HomeMy WebLinkAboutEnvironmental & Aesthetic Impact of Small Docks & Piers Jan 2003
DECISION ANALYSIS SERIES
The Decision Analysis Series has been established by
NOAA's Coastal Ocean Program (COP) to present
documents for coastal resource decision-makers which
contain analytical treatments of major issues or topics.
To learn more about the COP or Decision Analysis
Series, please write:
NCAA Coastal Ocean Program
1305 East-West Highway
Silver Spring, Maryland 20910
phone: 301-713-3020
fax: 301-713-4044
web: www.cop.noaa. Rov
Science for Solutions
NOAA's COASTAL OCEAN PROGRAM
Decision Analysis Series Number 22
ENVIRONMENTAL AND AESTHETIC IMPACTS OF
SMALL DOCKS AND PIERS
Workshop Report: Developing a Science-Based Decision Support
Tool for Small Dock Management, Phase 1: Status of the Science
Ruth Kelty
Steve Bliven
January 2003
U.S. DEPARTMENT OF COMMERCE
Donald L. Evans, Secretary
National Oceanic and Atmospheric Administration
Vice Admiral Conrad C. Lautenbacher, Jr., U.S. Navy (Ret.),
Undersecretary for Ocean and Atmosphere
National Ocean Service
Jamison S. Hawkins, Acting Assistant Administrator
National Centers for Coastal Ocean Science
Gary C. Matlock, Director
Report Authors
Ruth Kelty, National Centers for Coastal Ocean Science
Steve Bliven, Bliven and Sternack
Workshop Participants
Clark Alexander, Skidaway Institute of Oceanography
Rick Ayella, Maryland Department of the Environment
David Blatt, Connecticut Department of Environmental Protection
Steve Bliven, Bliven & Sternack
Jerry Brashier, Mississippi Division of Marine Resources
Dave Burdick, Jackson Estuarine Laboratory, University of New Hampshire
Alison Castellan, NCAA Ocean Service, Office of Ocean and Coastal Resource Management,
Richard Chinnis, South Carolina Dept. of Health & Env. Control, Office of Coastal Resource Management
Rick Crawford, Nautilus Environmental Services
Torrance Downes, Connecticut River Estuary Regional Planning Agency
Judy Gates, Maine Department of Environmental Protection, Division of Land Resource Regulation
Andrea Geiger, Coastal States Organization
Truman Henson, Massachusetts Office of Coastal Zone Management
Mike Johnson, NCAA Fisheries Service, Northeast Regional Office
Ruth Kelty, NCAA Ocean Service, National Centers for Coastal Ocean Science
Dave Killoy, US Army Corps of Engineers, New England District
Mike Ludwig, NCAA Fisheries Service, NE Fisheries Science Center
Regan Maund, Urban Harbors Institute, University of Mass., Boston
Bill Moyer, Delaware Dept. of Natural Resources & Environmental Control, Division of Water Resources
Ed Reiner, US EPA Region 1
Steve Resler, New York Department of State
Steve Rumrill, South Slough National Estuarine Research Reserve
Denise Sanger, South Carolina Div. of Nat. Res., Mar. Res. Div., Mar. Res. Research institute
Deborah Shafer, US Army Corps of Engineers, Waterways Experimental Station
Richard Smardon, SUNY-ESF Syracuse
Susan Snow-Cotter, Massachusetts Office of Coastal Zone Management
Ron Thom, Battelle Marine Sciences Laboratory
Peddrick Weis, UMDNJ - New Jersey Medical School
This oublication should be cited as: Kelty, R.A. and S. Bliven. 2003. Environmental and Aesthetic
Impacts of Small Docks and Piers, Workshop Report: Developing a Science-Based Decision Support
Tool for Small Dock Management, Phase 1: Status of the Science. NCAA Coastal Ocean Program
Decision Analysis Series No. 22. National Centers for Coastal Ocean Science, Silver Spring, MD. 69 pp.
This publication does not constitute an endorsement of any commercial product or intend to be an
opinion beyond scientific or other results obtained by the National Oceanic and Atmospheric
Administration (NCAA). No reference shall be made to NCAA, or this publication furnished by
NCAA, in any advertising or sales promotion which would indicate or imply that NCAA
recommends or endorses any proprietary product mentioned herein, or which has as its purpose
an interest to cause directly or indirectly the advertised product to be used or purchases because
of this publication.
Note to Readers
Environmental and Aesthetic Impacts of Small Docks and Piers is the proceedings from a January 2003
workshop sponsored by the National Centers for Coastal Ocean Science (NCCOS). The workshop,
which focused on the status of the science, is the first of a series designed to support the development of
a science-based decision support tool for small dock management. Future workshops will synthesize
information on regulatory, non-regulatory, and construction tools available to improve the management,
and reduce the environmental impacts, of small docks and piers.
The NCCOS provide a focal point through which NOAA, together with other organizations with
responsibilities for the coastal environment and its resources, can make significant strides toward finding
solutions to critical problems. By working together toward these solutions, we can ensure the
sustainability of these coastal resources and allow for compatible economic development that will
enhance the well-being of the Nation now and in future generations.
A specific objective of the NCCOS is to provide the highest quality of scientific information to coastal
managers in time for critical decision-making and in formats useful for these decisions. To this end, the
Decision Analysis Series was developed by the Coastal Ocean Program to synthesize information on
issues of high priority to coastal managers. As a contribution to the Decision Analysis Series, this report
provides a critical synthesis of the potential consequences of the construction, presence, and use of small
docks and piers on the coastal environment. A list of other available documents in the Decision Analysis
Series can be found on the last page of this report.
As with all of its products, the NCCOS is interested in ascertaining the utility of Environmental and
Aesthetic Impacts of Small Docks and Piers, particularly in regard to its application to the management
decision process. Therefore, we encourage you to write, fax, call or email us with your comments.
Please be assured that we will appreciate these comments, either positive or negative, and that they will
help us direct our future efforts. Our contact information is below.
Gary C. Matlock, PhoD.
Director
National Centers for Coastal Ocean Science
1305 East-West Highway, Silver Spring, Maryland 20910
phone: 301-713-3020 fax: 301-713-4353 email: nccos.webmaster@noaa.gov
web: https://coastaloceanscience.nos.noaa.gov
TABLE OF CONTENTS
Introduction
The Workshop
Background Paper
Workshop Agenda
Summary of the workshop Management Context
Panel on Impacts to Vegetation from Docks
Panel on Impacts from Contaminants Related to Docks
Panel on Impacts from Associated Boating Use
Panel on Impacts to Navigation and Riparian Uses
Panel on Impacts to Aesthetics and Quality of Life Issues
Managers' Response
Recommendations
Research Needs
Bibliography resulting from the workshop
An online bibliography has been posted on the NCCOS web site.
Future Steps
Appendix 1. Attendees' contact information
1
4
17
18
2O
3O
35
4O
41
53
55
58
58
59
6O
INTRODUCTION
Statement of Problem
Few issues confronting coastal resource individual and cumulative effects of residential docks
managers are as divisive or difficult to manage as and the uses associated with them. Ideally, this
regulating the construction of private recreational
docks and piers associated with residential
development. State resource managers face a
growing population intent on living on or near the
coast, coupled with an increasing desire to have
immediate access to
the water by private
docks or piers.
The numbers of
requests for permits
to construct docks,
and the numbers of
docks constructed
and used throughout
the nation's coastal
areas, have
increased in recent
years (e.g. see Fig.
1). A strong
economy, the associated increase in
discretionary spending, hcreasing boat sales,
and limited mooring and public docking facilities
all contribute to the trend. These docks and the
vessels using them impact:
· natural resources and their use,
· aesthetic values, including natural and
development area characteristics, and
· public access and uses of shoreline and
nearshore areas.
Coastal managers and others have indicated
there is a need for better understanding of the
0 900 ]
¢J~800 1
· -- 700 1
'O·600 1
=5001
/
._. 40o 1
. 30o 1
· '~"-- 200 1
[ 1
improved understanding would result in better aquatic
management that ensures that additional docks: (1)
do not harm the environment, (2) provide waterfront
property owners reasonable access to the water if
they choose to have it, and (3) do not adversely
affect public access,
navigation, or other
uses of the aquatic
environment.
The Coastal Zone
Management Act of
1972 (CZMA)
encourages states to
"exercise their full
authority over the lands
and water in the coastal
zone." In this broadly
stated goal, the CZMA
recognizes the need for
each state to develop a coastal management
program tailored to its unique needs and
circumstances. Nearly all coastal states and
territories have responded by developing programs
that include various means of regulating and
managing docks and piers.
Dock authorizations are now the single most
frequently sought permit from coastal managers.
Among a significant segment of the public, there is a
perceived "right" to have a dock. For example, 90%
of coastal South Carolina residents surveyed in 2001
want a dock, 86% felt docks increased their property
year
Figure 1. increase in permits issued for dock construction in South Carolina.
value, and 73%
thought they should be
allowed to build one
(Felts et at. 2001).
Many people consider
private residential
docks a normal and
characteristic part of
the coastal landscape
and often do not
understand why they
must undergo a long
and arduous permit
review process.
Others, however,
consider docks a
threat to public values and the environment, and
question why they are allowed at all. As coastal
areas are developed and the number of permit
requests increases, coastal managers are
looking for a rational, science-based decision-
making tool to guide their regulatory decisions.
As with other coastal activities, the construction
and use of private residential docks can create a
range of impacts~epending on both
geographically site-specific factors and the
perspective of the observer. There is
considerable evidence that docks shade, alter
patterns of water flow, introduce chemicals into
the marine environment, and impact public
access and navigation. The vessels using
docks also affect resources and human uses to
varying degrees. However, scientific
investigations and resulting literature quantifying
the biological effects associated with individual
and cumulative impacts are limited.
Furthermore, the existing literature is not well
known or understood by the general public.
Background to the workshop
State and local governments in Alabama,
Connecticut, Georgia, Massachusetts, New
Hampshire, Rhode Island, and South Carolina
are currently reviewing or revising the manner in
which they manage docks and piers. In
November 2000, a one-day workshop on dock
and pier science and management was held as
part of the Northeast Regional Coastal Zone
Management Program Manager's Meeting.
Southern and Caribbean managers expressed
interest in a similar workshop at their 2001
regional meeting. In response, OCRM hosted a
special session at the Coastal Zone '01 conference in
Ohio on management of docks and piers. This was
followed by a cover story in the fall issue of NOAA's
Coastal Services magazine.
Feedback from these initial efforts indicates that state
managers see a need for credible, relevant, and high
quality scientific analysis of the issue. They have
asked NOAA's National Ocean Service for further
assistance in developing the proposed tools and
expressed a willingness to help with the workshops
and assessments.
The workshop described in this document is an initial
step in this effortian effort to assess the state of
knowledge about the impacts of small docks on both
the natural environment and human uses thereof.
Further efforts may explore various means currently
available to minimize or alleviate the various impacts,
as well as their economic and social costs. Finally,
funding and support will be sought for a similar
working session on the regulatory and non-regulatory
tools available for management of docks.
NOAA's Coastal Services Center (CSC) is presently
conducting an assessment of laws, regulations, and
policies pertaining to dock management for the
southeastern U.S. (the states of North Carolina,
South Carolina, Georgia and Florida). Over time, it is
hoped that this effort will be expanded to include
many of the remaining 29 coastal states and
territories and to compile the information into a
searchable database. Such a system would facilitate
state-to-state interaction and comparisons, allowing
managers to see how similar regions have dealt with
specific permitting issues.
2
THE WORKSHOP
On 22-23 January 2003, NOAA's National Centers for Coastal Ocean Science hosted a workshop at the
University of Massachusetts Boston to review the available scientific knowledge about the impacts of
small, recreational docks. Twenty-two scientists and eight managers representing the Southeast, Gulf
Coast, Mid-Atlantic, Northeast, Great Lakes, and Pacific regions discussed what is known (and not
known) about how docks and associated boating activities individually and collectively impact vegetation,
sediments and sedimentation, contamination, navigation and public trust rights and interests, and
aesthetics/quality of life.
The workshop focused on relatively small, recreational docks associated with residential use. These
generally consist of a pike-supported walkway leading from the shore into the water and often have a float
at the water end of the structure. Floats may be bottom anchored or held in place by piles. The
structures may be used for boat landings, fishing, relaxing, or similar uses.
Workshop Objectives
· Synthesize existing scientific information on
direct, cumulative, and secondary effects of
small docks on the coastal environments
and their users.
· Identify gaps in research results related to
the impacts of small docks.
· Assess susceptibility of regions to the
negative impacts associated with docks.
Desired Outcomes
A summary of existing scientific knowledge
that can help managers guide the
implementation, development, or revision of
federal, state, and local dock regulations.
Identification of key elements needed by
managers to effectively evaluate permit
requests or develop area-wide plans.
Identification of gaps in research on the
environmental, social, and economic
impacts of small docks.
Development of a work plan to formulate
assessment protocols needed to guide
management actions, including a prioritized
listing of research needs.
Workshop Products
The desired outcomes of the workshop were
intended to be reflected in the following specific
products discussed in this document:
· A report summarizing the state of existing
scientific knowledge pertaining to the
impacts from small docks,
· A bibliography of publications pertaining to
the science and management of small
docks, and
· A prioritized list of research needs.
Discussion Topics
Workshop discussions were
address the following topics:
· vegetation,
· contaminants,
· boating impacts,
· navigation, and
· aesthetics.
designed to
These discussions led to a series of
recommendations for consideration by those
involved in residential dock and pier regulation,
construction, and use.
Background Paper
Developing a Science-Based Decision
Support Tool for Small Dock Management:
Status of the Science
Document prepared by:
Steve Bliven,
Biiven and Sternack
49 Plains Field Drive
South Dartmouth, MA 02748
Phone: (508) 997-3826
Fax: (508) 997-3859
E-maih Bliven@attbi.com
Introduction
Purpose of the document:
The following document is intended to provide a general background for participants at the workshop on
"Developing a Science-Based Decision Support Tool for Small Dock Management: Phase h Status of the
Science" to be held on 22-23 January 2003 at the University of Massachusetts Boston, it is not intended
to be a comprehensive survey of the literature related to small docks and their impacts; only as an
introduction to the various topics to be discussed,
Definition of small docks for the purpose of this paper and workshop:
The focus at the workshop will be on small, recreational docks designed for residential use. They
generally consist of a pile-supported walkway leading from the shore into the water and often have a float
at the water end of the structure. Floats may be bottom anchored or held in place by piles. The
structures may be used for boat landings, fishing or similar uses.
Purposes of the Workshop
1. To synthesize existing scientific information on direct, cumulative, and secondary effects of small
docks on the coastal environments and their users,
2. To identify gaps in research results related to the impacts of small docks, and
3. To assess susceptibility of regions to the negative impacts associated with docks.
Desired Outcomes:
· A summary of existing scientific knowledge that can help managers to guide the implementation,
development, or revision of federal, state, and local dock permitting processes to include
identification of key elements needed by managers to effectively evaluate a permit request or in
the development of an ama-wide plan.
· Identification of gaps in research on the environmental, social, and economic impacts of small
docks. Development of a work plan to formulate assessment protocols needed to guide
management actions, including a prioritized listing of research needs.
Workshop Products:
· A report summarizing the state of existing scientific knowledge pertaining to the impacts from
small docks,
· A bibliography of publications pertaining to the science and management of small docks,
· A prioritized listing of research needs, and
· A check-list of known impacts from small docks.
Impacts on Vegetation
Vegetation is critical as a food source, habitat, and protection against erosion--both on the shore or
marsh and submerged below the water line.
Impacts to plant productivity generally occur in one of two ways: · Short-term construction impacts
· Chronic impacts from shading
Construction Impacts
Activities during construction can destroy plants either above the tide line (e.g., Spartina or Distichlis) or
below (e.g., Zostera or Halodule) by pulling them from the substrate or destroying their root system. The
peat beds underlying salt marshes can be compacted through the improper use of heavy equipment.
Although these impacts are seemingly evident, limited research appears to have been done on the long-
term impacts of these activities.
In sea grass beds, the installation of pilings may have immediate impacts as well as cause long-term
changes. Installation through "jetting" with high-pressure hoses typically disturbs a surrounding area--
depopulating grasses there prior to construction. Once areas are depopulated, the presence of pilings
may lessen chances of regrowth. Beal, Schmit, and Williams (1999) suggest that changes in seagrass
communities in the vicinity of pilings may be caused by the modification of currents, sediment deposition,
attraction of bioturbators, and leaching from chemically treated wood. Shafer and Robinson (2001)
tracked the regrowth of Halodule wright# beneath docks in St. Andrew Bay, FL. They noted bare areas
from 35-78 inches in diameter around pilings, even though the docks had been constructed at various
times, suggesting that regrowth is affected by the presence of pilings. The authors found that where piles
were installed using Iow-pressure jetting techniques there was, "little or no sand deposition around the
pilings and the remaining seagrasses around the pilings looked healthy and had good growth around the
piling."
Sanger and Holland (2002) noted a path along each side of one new dock where vegetation had been
almost totally destroyed, presumably during construction. Resurveying the site 15 months later the
researchers found that S. alterniflora had recolonized the area and substantial recovery had occurred.
Chronic Shadino Imoacts
Both marsh grasses and sea grasses have adapted to living in extended periods of sunlight. Their
photosynthetic pathways vary from many terrestrial plants allowing them to be highly productive in their
natural settings. Shading can have significant impacts on the health and productivity of these plants.
Shaefer and Robinson (2001) indicate that light levels of 13-14 percent of mean daily surface irradiance
(SI) are necessary for survival of the seagrass Halodule wrightii. Shaefer (1999) also found that seagrass
densities were 40-47 percent less in areas shaded at levels of 16-19 percent SI. The summary of a
NMFS Technical Memorandum (Kenworthy and Haunert, 1991 ) noted that "the light requirements of
temperate and tropical seagrasses are very similar" requiring "at least 15 to 25 % of the incident liqht just
for maintenance." Research by Koch and Beer (1994) indicate that light levels of 300 to 500 _EmUs-1 are
necessary for Zostera survival in Long Island Sound and Narragansett Bay.
In a field study conducted in Waquoit Bay, Falmouth/Mashpee and Nantucket Harbor, Burdick and Short
(1999) found that the most significant factors affecting shading impacts on eelgrass from boat docks with
plank decking are height of the structure above vegetation, orientation of the dock (north-south versus
east-west) and dock width. The National Marine Fisheries Service suggests that spacing between
decking planks on the order of an inch or two has little effect on shading impacts. (Michael Ludwig,
NMFS, Personal Communication).
Kearney etaL (1983) studied impacts to marsh grasses from walkways/docks. They assessed the
impacts from "all the structures" within Connecticut's major salt marsh regions, collecting data on
vegetation density and height beneath and adjacent to the structures, and the physical dimensions of the
docks (width, height, plank width and spacing between planking--they did not include orientation). They
found that dock height was the only statistically significant variable. They further reported that the
vegetation density of Iow marsh grasses (Spartina alterniflora) was affected less by shading than high
marsh grasses (S. patens and Distichlys spicata). The opposite trend was noted in vegetation height--
possibly due to etiolation. No measures of biomass were taken. Docks less than 30-40 cm (12-16
inches) above the marsh shaded out all vegetation in all of the study sites. A subsequent effect of the
shading was reported to be accelerated soil erosion beneath structures passing over S. alterniflora at the
edge of the marsh.
The NMFS (Colligan and Collins, 1995) assessed dock impacts on vegetation in Connecticut, Rhode
Island, and Massachusetts with the results compiled in a "Pre-publication copy--not for distribution". This
study cast some doubt on the methodology and statistical analyses of Kearney et al (1983) but, because
it has not been released in a final form, it is difficult to evaluate the results.
Maguire (1990) measured the effects of shading by open pile structures on S. alterniflora density in a
fringe marsh in the York River Estuary (VA). The docks ranged in length between 15-20 m (~50-65 feet)
and .6 m-2.4 m (2-8 feet) wide. A computer program was developed to calculate the total number of
hours of shading produced by each structure based on height, width and orientation of the structure.
Based on the information from this program, correlation coefficients between shade duration and
vegetation density were calculated These displayed a wide range (+ 0.03 to -0.93 with 60% falling
between -0.70 and -0.93. The author attributes the wide range to a threshold phenomenon and that "a
more refined measurement that can account for temporal differences in light intensities reaching
vegetation as well as the response of the plant to the light that it receives may result in greater predictive
powers." The computer program developed as part of this project appears to hold promise as a predictive
tool. Unfortunately, no electronic copies of the program remain (the text of the program is available) and
it is written in Pascal. To be effective the program would have to be rewritten in a contemporary, and
more user-friendly format.
Sanger and Holland (2002) assessed impacts from 32 docks in the Charleston, SC area on S. alterniflora.
The structures represented a range of lengths, orientations, and ages. The researchers noted that the
plants under the docks were often taller than those adjacent to the dock. They suggested that this might
be affected by fecal material from birds resting on the structures. Reviewing the data of Maguire (1990)
the authors noted that the orientation of the docks did not seem to affect density.
Sanger and Holland (2002) then compared the area of marsh affected by docks to the total area within
creek systems and across the state. Using the numbers of docks present in 1999, their findings resulted
in an estimate of reduction in plant densities of between 0.03-0.72% of the total amount of $. alterniflora
w~thin local creek settings. Projected to total possible build-out of similarly sized docks in the creeks,
these figures increase to 0.18-5.45% decrease in marsh grass. Expanded to the area of S. alterniflora in
the eight coastal counties in the state at projected year 2010 dock numbers at the maximum size
presently allowable under regulation, an estimated density reduction of between 0.03-1.98% could be
attributed to dock impacts.
As noted above, Maguire (1990) produced a program to predict the amount of shading over a season that
would result from a dock of any given size. Burdick and Short (1998) prepared estimates of impacts to
Zostera from docks of specific height, width, and orientation. They did not attempt to develop a process
to assess the impacts from other sizes and orientation.
Questions for consideration:
1. Are the light level thresholds for maintenance or additional growth known for marsh grasses to a level
of certainty to make defensible decisions?
2. Is it known which parameters of the dock structure are critical to predict impacts to vegetation--either
marsh grasses or seagrasses?
3. Is there a tool available, or could one be developed to predict the impacts of specific structures, given
the design parameters?
4. The existing studies of marsh grasses looked at vegetation density and/or height. No measures of
biomass were recorded. To provide a prediction of energy source to the food web (as opposed to
appropriate habitat or erosion control), is this an important factor? If so has any research been done
on this topic?
Bibliography:
Baal, J.L., B.S. Schmit, and S.L. Williams. 1999 "The effects of dock height and alternative construction
materials on light irradiance (PAR) and seagrass Halodule wrightii and Syringodium filiforme cover."
Florida Department of Environmental Protection, Office of Coastal and Aquatic Managed Areas (CAMA).
CAMA notes.
Burdick, D.M. and F.T. Short. 1998. "Dock Design with the Environment in Mind: Minimizing Dock
Impacts to Eelgrass Habitats." An interactive CD ROM published by the University of New Hampshire,
Durham, NH.
Burdick, D.M. and F.T. Short. 1999. "The Effects of Boat Docks on Eelgrass Beds in Coastal Waters of
Massachusetts." Environmental Management, 23 (2): 231-240.
Colligan, Mary and Cori Collins. 1995. "The Effect of Open-Pile Structures on Salt Marsh Vegetation".
NOANNMFS Habitat and Protected Resources Division. Pre-publication copy-not for distribution. 44p.
McGuire, H.L. 1990. "The Effects of Shading by Open-pile Structures on the Density of Spartina
alterniflora." Unpublished Master's Thesis from the Virginia Institute of Marine Science.
Kearney, V., Y. Segal and M.W. Lefor. 1983. "The Effects of Docks on Salt Marsh Vegetation". The
Connecticut State Department of Environmental Protection, Water Resources Unit, Hartford, CT. 06106.
22p.
Kenworthy, Judson W. and Daniel E. Hauners (eds.) 1991. "The Light Requirements of Seagrasses;
proceedings of a workshop to examine the capability of water quality criteria, standards and monitoring
programs to protect seagrasses." NOAA Technical Memorandum NMFS-SEFC-287. NMFS Beaufort
Laboratory, Beaufort, NC 28516-9722.
Koch, E.W. and S. Beer. 1996. "Tides, light and the Distribution of Zostera marina in Long Island Sound,
USA." Aquatic Biology. 53: 97-107.
Sanger, DM and AF Holland. 2002. "Evaluation of the Impacts of Dock Structures on South Carolina
Estuarine Environments." SC Department of Natural Resources, Marine Resources Division Technical
Report Number 99. Charleston, SC.
Shaefer, D. 1999. "The Effects of Dock Shading on the Seagrass Halodule wrightii in Perdido Bay,
Alabama." Estuaries 22 (4): 936-943.
Shaefer, D. and J. Lundin. 1999. "Design and Construction of Docks to Minimize Seagrass Impacts."
US Army Corps of Engineers WRP Technical Note VN-RS-3.1 June 1999. Available at
www.wes.army.mil/el/wrtc/wrp/tnotes/vnrs3-1 .pdf
Shaefer, D and J. Robinson. 2001. "An evaluation of the use of grid platforms to minimize shading
impacts to seagrasses." WRAP Technical Notes Collection (ERDC TN-WRAP-01-02. US Army
Engineer Research and Development Center, Vicksburg, MS. Available at www.wes.armv.mil/el/wrao.
Impacts from Contaminants
Small docks and piers in coastal waters, either pile supported or floating, are not apt to have a
measurable effect on levels of dissolved oxygen or temperature. Such structures are generally too small
and, except in the most closed of lagoons or canals, the movement of coastal waters is sufficient to avoid
such impacts.
The most common contaminant-related concern related to docks is leaching from preservatives applied to
pilings or floats in locations that come into regular contact with wafer.
Oil based preservatives containing creosote (CRT) or pentachlorophenol (PCP), applied to the surface of
wood materials, leach readily and have demonstrated toxic effects. Most states have banned their use in
aquatic settings.
Wood pressure-treated with a chromated copper arsenate (CCA) is the most commonly used material for
pilings and decking for small docks. The form of CCA most often seen is comprised of 47.5% hexavalent
chromic oxide, 18.5% curpic oxide, and 34% arsenic pentoxide. Research has shown that in fact some
leaching does occur in saline waters (Weis et al., 1991,1992). There has been extensive study of the
toxicity of these compounds in the marine environment that suggests that the degree of toxicity depends
on the chemical form as it reaches the target organism. The forms will change over time and in response
to sediment types, amounts of organic material present, oxygen levels and water movement (Luoma and
Carter, 1991).
Laboratory studies by Weis et aL (1991, 1992) have shown that feachate from CCA-treated wood can be
toxic to estuarine species. Leaching decreases by about 50% daily once the wood is immersed in
seawater. Approximately 99% of the leaching occurs within the first 90 days (Cooper, 1990, Brooks
1990; in Sanger and Holland, 2002).
Elevated concentrations of metals from CCA-treated woods can be found in organisms living on treated
pilings and in the areas near to the pilings (Wendt eta/., 1996; Weis and Weis, 1996) Field studies by
Weis et al. (1998) found elevated concentrations of metals in fine sediments adjacent (within 1 meter) of
bulkheads constructed of CCA-treated material. At a limited number of sites elevated concentrations
could be seen at greater distances. In an unpublished "grey literature" study prepared for the New Jersey
Department of Environmental Protection however, Weis and Weis (1998) did not observe "any evidence
that CCA dock pilings are a source of metal contaminants in the Navesink/Shrewsbury Rivers." Pedrick
Weis reported similar findings at a Massachusetts Coastal Zone Management workshop in 2000. Sanger
and Holland (2002) report that, "it is unlikely that the bioaccumulation of dock lechates by marine biota is
having or is likely to have an impact on living resources in South Carolina estuaries and tidal creeks."
Reasons given are that the leaching generally occurs only when the dock is new, that the size of the area
around the dock that might be affected is small, and high rates of tidal flushing will dilute and flush any
accumulations in the water column.
Questions to consider:
1. Are there demonstrated impacts from preservatives used for the protection of wooden portions of
small docks? If so, what are the impacts?
2. Are them other contaminants of concern can be linked to small docks (as opposed to impacts
from associated boating which will be discussed later)?
Bibliography:
Brooks, K.M. 1996. "Evaluating the environmental risks associated with the use of chromated copper
arsenate-treated wood products in aquatic environments." Estuaries 19(2A):296-305.
Cooper, P.A. 1990. "Leaching of CCA from Treated Wood." Proc. Canadian Wood Preservation
Association I1: 144-169.
9
Luoma, S.N. and Carter, J.L. 1991. "Effects of trace metals on aquatic benthos.", in Newman, M.C. and
Mclntosh, A.W., Eds., "Metal Ecotoxicology: Concepts and Applications", Chelsea, MI., Lewis Publishers,
p. 261-300.
Sanger, D.M. and A.F. Holland. 2002. "Evaluation of the Impacts of Dock Structures on South Carolina
Estuarine Environments." SC Department of Natural Resources, Marine Resources Division Technical
Report Number 99. Charleston, SC.
Weis, P., J.S. Weis, and L.M. Coohill. 1991. "Toxicity to Estuarine Organisms of Leachates from
Chromated Copper Arsenate Treated Wood." Archives of. Environmental Contamination and Toxicology.
20: 118-124.
Weis, P., J.S. Weis, A. Greenberg, and T.J. Nosker. 1992 "Toxicity of Construction Materials in the
Marine Environment: A Comparison of Chromated-Copper-arsenate-Treated Wood and Recycled
Plastic." Archives of Environmental Contamination and Toxicology. 22: 99-106.
Weis, J.S. and P. Weis. 1996. "The effects of using wood treated with chromated copper arsenate in
shallow water environments: a review." Estuaries 19:306-310.
Weis, J.S. and P. Weis. 1998. "Effects of CCA Wood Docks and Resulting Boats on Bioaccumulation of
Contaminants in Shellfish Resources: Final Report to DEP." A report to the NJ DEP.
Wendt, P.H., R.F. Van Dolah, M.Y. Bobo, T.D. Mathews, and M.V. Levisen. 1996. "Wood Preservative
Leachates from Docks in an Estuarine Environment." Archives of Environmental Contamination and
Toxicology, 31:71-79.
Boating Impacts
Most small docks are associated with boat traffic. Being situated at the interface between land and water,
at least a portion of each dock is in the intertidal zone and extends through shallow areas. In many cases
this leads to potential environmental impacts. In 1994, a workshop on the impacts of boating was held at
the Woods Hole Oceanographic Institution. The results are summarized in Crawford etaL (1998). A
number of potential boating-related impacts were discussed. While noting that there were adverse
impacts, the presentations revealed that there were limited quantitative data available that could be used
as the basis for management decisions--although it was agreed that sufficient data exist to "substantiate
the inference that recreational ... motor boat traffic is far from a benign influence on aquatic and marine
environments." No differentiation was made between general boating activities and that taking place in
the vicinity of docks.
A second symposium on the topic, "Impacts of Small Motorized Watercraft on Shallow Aquatic Systems"
was held in 2000 at Rutgers. The results of this symposium were published in Kennish (2002).
Both workshops identified several issues of concern regarding boating activity including: · Impacts to submerged aquatic vegetation,
· Contamination from fuel discharges,
· Erosion on shorelines, and
· Resuspension of bottom sediments and turbidity.
Imoacts to submeraed bottom veoetation.
Boat propellers can directly damage submerged aquatic vegetation in shallow waters (Thayer et aL, 1975;
Kruer, 1998; Burdick and Short, 1999); impacts that may take years to heal. Thallasia sp., for example,
10
can take four to six years to recolonize a prop scar (Kruer, 1998). Damage to the plants and their
rhizome system often leads to both reduced habitat and destabilized sediments.
Contamination from fuel dischames:
Outboard motors associated with boating have long been associated with contamination of waterways.
Milliken and Lee (1990) provide a good summary of the early literature. Two-cycle engines release up to
20% unburned fuel along with exhaust gases (Moore, 1998). Moore (1998) compared the PAH output
from a two-cycle outboard engine with that from a four-cycle engine. Discharge from the two-cycle
contained five times as much PAH as from the four-cycle. Most of this difference was due to a reduction
in discharge of 2- and 3-ring compounds--those that are generally considered acutely toxic--in the four-
cycle. However, he found little difference between the levels of discharge of 4- and 5-ring compounds--
those generally related to chronic toxicity. AIbers (2002) notes that PAH concentrations in the water
column are "usually several orders of magnitude below levels that are acutely toxic", but those in
sediments may be much higher.
PAHs related to boating activities probably accumulate in bottom sediments (Sanger et al. 1999) where
they may be stirred up by boat traffic (Albers, 2002). However, Sanger and Holland (2002) were not able
to distinguish PAHs from dock-related activities from other anthropogenic sources.
Erosion on shorelines:
Many studies have related boat wakes with shore erosion (e.g., Zabawa et al. 1980; Camfield et al. 1980;
Hagerty etal., 1981). Most of these relate to boats moving at or near hull speed through waterways.
There was little found in the literature that pertained specifically to boats maneuvering near docks or
landing areas.
Resuseension of bottom sediments and turbidity:
Running a motorized boat through shallow waters produces two distinct types of wake: 1) the surface bow
wake that can lead to erosion of the shoreline as discussed above and 2) a pressure wave formed
beneath the boat hull that can impact the bottom (Crawford, 1998). Crawford (1998) describes two
components that make up the pressure wave; a Iow frequency wave caused by the motion of the hull
through the water and higher frequency waves produced by the action of the propeller. The pressure
wave does not fan out as does the surface wake and consequently has localized impacts. It is also a
greater in slow-moving hulls, modern planning hulls have a far lesser impact on bottem sediments
(Crawford, 1998; Hartge, 1998). Hartge (1998) also compared prop-driven boats with those that were
water-jet propelled and noted no major differences between the amount of resuspension of sediments; he
did note that slow-moving, heavy laden boats caused more turbidity than lighter, faster-moving boats.
Passage of slow-moving boats in shallow waters over fine sediments will produce turbidity, but Crawford
(1998) found in Waquoit Bay, MA that this was a short-term phenomenon. Ambient light sufficient for
maintenance of eelgrass was restored within 10 minutes of the passage of a vessel. The suspension of
bottom sediments also appears to be related to the presence of the odor of hydrogen sulfide.
Investigating impacts of bow waves from personal watercraft, Anderson (2000) found a wide range of
settling times of resuspended sediments. Depending on the nature of the sediments, settling times
ranged from 7 seconds to approximately 10 minutes.
Boats operating in the vicinity of docks are generally moving slowly so such impacts may be particularly
significant to these areas, although this does not appear to be demonstrated in the literature reviewed for
this paper.
"Prop dredging" is a specialized form of sediment suspension in which the propeller or water jets of a
vessel are used to move sediments out of a particular area; either as a purposeful action or as a by-
product of boating use. This typically occurs where docks are of insufficient length to reach water depths
appropriate to vessels being docked (Ziencina, 2002, pers. com.). This may lead to the loss of
seagrasses in the vicinity of a dock (Burdick and Short, 1999) either through physical disruption of the
vegetation or though burial by sediments.
11
Questions to consider:
1. What boating impacts have been sufficiently defined that they can form the basis of defensible
management decisions?
2. What other impacts should be evaluated?
3. Are the impacts of boating as related to docks significantly different from those of general boating? If
so, what are the differences and what is known about them?
Bibliography:
Albers, P.H., 2002. "Sources, fate, and effects of PAHs in shalrow water environments: a review with
special reference to small watercraft." In "Impacts of Motorized Watercraft on Shallow Estuarine and
Coastal Marine Environments." Journal of Coastal Research Special Issue 37. Michael Kennish, ed.
Anderson, Franz. 2000. "Effect of Wave-wash from Personal Watercraft on Salt Marshes". A final report
submitted to the NOAA/UNH Cooperative institute for Coastal and Estuarine Environmental Technology
(ClCEET).
Burdick, D. M. and F. T. Short. 1999. "The Effects of Boat Docks on Eelgrass Beds in Coastal Waters of
Massachusetts." Environmental Management, 23{2): 231-240.
Camfield, F. E., R.E.L. Ray and J.W. Eckert. 1980. "The Possible Impact of Vessel Wakes on Bank
Erosion." Prepared by USACOE, Fort Belvoir, Virginia, for US Department of Transportation and US
Coast Guard, Washington, D.C. Report No. USCG-W-I-80 114 pp. NTIS No. ADA-083-896.
Crawford, R. 1998. "Measuring Boating Effects of Turbidity in a Shallow Coastal Lagoon". In "The
Environmental Impacts of Boating: Proceedings of a workshop held at Woods Hole Oceanographic
Insititution, Woods Hole, MA December 7-9 1994." Technical Report WHOI-98-03. R. Crawford, N.
Stolpe and M.Moore. Eds.
Crawford, R. N.Stolpe and M. Moore, Eds. 1998. "The Environmental Impacts of Boating: Proceedings
of a workshop held at Woods Hole Oceanographic Insititution, Woods Hole, MA December 7-9 1994."
Technical Report WHO1-98-03
Hagerty, D. J., M.F. Spoor and C.R. UIIrich. 1981. "Bank Failure and Erosion on the Ohio River."
Engineering Geology, 17:141-158.
Kennish, Michael J., (Editor). 2002. "Impacts of Motorized Watercraft on Shallow Estuarine and Coastal
Marine Environments." Journal of Coastal Research Special Issue 37.
Kruer, Curtis. 1998. "Boating Impacts On Seagrass Habitats in Florida." In "The Environmental Impacts
of Boating: Proceedings of a workshop held at Woods Hole Oceanographic Insititution, Woods Hole, MA
December 7-9 1994." Technical Report WHO1-98-03. R. Crawford, N. Stoipe and M.Moore. Eds.
Hartge, P. 1998. "Boating Induced Turbidity." In "The Environmental Impacts of Boating: Proceedings of
a workshop held at Woods Hole Oceanographic Insititution, Woods Hole, MA December 7-9 1994."
Technical Report WHO1-98-03. R. Crawford, N. Stolpe and M.Moore. Eds.
Milliken, A. S., and V. Lee. 1990. Pollution impacts from recreational boating: A bibliography and
summary review. Rhode Island Sea Grant. P 1134. RIU-G-90-002. 26 pp.
Moore, Michael. 1998. "Aromatic Hydrocarbons: Two-Cycle vs. Four-cycle." In "The Environmental
Impacts of Boating: Proceedings of a workshop held at Woods Hole Oceanographic Insititution, Woods
12
Hole, MA December 7-9 1994." Technical Report WHOI-98-03. R. Crawford, N. Stolpe and M. Moore.
Eds.
Sanger, D.M., A.F. Holland and G.I. Scott. 1999. "Tidal creek and salt marsh sediments in South
Carolina Coastal Estuaries. L Distribution of trace metals." Archives of Environmental Contamination
and Toxicology 37:936-943.
Sanger, DM and AF Holland. 2002. "Evaluation of the Impacts of Dock Structures on South Carolina
Estuarine Environments." SC Department of Naturat Resources, Marine Resources Division Technical
Report Number 99. Charleston, SC.
Thayer, G.W., D.A. Wolff and R. B. Williams. 1975. "The Impact of Man on Seagrass." American
Scientist 63:288-296.
Zabawa, C., C. Ostrom, R. J. Byrne, J. D. Boon Ill, R. Waller, and D. Blades. 1980. Final report on the
role of boat wakes in shore erosion in Anne Arundel County, Maryland. Tidewater Administration,
Maryland Dept. of Natural Resources. 12/1/80. 238 pp
Ziencina, Mitchell. 2002. Personal Communication. Massachusetts Department of Environmental
Protection, Lakeville, MA.
Impacts on Sediments and Sedimentation
It has been suggested that pile-supported docks may cause changes to sediments and habitats in the
vicinity of the structure. This may occur through erosion, increased sedimentation, or resuspension and
movement of specific particulate sizes or types. Three principal impacts from docks have been discussed
in the literature or in review of proposed construction.
· Altering currents in the vicinity of the dock due to pilings disrupting flow or inducing scour in the
immediate vicinity of the piling,
· Disrupting sediments during piling installation,
· Suspension of sediments as floats or boats attached to docks touch or approach bottom at Iow
tides and lift sediments as they rise with the tide ("pumping").
Structures placed in moving water have the capability to disrupt the water's flow. Piles may cause
increased flow rates immediately around the structure. These modifications in the flow of water may
produce scour and erosion or increased deposition of sediments depending on the conditions and
structure. Either of these may affect shellfish or wildlife habitats.
There appears to be very limited research results available on the impacts on sedimentation from small
pile supported structures. What research has been reported was done in open ocean settings, not in
embayments, and most focused on the morphological changes to adjacent shorelines and bottom
topography--no information was located on the nature of sediment type change, if any, over time in the
vicinity of pile-supported piers.
Noble (1978) assessed the impacts of 20 piers--all situated within the Southern California Bight. These
piers ranged from 625-2,500 feet in length and 15-300 feet in width--far larger than the small
recreational facilities under consideration here. All of the piers studied had pile spacing greater that 4
times the diameter of the piles. Noble found that these piers "had a negligible effect" on sedimentation
and erosion of adjacent shorelines. He notes that his results support prior findings of Johnson (1973) and
Evert and DeWall (1975).
13
Miller et al., (1983), researching the impacts of a 1,840 foot long, 20 foot wide pier near Duck, NC on the
Atlantic coast found that the pier produced a permanent trough under the pier reaching a maximum depth
of 9.9 feet. Scour around individual pilings was noted to be on the order of 3.3 feet in depth. The pilings
in this case are 30 and 36 inches in diameter spaced 15 feet on center across the pier and 40 feet on
center along its length.
In an engineering study related to Lagoon Pond on Martha's Vineyard, MA (Poole, 1987) suggests that,
"At a wind angle of 90-o to a 50-foot pier with 5 pilings on each side [diameter of pilings not noted~SB.] can
[sic] produce eddy currents and flow friction 2 times the diameter of the pilings--minimally. This
means...a 30 percent reduction in flow. The area or parallel shoreline affected by the flow reduction
would be a factor of 2 to 3 times the pier length. Properties within 100 feet to 150 feet of a 50-foot pier
could be subjected to wrack algae accumulation, sand deposition and shellfish population changes." This
evaluation cites no research results and is based on predictive engineering calculations.
Anecdotal evidence suggests that the method of piling installation has varying impacts on sediments in
the vicinity of a dock (Ziencina, 2002 pers. com.) Jetting of pilings tends to cause greater disruption than
driving. Jetting suspends sediments and disrupts vegetation producing bare areas around pilings that
appear to be subject to scour. Shaefer (2001) found that using a Iow pressure pump to produce a starter
hole and subsequent insertion of a sharpened pile with a drop hammer in a sandy area "reduces the
physical removal and disturbance" of seagrasses in the area of the piling and results in little to no sand
deposition around the pilings.
Observational evidence indicates that changes in sediments occur when floats settle on the bottom at Iow
tide. As the floats rise they create a suction bring with it sediments. As wave action lifts and lowers the
float, sediment is "pumped" into resuspension. Additionally wave refraction in a downward direction may
also resuspend some sediments (Ludwig, 2003, pets. com.).
Questions for consideration:
1. What permanent impacts in sediment topography and type are produced by individual or
collections of small, recreational, pile-supported docks oither on the open coast or in
backwaters?
2. What are the impacts of various means of pile insertion in different settings?
3. What are the levels of impact from "pumping" due to floats settling on or near the bottom at Iow
tides?
Bibliography:
Evert, C.H., and A.E. DeWall. 1975. "Coastal Sand Level Changes in North Carolina". Draft Report,
Coastal Engineering Research Center, US Army Corps of Engineers.
Johnson, J.W. 1973. Proposal preparation for Department of Navigation and Ocean Development.
Unpublished information.
Ludwig, Michael. 2003. National Marine Fisheries Service, Milford (CT) Laboratory.
Miller, H.C., W.A. Birekmeir, and A.E. DeWall. 1983. "Effects of CERC Research Pier on Nearshore
Processes." US Army Coastal Engineering Research Center. Reprint 83-13.
14
Noble, Ronald. 1978. "Coastal Structures' Effects on Shorelines." In Proceedings of the Sixteenth
Coastal Engineering Conference, v. II1. American Society of Civil Engineers. New York, NY.
Poole, Bruce M. 1987. "Diagnostic/Feasibility Study for Lagoon Pond Oak Bluffs, Tisbury, MA" SP
Engineering, Inc. Salem MA
Shaefer, D and J. Robinson. 2001. "Evaluation of the use of grid platforms to minimize shading impacts
to seagrasses." WRAP Technical Notes Collection (ERDC TN-WRAP-01-02. U.S. Army Engineer
Research and Development Center, Vicksburg, MS. Available at www.wes.axmy.mii/el/wrap.
Ziencina, Mitchell. 2002. Personal Communication. Massachusetts Department of Environmental
Protection, Lakeville, MA.
Aesthetics/Quality of Life Impacts
From a manager's perspective, oftentimes the publicly-held concerns related to small docks are not really
related to the environment. They may be aesthetic in nature, a sense of over~levelopment of the shore,
or simply change. It is not uncommon for managers to hear very vocal outcries from one segment of the
population while the rest remains quiet--the manager generally has no idea whether this silence means
acquiescence or simply no opinion.
In an attempt to get a better sense of public sentiment regarding docks in South Carolina, Felts et aL
conducted surveys of the opinions of residents of coastal counties in the state (2001) and of dock owners
(2002). Some of their major findings include:
· 75% of the residents of coastal counties feel that property owners should be able to construct a
dock.
· 66% of the dock owners feel that docks should be regulated but only 50% of the residents feel the
same way. The authors offer two possible interpretations for the stronger acceptance of
regulation by dock owners: 1) they have their dock and would like future construction restricted or
2) they better understand the need to manage docks as they are closer to the issue.
· 75°/° of the dock owners feel that the length of docks should be restricted; nearly 80% feel that
the size should be restricted. In contrast, only 50% of the general public feels length should be
restricted.
· Approximately 20% of both the dock owners and the general public felt that docks are harmful to
the aquatic environment.
· 20% of the owners and 25% of the general public felt that docks detracted from the view of the
waterbody and shoreline.
· Approximately 75% of both dock owners and the general public feel that there are not too many
docks.
It is not clear whether these findings are transferable to other settings along the coast--other states or
regions within those states.
15
The aesthetic appeal of docks is an individual assessment. However, techniques have evolved that
appear to provide a reproducible or predictive assessment of the aesthetic values of an area and how
those might change with development. As seen in Felts etal. (2001,2002), a survey will provide some
sense as to the feelings of the public regarding docks, although these feelings may change when applied
to specific sites.
An assessment method applied in Blakely Harbor, WA to develop a build-out of all potential docks in the
harbor built to full length and size by existing regulation. Calculations were then made for several public
viewing areas around the harbor of how much of the viewshed would be impinged on by dock
construction. The "reductions" ranged from 27% to 78%. No suggestion was provided as to public
acceptance of these values.
Smardon (1988, 1986) and Galliano et aL (2000) have utilized assessment techniques to measure scenic
quality based on public aesthetic values. These have been utilized in planning and land use
management activities on public lands but are only beginning to be investigated for use as a regulatory
tool for docks. The State of Maine is in the process of preparing regulatory standards for dock aesthetics
(Gates, 2002, pers. com.).
Questions for consideration:
1. How significant are aesthetic/quality of life issues in regards to small docks?
2. Are there reproducible techniques to measure the aesthetic issues relating to docks and piers?
3. Are there "quality of life" or social issues other than those relating to the environment or aesthetics
that are measurable?
Bibliography:
Best, Peter N. 2002. "Blakely Harbor Cumulative Impact Assessment." City of Bainbridge Island (WA),
Department of Planning and Community Development.
Felts, Arthur A., M. Freeman, M. Radic, and K. Walsh 2001. "Survey of Coastal Residents' Perceptions
of Docks". Joseph P. Riley Institute for Urban Affairs and Policy Studies, College of Charleston, SC.
Prepared for the South Carolina Department of HEC.
Felts, Arthur A, and Marijana Radic. 2002. "Survey of Coastal Dock Owners' Perceptions of Docks".
Joseph P. Riley Institute for Urban Affairs and Policy Studies, College of Charleston, SC. Prepared for
the South Carolina Department of HEC.
Galliano, Steven J. and Gary M. Loeffler. 2000. "Scenery assessment: scenic beauty at the ecoregion
scale." General Technical Report PNW-GTR-472. US Dept. Agriculture, Forest Service, Pacific
Northwest Research Station.
Gates, Judy, Maine Department of Environmental Protection, Division of Land Use Regulation.
Smardon, R.C., J. F. Palmer and J. P. Felleman. 1986. "Foundations for Visual Project Analysis." John
Wiley and Sons, New York, NY
Smardon, R. C. 1988. "Visual impact assessment for island and coastal environments." Impact
Assessment Bulletin 6(1): 5-24.
16
WORKSHOP AGENDA
22 January:
Opening
· Welcome to the group
· Logistical information/housekeeping information
· Charge to the group--Workshop purposes, desired outcomes, agenda
· Connection between this Workshop and future activities
· Introductions of the participants
The Management Context: Introduction to management issues and needs related to smafl dock
management.
· Susan Snow-Cotter, Massachusetts Office of Coastal Zone Management
Panel Presentations and Discussion
Panels consisted of 15-minute individual presentation, a 5-minute question period after each
speaker, and a 20-minute discussion period following panel presentations.
Panel I: Impacts to vegetation from docks
· Dave Burdick, University of New Hampshire
· Ron Thom, Battelle Marine Sciences Laboratory, Sequim WA
· Deborah Shaefer, US ACOE, Waterways Experimental Station, Vicksburgh, MO
· Mike Ludwig, National Marine Fisheries Service, Milford (CT) Laboratory
Panel I1: Impacts from contaminants related to docks
· Pedrick Weiss, New Jersey Medical School
· Denise Sanger, South Carolina Department of Natural Resources
Panel II1: Impacts from associated boating use
· Rick Crawford, Nautilus Environmental Services, Cape Cod, MA
· Steve Ressler, New York Coastal Management Program
Panel IV: Impacts to navigation and riparian uses
· Dave Killoy, New England Division, US Army Corps of Engineers
Summary discussions from first day
23 January:
Panel V: Impacts to Aesthetics and Quality of Life Issues
· Judy Gates, Maine Department of Environmental Protection
· Richard Smardon, SUNY Syracuse
· Richard Chinnis, South Carolina Office of Coastal Resource Management
Managers respond to scientific status, develop research needs and recommendations based on
existing information
Wrap-up: General discussion of future steps
Managers meet to begin planning future steps
17
MANAGEMENT CONTEXT
Susan Snow-Cotter
Massachusetts Coastal Zone Management Office
A review of the volume and status of dock and
pier applications on Cape Cod, one segment of
the Massachusetts coastal zone, showed that
over the past five years there have been
approximately 250 applications for dock
construction. Of these 195 were approved and
63 denied. Of those 63 denials, only six
(approximately 10%) were upheld in the courts
(Fig. 2). This suggests that managers need
better means to review dock proposals and
make defensible decisions. For example, most
of the denials were aimed at protecting shellfish
and habitat but when challenged it was difficult
to clearly demonstrate the impacts to these
resources.
Both scientists and managers recognize that
there are significant regional differences in
resources, dock design, and impacts. However,
state and local regulators need a science-based
framework and guidance in order to make
reasonable decisions.
Docks affect coastal conditions and uses
including:
· Navigation--docks can both promote
and hinder navigation in waterways,
· Aesthetics---cumulative impacts are the
significant issue,
· Public access to and along waterways--
docks can promote public access to the
waterway but may also impede lateral
access,
Docks may impede public access along the
coast (Photo credit: S. Snow-Cotter).
Figure 2. About 78% of applications for docks in
Cape Cod were approved on the first review. After
the appeal process, less than 1% of applications
were denied.
· Shellfish habitat,
· Water quality--impacts result from materials
used in construction and scouring or
resuspension of sediments around pilings
and floats, and
· Vegetative cover--docks shade vegetation in
salt marshes and below the water.
In addition to their physical structure, the boating
associated with docks results in indirect or secondary
effects such as prop dredging/scouring and the
release of contaminants like oil, gas, detergents, anti-
fouling paints, etc.
The types of information needed by managers to
make defensible decisions include:
· A science-based understanding of the
ecological impacts from construction and use
over time,
· Techniques for practical approaches at a
local and state level that will allow for a
comprehensive harbor by harbor planning
and regulatory approach,
· A better understanding of the benefits of Best
Management Practices,
· Guidance on incorporating science into
statutes, ordinances, regulations, and rules,
and
· Techniques to factor cumulative impacts into
the planning and permitting process.
18
Question & Answer Period
Have you seen increased vessel size leading to proposals for larger family docks in
Massachusetts?
Absolutely. Not only are the proposed docks larger, larger boats need larger "buffer zones" to
navigate. It is important to ensure that the regulatory framework includes usage of the docks, not
just construction.
In Massachusetts, the environmental reviews are done at the local level with appeal to the state.
Is that because there are significant local concerns? This not the case in Georgia where there is
little concern at the local level and the feeling there is that there is no need for legislation. Must
local governments apply for ability to regulate at that level?
The Massachusetts Wetlands Protection Act (a state law with regulations issued by the state)
requires local municipalities to regulate impacts to wetland resources, including shellfish habitat,
salt marshes, land under the ocean, etc. Public trust standards are regulated at the state level,
but there is a provision for local boards to manage that aspect as well, although few have availed
themselves of that opportunity. Delaware has developed BMPs for docks and piers at the state
level that will be incorporated into state land regulations. We tapped into legislators interested in
the waterfront to help move this forward.
Were the issues involved in approving or denying pier permits mostly social/aesthetic or
ecological?
Both. In many instances there are no defensible standards and consequently the local decisions
may be unpredictable. This again shows the need for science-based guidance.
19
IMPACTS TO VEGETATION FROM DOCKS
Introduction
Submerged aquatic vegetation (SAV) and marsh grasses provide critical habitat, filter nutrients and
sediments, provide nursery habitat for fish and shellfish, stabilize bottom sediments, and form the basis of
the marine food web. Impacts to plant productivity generally occur in two ways: short-term construction
impacts and chronic impacts from shading. Irradiance under docks falls well below the requirements for
minimum maintenance (~3 M d-1) and full growth (= 5 M d'1) (Fig. 3). This results in reduced shoot
density, biomass, growth, and increased height
(probably due to etiolation), increased erosion,
undercutting of vegetation (Burdick and Short
1999). Susceptibility varies by species--Spartina
patens was most robust followed by Distichlis
spicata, then S. alterniflora (Kearney et al. 1983).
The significance of these shading impacts to the
coastal ecosystem as a whole varies by region.
in South Carolina, docks existing in 1999
reduced S. alterniflora cover by 0.03-0.72%.
Projected to a total possible build-out of similarly
sized docks in these creeks, the decrease in
marsh grass density was 0.18-5.45% (Sanger
and Holland 2002). In New England and
Florida, where coastal vegetation is already
severely impacted and reduced, the existing
and potential loss of vegetation associated
with dock shading is greater.
1200
Dock
1000'
800-
w 600.
Z
~ 400'
~ 200'
0
-36-32-28-24-20-16-12 -8 ~ 0 4 8 12 16 20 24 28 32 36
South No~h
DISTANCE (m)
Figure 3. Irradiance under docks is below the requirements for minimum
maintenance (~3 M d-l) and full growth (= 5 M d-l) (From Nightengale
and Simenstad 2001, Ron Thom, pers. comm.)
Dave Burdick
Jackson Laboratory, University of New Hampshire
In conjunction with Fred Short, Dave Burdick
investigated the impacts of docks on eelgrass
(Zostera marina) in Waquoit Bay,
Falmouth/Mashpee, Massachusetts. They
found that the presence of small docks leads to
fragmentation of eelgrass beds--primarily through
shading of the grasses (Fig. 4). They next examined
physical and biological parameters to better
understand how docks impact eelgrass and,
ultimately, how to minimize those impacts.
Specifically,Burdick and Short quantified dock
characteristics (length, width, height, construction
materials, age, orientation, and design), light
reduction under the dock, and eelgrass
characteristics (shoot density, canopy height, and
bed quality under the docks). They observed which
docks allowed the best eelgrass survival, and which
dock characteristics are the most important predictors
of eelgrass bed quality. This allowed them to
develop dock specifications designed to allow
eelgrass to thrive under docks.
Figure 4. The obvious impact of docks is
through shading of vegetation (Photo credit: D.
Burdick).
20
Under
b
b
AdJ~t
Figure 5. Eelgrass density (A) and canopy structure (B) were significantly lower under and near docks than at
reference sites (From Burdick and Short 1999).
Burdick and Short found lower eelgrass density
and greater shoot height under docks (Fig. 5).
Canopy structure (cm shoots/m2) was lower
under the docks. They concluded that light
levels of 15% of surface irradiance are the
minimum necessary for Zosters. Levels of
approximately 50-60% are necessary for health
beds.
Dock orientation (north/south, east/west) is a
critical predictor of eelgrass bed quality. They
calculated the light levels under various docks
using the factors of height of dock, width of
dock, and orientation and found they could
predict impacts. Using this information Burdick
and Short produced "Dock Design with the
Environment in Mind: Minimizing dock impacts
to eelgrass beds," an informational CD that
allows the user to see how different dock designs will
affect an eelgrass bed and the associated coastal
species (Fig. 6). In this CD they provided
calculations for a limited number of scenarios; ideally
they would like to produce a model that predicts
impacts from a larger combination of design factors.
They noted that the presence of docks in Waquoit
Bay is not the only factor contributing to loss of
eelgrass. Nutrient enrichment impacts eelgrass by
promoting epiphytes that live on and shade the grass
blades. It is not clear whether this situation made
grasses more susceptible to impacts from docks.
This study did not address the cumulative impacts
from eelgrass bed fragmentation. It is not clear
whether these impacts are simply additive, or
whether synergistic factors are at work.
Figure 6. Burdick and Short's CD shows how dock design affects seagrasses and associated aquatic species
and allows users to see how impacts vary with design.
21
Question & Answer Period
What is the management goal articulated for eelgrass?
Informally, the goal is no net loss. Submerged aquatic vegetation, including eelgrass, has been
designated as a Habitat Area of Particular Concern by several of the Fishery Management
Councils--in part because it provides Essential Fish Habitat.
What is the correlation between the age of a dock and its height?
They tend to cancel one another out. Older docks mean better eelgrass because they are thinner
and more rickety. Also, regulations for docks now require larger dimensions (i.e. wheelchair
access) and materials that are less indestructible. The best way to calculate success is if you
base everything on light reaching the eelgrass. This may be more direct than dealing with
complex biological indicators.
Many owners argue their docks only cover a small area and, therefore, don't cause a problem.
How would your research address that contention.
To this point fragmentation and cumulative effects have not been adequately considered so it is
difficult to tell how valid that contention is.
Ron Thom
Battelle Marine Sciences Laboratory, Sequim, WA
Ron Thorn's work was done in conjunction with
the renovation and expansion of ferry terminal
docks in the Pacific Northwest. Thom assessed
the potential impacts of the planned expansion
and worked with the company to minimize
environmental impacts during and after
construction. While commercial ferry structures
are considerably larger than private recreational
docks, many of the issues remain the same.
In addition to shading, impacts on eelgrass bed
health were predicted from:
· Initial construction impacts and maintenance
efforts
· Propeller wash (turbidity from boat traffic that
decreased light levels), and
· Biological impacts from crabs and starfish
eating the recovering shoots and drift algae
smothering the plants.
Thom quantified the
light requirements for
eelgrass (Zostera) in
the Northwest by
charting light
attenuation over depth
(the area has a 4-5
meter tidal range) and
comparing Zostera
shoot density against
depth. They found the
highest density at 350
micromoles PAR.
As part of this effort
they developed a
multiple stressor
model--a conceptual
model with mitigation as
an end point (Fig. 8).
Thom recommended
that the ferry company
modify the design of the
dock to lessen the
impacts to the Zostera
bed. By building a
longer, narrower dock,
the engineers were
able to extend the bulk
of the structure and associated shading impacts past
the eelgrass beds. Shading impacts were further
reduced by incorporating light transmission
techniques. Additionally, they removed all of the
eelgrass that would have been destroyed and
maintained the shoots for restoration projects.
There are a number of
techniques available to reduce shading and
increase light under docks, including grating,
glass blocks, sun tunnels, and applying
reflective material on the underside of docks
(Fig. 7). These have been shown to be effective
in the large ferry docks in Puget Sound.
Vegetation near this commercial ferry in
Washington State is impacted by shading and
propeller wash associated with the dock.
22
Figure 7. New materials used in ferry construction in Washington State. Top left: light under glass blocks. Top
center: Glass blocks used instead of traditional wooden planking, Top right: A sun prism. Bottom left and center:
Metal grating on a dock and light penetration below that dock. Bottom right: A sun tunnel. (Photo credit: R. Thom).
CONSTRUCTIO~
MAINTENANC
& OPERATIO~
IMPACTS
MAINTENANCE FERRY PROP
DISTURBANCE DISTURBANCE
EELGRASS LOWERPROD,
LOSS, EELG~ASSLOSS,
RETARDED RETARDED
RECRUITMENT RECRUITMENT
MITIGATIONI MODIFY MOVE DOCK
I
PROCEDURES; OFFSHORE
REPLANT
UNDISTURBED
MEADOW
DISTURBANCE DURING
CONSTRUCTION
DOCK IN PLACE
LOWER
LIGHT
1
LOWER PROD.,
~LOIAS$ LOSS,
RETARDED
RECRUITMENT
INCREASED
SESSILE
PREY
EEL~ASSLOSS, EEGLRASS
RETARDED LOSS
RECRUITMENT
1
RED. DOCK WIDTH: FEWER PILINGS; REPLANT
GLASSBLOCKS; REPLANT {OVERPLAN~
GRATE;
FEWER PILINGS;
REFLECTIVE
MATERIAL;
PLANT ADJACENT
AREAS
Figure 8. Conceptual model showing how mitigation can be used to minimize construction impacts (From
R. Thom),
23
Q.
A.
Q.
A.
Question & Answer Period
Does eelgrass senesce (age) in the winter?
It continues to grow during winter but adapts to be shorter, thicker, and greener.
Is the 5 mols figure for growth time dependent?
To be sure it would be necessary to do a carbon balance study, but generally this assumes
summer months. Otherwise the 5 mols is based on average daily sunlight.
Were the eelgrass restoration projects successful?
Yes, they have been successful in the Pacific NW. This type of project needs the right conditions.
We've found that the best way to proceed is to do environmental assessments and then establish
plantings.
Has the architectural shading model been used to predict impacts over the seasons? Could this
be adapted as a useful tool?
It's not the ultimate answer. We need an overall eelgrass model.
In the course of the survey throughout Puget Sound was drift algae a problem?
Yes. It gets caught up under the docks and was a problem.
Are eelgrass beds and their growth patterns comparable between the east and west coasts?
Yes, when water clarity is comparable.
Deborah Shaefer
US Army Corps of Engineers, Waterways Experimental Station
Dock construction has had negative impacts on
seagrass beds in the panhandle area of Florida
and Alabama. Up to 50 acres of seagrass were
destroyed in the early 1990s, and it was felt that
there was the potential for significant cumulative
impacts. As a result, the US Army Corps of
Engineers wanted to develop construction
guidelines and regulations. However, there was
a lack of data supporting such guidelines.
Shaefer and Lundin therefore started by
studying the effects of docks on the seagrass
Halodule wright# in Perdido Bay, Alabama.
The principal sources of dock impacts were
identified as:
· impacts from shading,
· destruction of seagrasses during
construction,
· prop scarring and hull grounding,
· alteration of bottom topography and
sediment characteristics, and
· contaminants leaching from treated wood
materials and from fuel spills.
Shaefer and Lundin examined shading and
construction impacts and experimented with
ways to minimize them. They selected docks
Docks along an Alabama coastline (Photo: D. Shaefer).
with a standard set of characteristics and then
quantified seagrass loss for those docks. To
minimize variability, all of the docks in the study were:
· oriented north to south,
· four feet wide,
· four feet above mean sea level,
· four to nine years old,
· located in an area of continuous seagrass
meadows, and
· located within a one-mile stretch of shoreline.
24
m 400 -
E
o
m 200-
Shallow Deep
Figure 9. Biomass of the seagrass Halodule wrightii
growing under docks (green) was 1/3rd lower than
biornass in adjacent unshaded (yellow) areas.
Shaefer and Ludin observed that light (PAR)
under the docks was below the saturation rate
between 10 am and 2:30 pm, for a total of 4.5
hours each day. Shoot densities were 40% and
47% lower in shaded plots at shallow and deep
locations, respectively. Biomass was reduced
30% and 33% in the same locations (Fig. 9). As
in other studies of shading impacts on seagrass,
Shaefer and Lundin found that shade-stressed
plants grow to greater heights, perhaps due to
etiolation. This suggests that seagrasses
posses mechanisms to compensate for light
reduction. They concluded that seagrasses
under docks can be maintained and bed
fragmentation eliminated, although density and
biomass are reduced.
A second part of the study was designed to
evaluate the effectiveness of grated decking
material as a means of transmitting light and to
demonstrate the possibility of Iow-impact
construction techniques. A series of docks were
built with varying the heights (4' vs. 5') and
sudace materials (traditional wood planking vs.
1" thick reinforced fiberglass grating with lx2"
openings). On a dock five feet above mean sea
level, the light levels never dropped below saturation.
On a four-foot high dock they dropped below
saturation only briefly during the day. Light levels
were much higher and seagrass grew better under
docks with grating rather than solid wood plank
decking (Fig. 10).
The State of Florida has
prohibited roofs on terminal
structures in an effort to
further reduce seagrass loss
resulting from dock shading.
In an investigation of impacts
associated with dock
construction techniques,
Shaefer noted that the high
pressure jet pump normally
used to install dock pilings
produced a six to seven foot hole around each piling.
The resultant "halo" might remain for 10 years without
seagrass regrowth. By sharpening the piling ends,
using a Iow pressure jet to start the pilings, and a
drop hammer to do the final installation, the size of
the "halo" was reduced. The smaller scar size will
make it faster and easier for seagrass to regrow.
Another way to minimize construction impacts is to
bring construction equipment in from the water on a
barge rather than driving heavy equipment through
the marsh.
The Corps has adopted these techniques as
guidelines for the Southeast. Despite these being
only guidelines, they are often followed by permit
applicants as a way of speeding the application
review process.
Time (HH:MM) Time (HHMM)
Figure 10. While light levels under traditional wooden plank docks (left) fell dramatically during the day,
grated decking (right) significantly reduced the shading impact of the dock.
control
25
Q.
A.
Q.
A.
Q.
A.
Q.
A.
Question & Answer Period
On your grid analysis - were any of the existing docks roofed?
No, regulatory guidelines currently prohibit construction of roofed docks.
How many roofed structures might you find in a stretch?
This area had approximately 15 roofed structures in a one mile stretch of coast.
Does grating come in different sizes?
Yes. It comes in different sized grates end varying thickness.
Is grating acceptable for a broad range of uses (e.g., does it preclude sunbathing, high heels, is it
hot underfoot, etc.)?
There have been some complaints, but it is generally well accepted.
Is it an aluminum product or plastic?
We use fiberglass. It is the amount of light passing through that is important, not the materials
utilized.
What's the cost of grating materials?
A 4' by 8' panel is about $500. This is approximately 20% more than wood planking for initial cost
(not including labor) but it tends to last longer, thereby minimizing the cost differential.
Have these regulatory guidelines been taken to court yet?
They have been out for 3-4 years and have been tested in court. Remember that these are
USACE guidelines. USACE can't require, but can guide people toward this end. All of these
guidelines are specific to North Florida.
Mike Ludwig
National Marine Fisheries Service, NE Fisheries Science Center
Mike Ludwig presented a discussion of
experiments conducted by Mary Colligan and
Cod Collins to quantify the impacts of docks on
the coastal environment. The study was
undertaken after the authors observed that:
· Permits for dock approval are the most
common permit requests received by
regulators.
· There is a perceived "right" to dock
construction.
· There is little in the way of defensible
management policy.
· There is no uniformity of design.
· There is little literature available about dock
impacts to marsh grasses.
· Consequently there is little justification to
deny permits.
Ludwig argued that the ongoing workshop was
necessary because of our failure as managers.
While there is a Constitutional right to riparian
access, we've extended that to include putting in
docks to increase property value and gain
access to deeper water. There is no absolute right to
a dock!
Colligan and Collins collected data on marsh grass
density and height directly under and adjacent to
each of 125 docks in Connecticut, Rhode Island, and
Massachusetts. As noted previously, height of the
grasses was greater under the pier, but the densities
were lower. Impacts varied by species with Spartina
alterniflora being the most affected followed by
Distichlis spicata and S. patens.
Colligan and Collins also experimented with reducing
impacts by shifting orientation and replacing solid
planks with grid material. Orientation seemed to
have an impact but it was not significant. Nor did use
of grid material reduce shading - light reduction under
the grid was almost the same as that measured
under traditional planks. This may be because in the
northern latitudes the sun did not get high enough in
the sky to shine through the grid (as it had in the
Florida experiments).
26
Figure 11. Undercutting of the vegetative mat near a dock (left) can lead to marsh slump (right) and the death of
marsh grass (Photo credit: M. Ludwig).
Erosion to areas adjacent to the dock was
increased--this was attributed to prop wash--
and there was an undercutting of the mat in the
sub-tidal range (Fig. 11). When this happens
the surface of the marsh slumps, falls out of its
growing zone, and dies. These would have the
additional benefit of providing habitat for
Spartina and would be an improvement over
bulkheads.
The conclusions of the study include:
· There are two principal impacts to plants, 1)
density--generally lowered, and 2) height--
generally increased.
· A north-south alignment seems to particularly
affect S. alterniflera.
· The height of docks affects different species
differently.
· Spacing between planks appears to have no
effect on plants.
· A grid deck may not be beneficial in higher
latitudes.
· Docks segment wedands and may inhibit
wetland functions and values.
· Dock impacts include increased erosion.
Figure 12. Installation of wire mesh baskets
filled with small stone can alleviate the
undercutting associated with many docks. It has
the additional benefit of providing habitat for
Spartina and is an improvement over bulkheads.
Ludwig noted that the impacts of pier alignment
merits further investigation. Regulations on pier
height to width ratios may prove useful, but second
order impacts on motile species such as birds need
to be investigated before these are adopted. In
conclusion, Ludwig suggested that a little "intestinal
fortitude" and the increased use of shared public
docks as an alternative to constructing more private
docks might better protect public resources.
Question & Answer Period
Q. It is misleading to suggest we, as regulators, can deny riparian property rights in the interest of
the public trust because our laws are simply not there at this point. We may have failed as a
society, but not as regulators.
A. Look at Common Law and the Constitution for the basis of these types of laws.
27
In some instances, in an attempt to minimize fragmentation of wetlands, long walkways to tidal
creek have been requested, but the applicants have been denied and told to walk. Is it better to
allow them to trample the wetland?
The sense is yes. It is better to allow a foot path than a walkway. In 2002 there was a case that
was denied on this basis. Most of plant growth is done by the end of June before the major
summer boating season. Therefore, people are probably not walking. If they do walk they should
be encouraged to use the same path repeatedly because this flora is so delicate.
Comment: Based on our work in NC, Spartina can recolonize after being trampled, but it is a slow
process. Orientation didn't appear to be a factor there. A reduction of light of 71% was found
with both tall and short docks.
Did you vary grid height in your investigations? Height is a major factor.
We had a limited number of investigations with all structures being between three-four feet high.
Our grid material is thicker than some. It is Morton* safety grip planking that is designed to allow
significant light passage. It is produced by Central Steel & Wire Company. They carry the
Morton Open-Grip Grating, Standard Planks that I showed in the presentation. You can see the
specifications and decking at www.centralsteel.com.
Shoreline erosion in one of your slides appears to be attributed to a dock - did you look at
orientations, etc.?
No. It seemed that shoreline erosion depended more on boat use and type (i.e., prop
dredge/wash, etc.). In other words, human behavior is related to erosion impacts. Wave
focusing could also be responsible for some erosion.
General Discussion on Impacts to Vegetation
Question to the group: Are the impacts on vegetation sufficiently well known to develop a management
assessment tool? If so, what sort of tools would be appropriate?
Comment: Managers must determine what level of impairment is acceptable and then develop a
mechanism to determine whether the impacts of a dock or series of docks will go beyond that
acceptability.
Comment: In making a regulatory decision it is important to consider all of the pertinent factors--impacts
on vegetation, on navigation, on erosion/sedimentation, etc. While it is not necessary to be technically
"perfect" it is important to show that all of the factors have been assessed. This is best done through the
use of a checklist.
Comment: The use of a conceptual model w~uld be useful to promote understanding between factors,
structure, and function. This has been done for specific projects in the Pacific NW (Columbia Model).
This model could be linked to impacts on specific types of vegetative communities--submerged marsh,
submerged aquatic vegetation---and could incorporate regional differences. A level could then be added
stating possible management options. This could be augmented by a list of management options and
associated impacts.
Comment: A useful method is to establish guidelines that show applicants that if they build a dock that
meets a defined set of criteria, that they will get a dock. New York has established such guidelines and
they have successfully been defended in court. If you design your regulation around legitimate objectives
and take a rational approach, the courts will back you.
Comment: Although we suspect that there are cumulative impacts, we really don't have any research on
the topic. It's not really clear whether the problem is docks or development in general.
28
Summary and Recommendations
Shading under docks and piers is clearly documented, and associated biological impacts on aquatic
vegetation have been quantified for some SAV and grass species. However, these impacts are species
specific and vary with latitude. Further studies are needed to understand the impacts of dock shading on
more species and in other geographic regions. There is also a need to identify and better quantify
secondary effects of docks on vegetation. These include impacts to SAV beyond the footprint of
approved docks such as the halo effect around a dock, or unpermitted "add-ons" like floating docks, roofs,
observation decks, etc.
A conceptual model explaining the factors controlling the types and magnitude of potential impacts should
be further developed. It will be important to define types and accuracy of information that would feed into
this conceptual model and to identify information gaps. This led to the following recommendations: · Develop a conceptual model.
· Prepare a synthesis paper that draws together all of the existing data,
· Develop a searchable database/website that could be a repository for relevant data.
· Develop checklists of parameters that managers should consider in the permitting process (tailored
to localities).
29
IMPACTS FROM CONTAMINANTS RELATED TO DOCKS
Summary
The most common contaminant-related concern
associated with docks is leaching from preservatives
applied to pilings or floats in locations that come into
regular contact with water. Many states have banned
the residential use of creosote or pentachlorophenol
in aquatic settings (they leach readily and have
demonstrated toxic effects); and consequently wood
pressure-treated with a chromated copper arsenate
(CCA) is the most commonly used material for pilings
and decking for residential docks. CCA also leaches
in saline waters (Weis etaL 1991, 1992). The degree
of toxicity depends on both the concentration and the
chemical form as it reaches the target organism and (Photo credit: P. Weis)
can change over time and in response to sediment
types, amounts of organic material present, oxygen levels and water movement (Luoma and Carter
1991). Ninety-nine percent of the leaching occurs within the first 90 days (Cooper 1990, Brooks 1990).
In areas of Iow water flow, elevated concentrations of chromium (Cr), copper (Cu), and arsenic (As) can
be found in fine sediments adjacent to bulkheads constructed of CCA-treated wood and in organisms
living on and around treated pilings (Weis and Weis 1996, Weis et al. 1998). Dilution appears to reduce
these impacts; the bioaccumulation of dock leachates by marine biota did not impact survival of
mummichogs, juvenile red drum, white shrimp, or mud snails in South Carolina estuaries characterized by
higher flow rates (Wendt et al. 1996). However, tidal flushing thresholds for contaminant impacts have
not been identified, and data does not exist to evaluate the dilution capacity of an area.
Peddrick Weist and Judith S. Weis2
~Aquatic Toxicology Laboratory, Dept. of Radiology, UMDNJ, NJ Medical School
2D , .
ept. of B~olog~cal Sciences, Rutgers Un vers ty
When CCA-treated wood products are used in
estuaries--for dock pilings, floats, or bulkheads--
contaminants leach out of the wood. These
contaminants may be taken up by organisms living
on the wood, transferred to consumers, enter
sediments and the benthic organisms that live
there, and/or wash away with the tides or currents~
(Fig. 13).
Weis and Weis observed elevated levels of copper
and arsenic in algae growing on open water docks
in Pensacola Beach, Florida (Weis and Weis 1994,
Fig. 14). A subsequent laboratory experiment
showed that snails fed algae grown on CCA-
treated wood became inactive in 3-4 weeks and
eventually ~rled up inside their shells and died
(Weis and Weis 1992). This was supported by a
field study showing that oysters living on bulkheads
made of CCA-treated wood had taken up
measurable concentrations of copper and were
METALS tN ALGAE
PEN~ACO~A E[E~H, FL
Figure 14. Copper and arsenic were elevated in algae
growing on docks (From Weis, J.S., & P. Weis. 1994.
Arch. F~nviron. Contain. ToxicoI. 26: t 03-] 09
smaller than contro~ populations (Weis et. al 1993).
When CCA concentrations are high enough, oyster
digestive glands shrink.
30
ENVIRONMENTAL IMPACT OF LEACHATES
Figure 13. Some of the contaminants leaching out of wood is taken up by organisms living on the wood,
some is transferred to consumers, some may enter sediments and the benthic organisms that live there,
and some is washed away by the tides or currents. (From Weis, J.S., and P. Weis 1992. J. Exp. Mar. Biol.
Ecol. 161: 189-199.)
Contaminants have been measured in
sediments adjacent to CCA-treated wood, and
these contaminants accumulate in animals
living in and feeding on those sediments (Weis
and Weis 1994, Fig. 15). In areas bulkheaded
with CCA materials, fine sediments, and Iow
water flows (e.g., canal communities in NJ),
contamination may extend up to 10 meters,
although the highest levels are found within the
first meter. Newer wood leaches more rapidly
than weathered material and most leaching
occurs in the first few months.
There has been no evidence of trophic transfer
from amphipods to fish or higher vertebrates,
but species richness was depressed in areas
with higher contaminant levels.
As almost all of the research work presented by
Weis is with bulkheaded areas, it is unclear
what impacts there will be from a limited
number of pilings for docks. Issues to consider
include the area of exposed surface of CCA-
treated materials, the newness of the materials
used, the types of sediments in the area, and
the flow of water through the system.
Alternatives to CCA-treated materials include
recycled plastics, untreated woods, steel or
concrete.
METALS IN SEDIMENTS BY CCA WOOD
OPEN Y~gff E R
DISTN'~E FROM ~JU~F..AO
METALS IN SEA CUC~JMSERS
Figure 15. Contamin~~ and s~iment
feeders ne~ CCA-~eated woods. (From Weis, J.S., & P. Weis.
1994. Arch. Environ. Contain. Toxicol. 26: 103-109),
31
Question & Answer Period
Q. You mentioned different findings in Delaware and Pensaco a Bay Florida. Was there a
significant difference in the tidal range between the two sites?
A. The tidal range ~s substantially greater in Delaware than Florida. This is key as the amount of
water tlow greatly impacts levels of copper and other contaminants concentrated in the area.
Q. Can recycled plastics be used for piling_s, as well as decking?
A. They can be used for both but they can t be driven in With ~ drop hammer. There is a version
that can be screwed in that s much tess disturbing to the sediments and protects the pilings.
Q. Did you look at toxic impacts in copepods?
A. No. but we did took at trophic transfer' and conduct some mpact stud es
Q. Has any of your information been presented to EPA to apprise them of these environmental
contaminants?
A. Yes, but I don't know what their response is.
Denise Sanger
South Carolina Division of Natural Resources, Marine Resources Division, Marine
Resources Research institute
Denise Sanger presented research results from
two studies: (1) a study undertaken by Priscilla
Wendt and Robert Van Dolah, and (2) a study
undertaken by Denise Sanger and Fred Holland.
The Wendt and Van Dolah study was published
in Archives of Environmental Contamination and
Toxicology in 1996. The study was designed to
evaluate the effects of wood preservative
leachates from dock structures in South Carolina
and was conducted in two phases. Phase one
of the project was designed to compare creeks
with docks to reference creeks without docks.
Three conditions were surveyed:
· The concentration of copper, chromium,
and arsenic in sediments and oysters;
· The acute toxicity of sediments to a
marine bacterium (i.e., Microtox) and a
micro-invertebrate (i.e., Rotifer); and
· The physiological condition of the
sampled oysters.
One composite sediment sample and one
composite oyster sample were taken in each
creek at varying distances from the docks (<lm
and >1 Om) and in reference creeks.
Concentrations of copper in oyster tissue from
animals attached to pilings were significantly
higher than those in oysters collected away from
the pilings and from reference sites. However,
Wendt and Van Dolah did not find physiological
differences between the sampled groups.
Sediment copper, chromium and arsenic
concentrations were not different among the
sediments collected near docks, greater than 10m
away from docks and in reference areas.
Furthermore, no acute toxicity was observed.
Photo credit: D. Sanger.
The second phase of the Wendt and Van Dolah study
focused on recently constructed docks. In situ
bioassays measured mortality in white shrimp, red
drum, mud snails, and mummichog placed adjacent
to five 4-12 month old docks after a 96 hour period.
These results were compared to mortality in animals
placed in reference areas. A six-week study of oyster
bioaccumulation of metal and its relationship to
32
growth was also conducted. There was no
decrease in survival of the four species in the
96-hour assays. In addition, there were no
differences in the deployed oyster tissue metal
concentrations or in their growth.
The second study, conducted by Sanger and
Holland and published in a 2002 SCDNR/MRD
technical report, examined cumulative impacts
of docks. Spartina shading, sediment
contamination, and impacts on nursery habitat
were examined in an effort to address as wide a
range of impacts as possible within a limited
budget. Only the sediment contamination and
nursery habitat research in both small and large
tidal creeks was presented at this workshop.
No new data was collected for this portion of the
study as pre-existing data from two projects
performed at SCDNR were used. The small
tidal creek data set was pulled from the Tidal
Creek Project (TCP) which defined small tidal
creeks as <20m wide. The large tidal creek data
set utilized data from the South Carolina
Estuarine and Coastal Assessment Program
(SCECAP). Large tidal creeks were defined as
creeks between 20m and 100m wide. The small
tidal creek data set compared creeks with no
development (reference) to creeks with
suburban development and no docks (suburban-
no docks) to creeks with suburban development
and docks (suburban-dock) (Fig. 16). The large
tidal creek data set compared creeks with no
docks (no docks) to creeks with Iow numbers of
docks (Iow docks) to creeks with high numbers
of docks (high docks).
In general, both the small and large tidal creek
data sets showed:
· CCA contaminants did not increase with
increasing numbers of docks.
· Higher levels of PAHs were measured in
creeks with suburban development and
docks, but the higher levels were probably
due to the suburban development and not
the docks;
Figure 16. Sites selected for the cumulative impact
study compared reference areas in South Carolina to
suburban areas with and without docks (from D.
Sanger).
Changes were found in the small tidat creek
benthic community, but again this was probably
more related to the suburban development of the
up~and; and
Suburban development may reduce fish and
crustacean abundances, but dock structures may
also provide structure that attracts them.
The overall conclusions of these two portions of this
study were: (1) chemical and biological effects were
observed with increasing impervious cover and
increasing dock numbers; and (2) docks are not the
problem, they are a symptom of the much bigger
problem which is development of the uptands.
what iS t~e to!e of O~tboard ~0te[s and PAH? it seems that it COUld be a bigissue; ;
cree~s With docks bUt the uP!and de~e!epment masked any effect that may be due t° docks
unfortunately it WOUld be hard to design a StUdy t° evaluate this question due to teasing 0St
33
recreational boat use unassociated with docks compared to recreational boat use associated with
docks would be difficult.
Is it safe to say that CCA-treated wood has no impacts in areas of flushing, but does in areas of
Iow flow?
That is generally what our research, combined with that of Dr. Weis, indicates. Impacts are
greatest directly after the wood is put into the water. It should also be noted that the
contaminants don't just disappear. They may flow out of the system but we don't know where
they go and whether they are having impacts elsewhere.
Comment: Delaware has dealt with impacts of bulkheads by not allowing them anymore. There is almost
always a better way to deal with erosion. You can replace existing ones, but in the process
applicants are required to dig out the old one.
You noted that species richness of fish and crustaceans increased in creeks with suburban
development and docks compared to suburban creeks with no docks and reference creeks - did
you consider species composition?
We did evaluate individual species in our analyses but did not look at a true shift in the fish and
crustacean species composition which is something that could be considered in the future.
Given that most of the contaminants leach out in the initial 90 days, if a permit requires that the
CCA-treated wood be seasoned before building would this a be a useful precaution?
Only if the wood is in contact with water (e.g., rain). Once again, however, those chemicals must
go somewhere.
34
IMPACTS FROM ASSOCIATED BOATING USE
Summary
Most docks are for private recreational boating accessory to private residential uses of upland areas.
issues of concern include impacts to submerged aquatic vegetation, contamination from fuel discharges,
increased use of vessels in shallow nearshore areas, erosion of shoreline and flats, turbidity and
resuspension of bottom sediments, noise, and disturbance of wildlife (Crawford et al. 1998, Kennish
2002) and interference with other uses of nearshore areas. However, these impacts are difficult to
quantify. Based on the limited quantitative data available, scientists agreed that, motor boat traffic is far
from a benign influence on the aquatic and marine environments, and identified quantification of boating
impacts as a research need.
Rick Crawford
Nautilus Environmental Services, Falmouth, MA
The general topic of impacts from boating usage
in shallow estuaries has been of interest to
managers and researchers for over three
decades. Recently there have been two
significant workshops (1994 and 2000) to review
the state of knowledge on the subject.
Concerns commonly associated with boating
use include:
· Damage to submerged aquatic vegetation;
· Water quality contamination associated with
discharges of PAH and other petroleum by-
products;
· Erosion of banks, marsh edge and tidal flats;
· Resuspension of sediments and resulting
turbidity;
· Impacts from noise; and
· Disturbance of wildlife.
Because docks are in the most shallow areas of an
embayment and are the location where refueling may
take place and engines are started and stopped,
impacts are apt to be particularly significant there.
Propeller scarring of vegetation and "prop dredging"
of sediments are perhaps the most obvious impacts
in the shallow waters adjacent to docks (Fig. 17).
As a boat moves through the water there are two
principal forces produced (also see Figure XX):
· The primary wake (or bow wake) that is related
to water displacement by the boat that moves
out to the side and can cause bank erosion;
and
· The secondary wake (or prop wash) related to
engine and propeller effects that moves behind
the boat and down and causes sediment
resuspension and damage to submerged
aquatic vegetation.
Figure17. Propeller and mooring chain scour marks near docks (left) and propeller wash scour marks in Waquoit
Bay (right). (Photo credit: R. Crawford).
35
PRIMARY
WAKE
SECONDARY
WAKE
Figure 18. Primary wake travels awayin widenir~g
path; effects add to naturally occurring
disturbances (waves). Secondary wake
disturbance area remains narrow and limited; it is
an unnatural disturbance (From R. Crawford).
At s~ow speeds, such as those near a dock, it is
the secondary wake and physical contact
between the hull and/or prop that is apt to have
the most significant impacts. However, these
secondary wake impacts are difficult to quantify
accurately because they vary widely from boat to
boat and are based on environmental conditions.
Propeller thrust characteristics are also highly
variable, and depend on propeller size, thrust angle,
clearance over bottom, engine power, hull shape,
operating conditions (e.g, speed, state of the tide,
weather, number of passengers), and operator
choices.
Although environmental damage caused by boat
operation in shallow waters can be quite obvious,
despite the ongoing research, there has been limited
progress in finding quantifiable, predictable impacts
from boating uses.
Conclusions:
· Using sediment resuspension to assess
impacts is not recommended.
· Small-scale measurements are too variable,
the broader the scale the better.
· Parameters like light attenuation can be easily
measured but the greatest impacts can be
short-term phenomena that are better
monitored with a recording device (an
expensive device).
· It is difficult to ascribe generic impacts resulting
from a boating activity.
· More research is needed--however the
research is expensive and very time
consuming.
Q.
A.
Q.
A.
Question & Answer Period
Considering the photographs showing clear prop scarring in vegetative beds, why do you draw
such negative conclusions about being able to predict boating impacts?
Despite having visual evidence of obvious damage, it's very hard to quantify what caused it.
What kind of impacts were you trying to assess through the use of a light meter?
We were trying to determine how much sediment is disturbed by various boat propellers.
Acoustic doppler current profilers have been used successfully in studying prop wash effects
behind ferries. Have you tried them?
This kind of equipment doesn't work well in the shallow water situations being considered here.
Researchers at Texas A&M have developed a model on propeller energy and disturbance.
I'm not familiar with that specific model, but the problem with models is that the conditions are
constantly changing once you're out in the field.
36
Steve Fle$1er
New York Department of State, Coastal Management Program
The management of docks and their associated
uses, including recreational boating, involves
consideration of human uses and values - and
that has been used to drive approaches to
managing them in New York. Generally, the
primary purpose of private
docks, from privately owned
upland, accessory to the
private residential use of the
upland, is to gain private
access to the water for a
range of private purposes.
These uses may include
pedestrian access across
vegetated and other intertidal
areas to the water and
vessels moored to the dock,
launching of small vessels
such as canoes or kayaks,
and mooring larger vessels,
whether powered by sailor
motor).
It is not always necessary to conduct detailed
individual site-by-site assessments of docks or
vessels using them. Likewise a detailed
understanding of the specific types and degrees
of impacts associated with a dock is not always
prerequisite to developing and making
regulatory decisions. A valid and much easier
approach, based on generally understood
resource and human use values, is through the
designation of areas that have special or high
value wetland or other natural resource or
character values based on physical or other
characteristics.
Based on experience, mangers understand that
docks and the uses of vessels associated with them
have various types and levels or degrees of physical
effects on resources and uses of them. If the overall
objective in high value
habitat or other areas
with desired
characteristics that
should be protected is to
protect, maintain~ or
restore the viability of an
area as a habitat, or for
other purposes, and the
value of the habitat or
other characteristics is
recognized and
considered in decision-
making standards, the
effects of docks and
vessels using them can
(Photocredit:S~Snow-Cotter) be regulated and in
certain instances
prohibited to prevent or minimize impairments to
important characteristics, functions and values of
important habitats and other areas.
New York has worked with municipalities to develop
understandings of varying circumstances and needs
relating to protection and uses of differing coastal
areas, and to determine municipal needs and desires
regarding docks and their uses. Public outreach
efforts are included in assessing areas and
considering the generally understood effects of docks
and vessels, and involve community consensus-
building regarding the protection of resources and
areas and appropriate uses of them. This
consensus-building involves consideration of human
values regarding docks and their associated uses,
including the effects of vessels and other uses and
values associated with them and with other use and
values.
(Photo credit: S. Snow-Cotter)
This consensus-building results in the development
of regulatory decision-making regulatory standards
for docks and, in certain cases, the uses of vessels in
special management areas. If a goal is developed to
allow or encourage docks and vessels associated
with them, or to limit them, the State Coastal
Management Program provides recommendations,
suggestions, and technical assistance in developing
the regulatory and other means for doing so,
(Photo credit: S. Snow-Cotter).
including the means of minimizing adverse
effects in certain areas where there is a need to
minimize those effects. This is usually done
through area-wide or water-body based
planning, based on the unique circumstances of
specific water bodies and resources and human
use vatues associated with them~
Richard Crawford summarized some of the
adverse effects of vessels, including those using
docks. Richard Smardon will address aesthetic
considerations regarding docks and vessels
using them. Those and other affects discussed
at this and other workshops are generally
understood. We do not know absolutely all of
the many and varying types and degrees of
effects resulting from docks and vessels, and it
is extremely difficult if not impossible in many
circumstances to quantify those effects
absolutely. However, we can and do develop
standards and base regulatory and other
decisions on our general understandings in
order to achieve legitimate governmental
objectives, using a wide range of available
authorities.
Private docks on publicly owned underwater
lands and in public waters, accessory to the
private residential use of privately owned
uplands, affect public resources and areas and
uses of them. They do not advance legislative
public purposes or state or national coastal
management objectives. They serve only the
personal private use of the upland property
owner, whether for general private pedestrian
access to the water or for the mooring of private
recreational vessels, impairing publicly owned
natural resources and legitimate public uses of
nearshore areas to varying degrees. Vessels using
or associated with docks, and the uses of vessels for
a wide range of activities (i.e. water skiing in
nearshore areas) also have a wide range of effects,
including the suspension of sediments in shallow
nearshore areas, erosion and scour of shoreline
areas and wetlands from vessel wakes and prop
wash, the introduction of certain pollutants in the
water column, noise, and conflicts between other
legitimate public uses of nearshore areas.
Government allows the owners of upland property
abutting the water some types and degrees of
impairments to, and interference with, resources and
public uses associated with docks and vessels
associated with and using them. Government has
considerable latitude in deciding the types and levels
of allowable private access to and uses of publicly
owned lands, waters, and resources, and
interference with legitimate public uses and values
associated with public resources and uses of them.
While private upland property owners generally have
rights to construct docks for access to the water for
navigation, this right is limited to the minimum
necessary for access to the water for navigation.
Furthermore, this right does not always include the
Boat lifts are increasingly common in small tidal creeks
in South Carolina (Photo credit: R. Chinnis).
right to construct a dock and moor a vessel to iL The
decision to allow greater encroachments into (and
impairments to) publicly owned resources and
legitimate public uses of in-water areas and
resources through the construction and use of docks
and vessels associated with them, is at the discretion
of the states or other levels of government entrusted
with the management of public resources, and the
legitimate rights of the public to appropriate access to
and use of those resources.
38
It has been our experience in New York that
courts do not second guess managers when
their regulatory standards and decisions are
based on legitimate governmental authorities
and objectives, are well documented, and are
based on logical, rational decision-making and
understandings.
The range of legitimate governmental objectives
related to the regulation of docks and vessels
associated with them include:
· protecting or providing for general public
access along the shoreline and water for
legitimate public purposes (such as strolling,
wading, swimming, shellfishing, fishing,
surfcasting, etc);
· protecting or providing for general public
navigation, whether by canoe or kayak,
sail, or motorized vessels;
· protecting or providing for important public
or other water-dependent uses and the
protection of natural resources;
· protecting or providing for certain
development or other characteristics,
including the maintenance or protection of
aesthetic or cultural characteristics and
values; and
· general public safety.
(Photo credit: S. Snow-Cotter)
in summary, we generally understand the effects of
docks, vessels, and their uses on coastal resources,
areas, and other human uses. We do not know
absolutely the degree of all of their effects. However,
the available information regarding, and our
understandings of, those effects and available
governmental authorities, have been and are
sufficient to develop regulatory decision-making
standards and make defensible regulatory decisions.
Comment: It seen
amen : value
and allowable usage.
How does ~
Question &Answer period
determining what
; { desired; and askin
make sense m
39
IMPACTS TO NAVIGATION AND RIPARIAN USES
Dave Killoy
US Army Corps of Engineers, New England District
Increased development has led to increased
conflict between coastal resource users. The
clear difference between access to water
(riparian rights) and permission to extend a
structure into the water is not always clear to
property owners. In most cases, the land under
the water is held in public trust by the states.
Because navigation is a public trust rights, any
structure that encroaches into the water must be
reviewed for navigational impacts.
In 1991, in an effort to preempt potential user
conflicts and streamline the review process, the
New England District of the Army Corps of
Engineers developed guidelines to minimize
dock impacts to navigation. These guidelines
were revised in 1996 and copies are available
from the District.
The guidelines limit the impact of docks on
navigation by:
· Prohibiting structures that extend into
Federal Navigation Projects or traditional
navigation ways.
· Allowing a new structure where a similar
adjacent one already exists. The new
structure should not extend beyond the length of
the existing one. Exceptions are for structures
that improve and are available for public use (i.e.,
municipal or communal docks).
· Limiting the length of structures to less than 25%
of the width of a waterway. Where structures
extend from both sides of the waterway, at least
50% of the waterway should be navigable.
Where there is no physical width constriction
(because the waterway is wide), dock length
should be limited to 600 ft.
· Discouraging the placement of a structure within
25 feet of riparian lines (extensions of property
lines). This establishes a minimum of 50 feet
between docks, a distance designed to allow for
navigation by most vessels.
· Recommending that moorings be located close to
applicant's property. When mooring area is far
from the property, the location should be justified
and the applicant should list potential impacts to
public use of the area.
While the guidelines were developed as a basis for
design, and not as a regulatory policy, they have
been adopted into local ordinances by several
municipalities in New England.
40
IMPACTS TO AESTHETICS & QUALITY OF LIFE
Summary
From a manager's perspective, oftentimes the publicly-held concerns related to small docks are not really
related to the environment. They may be aesthetic in nature, a sense of over-development of the shore,
or simply change. It is not uncommon for managers to hear very vocal outcries from one segment of the
population while the rest remains quiet.
In an attempt to get a better sense of public sentiment regarding docks in South Carolina, Felts et al.
conducted telephone surveys of the opinions of residents of coastal counties in the state (2001, n=384)
and of dock owners (2002, n= 423).
· 75% of the residents of coastal counties felt that property owners should be able to construct a
dock.
· 66% of the dock owners and 50% of residents felt that docks should be regulated.
· 75% of the dock owners felt that the length of docks should be restricted; nearly 80% felt that the
size should be restricted. In contrast, only 50% of the general public felt length should be
restricted.
· <25% of dock owners and the general public felt that docks are harmful to the aquatic
environment or detracted from the view of the water body and shoreline.
· ~75% of dock owners and the general public feel that there are not too many docks.
It is not clear whether these findings are transferable to other states or regions within those states.
While the aesthetic appeal of docks is an individual assessment, techniques have evolved that appear to
provide a reproducible or predictive assessment of the aesthetic values of an area and how those might
change with development. Visual impacts assessments (VlAs) developed by Smardon (1986, 1988)
consider landscape compatibility, scale contrast, and spatial dominance.
In contrast to the social survey method discussed above, in which respondents are asked to express their
perception of an abstract issue over the phone, VlAs present respondents with a concrete image that
shows how the visual landscape would be affected by a proposed change. With computer technology,
these "post-construction" images are realistic
and easy to make. VlAs indicate that, when
shown two images of a shoreline, the vast
majority of people select the same image as
being aesthetically preferable, and results
from these assessments are reliable and
repeatable.
In general, aesthetic preferences are for
open/distance water views, enhanced water
access, historic or generic coastal
development, water related development,
and diverse, well maintained vegetation.
People disliked development in undeveloped
coastal landscapes and tourist-like
commercial development (Banerjee 1987,
Knutson et al 1993, Shannon et al. 1990,
Smardon 1987, Steinitz 1990).
(Photo credit: R. Smardon)
41
(Photo credit: J. Gates)
Aesthetic or visual impacts have been used
as a basis for denying permit applications in
Maine and New York. Maine's Natural
Resources Protection Act (Title 38 §§ 480-A
through Z), Standard 1 specifically requires
an applicant to demonstrate that a proposed
activity will not unreasonably interfere with
existing scenic and aesthetic uses. Chapter
315, which is currently in review by the State
of Maine, explains regulatory concerns
(including visual impacts), establishes a
standardized procedure for evaluating visual
impacts, and explains options to mitigate
adverse impacts to existing scenic and
aesthetic uses.
Broad scale socio-economic assessments are necessary to determine:
· public awareness and opinion of environmental and socioeconomic costs and benefits of the increase
in private, residential docks and piers,
· which coastal uses the public values and how residential docks and piers relate to those uses, and
· the human use patterns for existing docks including which dock owners use their docks and which
have them as "porch furniture/'
These assessments probably need to be a combination of a VIA and traditional public opinion survey.
Results from these assessments will tell researchers and managers where to put emphasis in education
and outreach efforts, and are critical to the development of regional scale dock policies.
Richard Smardon
State University of New York, Syracuse
Richard Smardon's presentation
focused on the aesthetic
impacts of fixed and floating
docks and piers and associated
boating activities (boardwalks
and promenades have their own
impacts). For example, views
from the shore can be open,
have a panoramic edge, or be
filtered. Generally the public
dislikes views being filtered
through structures (e.g. docks).
Figure 19. Computer simulation of a dock build out in Massachusetts.
(Photo credit: MA Coastal Zone Management Office).
Visual impact analyses (VlAs) grow from
comparisons between existing settings and
proposed changes. This allows members of the
public to evaluate how much change a
landscape can absorb. For example,
simulations of views may be set up to show what
build-out will look like (Fig. 19, 20, 21). For this
process it is important to:
· document angle of the lens used,
· note the distance to the object,
provide the aspect or angle of the viewer, and
provide the location of the viewpoint where the
picture was taken.
Sea Grant has set up a web site at
www.coastal.lic.lisc.edu/bluelake.htm that allows the
viewer to view Great Lakes landscapes with different
levels of home build out and docks.
Visual Perception Studies of Coastal Settings
There is no visual assessment process specifically
designed for small decks and piers, but assessments
42
Figure 20. Side by side comparison yields different impacts. From
Smardon & Karp 1992)
of coastal activities on aesthetics and visual
impact conducted by Mann (1979) and Smardon
and Hunter (1983) come close. The Visual
Resources Assessment Process (VRAP)
designed by Smardon et al. (1988) for the US
Army Corps of Engineers to assess visual and
aesthetic impacts for all water resource type
projects is also useful.
Smardon presented an overview of visual
perception studies that include coastal
structures. Interestingly, docks are listed as
both positive and negative attributes. Critical
characteristics of docks in these cases are the
condition of the dock (well maintained vs.
deteriorating) and the number and array of
docks compared to the visual quality and
diversity of the shoreline landscape. Methods
and results from individual studies are
presented in Table 1 (facing page). These
assessments indicate that the public likes:
coastal development that is "generic" or
historical (i.e., "fits with the context"),
open/distance water views, and diverse but well
maintained vegetation. Structures perceived as
marine or water related are preferred, as are
those that enhance water access. "Tourist-like"
development and development in an
undeveloped coastal landscape are disliked.
Two studies indicate that resident's perceptions
of what fits with the coastal landscape is
distinctly different from visitors: Wohlwill's 1983
study assessed visual perception of simulated
levels of development on the Santa Barbara,
CA coastline; and Zube and
McLaughlin (1978) assessed
perceptions of visitors and
residents to photos of the Virgin
Islands coastline in St. Johns, In
both studies, residents were more
tolerant of coastal development if
economic income is generated to
benefit the community,
Other factors that affect visual
perception include the level of
existing development in an area,
the use of proposed development,
and age of the respondent. In
working or mixed-use coastal
areas, judgments are not clear-cut,
but visitors and residents tend to
be more critical of coastal
aesthetics in parks and
undeveloped settings than in
developed areas. Finally, older
residents are generally more tolerant of coastal
commercial development.
The only study that specially assesses visual impact
of docks on the coastal landscape was by Felts et al
(2001) in South Carolina. This was not a visual
perception study that asked respondents to react to
images or photos, but was a multi-item questionnaire
asking South Carolina residents a number of
questions about docks. The results of this study are
discussed later in this panel.
In summary, the major aesthetic impacts of docks
and piers are due to lack of upkeep. In addition to
Figure 21. Cross Lake "before" image (left) vs. Cross
Lake: Simulation. Note light/shadow + water texture
(From Smardon & Karp 1992).
43
Table 1. Review of coastal perception studies.
Methodology Positive Attributes Negative Attributes Source
Urban Los Angles water, activities, beach area inappropriate structures, Banerjee
respondents were shown high level of and Gollub
panoramic images and video development 1976
clips.
Photos of water resource beaver ponds, lakes, wildlife uncompleted projects, Gauger
development projects in pollution, oil tanks, and Wycoff
varying stages were sorted eroded banks, 1973
into piles according to scenic excavation
quality.
Scenic river boaters in river scenes, trees, houses set in the metal pipes, powerlines, Cherem
Wisconsin were given woods, rapids, developed recreation bridges, abutments and
cameras and told to areas Traweek
photograph both positive and 1977
negative aspects of the river
visual experience.
Preference ratings of mounted visually contrasting rocks and trees, lower relief, lower Knutsen,
3hotos were used visual island form variation, varied color and variety, presence of Leopold,
attributes of islands and texture, clear edges buildings and and
shoals within the Thousand development on the Smardon
Island area on the St. islands and shoals 1996
Lawrence River between US
and Canada.
In this study of landscape void of humans, habitat degradation, private Palmer
perception in Dennis exploitation 1978, 1983
Massachusetts on Cape Cod,
~60 photos taken by town
residents were sorted by the
town's people into piles
according to landscape type
and scenic quality.
Photos of representative lack of development litter and debris, erosion, Naiman
coastal areas were used to water appearance, 1987
assess perception of coastal presence of shoreline
areas throughout NY. structures
For this study of views to the views or access to water, vegetation, utilities, trailer parks, Smardon
St. Lawrence River from Cape natural landscape, rural image, water screening or blocking et al. 1987
Vincent to Hammond, NY, features, views to opposite shore, views, signage,
North Country residents and uniqueness, edge variety, superior or excessive vegetation,
students rated photos of elevated views, fences, dirt roads flat topography, general
views, clutter, boats and docks,
poorly maintained areas
Photos and video were taken islands with vegetation, marsh 'and oil tanks, rocky dike and Shannon
of views to the St. Lawrence emergent vegetation along the shoreline, industrial plant, industrial and
River from the road and from vegetation rising in steps, dense plant, power lines, Smardon
the water from Massena to vegetation down to the water, unique tree shipping lock, dam, 1990, 1996
Ogdensburg, NY were shown forms, golf course, grass area with steep rocky shoreline
to student subjects, grazing livestock, boat launch, grassy w/little vegetation,
knoll with little vegetation, stone causeway, power
breakwater, authority dam
Visual perception of views sense of mystery (they wish to be further developed or urbanized Steinitz
taken from the loop road in drawn into the scene), coastal landscape, evidence of 1990
Arcadia National Park in development that is generic to the Maine crowed use, tourist-
Maine was measured by landscape or with a distinctly" historical" oriented commercial
asking for positive and character, water views, long distance development
negative characteristics, views, '1olded" or multi-layered landscape
(typically mountains and islands), diverse
and well maintained vegetation
distribution in the foreground and middle
ground of the view.
44
deteriorated structures, water quality
considerations, wildlife disturbances, and the
spacing or density of docks were important.
These impacts can be mitigated by:
· Contrast reduction,
· Reduction in height and size,
· Using "natural" or "traditional" materials,
· Increasing the distance between docks,
· Enhancing public access,
· Providing interpretive sites (historic or
heritage uses), and
· Establishing setbacks along the shoreline for
other structures.
Recreation User Perception Studies
Beaches: Beach aesthetic preference studies
indicate a divergence in beach preference.
Higher educated older residents prefer natural
beaches with tow intensity of uses with attractive
trees, whereas younger users prefer city
beaches with facilities and do not mind crowds
(Cutter 1979, Peterson and Neuman 1969). In
general, cleanliness, convenience and
aesthetics are desirable (Cutter t979). Carls
(1974) found that greater numbers and
development reduces preference on
Massachusetts's beaches on Cape Cod.
Boating: Tolerance to crowds and user patterns
depends on the type of boater and whether the
boater is a resident or visitor. Power boaters are
most tolerant of other uses, sailing boaters are
less tolerant, and fishing and non-motorized
boaters are least tolerant of multiple uses (Lime
1970). Permanent residents are more
concerned about displacement, safety, litter and
marine waste then visitors (Droggin et al. 2000).
Water Quality: Literature on
perceptions of water quality by
recreational users indicates
concern for impacts of boating
activity associated with docks.
Water quality problems
commonly mentioned by
recreational users are: films of
gas and oil, solid waste
(bottles and cans), use of
pesticides and herbicides,
sedimentation/turbidity, beach
pollution. Boaters are most
sensitive to water quality and
are the first to notice muddy or
foamy, unusual colors and objects, green scum
and algae, sewage, and solids. Fisherman
Historic water structures are generally considered
scenic, tourist-like commercial structures are disliked.
(Photo credit: J. Gates)
notice films and dead fish, and cottage owners notice
strange odors, algae, and skin irritations.
Shoreline Planning
Guidance material for coastal planning purposes and
docks is part of the Wisconsin Sea Grant Coastal GIS
Applications Project (Hart and Sutphin, undated and
http://www.coastaUiclwisc.edu/bluelake.htm). This
site includes alternate layouts for coastal planning
with an interactive GIS/3D animated software that
allows one to envision different coastal development
futures under different zoning and setback
requirements. In terms of prescriptive planning and
design guidance - the most detailed for coastal
development is the Victoria Coastal Council's (1988)
Siting and design principles on web site
http://www.vcc.vic.(~ov.au/sitino/auidelines.htm
Shoreline regulations
Many states have regulations governing coastal zone
land use (Smardon and Karp 1992) and marina siting
and operation. Shoreline and
water area zoning has been
proposed, but is rarely
implemented. Only two water
body areas (to authors
knowledge) have restrictions
on the number of docks, or
dock length and design: Lake
Tahoe, (Smardon t992,
1997) and lakes in the
Adirondack Park in New York
State (Smardon 1992).
Because of the Lucas case
Coastal development can impact views.
(Photo credit: R. Smardon) in South Carolina (see Nolan
1997) and the threat of
takings of private property rights via regulation of
allowed coastal uses and development - one needs
to be extremely careful in this area.
45
Question & Answer Period
How do you know that, if you follow the process and get public input, that the result (change in
visual impact) arises from the process rather than from getting people to simply communicate?
The process is good for getting an iterative discussion started.
Comment: In our experience in Maine, it doesn't matter whether it is the process or not--you get same
result.
How many view points do you use - only one?
No, six or seven is the magic number.
Q. Do these analyses actually lead to design changes?
46
A. Yes, often when we recommended that project proponents 'soften" the structures they do as
means of gaining public acceptance, In mar~y instances aesthet cs became a huge issue with t~'
public and were fundamental to getting these projects done.
Q. Could you do it back_w.,a_rds? Take developed shoreline and restore it?
A. Probably not, but that s an interesting idea. Reactions vary. People are attached to things in the
landscape.
Judy Gates
Maine Department of Environmental Protection, Division of Land Resource Regulation
In recent years there has been a growth in
permit applications for docks and with it an
increased expectation for att-tide access which
means that structures must have heavier
construction and be larger in size and length.
The Maine Natural Resources Protection Act
(NRPA) (Title 38 § 480, A-Z) specifically
requires an applicant for a dock or other coastal
structure to "demonstrate that a proposed
activity will not unreasonably interfere with
existing scenic and aesthetic uses." The
supporting regulation, Chapter 315, has been
developed over the past year to provide a tool
for assessing and mitigating impacts to existing
scenic and aesthetic uses.
Maine's DEP has found that to get the highest
level of protection, it needs to get involved with
the first structure in a newly developing area. In
the past 5 years they have denied permits for
docks proposed in places were there was no
previous development.
There have been several court cases that tested
decisions under these rules, including:
· Kolsaka vs. ME--in this case a permit denial
was overturned because it was "too vague";
and
· Anne Hannum vs. ME Board of
Environmental Protection--in this instance
the proposed pier interfered with aesthetics
and boat traffic. Additionally, there was
potential for interference with seal pupping
and endangered terns that are about a
quarter of a mile away. The ruling was
based on the use of the structure, not the
structure itself~
In response to a concern that future cases will
be lost because the NRPA standard concerning
existing scenic and aesthetic uses is
Undeveloped coastline in Maine. (Photo credit: J. Gates).
unconstitutionally vague, Maine's Department of
Environmental Protection developed Chapter 315.
This chapter codifies and standardizes aesthetic
concepts by
· Specifying state regulatory concerns,
· Defining visual impacts,
· Establishing a procedure for evaluating visual
impacts,
· Establishing when a visual assessment may be
necessary,
· Explaining the components of a visual
assessment, and
· Describing avoidance, mitigation, and offset
measures that may eliminate or reduce adverse
impacts to existing scenic and aesthetic uses.
Under Chapter 315 visual impacts will be determined
by considering:
· Landscape compatibility of the proposed
structure;
· Scale contrast; and
· Spatial dominance.
47
This process has played out in a series of
decisions illustrated in Figures 22 - 24. In Case
1, a large coastal resort proposed a marina for
its users that would have blocked a public view
of a historic beakwater and lighthouse. This
application was withdrawn after the DEP issued
a draft denial based on the projects impact on
existing scenic uses. In Case 2 the proposed
dock was allowed because it did not interfere
with scenic values of the viewshed. In Case 3,
DEP found that the proposed dock would
interfere with significant public scenic views and
asked the proponent to consider other locations.
This case is particularly interesting in that there were
no direct resource impacts from this individual dock.
However, the dock would have been located in the
only natural fjord on the East coast and would have
been the only dock visible for users of Acadia
National Park viewing the fjord from a popular hiking
trail. Consequently the project was denied, but at this
date is still within the timeframe for appeal. In this
instance, the denial was partly based on existing
alternatives for coastal access available to the
applicant that would preclude construction of the
proposed pier.
Figure 22. Case 1: The application for this dock was withdrawn after visual impact assessment
revealed that it interfered with public scenic views.
The Samoset resort is adjacent to the 100 y.o. Rockland
Breakwater. The Resort itself has already changed the
character of the shoreline, so looking solely at the view
from the water and considering the developed nature of
Rockland Harbor, visual quality might not be at issue.
The resort has historically allowed the public to cross
from a neighboring park, across the intertidal and
subratidal to access the breakwater. This is the only
access point to the breakwater,
From the park and beach, the public has an
unobstructed view of the mile long breakwater and the
lighthouse at the end, as well as a view of Owls Head
across the bay.
A modified photo showing the proposed marina's
proximity to the Rockalnd breakwater, The proposal
placed the pier directly next to the park. Because
the pier would have been higher than the
breakwater, the public's view of and access to the
breakwater would have been impeded, Faced with
a draft denial, the applicant withdrew.
48
Figure 23. Case 2: The ME DEP determined that this pier (left), which had the dubious benefit of being permitted
after it was built, did not interfere with the reason that the view was found to be scenic. As is not unusual, the party
declaring a scenic impact was a neighbor, whose grandfathered lot potentially constituted a larger impact to the
visual quality of the north side of the island (right). This project caused the DEP to think carefully about whose view
they are charged with protecting, and reinforced the concept that it is the public's view that the legislature was
concerned with when it adopted the NRPA.
Figure 24. Case 3: Looking toward the shore where the
pier was proposed, it was easy to determine that the
dock would not interfere with the visual quality of the
shoreline any more than the existing development (top
right). This was not the first pier proposed in the area,
and in fact there are several along the adjacent shoreline
(bottom left). Cumulative impact may have been an
issue, but in this case there is a good distance between
the piers and the additional direct impacts from this pier
were unlikely. However, the coastal resource of concern
is Somes Sound, the only natural fjord on the east coast.
The view in this photo (bottom right) is from the top of
Flying Mountain, one of the most popular hikes in Acadia
National Park. The proposed dock would be clearly
visible from the trail and summit of Flying Mountain,
while the existing docks are not,
49
The DEP initiated development of the guidelines
in April 200t and held an internal review in
October 2002. The draft rule has been posted
and a public hearing will be held April 3, 2003,
with public comments due by April 14.
As part of the process, a Standard Operating
Procedure (SOP) for visual assessments was
developed to provide consistency in decision-making
among staff and improve the decision-makers' ability
to document decisions. Under the new process, it is
predicted ~hat less than one percent of applications
will have any additional requirements beyond what
the law and the DEP already require.
Question & Answer Period
Q. Have any oca governments adopted this process?
A. Not yet, local governments seem to be waiting until the rules pass all of the legal hurdles,
Q. What alternatives to building a dock are considered (i.e., ,,m_arina slips, moorings, etc.)?
A. We cons der what app cant~ a ready ho d as we as what s avai able.
Q. Do you consider the objections of neighbors with scemc issues?
A, Yes, but not exclusively. We are mu(~h more concerned with the pubtic's view as specified in the
preamble of the NRPA, We primarily look at the viewshed from publicly accessible viewpoints.
How sensitive do yOL have to be to comments from self-interested commentators (realtors,
developers) on the new rule,'?
A. We have spoken with them throughout this process. They d like to see more consistency as well.
Chapter 315 is simply further guidance - the existing regulations already require applicants to
show that their project will meet all of the NRPA standards.
Q. How does this proposed rule on visual effects work with other rules regarding ecology etc.? Are
the processes the same?
A. The same department considers water quality and the other factors.
Richard Chinnis
South Carolina Department of Health and Environmental Control,
Office of Coastal Resource Management
In South Carolina permit applications have
increased ten-fold over the past 20 years, from
80 in 1982 to over 800 in 2002. In addition,
many docks are now designed with lifts to bring
boats out of the water. This has had the benefit
of keeping boats off the mud bottom but it has
the adverse effect of allowing larger boats to
dock in small tidal creeks (Fig. 25).
Existing regulations in South Carolina set the
maximum length of docks at 1000 feet. State
managers have attempted to have this
shortened to 500 feet, but legislative support is
lacking.
Figure 25, The use of boatlifts means that now you see not
only the dock, but the entire profile of the raised boat as
well. (Photo credit: R. Chinnis).
50
To find out more about public
perceptions of docks, the DHEC
sponsored two public attitude
surveys that were conducted by
Felts et al.
Figure 26. Proposed docks across from the historic Magnolia Gardens
were denied because they would interfere with scenic views from the
garden. (Photo credit: R. Chinnis).
Managers in South Carolina have the authority
to review docks for visual impacts. To date, they
have had a 100% success rate in denying
permits on these grounds in areas designated
for special protection such as the Ashley River.
In one instance a project proponent subdivided
her property and proposed
to build a dock on each of
seven lots. Her property
was across the river from
a Historic garden (Fig. 26).
After testimony to the
effect that the docks would
degrade the visual
enjoyment of visitors to the
public garden, the permits
were denied.
Last year, there were 42
appeals of dock permits.
In most oases, the
appellants were annoyed
that too many docks are being permitted without
consideration of cumulative or aesthetic impacts.
One sought opinions from coastal
residents, the second from dock
owners. Generally, people feel that
docks add to property values. A
court assessor claimed that a
permit alone can enhance property
value by $300-600K. Furthermore,
the majority (~75%) of residents of
coastal counties felt that:
· property owners should be
allowed to build a dock,
· docks are not harmful to the
aquatic environment,
· docks do not take away from
views, and
· there are not too many docks.
However, 66% of dock owners and
50% of residents agreed that docks
should be regulated and their size
restricted. Half of those surveyed thought that
boating uses are harmful, and 59-76% felt that there
are places where docks should not be built.
If they have to be regulated, most residents felt that
regulation by local, rather
than state government is
more appropriate.
However, local
governments do not want
to do the regulation--they
have neither the budget
nor expertise.
Presently, docks are
limited to three feet above
mean high tide and four
feet in width and can only
be built on lots 75 ft wide
or wider. Despite
resistance to restrictions
on roofs or coverings (as
indicated in the survey), present regulations do not
allow roofs if no one else near by has one. Where
they are allowed the maximum is 12 ft above the
deck level including peak of roof, weather vane, etc.
51
Q.
A.
Q.
A.
A.
Q.
A.
Question & Answer Period
Do you consider other structures in the area?
No, because we use dated (1986) aerial photos.
In Loyd Harbor, NY, they had two assessors look at values of properties with and without docks.
The potential to have a dock (or having one) didn't affect property value. The value of the
watedront lot was similar to inland lots, development pattern and services were more important.
So were the increases in property value real or perceived?
Analyses have not been conducted, but our opinions regarding these sorts of property value
impact issues are based on the testimony of appraisers in court.
Can you argue that a neighbor's dock devalues surrounding property values?
That question was asked in the survey. The public does not think this is the case.
Is there a correlation between dredging requests and proliferation in docks?
Not really. We do not permit dredging in natural creeks along which most Of these docks are built.
Do you have a sense of the demographics of people interviewed for survey?
It was weighted toward white-collar college graduates. For more information take a look at the
website. It can be downloaded from the Hot Topics section of the South Carolina Department of
Health and Environmental Control website: http:#www.s~dhec.net/ocrm/.
How do you deal with shading?
We deal with shading by requiring dock master plans that show alignment. We have some
flexibility, but other than specific regulations we can't do much about height and width.
What are dock master plans?
They are part of our newer process. Any project that requires another permit (£e., wastewater)
from the state or federal government must provide a dock master plan according to specific
guidelines. Applications are posted for the public on the website every week (see
http://www.scdhec.net/ocrm/).
Are dock master plans required in previously developed areas?
No, only since 1993 have dock master plans been required.
No pictures were shown during the survey to participants? It is somewhat scary to have that
survey out there.
That is correct, the survey was conducted on the telephone. We had no role in designing the
survey--showing participants some pictures might have resulted in a different response.
52
MANAGEMENT RESPONSE
Following the presentations, the managers were asked to respond, either commenting on how the
material presented met their needs or to make recommendations for best use of the materiaL The
following are drawn from that discussion.
Comment: This sort of workshop is taking us in
the right direction. There is a strong need
for research that will quantify impacts and
help managers explain why they are
approving or denying docks. Managers
need to know what species and habitats will
be affected and whether there is the
possibility of mitigating
the impacts~
The idea of a
conceptual model is
very welcome. Based
on such a model,
managers could
generate an overall
p~an, policy, or
guidelines to avoid
site-by-site analyses.
Scientifically backed,
broad policies add to predictability and
understanding by legislators--whose
support is critical--and the regulated
community.
Comment: Matrices have been used in some
instances with a fair degree of success. In a
proposed sub-division in Delaware the
developer promised a dock for each of some
40+ lots. Rather than reviewing this many
individual permits over time, state managers
developed a generat plan that assessed the
cumulative impacts and determined that the
system could handle 20 docks without
unacceptable impacts. Under appeal, it was
found that this was a reasonable approach
and the 20-dock limit was upheld.
of cumulative impacts. While managers have
some sense of the impacts of individual docks, it
is not known whether cumulative impacts are
additive, exponential or otherwise. Additional
research on systems where there are multiple
docks is necessary.
Comment: It is important
to put proposed docks in
their environmental
context. In South
Carolina, where there is
a considerable amount of
salt marsh, shading
impacts may be minimat
when compared with the
amount of the resources.
In other states, or even in
particular creeks in South
Carolina, full build-out
may not be appropriate,
Comment: There needs to be an assessment of the
impacts of the "no build option" as well as from
dock construction and use. if a dock is not
permitted, the result may be additional foot traffic
across a marsh or tidal flat or boat storage on the
shore. We have little solid data on the impacts of
this sort of use as compared with a dock to meet
the same needs.
Comment: it was very useful to get a better
understanding of the validity of viewshed
analyses. This information needs to be
incorporated in project assessment and the
techniques need to be more widely disseminated.
Comment: Managers realize that it is difficult if
not impossible to establish specific
thresholds or standards for all impacts.
However, the best available information on
the various impacts will help managers
make more informed decisions on
approvable designs and on when a
proposed project should be denied.
Comment: There is little information on the topic
53
Comment: There has been little peer-reviewed
information published on the topic of
shading impacts to salt marsh vegetation. It
is important to have better information on
this topic and perhaps more research.
There presently is no tool available to
managers to predict shading impacts.
Comment: Better outreach to the affected
community and their legislators and elected
officials is critical. Providing defensible
science-based information can help frame
policy and regulatory decisions and lead to
acceptance. It is often difficult to clearly
explain and justify changes in regulatory or
assessment processes and consequently
there is a need for clear scientific data. Along
with any guidelines should be a clear rationale of
what the intended goal is and on what
information decisions will be based.
Comment: There is a need for flexibility in the review
process. By identifying and clearly stating social
and environmental goals and putting each project
into its context decisions will be more
understandable. -this requires the development
of critical decision points for these goals.
Comment: A~I of this underscores the need for the
development of a conceptual model or matrix to
be utilized in decision-making.
54
RECOMMENDATIONS
Coastal Planning and Regulation
· Base licensing decisions on small docks on __
impacts to habitats, water quality, and
existing uses, which include navigation, --
recreation, and scenic and aesthetic
values.
· Mandate that the purpose and use of a
dock be water dependent.
· Educate that public trust and riparian rights ~'~ - ~,
only allow waterside property owners ~ ~'~
access to the water--the use of public
waterways for a dock is a privilege, not a
right of ownership. There is no absolute
right to a dock for a large boat.
· Charge responsible application fees for the
use of public trust lands where managers
rely on permitting to regulate docks. Fees
should reflect the property value increase
the dock owner wilt receive and a portion of
the fees should be applied to mitigating for
lost or damaged resources associated with
the permitted structure.
· Incorporate results from environmental and
socioeconomic assessments to develop
regional scale dock policies that (1) provide
incentives for home owners who elect not to have
docks or groups of homeowners that chose a
shared dock strategy (e.g. reduced property
taxes for short-term and permanent easements
against a dock), and (2) include a dock mitigation
strategy and plan that can be supported at the
local, state, and national level.
Environmental Mitigation Strategies
· Minimize shading impacts on vegetation by
limiting the following parameters:
Height: maintain a four-foot minimum
elevation over the marsh face or mean
high water (In New England that height
may need to be greater.)
Width: limit the width to a
maximum of four feet (with
exceptions for handicap
access and American
Disabilities Act issues)
Orientation: orient as close ~
as possible to North-South.
Length: limit length to the
minimum needed to reach
water navigable at mean
Iow water.
· Consider alternatives to CCA-
treated lumber in areas of Iow
flushing.
· Reduce shading impacts by using grated
material as decking (especially in Southern US).
· Increase illumination under docks by
incorporating light tunnels or reflective deck
bottoms.
· Keep heavy equipment off the
marsh face unless it is
especially designed to avoid
peat compaction. Float
construction materials in from
the water side, and work as
much as possible from the
water or existing structures.
· Avoid high pressure jetting for
piling installation--sharpen
piling tips and make initial
insertion with Iow pressure
jetting or by utilizing a drop
hammer.
55
Accounting for Visual Impacts
· Consider aesthetics in the permitting
process.
· Predict aesthetic impacts reliably by
incorporating Visual Impact Assessment
techniques into the permitting process.
· Conduct public opinion surveys to establish
general values and levels of awareness;
they are greatly improved when preceded by
a visual characterization. (The surveys do
not provide aesthetic valuations.)
Minimizing Impacts to Navigation
· Discourage structures that extend >25%
across a waterway
· Redirect structures extending into Federal
Navigation Projects or traditional navigation
paths.
56
RESEARCH NEEDS
Subsequent to the presentations, the managers in attendance met to discuss research needs from their
perspective. These are summarized in the following list. No priorities were applied to the items on the
list.
· The cumulative impacts from docks and their associated uses and how they can be avoided,
minimized or mitigated.
· The relationship between the presence, construction, and/or use of docks and vegetative habitat
fragmentation.
· The regional differences, if any, between impacts from docks.
· Light requirements for marsh and submerged aquatic vegetation by region.
· A method or model to predict shading impacts from proposed docks.
· Better understanding of impacts to shellfish and fisheries, habitat for shellfish and fisheries, and
on shellfishing and fishing.
· Monitoring protocols to measure impacts from docks over time.
· Impacts of docks on sediments, sedimentation, and hydrodynamics.
· Public perceptions and understanding of the benefits and detriments of docks.
· The impacts of a no-build scenario (i.e., foot traffic, dingy storage, etc. on inter-tidal and supra-
tidal resources.
· Better understanding of the overall effects of docks and their associated uses on: resource
functions, characteristics, and values; development and aesthetic characteristics and values; and
human uses of coastal areas and resources.
Non-research needs identified by the managers included:
· Additional information on the technical aspects and capabilities of dock design and construction in
order to minimize impacts.
· Establishment of an outreach or education plan and materials to inform the general public and
those seeking to construct docks about potential impacts, purposes and nature of regulatory
programs, and techniques of dock construction.
57
BIBLIOGRAPHY RESULTING FROM THE WORKSHOP
During the course of preparing for and presenting this workshop an extensive bibliography was
developed. This will be supplemented and posted on the NOAA National Centers for Coastal Ocean
Science website: http://www.coastalscience.noaa.gov. Full references for literature cited in this report are
included in the online bibliography.
The bibliography is searchable for the following keywords: vegetation, shading, contaminants, sediments,
boating, recreational uses, navigation, planning, public access, recreation, and aesthetics, as well as by
author, and title.
58
FUTURE STEPS
Prepare a peer-reviewed synthesis document on the impacts of small docks.
It was strongly suggested that there is a need for a thorough, peer-reviewed synthesis report on the state
of the scientific knowledge related to the impacts of small docks. The background paper included in this
proceedings provides a starting point but a much more thorough review is needed.
In addition to expanding on the material in the background paper prepared prior to the workshop, the
synthesis document should:
· Address regional differences in affected environment, dock design and impacts
· Provide a clearer description of the nature of the problem(s)--real or perceived
· Characterize the various designs and construction of docks (i.e., the range of structures) as welt as
the activities related to dock use
· Determine impacts for each element of dock structure (e.g. pylons, etc.)
· Address both project-specific and cumulative impacts.
Develop bibliography related to the science of dock impacts.
As part of the preparation and presentation of this workshop, an initial bibliography related to docks was
prepared. Several of the presenters submitted additional bibliographic material. This should be
expanded and made availablo possibly through a web site--for researchers and managers. Plans
should be made to maintain the bibliography with current research.
Host additional workshops on:
· Available technologies for dock design and construction
This workshop would bring together managers, representatives of the dock design and construction
industry, and those famitiar with new and innovative techniques and materials to help managers
better understand the options available in dock design and construction.
· Available management techniques: regulatory and non-regulatory
A workshop providing information on the management techniques and tools available at the local,
state, and federal level would provide a basis for refining planning and regulatory programs. This
should include a review of the legal parameters that apply to docks and case studies of successful
(and perhaps unsuccessful) programs.
Prepare a state-by-state checklist of regulatory tools and programs used to manage docks and
precedent-setting court decisions.
Present workshop findings. The following presentations are scheduled:
· Emerging Technologies, Tools, & Techniques - January 2003, Coco Beach, FL
· Southeast Coastal Program Managers' Meeting - February 2003, Wrightsville Beach, NC
· Coastal Zone '03 - July 2003, Baltimore, MD
· Society for Conservation Biology Annual Meeting - June 2003, in Duluth, Minnesota
Establish a dedicated web site for dock impacts and management discussion.
Develop a checklist of known and potential/implicated impacts from small docks.
Develop a conceptual model that will allow managers to assess the impacts of single dock
proposals or develop a regional dock management plan.
59
APPENDIX 1: PARTICIPANTS' CONTACT INFORMATION
Address P hone Emall
Name
Clark Alexander Skidaway Institute of 912.598.2329 clark~skio. Deachnet.edu
Oceanography fax:
10 Ocean Science Circle 912,598,2310
Savannah, GA 31411
Rick Ayella MD Dept. of the Environment 410.537.3835 ravella~mde.state.md.us
1800 Washington Bird
Baltimore, MD 21230
David Blatt CT Dept Environmental Protection 860,424.3034 david.blatt~Do.state.ct.us
79 Elm Street fax:
Hartford, CT 06106 860.424.4054
Steve Bliven Bliven & Sternack 508.997.3826 Bliven~attbi.c(~m
49 Plains Field Drive fax:
South Dartmouth, MA 02748 508.997.3859
Jerry Brashier Permitting Bureau Director 228.374.5022 Jerrv.brashier~dmr.state.ms.us
Division of Marine Resources x 5028
1309 Rosemont Drive
Gautier, MS 39553
Dave Burdick Jackson Estuarine Laboratory 603.862.2175 dburdick~cisunix.~nh.edu
University of New Hampshire
Durham, NH 03824
Allison Castellan NOAA, OCRM 301.713.3155 Allison.Castellan(~noaa.oQv
1305 East West Highway, Room x225
11208
Silver Spring, MD 20910-3282
Richard Chinnis OCRM 843.747.4323 chinnira(~dhec.sc.oov
SC Dept. Health & Env Control x 129
1362 McMillan Ave, Suite 400
Charleston, SC 29405
Rick Crawford Nautilus Environmental Services 508.790.8322 rcrawfordCwhoi.edu
1815 Falmouth Road, Unit H-2
Centerville, MA 02632
Torrance Dowries Connecticut River Estuary Regional 860.388.3497 ihtdownes01~vahoo.com
Planning Agency
455 Boston Post Road
P.O. Box 778
Old Saybrook, CT 06475
Judy Gates Division of Land Resource Reg. 207.287.7691 Judv. Gates~maine.eov
Maine DEP
17 State House Station
Augusta, ME 04333
Andrea Geiger Coastar States Organization 202.508.3860 aoeioer~sso.org
Hall of States, Suite 322
444 North Capitol St, NW
Washington, DC 20001
Truman Henson Massachusetts CZM 508.362.1760 Truman. Henson('~state.ma.us
3195 Main Street, Route 6A
P.O. Box 220
Barnstable, MA 02630
Mike Johnson NMFS Northeast Regional Office 978.281.9130 Mike. R.Johnson~noaa.aov
One Blackburn Drive fax:
Gloucester, MA 01930-2298 978.281.9301
Ruth Kelty National Centers for Coastal Ocean 301.713-3020 ruth.keltv(~noaa.aov
Science x 133 Fax
1305 East-West Highway, SSMC 4, 301.713.4353
6O
rm. 8215
Silver Spring, MD 20910
Dave Killoy NE District 978.318.8490 David. H.Killov~usace.armv.mil
US Army Corps of Engineers
698 Virginia Road
Concord, MA 01742-2751
Mike Ludwig NMFS NE Fisheries Science 293.882.6504 MichaeI.Ludwia~noaa.aov
Center
Habitat Conservation
Milford Laboratory
212 Rogers Ave
Milford, CT 06460-6499
Bill Meyer DE Dept Nat Res & Env Control 302.739.4691 william.mover~state.de.us
Div. Water Resources
89 Kings Highway
Dover, DE 19901
Ed Reiner US EPA Region 1 617.918.1692 Reiner.ed(~eea.eov
1 Congress St., Suite 1100 (CMA) fax.
Boston, MA 02114 617.918.0692
Steve Resler NYCMP-NYS Dept. of State 518.473.2470 sreslerCdos.state.nv.us
41 State Street fax:
Albany, NY 12231-0001 518.473.2464
Steve Rumrill South Slough National Estuarine 541.888.2581 Steve. Rumrill@state.or. us
Research Reserve x 302
P.O. 5417 fax
Charleston, OR 97420 541.888.3250
Denise Sanger Marine Resources Research Inst. 843.953.9087 sanoerd(~mrd.dnr.state.sc.us
Marine Resources Div. SCDNR
217 Fort Johnson Rd.
Charleston, SC 29412
Deborah Shafer EE/W 601.634.3650 ShaferDC)wes.armv.mil
Army Corps of Engineers fax:
Waterways Experimental Station 601.634.3205
3909 Halls Ferry Road
Vicksburg MS 39180
Richard Smardon SUNY-ESFSyracuse 315.470.6636/ rsmardon~mailbox.svr.edu
106 Marshall Hall 6576
1 Forestry Drive fax:
Syracuse, NY 13210 315.470.6915
Susan Snow- Massachusetts CZM 617.626.1202 Susan.snow -cotter('~state.ma.us
Cotter 251 Causeway Street, Suite 900
Boston, MA 02114-2199
Ron Thom Battelle Marine Sciences Lab 360.361.3857 Ron. Thom~Dnl.aov
1529 W. Sequim Bay Road fax: 360-681-
Sequim, WA 98382 3681
Peddrick Weis Dept of Radiology/G-621 973.972.4409 weis~umdni.edu
UMDNJ - New Jersey Medical
School
Newark, NJ 07101-1709
61
OTHER TITLES IN THE DECISION ANALYSIS SERIES
1. Synthesis of Summer Flounder Habitat Parameters (K.W. Able and S.C. Kaiser, May 1994)
2. Technology and Success in Restoration, Creation and Enhancement of Spartina Alterniflora Marshes
in the United States [2 volumes] (G. A. Matthews and T.J. Minello, August 1994)
3. Bibliography of Synthesis Documents on Selected Coastal Ocean Topics (E.V.Collins, M. Woods, I.C.
Sheiffer, J. Beattie, October, 1994)
4. Marine Eutrophication Review (K.R. Hinga, H. Jeon, N.F. Lewis, January 1995)
5. Economic Valuation of Resources: A Handbook for Coastal Resource Policymakers (D.W. Lipton, K.
Wellman, June, 1995)
6. Methodologies and Mechanisms for Management of Cumulative Coastal Environmental Impacts
(Vestal, B., A. Reiser, et al., 1995)
7. Forestry Impacts on Freshwater Habitat of Anadromous Salmonids in the Pacific Northwest and
Alaska - Requirements for Protection and Restoration. (M.L. Murphy, October, 1995)
8. Watershed Restoration - A Guide for Citizen Involvement in California (W.F. Kier, December 1995)
9. Atmospheric Nutrient Input to Coastal Areas - Reducing the Uncertainties (R.A. Valigura, W.T. Luke,
R.S. Artz, B.B. Hicks, June, 1996)
10. Harmful Algal Blooms in Coastal Waters: Options for Prevention, Control and Mitigation (D.F. Boesch,
D.M. Anderson, R.A. Horner, S.E. Shumway, P.A. Tester, T.E. Whitledge, February, 1997)
11. Change in Pacific Northwest Coastal Ecosystems (Edited by G.R. McMurray and R.J. Bally, April,
1998)
12. Guidelines for the Conservation and Restoration of Seagrasses in the United States and Adjacent
Waters (M.S. Fonseca, W.J. Kenworthy, and G.W. Thayer, November 1998)
13. Bering Sea FOCI Final Report 1998 (Edited by S.A. Macklin, December 1998)
14. Nutrient Enhanced Coastal Ocean Productivity in the Northern Gulf of Mexico (Edited by Wiseman,
Rabalais, Dagg & Whitledge 1999)
15. Characterization of Hypoxia: Topic 1 Report for the Integrated Assessment on Hypoxia in the Gulf of
Mexico. (Rabalais, N., R.E. Turner, D. Justic, Q. Dortch, and W. Wiseman Jr. 1999)
16. Ecological and Economic Consequences of Hypoxia: Topic 2 Report for the Integrated Assessment
on Hypoxia in the Gulf of Mexico. (Diaz, R.J., and A. Solow. 1999)
17. Flux and Sources of Nutrients in the Mississippi-Atchafalya River Basin: Topic 3 Report for the
Integrated Assessment on Hypoxia in the Gulf of Mexico. (Goolsby, D.A.W.A. Battalin, G.B.
Lawrence, R.S. Artz, B.T. Aulenbach, R.P. Hooper, D.R. Kenney, and G.J. Stensland. 1999)
18. Effects of Reducing Nutrient Loads to Surface Waters within the Mississippi River Basin and the Gulf
of Mexico: Topic 4 Report for the Integrated Assessment on Hypoxia in the Gulf of Mexico. (Brezonik,
P.L.V. Bierman, Jr., R. Alexander, J. Anderson, J. Barko, M. Dortch, L. Hatch, G. Hitchcock, D.
Kenney, D. Mulla, V. Smith, C. Walker, T. Whitledge, and W.J. Wiseman, Jr. 1999)
19. Reducing Nutrient Loads, Especially Nitrate-Nitrogen to Surface Water, Ground Water, and the Gulf
of Mexico: Topic 5 Report for the Integrated Assessment on Hypoxia in the Gulf of Mexico. (Mitsch,
W.J., J.W. Day, Jr., J.W. Gilliam, P.M. Groffman, D.L. Hey, G.W. Randall, and N. Wang. 1999)
20. Evaluation of the Economic Costs and Benefits of Methods for Reducing Nutrient Loads to the Gulf of
Mexico: Topic 6 Report for the Integrated Assessment on Hypoxia in the Gulf of Mexico. (Doering,
O.C., F. Diaz-Hermelo, C. Howard, R. Heimlich, F. Hitzhusen, R. Kazmierczak, J. Lee, L. Libby, W.
Milon, T. Prato, and M. Ribaudo. 1999)
21. COASTAL: The Potential Consequences of Climate Variability and Change. (Edited by D.F. Boesch,
J.C. Field, and D. Scavia. October 2000)
22. Environmental and Aesthetic impacts of Small Docks and Piers, Workshop Report: Developing a
Science-Based Decision Support Tool for Small Dock Management, Phase 1: Status of the Science.
(Kelty, R.A. and S. Bliven. January 2003)
62
U.S. Department of Commerce
National Oceanic and Atmospheric Administration
Coastal Ocean Program
1315 East-West Highway
Silver Spring, Maryland 20910