY 10047
... ~~. Sf~l".;C -....: C:f
-
Mr. Edward Panarello
President.
New York-New Jersey
Port Promotion Association
343 Court St.
Brooklyn, NY 11231
.
.
Dr. Richard Peddicord
U.S. Army corps of Engineers
Waterways Experiment Station
Vicksburg, MS 39108
Mr. Edward G. parthe
Shoreline Consulting Co.
P.O. Box 479
Lindenhurst, NY 11757
- 102 -
Mr. Mario Paula
Water Quality Compliance Section
New York District, US Army Corps of Engineers
26 Federal Plaza, 19th Floor
New York, NY 10~78
Mr. Larry Penny
Town of Easthampton
159 Pantigo Road
East Hampton, NY 11937
JANICE ROLLWAGEN
U.S. E.P.A.
Mr.Charles E. Pound
President
Aqua Dredge, Inc
70 Bryram Ridge Roac
Armonk, NY 10504
Mr. Michael Ritchie
Village l'.anarrer
Village of Port Chester
Port Ch~ster, NY 10513
Mr. Hal Rose
NYC Dept. of City Planning
Two Lafayette Street, Room 2208
New York, NY 10007
Mr. Richard RosaMilia
Great Lakes Dredge and Dock Co.
2747 Richmond Terrace
PO Drawer K
Staten Island, NY 10303
Mr. Quintin Ross
NYS Pover Authority
123 Main St,
,:hite Plains, NY 10601
, '.
.
.
.
.. .
:
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..
- 103 -
Mr. Norman Rubinstein
U.S. Environmental ProtectiJn Agency
Environmental Research Laboratory
South Ferry Road
Narragausett, RI 02882
"
.
.
Mr. Steven Sanford
Division of Wildlife
NYS Department of Environmental Conservation
State University of New York @ Stony Brook
Building 40
Stony Brook, NY 11790
.
.
Mr. Peter Sanko
Peter Sanko Associates, Jnc.
64 N. Main St.
Southampton, NY 11968
Mr. Peter L. Sattler
Senior Er!vironmenta~ rlan~E~
Interst<:t(. Sanitat~cr. Corc.r..issicr:
311 West 43rd St
New York, NY 10036
.
. C
Mr. Donald Scanlon
Nassau County Department cf Health
Bureau of Water Pollution Control
240 Old Country Road
Mineola, NY 11501
"
.
.
,
,
Mr. Lawrence Schmidt
Acting Director, Planning Group
Department of Environmental Protection
State of New Jersey
CN 40?
Trenton, NJ 08625
Mr. William Slaoe
NYS Power Author~ty
12:: Main St.
White Plains, NY 10601
- 104 ~.
Mr. William Slezak, Chief
Navigation Branch
US Army Corps of Engineers, New York
District
26 Federal Plaza
New York, NY 10278
"
Mr. Tom Sperry
U.S. Fish and wildlife Service
US Department of the Interior
Brookhaven National Laboratorv
Upton, NY 11973 -
..
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<<
Mr. Mark Tauro~ina
Daniel s.\~atchez and Associates, Inc
555 AIda Road
Mamaroneck, NY 10543
I,
Mr. Jay Tanski
Regional Extension Specialist
Sea Grant ~xtensicn Program
Marinp Sciences ~esearch C~r-ter
SUNY @ Stony Brook, Building H
Stony Brook, NY 11794
Mr. John Tavolaro, Chief
Water Quality Compliance Section
U.S. Army Corps of Engineers NY District
26 Federal Plaza, 19th Floor
New York, NY 10278
,. .
Mr. Robert D. Teeters
243 Willowbrook Ave
Stamford, CT 06902
.
.
.
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ARAM TERCHUNIAN
N.Y.S. COASTAL MGMT PROGRN1
Mr. Lawrence Tuthill
12l~, Inlet Lane
Greenpcrt, NY 11944
- 105 -
Mr. Pieter Van Volkenberg
Bureau of Shellfish
NYS Department of Environmental Conservation
State University of New York @ Stony Brook
Building 40
Stony Brook, NY 11790
a
.
Mr. John Vanderveer
Superintendent of Environmental
Control
Town of Oyster Bay
150 Miller Place
Syosset, NY 11791
.
.
. Ms. Roberta Weisbrod
NYS Department of Environmental Conservation
Region 2
2 World Trade Center
New York, NY 10047
Mr. Rotert Wi1~
Envirocmentol Branc~
New York District, US Army Corps of Engineers
26 Federal Plaza, 19th F1eor
New York, NY 10278
Mr. John Zammit, Chief
Operations Division
U.S. Army Corps of Engineers
New York District
26 Federal Plaza, 19th Floor
New York, NY 10278
.
Dr. Gary Zarillo
Marine Sciences Research Center
SUNY @ Stony Brook, Building H
Stony Brook, NY 11794
~
.
.
Mr. Christopher Zeppie
NYS Power Authority
123 Main St.
White Plains, NY 10601