Vegetated buffers in the coastal zone a summary review and bibliography

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Alan Desbonnet
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Pamela Pogue
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Virginia Lee
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Nicholas Wolff

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This publication was funded by the NOAA Office of Sea Grant,
U.S. Department of Commerce, under Grant #NA 89 AA-D-SG-
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This document should be referenced as:
Desbonnet, A., P. Pogue, V. Lee and N. Wolff. 1994. Vegetated
Buffiei-s in the Coastal Zone-A SuminarY Review and Bihliogra-
ph@v. Coastal Resources Center Technical Report No. 2064.
University of Rhode Island Graduate School ofOceanography.
Narragansett, RI 02882. 72 pp.

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Vegetated Buffers
in the Coastal Zone

A Summary Review
and Bibliography

Alan Desbonnet
Pamela Pogue
Virginia Lee
Nicholas Wolff

Coastal Resources Center
Rhode Island Sea Grant
University of Rhode Island

July 1994

ISBN 0-938 412-37-x

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CHAS. SC 29408-2623

Acknowledgments

We are grateful to the many people who provided material and insights for
this manuscript: Dr. Art Gold - Department of Natural Resource Science, Univer-
sity of Rhode Island; Grover Fugate, Dave Reiss, Mark Imperial, Jeff Willis, and
Jim Boyd - Rhode Island Coastal Resources Management Council; Scott'Millar -
Rhode Island Department of Environmental Management. We also gratefully
acknowledge the Pell Library staff at the University of Rhode Island Graduate
School of Oceanography for collecting many manuscripts and publications that
were difficult to find. Comments, suggestions, and critical review of the manu-
script by Peter Groffman, New York Botanical Garden, Institute of Ecosystem
Studies; Heather Crawford, Connecticut Sea Grant; Elizabeth Gibbs and Tony -
Corey, Rhode Island Sea Grant; and Laurie McGilvray, National Oceanic and,
Atmospheric Administration, Office of Ocean and Coastal Resource Manage-
ment,.greatly improved the finished document from earlier versions.

Table of Contents

Acknowledgments
1. Introduction ......................................................................................................................................5
� Definition of vegetated buffer ......................................................................................................5
� Multiple benefits ..........................................................................................................................6
11. Vegetated Buffer Use and Effectiveness: A Review .....................................................................9
0 Nonpoint Source Pollution Control ...............................................................................................9
0 Critical Variables Affecting Pollutant Removal ...........................................................................9
Surface Water Flow ........................................................................................................... 10
Groundwater Flow ............................................................................................................. 10
Slope .................................................................................................................................. 11
Soil Characteristics ........................................................................................................... 12
Pollutant Characteristics .................................................................................................... 13
VegetationType ................................................................................................................. 14
Grasses ........................................................................................................................... 15
Woody-stemmed Species ................................................................................................. 18
Buffer Width ...................................................................................................................... 19
Removal of sediment and suspended solids ................................................................... 21
Removal of total and nitrate-nitrogen ............................................................................ 24
Removal of total phosphorus ......................................................................................... 24
Performance standards .................................................................................................. 24
w Wildlife Habitat Protection ........................................................................................................ 26
a Erosion and Flood Control .......... :,** ............. 29
0 Historical and Cultural Preservation .......................................................................................... 31
0 Scenic and Aesthetic Enhancement ............................................................................................ 31
0 General Guidelines for Multiple-use Vegetated Buffers ............................................................. 31
0 Implementation Approaches to Multiple-use Vegetated Buffer ................................................ 32
The "Ideal" Buffer ............................................................................................................ 34
Contour .......................................................................................................................... 34
Vegetation ...................................................................................................................... 34
III. Use of Vegetated Buffers in the Coastal Zone .......................................................................... 37
� Application and Approach .......................................................................................................... 37
� Public Perception ....................................................................................................................... 37
a Management and Maintenance .................................................................................................. 38
� An Example: Rhode Island's Coastal Buffer Program ............................................................... 38
� State Coastal Buffer Programs: A Summary .............................................................................. 39
IV. Selected Bibliography .................................................................................................................. 47
V. Appendices ..................................................................................................................................... 65
Appendix A - The Rhode Island Coastal Zone Buffer Program .......................................................... 65
Appendix B - The Rhode Island Coastal Zone Buffer Program: Management Guidance ................... 69

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1. Introduction surface water runoff. As a result of their association
with reducing the impact of development and
Recent events, such as algae blooms; fish kills; landscape alteration on water resources, vegetated
closure to harvest of finfish and shellfish stocks; buffers are now being routinely employed as a tool
increased coastal development, tourism, and recre- for managing the environment. Vegetated buffers
ation; loss of tidal wetlands and wildlife habitat; and are often implemented, for instance, to mitigate the
scenic degradation of coastal viewsheds, all have effects of nonpoint source pollution by removing
increased our awareness of the need to preserve, pollutants from runoff through plant and microbial
protect, and restore our nation's coastal resources. uptake, microbial degradation and conversion,
The problems observed along the coastal zone are physical trapping, and chemical adsorption. Phillips
not the result of any single event, but rather are a (1989a) describes vegetated buffers as "one of the
result of multiple changes that, when added together most effective tools for coping with nonpoint source
over time, have frayed and split the threads that link pollution." The U.S. Environmental Protection
together ecosystem functions. In response, manage- Agency (EPA, 1993) states: "...constructing vegeta-
ment schemes and regulations are developed that we tive treatment systems, will be considered in all
hope will slow the rate of ecosystem change, coastal watershed pollution control activities."
smooth the frayed threads, and splice back together Statements such as these give significance to the use
the severed links. One such management effort can of vegetated buffers, and further contribute to their
be the application of vegetated buffers for use in the adoption and use for the control of nonpoint source
coastal zone. Vegetated buffers have been applied in pollution in current resource management schemes.
the fields of forestry and agriculture to moderate Resource managers are beginning to view
nonpoint source degradation of water courses, in vegetated buffers as one method of working toward
wildlife management to improve and provide compliance with recently drafted National Oceanic
habitat, and in landscape architecture to improve and Atmospheric Administration (NOAA) and EPA
visual appeal. While great emphasis is being placed nonpoint source pollution control measures. The
on the use of vegetated buffers to abate nonpoint practice of implementing vegetated buffers, how-
source degradation of waterways, none of the above ever, has generally focused upon their use as a "best
uses are exclusive of the others. It makes both good management practice" (BMP). Overall, there is a
sense and good economics to pursue a multiple-use lack of understanding with regard to developing
application of the vegetated buffer concept in vegetated buffers to provide benefits beyond what a
coastal ecosystems. typical BMP can provide. For instance, EPA (1993)
It is the intent of this document to formulate states: "The term [vegetated buffer] is currently used
concepts and ideas pertaining to the development of in many contexts, and there is no agreement'on any
vegetated regions along the coastal zone that pro- single concept of what constitutes a buffer, what
vide multiple benefits once implemented. It is not activities are acceptable in a buffer zone, or what is
the intent of this review to provide the specific an appropriate buffer width." This statement empha-
details, or provide critical comparison, of runoff sizes the lack of general understanding and the
sources and buffer effects when located on specific common confusion concerning the use and effec-
types of soils, for instance. There are many reviews tiveness of vegetated buffers as a resource manage-
of this type available in the published literature. ment tool.
This review differs from other published reviews of Further confusion arises from the distinction,
vegetated buffer uses in that it attempts to synthe- noted in Table 1, between a vegetated filter strip and
size a broad spectrum of buffer benefits, effective- a naturally vegetated area. Filter strips are typically
ness, and the variables that determine effectiveness. considered a BMP engineered for a specific pur-
pose, such as sediment removal. Forested buffers,
0 Derinition of vegetated buffer on the other hand, are typically natural areas left
Of the variety of definitions found in the litera- along stream and river banks to mitigate the effects
ture (Table 1), all include the concept of a vegetated of logging on in-stream trout and salmon habitat.
buffer acting as a transitional zone between differ- These practices are commonly considered separate
ing land uses, and/or as a barrier to, and filter of, entities - one edge of field (filter strips) and the

other edge of stream (forested buffers) despite 0 Multiple benefits
their similarities in purpose. Together they make up Vegetated buffers often produce many benefits
a range of functional uses greater than either consid- that are neither well-documented nor originally
ered alone. intended. They can be used for providing wildlife
This review incorporates information taken from habitat; for promoting visual diversity; for bird
both vegetated filter strip and forested buffer stud- watching, hiking, and picnicking; for preserving the
ies, since the use of both is important in developing integrity of historical and cultural sites; for flood
a general understanding of the effectiveness of zone management by setting development back
vegetated buffers', particularly from a multiple-use from the immediate banks of waterways; and for
perspective. When'the terin "vegetated buffer" is protecting structures from storm damage. Establish-
used in this document, particularly with regard to ment of vegetated buffers throughout the coastal
management implications for the coastal zone, it zone also can help provide for the long-tenn eco,-
specifically refers to naturally vegetated areas. that nomic viability of the resource by maintaining an
have been, or are being, set aside along the coast- aspect of the natural wilderness of the coast that
line, whether grassy or wooded. When reference is draws people to'the shoreline.
made to designing vegetated buffers where they Vegetated buffer programs, however, are rarely
presently do not exist, the intent is to develop a developed to fully consider the multiple benefits and
vegetated area that mimics native vegetation appro- uses that they offer to resource managers and to the
priate to the same locale. Our choice of the term general public. The "single use/single benefit"
,'vegetated buffer" keeps with its original use to approach used more often tends to alienate some
designate naturally vegetated areas, but we develop sector of the public that does not view that single
furt her the concept of multiple, use and multiple use/single benefit as a priority. Public awareness
benefits for this versatile management tool, as that the vegetated buffers support multiple benefits
adapted from information on both natural and - pollution control, wildlife habitat diversification,
engineered vegetated buffers. and scenic improvement, for instance - may lead
to more effective implementation, as well as giving
Table 1. A selection of definitions for vegetated buffers.

Reference Definition
Palfrey and Bradley, 1982 Zones of undeveloped vegetated land extending from the banks or high water mark of a
water course or water body to some point landward. Their purpose is to protect the
water resources, including wetlands, they adjoin from the negative impacts of adjacent
land use.
Dillaha et al., 1986a Bands of planted or indigenous vegetation used to remove sediment and nutrients from
surface runoff.
Soil Conservation.Service, 1989 Strips of grass or other vegetation that trap pollutants from land areas before they
reach adjacent water bodies.
Chesapeake Bay Local Assistance Act, An area of natural or established vegetation managed to protect other components of a
1990 Resource Protection Area and state waters from significant degradation due to land
disturbances.
Brown et al., 1990 Transitional areas between two different land uses where one mitigates the impact
from the other.
Palmstrom, 1991 Intended to provide a neutral area to lessen the impact of man's activities (i.e.,
fertilizer use, on-site septic systems, urban runoff) on sensitive resources.
Comerford et al., 1992 A barrier or treatment area protecting adjoining areas from the off-site effects of some
disturbance.
Dodd et al., 1993 ..... strips of land in transitional areas between aquatic and upland ecosystems. From a
water quality management perspective, riparian buffers can be defined as areas designed.
to intercept surface and subsurface flow from upland sources for the purpose of
improving water quality.
EPA, 1993 Strips of vegetation separating a water body from a land use that could act as a
nonpoint source.

greater incentive for voluntary adoption and partici- coastal zone ultimately derives its health. Anything
pation in such programs. less than a system-wide approach will result, as it
Before vegetated buffers can become an effec- has in the past, in only partially solved problems.
tive multiple-use management tool, however, their The implementation of vegetated buffer programs,
variable uses and effectiveness must be better however, regardless of the environment in which
understood by resource managers, who can then they are applied or the care and effort taken in their
develop programs to maximize the benefits and design and development, can neither take the place
minimize the shortfalls for their use along the of, nor fully mitigate, the effects of poor land
coastal zone. The implementation of vegetated management techniques. Vegetated buffers should
buffer areas in the coastal zone can directly assist in be considered a tool that can assist in the restoration
pollution control, habitat diversification, and visual of coastal and watershed ecosystems once sound
beautification. The application of multiple-use vege- land management practices have been developed
tated buffers, however, will best be implemented at and put into general practice, and not as an inexpen-
a watershed scale to protect the rivers and streams, sive technological savior to mitigate poor land and
and in effect, the entire ecosystem, from which the other natural resource management practices.

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11. Vegetated Buffer Use and along watercourses throughout the world. Many of
these are engineered control measures designed to
Effectiveness: A Review mitigate the off-site impacts of development -
catch basins, settling ponds, and grassy swales, for
0 Nonpoint Source Pollution Control instance. The implementation of vegetated buffers
Nonpoint source pollution of our nation's as BMPs has generally been practiced by resource
waterways is of major concern for natural resources managers with the intent of removing sediments and
policy and management. The U.S. EPA recently attached pollutants from runoff water. This practice
estimated that 50 to 70 percent of the nation's is well-supported and documented in the literature,
threatened or impaired surface waters were being where numerous studies can be found that describe
adversely affected by agricultural nonpoint source the design and effectiveness of vegetated buffers as
inputs, and that five to 15 percent of threatened or a BMP. Other measures employ increased planning
impaired surface waters were being adversely to abate the impacts of future development. Rezon-
affected by urban runoff (Griffin, 199 1). Concern is ing, cluster development, setbacks from water-
also growing for the degradation of groundwater courses, and defining naturally vegetated areas as
due to nonpoint source impacts, which has implica- buffers are some examples of planned mitigation
tions with regard to subsurface recharge to streams, measures. Naturally vegetated buffers have typically
rivers, lakes, and estuaries, as well as to drinking been applied as habitat preservation measures,
water supplies. A national survey of wells con- except within the field of forestry, where they have
ducted by the U.S. Geological Survey found that been extensively applied for sediment control.
nearly 6.5 percent contained nitrate concentrations In order to assess the potential value of imple-
in excess of the EPA-established safe drinking water menting vegetated buffers as a nonpoint source
standard of 10 mg/l nitrate-nitrogen (Madison and pollutant control measure, the many variables that
Brunett, 1985). affect how buffers remove pollutants from runoff
Recent estimates of the impact of nonpoint must be understood. A better understanding of how
source pollution have pushed forward a new era of vegetated buffers work, and what factors limit their
regulation to abate water quality degradation. use and effectiveness as pollutant removal mecha-
NOAA and EPA have both drafted new guidelines nisms, will assist in evaluation and implementation
for regulations to limit nonpoint source pollutant of practical and functional vegetated buffers.
impact on surface waters. Under the purview of
Section 6217 of the Coastal Zone Management Act E Critical Variables Affecting Pollutant
and Section 319 of the Clean Water Act, the man- Removal
dated regulation of nonpoint.source pollutants will Vegetated buffers are typically employed with
begin in earnest. the primary objective of removing sediment and its
The control of nonpoint sources of pollution, attached pollutants from surface water runoff. Pol-
however, will not occur as easily as for point lutant removal is primarily achieved by slowing the
sources, which can usually be clearly identified, surface water flow that transports sediments, allow-
quantified, acted upon, and monitored for compli- ing time for the settling of sediments and the pollut-
ance to discharge standards. Nonpoint sources, by ants adhered to them. The effectiveness of a veg-
their very nature, are most often diffuse, cryptic, not etated buffer in removing pollutants, however, will
easily monitored, and in many ways not fully vary according to a number of conditions, such as:
understood. A further problem is that, even when a - Soil type in the buffer
nonpoint source is clearly identified, it is often not - Depth of the water table in the buffer
the sole cause of any observed degradation of water - Type, density, and age of vegetation in the
quality or habitat. Instead, it is usually a result of the buffer
cumulative impact of many nonpoint sources within - Pollutant concentrations contained in the
the area. runoff water entering the buffer
Although numerous problems are inherent in - Land use and size of areas draining into the
controlling nonpoint sources of pollution, abatement buffer
methods are being developed and implemented

- Hydrologic regime of the area within and limitation to buffer effectiveness during the review
adjacent to the buffer of riparian buffers implemented on agricultural
- Width of the buffer lands in the state of Virginia. Nearly all the veg-
- Residence time of water in the buffer etated buffers inspected. needed some form of
- The path of runoff water into and through the maintenance or engineering to reduce channeli-
buffer -zation of flow, and to increase effectiveness in the
removal of sediment and pollutants from surface
Due to the inherent variability in the conditions runoff. The natural tendency of water to move in
that determine the effectiveness of vegetated buffers discrete channels may be one of the greatest impedi-
for the removal of pollutants, no single "best buffer" ments to successful buffer implementation for
has been identified for widespread application. nonpoint source pollution control, particularly when
However, with better definition of those variables implementing nonengineered vegetated buffers.
that -determine buffer effectiveness, a better under- When depth of the surface water flow is such
standing can be gained as to what conditions, in that vegetation in the buffer is submerged, effective-
general, promote pollutant removal effectiveness. ness is reduced. As submergence increases, filtering
efficiency of the buffer declines to zero (Karr and
Surface Water Flow Schlosser, 1978; Barfield et al., 1979). When storm
In order for a vegetated buffer to effectively events occur, such as sudden thunderstorms, precipi-
remove pollutants and sediments, the surface water tation.can often be extremely, heavy, submerging; the
flow through the vegetated buffer must be slow, buffer and allowing an initial heavy flow of pollutants
shallow, and uniform (Broderson, 1973; Dillaha et into receiving waters. All vegetated buffers may exper-
al., 1986a). Surface water runoff should progress as ience temporary ineffectiveness during thunderstorms
shallow "sheet flow," and not become channelized or similar events that bring heavy precipitation.
as it moves across the buffer area. Slow flow allows
for pollutants - which are often adsorbed to Gr oundwater Flow.
sediments - to settle out and become incorporated As surface soils become saturated, water may
into surface soils (Lee et al., 1089). Settling will be move vertically rather than horizontally through the
most pronounced in runoff that contains large-sized soil layer and enter into the groundwater recharge
sediment particles, and less pronounced in those system. The net movement of groundwater depends
containing fine silts and particulates, which often on soil type, subsurface impermeable layers, geol-
require long retention times and Very slow flows in ogy, hydrologic regime, and slope. Groundwater
the vegetated buffer to effectively settle. Slow flow carries soluble pollutants that have passed through
also promotes utilization of nutrients by plants, soils in percolated water. As it eventually recharges to
assists flood control by allowing water to percolate lakes, rivers, streams, and coastal waters, it can be-
into the soil, and reduces erosion within the buffer come a source of pollution to surface waters. Ground-
area. Rough surfaces, which better reduce flow water may also move into -subsurface aquifers and
velocity and promote sheet flow, result in greater degrade potable water supplies. In areas such as the
pollutant and sediment removal than smooth sur- coastal northeastern United States, groundwater
faces (Flanagan'et al., 1986;"Williams and Nicks, recharge can be a: significant source of nitrogen
1988)., enrichment to coastal waters (Valiela et al., 1992;
Field tests, however, indicate that naturally Weiskel and Howes, 1992). Leachate from septic
occurring vegetated buffers are generally incapable tanks, leaking underground storage tanks, landfills,
of inducing sheet flow from storm water runoff due and accidental spills can all enter the groundwater
to the natural tendency of water to move in discrete system, eventually entering coastal waters.
channels. Dillaha et al. (1986a) report a range of 40 Vegetated buffers, however, may only be able to
to 95 percent reduced efficiency of sediment, nitro- remove a limited number of pollutants from ground-
gen, and phosphorus r ernoval in vegetated buffers water - nutrients and some metals, for instance.
when runoff flow through the buffer area deviated Oils, most metals, and pesticides will generally not
from shallow sheet flow. Channelization. of flow be effectively removed by vegetated buffers once
through the buffer was cited as a major problem and they have entered the groundwater recharge system.

Furthermore, vegetated buffers located over deep removal of nitrate contained in both surface and
water tables are not usually effective in the removal groundwater supplies. A series of related studies by
of pollutants from subsurface flow. Deep groundwa- Gold et al. (1991), Simmons et al. (1992), and
ter flows can move over considerable distances and Groffman et al. (1992), reported that nitrate removal
over relatively long time frames (Hynes, 1983), and was greater in areas with shallow water tables than
at depths where plant root systems are unlikely to in those with deep water tables during both dormant
reach them. Areas that are recharged from deep and growing seasons. Ambus and Lowrance (1991)
groundwater flows often receive pollutant inputs found that 68 percent of the denitrification they
from distant sources that may have originated observed occurred in the top two centimeters of soil.
decades ago. A time lag may therefore develop A shallow water table keeps groundwater close to
between both cause and effect, as well as between the surface and in the area where carbon sources
the implementation of abatement measures and any (i.e., organic leaf litter) are most likely to promote
observable effects. the growth of denitrifying microbes. Correll and
Nutrient uptake and utilization by plants can be Weller (1989), based on biomass removal estimates
a major pathway of nutrient removal from ground- for nitrate-nitrogen, suggest that denitrification may
water supplies in a vegetated buffer. In areas that be the most important nitrate removal mechanism
contain a shallow aquaclude (a subsurface imperme- from groundwater in forested areas.
able soil layer), subsurface flow may be more There is, however, some concern that use of
horizontal than vertical, increasing the likelihood of vegetated buffers to treat surface water runoff may
groundwater being reached by the roots of overlying actually increase groundwater nitrate and other
vegetation. In a forested area located over a shallow soluble pollutant concentrations by promoting
aquaclude (less than four meters deep), Peterjohn percolation into soils. Gold et al. (1989) and
and Correll (1984) reported an 80 percent removal Weiskel and Howes (1992) have both reported that
of nitrate from surface water flow, and Correll and nitrate can readily travel through soils and into
Weller (1989) reported an 84 to 87 percent removal groundwater supplies with little or no removal in
of nitrate from groundwater. In these instances the transit. This may be true for many soluble forms of
subsurface aquaclude kept the groundwater avail- pollutants, particularly in areas with highly penne-
able to the root systems of plants in the buffer for able or very well-drained soils (Schwer and
uptake, as well as keeping it available to denitrify- Clausen, 1989). Under some soil conditions - well-
ing microbial communities. drained, sandy soils, for instance - the vegetated
A major pathway for nitrate removal in ground- buffer could slow surface flow, promoting rapid
water is denitrification. The process of denitrifica- percolation of surface water to groundwater, and
tion, which converts nitrate to nitrogen gas, which is actually degrade potable water supplies or coastal
then released to the atmosphere, is reliant upon the waters. It is presently unclear, however, to what
existence of a microbial community of denitrifying extent this event occurs, and further study is needed
bacteria. The microbial community is partly reliant to determine if and when vegetated buffers promote
upon anaerobic conditions - a circumstance in groundwater contamination.
which no free oxygen is present. The oxygen
present in nitrate (NO 3) is utilized for metabolism Slope
by the microbial community, and nitrogen gas is Areas of steep slope do not allow for long
released to the atmosphere as a metabolic by- retention time of runoff water, and since pollutant
product. A further limitation to this process is the removal is at least partially time-dependent (i.e., to
availability of a source of carbon (organic material) allow plant uptake and deni'trification to occur),
to support the microbial community (Obenhuber steep slopes reduce vegetated buffer effectiveness.
and Lowrance, 1991). Soils that are poorly drained Furthermore, steeply sloped areas negate the veloc-
and rich in organic materials will typically provide ity-reducing effects of surface roughness, and
conditions that promote denitrification. thereby promote erosion. Even though a steeply
Areas with a shallow water table, such as sloped area may be thickly vegetated, it may be
wetlands and areas with poorly drained soils, most ineffective at removing sediments and pollutants
readily provide the conditions conducive to the because it promotes erosion and channelization of

flow through the buffer area. The shallower the be deposited on the leading edge of the buffer area,
slope, the longer the residence time, the slower the forming a berm (Magette et al., 1986; Robat and.
flow, and the greater the ability of sediment and Sabol, 1988). Once a berrn is formed at the leading
pollutants to settle and be removed from the runoff. edge of the vegetated buffer, water will be chan-
A slope of less than 15 percent reportedly neled around the buffer, rendering it uselesg. Even-
allows for adequate retention time and pollutant tually the berm will be breached, causing
removal, while steeper slopes may not be suitable channelization of flow into the vegetated buffer,
for vegetated buffers due to the slopes'erosion increasing erosion and reducing buffer effectiveriess
potential and lack of adequate retention time for pollutant and sediment removal.
(Schueler and Bley, 1987; Niewswand et al., 1990;
Palmstrom, 1991). Clark (1977) gives some ex- Soil Characteristics
amples of minimum buffer widths for water quality Soils with high pen-neability generally provide
protection according to slope and soil erodibility: he greater filtration of sediment and attached pollutants
recommends a minimum width of 10 meters for (Chescheir et al., 1988; Lee et al., 1989). Once the
areas with no slope on slightly erodible soils, pollutants enter the soil layer, they can become
extending to 50 meters for 30-percent slopes on incorporated through physical, chemical, and
severely erodible soils. Trimble and Sartz (1957) biological interactions. However, highly permeable
suggest adding an extra 0.6 meters of vegetated soils, such as sandy soils, may allow for the rapid
buffer width for each one'--percent increase in slope movement of water into the groundwater recharge
within the vegetated bufferfor minimum effective- system. The movement may be so rapid that no
ness, and a 1.2-meter increase per one percent slope removal of pollutants is'allowed by plants, and only
increase to attain greatest water quality protection. minimal removal by physical and chemical adsorp-
Broderson (1973), in a study of the effectiveness of tion, particularly for dissolved forms of pollutants.
forested buffers to remove sediment from runoff Figure 1 shows that well-drained soils are only
before the runoff enters a stream, suggests that half as effective for the removal of nitrogen as
fifteen-meter buffers are sufficient at slopes less poorly drained soils. Sandy soils provided the least
than 50 percent, and a maximum 66-meter buffer is nitrogen removal, regardless of drainage capacity'
sufficient for extremely sloped areas. Comerford et Ehrenfeld (1987) found that nitrogen from septic
al. (1992) note, from a review of the literature, that system leachate moved greater distances vertically
slopes greater than 30 percent generally allow than horizontally through the permeable sandy soils
inadequate retention time in a vegetated buffer for of the New Jersey Pinelands, where the nitrate-laden
any significant denitrification to occur. septic leachate quickly percolated below the root
Slope of the area preceding the vegetated buffer zone of buffer vegetation. In some soils, vegetated
also can affect pollutant and sediment removal. buffers that are not located directly in the septic
Steep slopes leading into a flat buffer area often system leach field plume will be ineffective in
tend to cause the bulk of the transported sediment to removing nitrate. The contaminants contained in

Figure 1. Nitrogen removal in sand loam clay-loam
various poorly drained and well-
drained soil types. Nitrogen Poorly drained
removal is more than doubled in
poorly drained soils compared to
well-drained soils. Sandy soils sand loam clay-loam
provided poor nitrogen removal
regardless of soil wetness. Data Well-drained
from Groffman and Tiedje, 1989a.

0 5 10 15. 20 25 30 35 40 45 @0
Nitrogen Removal (kg/N/ha)

septic system leachate can readily enter nearby consistently removed. Other metals may therefore
waterways under these conditions. not be effectively removed from surface runoff by
Poorly drained soils generally retain water long vegetated buffers, even in buffers with conditions
enough, and often under conditions favorable conducive to metals removal, and other methods
enough, that pollutant removal is accomplished. may need to be explored if removal of metals is of
Figure I presents a range of nitrogen-removal data major concern.
reported by Groffman and Tiedje (1989a) for a
variety of soil types and conditions. Poorly drained Pollutant Characteristics
soils were found to be more than twice as effective Many studies indicate that most pollutants and
as well-drained soils for the removal of nitrogen. nutrients transported by surface runoff are attached
Poorly drained soils that contain a higher organic to sediments. This tends to be true for metals
content are more apt to promote the growth and (Zirschky et al., 1989), pesticides (Lake and
maintenance of denitrifying microbial communities Morrison, 1977), phosphorus (Karr and Schlosser,
and hence greater nitrogen removal (Nichols, 1983; 1977; Chescheir et al., 1988; Lee et al., 1989), and
Peterjohn and Correll, 1986; Groffman et al., some forms of nitrogen (Karr and Schlosser, 1977;
199 1 a). In cases where long residence time occurs Chescheir et al., 1988). Nitrate, however, has less
in saturated, organic soils, nitrogen removal may be affinity to sediments, and is most often found in a
high (Cooper, 1990). These conditions are typically dissolved phase (Chescheir et al., 1988). Runoff that
found in salt marshes, wetlands, and wet forests, all characteristically contains pollutants bound to
of which have been repeatedly reported to express sediment need only move through a buffer able to
high denitrification potential. Saturated, organically remove the sediment load. When runoff characteris-
rich soils, therefore, can be useful in the removal of tically carries pollutants in dissolved or soluble
both soluble and sediment-bound pollutants, while forms, the buffer area will need to promote long
sandy soils may be most effective in removing retention times in order for those pollutants to be
sediments and bound pollutants, and soluble forms effectively adsorbed to soils or utilized by plant and
only marginally. microbial communities.
Soils rich in clay content are often relatively The effectiveness of pollutant removal will be
impermeable, and removal of pollutants from related to the concentration of pollutants entering
surface waters by soil percolation can be low. the vegetated buffer from outside sources. Much of
Scheuler and Bley (1987) do not recommend the reviewed literature reports testing buffer effi-
vegetated buffers as effective pollutant removal ciency in response to sources that have very high
mechanisms in clay-rich soils. Mixed clay soils, concentrations of incoming pollutants, particularly
however, as shown in Figure 1, often are effective in sediments and nutrients. For instance, Edwards et al.
the removal of pollutants. Clay soils often have high (t983) measured concentrations of total suspended
affinities for binding positively charged pollutants, solids, nitrogen, and phosphorus entering grassed
particularly metals, by acting as a cation (negatively buffers from a cattle feedlot to be: 10,200 mg/l TSS;
charged) exchange site. Provided the clay soils are 705 mg/l N; 152 mg/l P. In most cases, very favor-
not compacted, and runoff over the area is slow, able removal efficiencies were reported, despite a
pollutant removal via chemical binding may be high input rate. In the Edwards et al. (1983) study,
significant (Zirschky et al., 1989). Chemical re- removal rates of 87 percent TSS, 83 percent N, and
moval, however, is finite: once metals are adsorbed 84 percent P were recorded after the feedlot runoff
to soils, they can be freed for transport by further had moved through a settling basin and sixty meters
chemical or physical disturbance of the soil layer, of grassed buffer. This may suggest that vegetated
and may be moved during the next runoff event. A buffers treating more "average" concentrations of
ranking of stability of soil-bound metals given in pollutant inputs might produce even greater removal
Baker and Chesnin (1975) shows that copper has the efficiencies than those reported in the published
greatest tendency to remain stable once adsorbed. literature (see Schueler (1987), for example, for
Zirschky et al. (1989), experimenting with copper, average concentrations of various pollutants con-
nickel, zinc, cadmium, chromium, iron, lead, and tained in urban runoff water).
manganese, found that only copper and zinc were In contrast, Nichols (1983) reported that re-

moval efficiency for nitrogen and phosphorus dramatically. Wong and McCuen (1982) similarly
decreased as loading of those nutrients into a found that disproportional increases in buffer width
wetland treatment area increased. Reuter et al. from 33 to 66 meters - were required to in-
(1992) report similar results. The U.S. Army Corps crease sediment removal efficiency of a grassed
of Engineers (199 1) suggests that, despite reported buffer from 90 to 95 percent. The largest sediment
high removal efficiencies for pollutants in vegetated particles are generally deposited within the first few
buffers, high pollutant loading rates into the buffer meters of the vegetated buffer, leaving the fine silts
may result in degradation of adjacent sensitive water and clays in suspension. For example, Neibling and
bodies. For example, Castelle et al. (1992) reported Alberts (1979) reported that only 37 percent of clay-
that 55 percent of the assessed buffers implemented sized sediment and particulates were removed
to protect wetlands that bordered residences using within a 0.6 meter width of grass vegetated buffer,
lawn, maintenance systems showed impacts from while 91 percent of the"total sediment load was
fertilizer applications. The sympto ins ranged from removed within the same effective buffer width..
increased wetland plant growth'to wetland plant Wilson (1967) found that most coarse-grained
-death from nitrogen toxicity. Under high pollutant sediment was removed in 3.3 meters, most silt in 15
loading conditions, the percentage of pollutants not meters, and most clays by 90 meters in a buffer
removed may be sufficient to cause degradation of vegetated with Bermuda grass.
water quality and other resources. This is further Relatively narrow buffers, provided they pro-
exemplified by the study of Edwards et al. (1983), mote shallow sheet flow through the buffer area,
in which, despite high removal rates (87 percent will effectively remove coarse-grained sediments
TSS, 83 percent N, 84 percent P), the pollutant load and their associated pollutants. Wider buffers,
leaving the sixty-meter grass buffer was high (988 however, will be required to remove smaller-sized
kg TSS, 63 kg N, 15 kg P), as were concentrations particles of sediment and the pollutants adsorbed to
(3,840 mg/l TSS; 260 mg/I N; 51 mg/l P). Although them. Pollutants in dissolved forms may require
high pollutant removal rates in vegetated buffers even greater buffer width to be effectively removed
will certainly reduce loadings to receiving water, by chemical interactions, plant uptake, or microbial
they may not necessarily equate to protection of transformation.
water quality.
Over time, a vegetated buffer may become Vegetation Type
"saturated" with sediments and pollutants, reducing The vegetative ground cover within a buffer
overall removal efficiency. Eventually the buffer serves multiple purposes with regard to overall
could become a source of pollutants to adjacent buffer effectiveness by removing pollutants, provid-
water bodies. It is well known that physical distur- ing.habitat, and creating aesthetic appeal. The type,
bance can cause pollutants trapped in a vegetated density, and age of the vegetative ground coverplay
buffer to become available for transport out of the a large role in determining the effectiveness of . I
buffer area. However, not enough research has been pollutant removal, the habitat value to wildlife, and
conducted on vegetated buffers to adequately assess the overall aesthetic appeal of the vegetated buffer.
either the conditions that lead to saturation with The vegetative ground cover contained in a buffer
pollutants or the circumstances under which an un- can be manipulated, often in a cost-effective man-
disturbed vegetated buffer becomes a pollutant source. ner, to better achieve the goals for which the veg-
Karr and Schlosser (1977) note that pollutants etated buffer was implemented. For instance, the
contained in surface runoff are generally bound to vegetative cover in the buffer could be manipulated
smaller-sized sediment particles, such as silts and to enhance the removal of various pollutants of
clays, and that the effectiveness of any vegetated concern, thereby providing some flexibility to
buffer will partially depend on how well it removes
resource managers, for achieving their specific goals.
silts and clays from runoff water. Clay sediment in Table 2 provides a range of removal rates
runoff generally exists at very small sizes, and Karr reported in the literature for nitrogen, phosphorus,
and Schlosser (1978) report that, ag particle size and sediment in both g'rassed and forested buffers
decreases, the buffer width required to remove a and over a variety of site-specific conditions.
greater percentage of those particle sizes increases Nitrogen was the most widely reported pollutant

with regard to removal in vegetated buffers. The where the primary pollutant of concern is sediment
removal rates provided in Table 2 may be useful to (and its adsorbed pollutant load). The results of
resource managers for estimating potential nitrogen grassed buffer studies are generally reported as
removal in implemented buffers, based upon vegeta- percent removal and typically have treated source
tion and other general characteristics. In the event areas with a high pollutant load. Studies of wooded
that pollutant loadings were able to be estimated, buffers generally have focused on naturally forested
actual removal rates for a proposed vegetated buffer areas, with the removal of nitrogen the primary
could be estimated, based upon Table 2 and site- focus. Nitrogen removal typically is through bio-
specific data, and the buffer area modified in order logical rather than physical/chemical pathways,
to achieve the desired pollutant removal goal. such as denitrification and plant uptake and storage.
The removal rate values for nitrogen presented Forested buffer studies less often reported source
in Table 2 are graphically presented in Figure 2 to areas that contained high pollutant loads, and
visually show the range of nitrogen removal rates in generally treated logged or urban areas rather than
grassed and forested buffers. The range of nitrogen livestock and agricultural areas. The result is very
removal rates represented in Figure 2 shows that, much two separate bodies of knowledge, which
overall, grassed buffers have greater nitrogen have taken two separate paths of study. This makes
removal potential than forested buffers. Forested for some difficulty in directly comparing grassed
areas, particularly wet forests, are frequently noted and forested buffer studies, as the methods and
in the published literature to be more effective reporting of results are generally different. Enough
nitrogen removers than grassed areas. In Figure 2, of each, however, has been reported in similar units
however, grassed buffers are shown to have the that some preliminary comparisons can be made and
potential to remove nitrogen at a rate approximately relationships proposed.
three times greater than that of forested areas. The
potential for forested areas to remove nitrogen may Grasses
be underestimated in the presented data, since some Grasses tend to be very effective in reducing
of the grassed buffers were treated with direct overland flow, as well as being effective nutrient
nitrogen applications (fertilizers), thus providing a and sediment removers. Removal rates reported in
greater representation of their overall nitrogen Table 2 and used in Figure 2 show that grassed buf-
removal potential. Studies conducted with forested ffers treated with fertilizer applications can remove
buffers generally did not include fertilizer treat- up to 290 kg N/ha/yr. Despite high reported removal
ments; therefore, their range of potential nitrogen rates and efficiencies, it is often unclear how this re-
removal may be underestimated. However, unfertil- lates to water quality protection. Morton et al.(1988)
ized control plots of Kentucky bluegrass utilized by found nitrate leachate concentrations leaving fertil-
Morton et al. (1988) had removal rates of only 2.0 ized plots of Kentucky bluegrass to be well below
kg/N/ha/yr, which is considerably lower than the the EPA drinking water standard of 10 mg/I nitrate-
lowest removal rates reported for forested areas (see nitrogen. Nitrate concentrations ranged from 0.51 to
Table 2 and Figure 2). Furthen-nore, fewer studies 4.02 mg/l, with the higher values found leaving
for grassed buffers reported removal in kg/ha/yr heavily fertilized, overwatered experimental plots.
than for forested buffers, and the average removal The *results of this study suggest that home lawn
rate for grassed buffers may more closely approxi- fertilization practices may not always pose a direct
mate those for forested, given greater representation threat to drinking water supplies. Although these
(see Figure 2). reported concentrations do not appear threatening to
Grasses and woody-stemmed species are de- potable water supplies, concentrations at the upper
scribed separately below because of the unique portion of the range could, when combined with
characteristics of each type, as well as the differ- other sources of nitrogen, contribute to eutrophica-
ences each group exhibits in the removal of sedi- tion of coastal waters. This may be particularly true
ment and pollutants from runoff. Furthermore, the in the temperate coastal zone, where soils are
literature on the two types of ground cover is very typically composed of glacial till and sand, which
different. Most of the work completed for grass often allow rapid movement of groundwater to
buffers comes from studies of vegetated filter strips coastal waters with only minimal removal of nitrogen.

Table 2. Removal rates for various pollutants in vegetated buffers. The values reported for removal in grassed buffers may
be high relative to forested buffers because most received direct fertilizer treatments, whereas forested buffers did not. Removal
rates for forested buffers may therefore be underestimated with regard to their actual removal potential. [1 kilogram 2.2
pounds; I hectare = 2.47 acres]

Reference Removal Rate Details
NITROGEN
Ehrenfeld, 1987 75 - 80 kg NAWyr Hardwood wetland getting septic tank leachate
Ehrenfeld, 1987 45 - 56 kg N/ha/yr Pine upland getting septic tank leachate
Ehrenfeld, 1987 68 - 69 kg N/ha/yr Oak upland getting septic tank leachate
Peterjohn & Correll, 1984 77 kg N/ha/yr Mid-Atlantic coastal plain forest trees
Palazzo, 1981 290 kg N/ha/yr Orchard grass; sewage waste treated
Fail et al., 1986 50 kg N/ha/yr Plant uptake and storage in a coastal plain riparian forest
Cole & Rapp, 1981 75.4 kg N/ha/yr Mean of 14 temperate deciduous forests
Lowrance et al., 1984c 51.8 kg N/ha/yr Aboveground plant storage in riparian forests
Lowrance et al., 1984c 31.5 kg N/ha/yr Denitrification in riparian forests
Morton et al., 1988 2.0 kg N/ha/yr Kentucky bluegrass control plot
Morton et al., 1988 32 kg N/ha/yr Kentucky bluegrass; overwatered and fertilized
Brown & Thomas, 1987 194 kg N/ha Bermuda grass on sandy soils with repeated harvesting
Peterjohn & Correll, 1984 11 kg/ha particulate organic N Riparian forest treating agricultural watershed
Peterjohn & Correll, 1984 0.83 kg/ha ammonium N Riparian forest treating agricultural watershed
Peterjohn & Correll, 1984 2.7 kg/ha nitrate N Riparian forest treating agricultural watershed
Peterjohn & Correll, 1984 45 kg/ha nitrate N in Riparian forest treating agricultural watershed
groundwater
Groffman & Tiedje, 1989a 10 kg N/ha/yr Well-drained loam
Groffman & Tiedje, 1989a I I kg N/ha/yr Somewhat poorly drained loam
Groffman & Tiedje, 1989a 24 kg N/ha/yr Poorly drained loam
Groffman & Tiedje, 1989a 18 kg N/ha/yr Well-drained clay-loam
Groffman & Tiedje, 1989a 17 kg N/ha/yr Somewhat poorly drained clay=loam
Groffman & Tiedje, 1989a 40 kg N/ha/yr Poorly drained clay-loam
Groffman & Tiedje, 1989a 0.6 kg N/ha/yr Well-drained sand
Groffman & Tiedje, 1989a 0.8 kg N/ha/yr Somewhat poorly drained sand
Groffman & Tiedje, 1989a 0.5 kg N/ha/yr Poorly drained sand
Groffman et al., 1991 a 311 g NAWday Well-drained aerobic forest soil with nitrate added
Groffman et al., 1991a 365 g N/ha/day Poorly drained aerobic forest soil with nitrate added
Groffman et al., 1991a 7,889 g NAWday Tall fescue on aerobic soil with nitrate added
Groffman et al., 1991a 4,537 g N/ha/day Reed canary grass on aerobic soil with nitrate added
Groffman et al., 1991a 1. 1 g NftWday Well-drained anaerobic forest soil, no nitrate added
Groffman et al., 1991 a 1,306 g N/ha/day Well-drained anaerobic forest soil, nitrate added
Groffman et al., 1991a 13.1 g N/ha/day Poorly drained anaerobic forest soil, no nitrate added
Groffman et al., 1991a 1,402 g N/ha/day Poorly drained anaerobic forest soil, nitrate added
Groffman et al., 1991a 1.0 g N/ha/day Tall fescue on anaerobic soil, no nitrate added
Groffman et al., 1991a 17,208 g N/ha/day Tall fescue on anaerobic soil, nitrate added
Groffman et al., 1991 a 1.0 g NAWday Reed canary grass on anaerobic soil, no nitrate added
Groffman et al., 1991a 15,208 g NftWday Reed canary grass on anaerobic soil, nitrate added
Warwick & Hill, 1988 0.05--0.53pg N/m2/day Sandy sediments
Warwick & Hill, 1988 0.08-1.20 pg N/m ,2/day Organic sediments
Warwick & Hill, 1988 1.05-3.19 gg N/M2/day Watercress bed detritus and sediments
Hook & Kardos, 1977 388 kg N/ha/yr Reed canary grass; sewage waste treated
Rhodes et al., 1985 0.341-7.265 g N/hr/acre Mean of I 11 high-altitude wet meadow samples
Lemunyon, 1991 99.3 / 37.5 kg N/ha Smooth Bromegrass in 15m2 well-drained plot; urea treated
Lemunyon, 1991 56.1 /20.6 kg N/ha Garrison grass in 15m2 well-drained plot; urea treated
Lemunyon, 1991 73.9 / 48.9 kg N/ha Kentucky bluegrass in 15m2 welTdrained plot; urea treated
Lemunyon, 1991 87.6 / 38.4 kg N/ha Orchard grass in 15m2 well-drained plot; urea treated
Perrenial ryegrass in 15m2 well-drained plot; urea treated

Table 2. Removal rates for various pollutants in vegetated buffers. Continued

Lemunyon, 1991 80.9 / 34.1 kg N/ha Reed canary grass in 15m2 well-drained plot; urea treated
65.2 / 3 3.5 kg N/ha
Lemunyon, 1991 Sweet vernal grass in 15m well-drained plot; urea treated
Lemunyon, 1991 78.2 / 37.9 kg N/ha Tall fescue in 15m2 well-drained plot; urea treated
Lemunyon, 1991 40.5 / 11.7 kg N/ha Big bluestern in 15m2 well-drained plot; urea treated
Lemunyon, 1991 29.1 / 18.5 kg N/ha Switcligrass in 15m2 well-drained plot; urea treated
Hill & Sanmugadas, 1985 37-412 mg N/m2/day 24-hour stream sediment incubation
Hill & Sanmugadas, 1985 33-223 ing N/m 2/day 48-hour stream sediment incubation
Schellinger & Clausen, 1992 0.72 kg/m 21yr TKN 22.9 X 7.6m mixed species grass buffer; 2% slope
Schellinger & Clausen, 1992 0.32 kg/m 2/yr Ammonia-N 22.9 X 7.6m mixed species grass buffer; 2% slope
PHOSPHORUS
Peterjohn & Correll, 1984 3.0 kg/ha total particulate P Riparian forest treating agricultural watershed
Lowrance et al., 1984c 3.8 kg P/ha/yr Aboveground plant storage in riparian forests
Schellinger & Clausen, 1992 0. 15 kg/m 2/yr TP 22.9 X 7.6m mixed species grass buffer; 2% slope
Schellinger & Clausen, 1992 0. 12 kg/m 2/yr Dissolved p 22.9 X 7.6m mixed species grass buffer; 2% slope
Schellinger & Clausen, 1992 0.09 kg/m 2/yr Ortho P 22.9 X 7.6m mixed species grass buffer; 2% slope
Cole & Rapp, 1981 5.6 kg P/ha/yr Mean of 14 temperate deciduous forests
SEDIMENT & OTHER
Peterjohn & Correll, 1984 4.1 kg/ha/yr of particulates Riparian forest treating agricultural watershed
Schellinger & Clausen, 1992 1. 13 kg/m 2/yr TSS 22.9 X 7.6m mixed species grass buffer; 2% slope

Figure 2

Figure 2. Ranges of nitrogen removal
for grass and forested buffers. The
heavy line contained in the bar Grass N 3
represents the mean of the data that
n W@v
constitute the range. Data taken from
Table 2. [1 kilogram 2.2 pounds; I
hectare 2.47 acres]

Forest N=7

0 50 100 150 200 250 300
Nitrogen Removal (kg/N/ha/yr)

Grasses are desirable as part of the vegetative removal of pollutants from groundwater (Ehrenfeld,
matrix that constitutes the vegetated buffer. They are 1987; Groffman et al., 199 1 b). In general, hardwood
generally able to respond rapidly to increased species .are better nitrogen removal mechanisms
concentrations of nutrients, grow rapidly and than are conifer species (Spur and Barnes, 1980),
densely, and typically grow well in nearly all but the overall removal of pollutants will vary
climates. Thickly planted, clipped grasses provide a according to characteristics of the forested buffe-r
dense, obstructive barrier to horizontally flowing site - such as vegetative composition, depth to the
water. This increases the roughness of the terrain, water table, and hydrology.
which reduces flow velocity, promotes sheet flow, For wooded buffers, poorly drained forest plots
and inc 'teases sediment and adsorbed pollutant have been found to provide greater denitrification
removal efficiency. This also increases residence than well-drained forest plots by creating better
time in the buffer, which promotes uptake of nutri- living and growth conditions for denitrifying mi-
ehts by plants. Low-cropped grasses, however, may crobes, as well as by keeping water within the organ-
not be adequate in areas that-experience frequent ically enriched surface soil layer 'and close to root
flooding, as they are rendered temporarily useless systems of resident vegetation (Correll, 1991; Groff-
when submerged. Grasses that are to be used as part man et al., 1992). Figure 2 shows removal rates as
of the vegetated matrix of the buffer should there- high as 85 kg N/ha/yr have been reported for nitro-
fore be left in an uncut condition, or at least not cut gen removal in forested areas. The range of nitrogen
below a height of three or four inches. A worst-case removal rates for forested buffers is small, suggest-
grassed buffer would be one that is highly mani- ing that removal and storage in these sites are, on
cured and clipped low, resembling a golf course average; fairly consistent. With regard to plant
putting green. These become flooded very easily, uptake, Ehrenfeld (1987) found that brush species
thus being rendered useless as a pollutant filter. did not show an increased nitrogen content *in the
Medium height, thickly growing grasses represent presence of septic system leachate, while hardwood
the ideal for a grassed buffer area. and conifer species did. This suggests that species
The use of grasses in vegetated buffers has with shallow root systems may often be ineffective
many maintenance benefits. Mowing is relatively at removing nitrogen from groundwater supplies,
easy, and the clippings can be readily collected for a except in poorly drained areas where groundwater
more permanent removal of nitrogen and other remains near surface soils. Areas with a deep water
pollutants from the buffer area. Considering that table will need to rely on deep-rooted species to
grasses - particularly thickly growing covers - realize any nitrate removal prior to recharge from
are also effective at reducing runoff velocity, they groundwater supplies to nearby waterways.
may be used with the additional effect of promoting There is considerable variation in the docu-
slow, shallow sheet flow of runoff into a naturally mented nitrate-reducing capacity of forested buffers,
wooded buffer area. Although grasses are effective 'depending on site and climate. Whole-watershed
as vegetated buffer species, they lack the versatility studies conducted by Peterjohn and Correll (1984)
required of multiple-use buffers - for preserving and Lowrance et al. (1984a,b) report high levels of
wildlife habitat or promoting visual diversity, for nitrate removal from surface water within forested
instance - and generally are not suitable for use as buffers of mid-Atlantic latitudes, while work con-
the only cover within a multiple-use vegetated ducted by Warwick and Hill (1988) noted very little
buffer area. Grasses therefore are suitable as part of nitrate removal in.northem latitudes (Canada).
the vegetated matrix that makes up the buffer area, Warwick and Hill (1988), however, did note that
or as ground cover in the area immediately preced- reduced nitrate removal at their study site may have
ing the naturally vegetated buffer. been-at least partially due to minimal retention time
of runoff during their experiments, and that in-
-Woody-stemmed Species creased retention time of runoff water in a forested
Woody-stemmed species generally have deeper buffer should increase nitrate removal efficiency.
and more well-developed root systems than grasses, Groffman et al. (1992) and Simmons et al.
and when the root system is greater than t wo feet (1992), in companion studies, noted that nitrate-
deep, the vegetated buffer may be effective for the nitrogen reduction in a vegetated buffer is domi-

nated by plant uptake during the growing season, in buffer management schemes. The removal of leaf
but that soil microbial denitrification is the domi- litter, however, results in the loss of organic/detrital
nant nitrate removal mechanism during the dormant material to soils in the vegetated buffer, changing
season. Denitrification during the dormant season one of the conditions - high organic content -
was a result of a higher seasonal water table that that promotes the growth of denitrifying microbial
allowed nitrate-laden waters to remain near surface communities. The positive or negative effects of leaf
soils, which are richer in organic content and allow litter removal may be site-specific (e.g., presence of
for microbial denitrification. Groffman et al. a high water table).
(1991b) reported that nitrate removal decreased by
64 percent between the growing and dormant Buffer Width
seasons in their study of vegetated buffers in Rhode Buffer width variability is one of the most
Island, while Correll et al. (1992), during a study of versatile tools available to the resource manger.
vegetated buffers in Maryland, reported 97 percent Other variables that affect the efficience of veg-
nitrate removal rates from groundwater in the fall etated buffers in the removal of pollutants are often
@growing season), declining to 81 percent removal unchangeable, or at least may not be altered in a
in winter months (dormant season). very cost-effective manner. Buffer width, however,
These findings suggest that, at least in temperate is often easy to manipulate in order to better achieve
latitudes, seasonal variability in vegetated buffers the desired affect (e.g., water quality protection).
can be expected. Actively growing vegetation will Table 3 lists vegetated buffer widths reported in
be effective at nutrient removal during summer the literature to be adequate for generalized purposes.
months, when coastal waters are typically most sus- The range of buffer widths runs from two
ceptible to nutrient inputs. During the dormant meters to nearly 200 meters, with a variety of
season of vegetation, at least in areas where ground- vegetation types reported. These data are presented
water can rise near the soil surface, denitrification graphically in Figure 3, showing the overall range of
will continue to remove nitrate, but possibly at a re- values reported to be adequate to protect water
duced rate. Cold weather months, however, may quality in several categories of water bodies. The
result in vegetated buffers becoming ineffective as the values contained in the table and figure suggest that
ground freezes and becomes generally impermeable. even relatively narrow buffers (less than 10 meters
Although not as simple as mowing the grass, se- wide) have some reported value as a resource
lective harvesting of woody-stemmed species is pos- mangement tool for the protection of water quality.
sible, thereby permanently removing nutrients from Based upon mean values reported by category,
the vegetated buffer system (Lance,1972; Leak and however, forty-five meter buffers appear adequate to
Martin, 1975; Todd et al., 1983; Lowrance et al., protect water quality in general, at least within
1984c; Ehrenfeld, 1987). Should a vegetated buffer freshwater systems and areas where sediment and
not be periodically harvested, eventually the nitro- adsorbed pollutants are the major concern.
gen stored in plant tissues will reenter the system Table 4 presents a range of pollutant removal
through decomposition. Woody-stemmed species effectiveness values, according to buffer width,
are good long-term nitrogen sinks, but removal of reported in the literature. Although values for the
the entire plant also removes the nitrogen uptake removal of other pollutants may have been given in
and storage mechanism. As trees are removed from the publications cited, those presented in Table 4
the buffer area, they will need to be replaced for con- sediment, total suspended solids (TSS), nitrogen,
tinued nutrient removal at a more or less steady rate. nitrate, and phosphorus - were reported most
Ehrenfeld (1987) noted that most primary frequently, and were felt to provide the best range of
production by trees is converted to leaf materials, values for review purposes. Also provided in the
and Peterjohn and Correll (1984) found that 81 table, when given in the original manuscript, is
percent of the nitrogen uptake in a riparian buffer information on runoff (pollutant) source, vegetation
was returned to the forest floor as leaf litter at the type(s), and slope of the buffer.
end of the growing season. Removal of leaf litter What is immediately obvious is the variability
from vegetated buffers may therefore be considered in pollutant removal over both the range of buffer
an effective permanent nitrogen removal mechanism widths and within similar buffer widths surnmerized

Table 3.- Recommended vegetated buffer widths for pollutant removal, giving the desired effect of the implemented
buffer. The reported values are generally intended, as minimum buffer width values to achieve the desired purpose. [I meter
3.28 feet]

Author(s), Width (m) Objective Specifics
in: Comerford et all 1992 2 Maintain stream channel stability Ozark Mts
Ahola, 1990 2-10 Stream habitat protection
Ahola, 1990 5-20 River/lake protection '
Scheuler and Bley, 1987 7 Low level pollutant removal Grassed buffer
in: Comerford et al., 1992 7-12 General purpose use Low slope; rural land
Palmstr6m, 1991 7.6 1 General purpose use
Doyle et al., 1975 7.6 Protect water quality from animal wastes Forested buffer
in: Comerford et al., 1992 8 Protect general water quality
in: Comerford et al., 1992 9 Protect water quality from ground-based
herbicide applications
Martin et al., 1985 10 - Protect water quality from clear-cut Forested buffer
Clark, 1977 10 General purpose use 0% slope over slightly erodible
I soils
Swift, 1986 10-19 Protect general water quality Road runoff sediment
Trimble & Sartz, 1957 10.6-12.2 Protect water quality from logging <10% slope
Florida Div. Forestry, 1990 11 Protect general water quality Primarily strearnside
in: Comerford et al., 1992 11 Protect small stream water quality Forested buffer
in: Comerford et al., 1992 12-24 Protect general water quality Forested buffer
in: Comerford et al., 1992 12-83 Moderate erosion protection Forested
in : Comerford et al., 1992- 15 Protect water quality from pesticides
Phillips, 1989b 15-60 Protect general water quality Well-drained soils
in: Comerford et al., 1992 15-103 Severe erosion protection Forested buffer
Corbett & Lynch, 1985 20-30 Protect water quality from logging Forested buffer
Clark, 1977 23 Protect water quality from logging Forested buffer
Moring, 1982 30 Protect salmon egg and juvenile Forested buffer
development
En-nan et al., 1977 30 Protect stream water quality from logging Forested buffer
USACE, 1991 30 90%-removal of TSS Grassed buffer
in: Comerford et al., 1992 30 Protect water quality from aerial herbicide,
applications
in: Comerford et al., 1992 31 Protect large stream/river water quality Forested buffer
Phillips, 1989b 40-80 Protect general water quality Poorly drained soils
Clark, 1977 45 Protect general water quality 30% slope over severely erodible
soils
Clark, 1977 46 Protect general water quality
in: Comerford et al., 1992 91 Protect private residences from aerial
herbicide applications
Phillips, 1989b 93 Protect stream water quality Under all conditions
Roman & Good, 1983 100 Wetland protection NJ Pinelands habitat
Brown et al., 1990 178 Protect wetland water qu'ality

in Table 4. This variability in vegetated buffer pol- sources with differing input concentrations (see
lutant removal effectiveness is a direct result of the Table 4). The relationships between percent removal
site-specific conditions previously discussed. Most and vegetated buffer width given here, therefore,
of the reported pollutant removal values come from integrate buffer effectiveness over a range provided
studies that have utilized buffers vegetated with in the literature, and are to be interpreted as general-
grasses to treat runoff from sources rich in pollu- ized, or average, pollutant removal effectiveness.
tants - manure, sewage spray, and feedlots for in-
stance. The range of values for removal effectiveness Removal of sediment and suspended solids
presented in Table 4 may therefore be biased toward Sediments are readily removed from surface
the treatment of extreme pollution sources, compared water runoff moving through vegetated buffers. This
to what may be considered typical for runoff water. is evident from Table 4 and is further exemplified in
Furthermore, studies of grassed buffers have provided Figure 4, which shows that removal efficiencies are
most of the data summarized in Table 4, with the result typically high, even for relatively narrow vegetated
that forested buffers are potentially underrepresented buffers. From the modeled relationship, a vegetated
with regard to pollutant removal efficiency. buffer of even two meters in width could be ex-
The data presented in Table 4 are graphically pected to remove about sixty percent of the sedi-
shown in Figure 4 through Figure 8 for sediments, ment load entering the vegetated buffer. A twenty-
total suspended solids, nitrogen, nitrate, and phos- five-meter-wide vegetated buffer could be expected
phorus. An associated "best fit" curve - a logarith- to remove about eighty percent of sediment inputs.
mic function using percent removal as the depen- Only slight increases in removal efficiency with
dent variable - is also provided to show the mod- increasing buffer width are noted for buffers greater
eled relationship between buffer width and pollutant than 25 meters wide. Overall, vegetated buffer
removal efficiency. The relationship between buffer width must increase by a factor of 3.5 in order to
width and polutant removal agrees with those achieve a 10 percent increase in the removal of
previously developed by Karr and Schlosser (1978), sediment in the vegetated buffer. Although the
Wong and McCuen (1982), and others, in which majority of data that was used to develop the curve
removal efficiency increases rapidly up to a certain shown in Figure 4 comes from grassed buffers, the
buffer width, after which large increases in buffer few reported values that come from forested buffers
width are needed to improve removal efficiency by are high, particularly at larger buffer widths.
even a small amount. It is important to note that the The pattern noted for the removal of total
data used to construct the graphs in Figures 4 suspended solids JSS; Figure 5, following page) in
through 8 do not come from a single, controlled vegetated buffers is similar to the relationship seen
study, but from a wide variety of studies reported in for the removal of sediment. In vegetated buffers six
the literature. The studies were conducted at a meters in width, the expected removal efficiency for
variety of sites and treated different pollutant TSS is about sixty percent. Eighty percent removal
igure 3

Figure 3. A range of vegetated
buffer widths reported in the
literature to be adequate for the Rivers and Lakes N=3
protection of water quality in
various water body types. The range
represents buffer widths noted in the
literature, as reported in Table 3. The Stream N=7
General category contains buffer
widths that were reported to protect
water quality, but were not specific to General N= 13
a type of water body. The heavy line
contained in the bar represents the
mean of the data that make up the 0 10 20 30 40 50 60 70 80 90 100
range. [I meter = 3.28 feet] Buffer Width (m)

Table 4. A summary of pollutant removal effectiveness values according to width of the vegetated buffer. Removal
efficiency values are given as percen 't removal for each of the various pollutants treated in the vegetated buffer sediment,
TSS, total nitrogen, total phosphorus, and nitrate-nitrogen. [I meter = 3.28 feet]

PollutantRemoval
Author(s) Width (m) Sediment TSS N P N03
Doyle et al., 1977 0.5 9VO 00/0-
Neibling, & Alberts, 1979 0.6 91%
Neibling & Alberts, 1979 0.6 37%
Neibling & Alberts, 1979 12 78%
Doyle et al., 1977 1-5 8% 57%
Neibling & Alberts, 1979 2.4 82%
Doyle et al., 1975 3.8 95% 99%
Doyle et al., 1977 4.0 62% 68%
Young et al., 1980 4.06 84% 83% 9170
Dillaha et al., 1988 4.6 31% 070 2%
Dillaha et al., 1988 4.6 87% 61% 63%
Dillaha et al., 1988 4.6 76% 67% 52% 3%
Magette et al., 1987 4.6 72% 1 17% 41%
Dillaha et al., 1986b 4.6 63% 63% 63%
Neibling & Alberts, 1979 4.9 83%
bling & Alberts, 1979 6.1 90%
Doyle et al., 1975 7.6 96% 99%
Schellinger & Clausen, 1992 7.6 401b 15% 601o
Schellinger & Clausen, 1992 7.6 27% 1 16% 18%
Dillaba et al., 1988 9.1 58% 7% 19%
Dillaha et al., 1988 9.1 95% 77% 80% 401o
Dillaha et al., 1988 9.1 88% 71% 57% 17%
Dillaha et al., 1986b 9.1 78% 78% 78%
Magette et al., 1987 92 86% 51% 53%
Thompson et al., 1978 12 45% 55% 46%
Bingham et al., 1978 13 28% 25% 28%
Mannering & Johnson, 1974 15 45%
Doyle et al., 1977 15.2 97% 99%
Lake & Morrison, 1977 15.2 46%.
Peterjohn & Correll, 1984 19 90%, 62% OVO 60%
Young et al., 1980 21.3 81%
Young et al., 1980 21.3 75%
Schwer & Clausen, 1989 26 95% 1 92% 89%
Young et al., 1980 27.4 93%
Young et al., 1980 27.4 66% 87% 88%
Young et al., 1980 27.4 82% 84% 81%
Edwards et al., 1983 30 23% 31% 29%
Doyle et al., 1975 30.5 98% 99%
Patterson et al., 1977 35 71%
Thompson et al., 1978 36 69%. 61% 62%
W-ong & McCuen, 1982 45 90%
Woodard, 1988 57 99%
Edwards et al., 1983 60 87% 83% 84%
Baker & Young, 1984 79 1 99%
Kaff & Schlosser, 1978 91 55% 1 50% -
Karr & Schlosser, 1978 215 97.5% 90%
Karr & Schlosser, 1978 99C/O 97%
Lowrance et al., 1984 85% 30-42% 8 '30/b
Jacobs & Gillam, 1985 99%
Rhodes at al., 1985 99%
@
95
'8

950/o

66
82 0
0
23E

Reuter et al., 1992 85% 97% 85-90%
Schipper et al., 1989 98%

Table 4. A summary of pollutant removal effectiveness values according to width of the vegetated buffer.
Continued

Runoff source Vegetation Slope Other
Dairy manure Grass-fescue 10% 90 mT/ha.
Bare soil Grass 701o For coarse-grained sediments
Bare soil Grass 7% For clay-sized particles
Bare soil Grass 7% For clay-sized particles
Dairy manure Grass 90 mT/ha
Bare soil Grass 7% For clay-sized particles
Dairy manure Forest/scrub 35-40% Gravely, silt-loam soils
Dairy manure Grass
Dairy feedlot 401o
Dairy manure Orchard grass 501b Concentrated flow
Dairy manure Orchard grass 11% Av. 10,000 kg/ha manure application
Dairy manure Orchard grass 16% Av. 10,000 kg/ha manure application
Dairy manure Forest/scrub 35-40% Gravely, silt-loam soils
Fertilized cropland Orchard grass
Bare soil Grass _71/_0 For clay-sized particles
Bare soil Grass 791, For clay-sized particles

-Dairy yard runoff Fescue & rye mix 201o Poorly drained, surface sample
Dairy yard runoff Fescue & rye mix 2% Poorly drained, subsurface sample
Dairy manure Orchard grass 501o Concentrated flow
Dairy manure Orchard grass 11% Av. 10,000 kg/ha manure application
Dairy manure Orchard grass 16% Av. 10,000 kg/ha manure application

Dairy manure Orchard grass
Poultry manure Fescue 6-8%
Bluegrass sod
Dairy manure Forest/scrub 35-40% 90 mT/ha; Gravely, silt-loam soils
Bluegrass sod
Agricultural runoff Forested
Feedlot runoff Corn 401o
Oats 401o
Milk house waste Fescue & rye mix 2%
Corn 401o 25-year, 24-hour storm simulation
Orchard grass 401o 25-year, 24-hour storm simulation
Sorghum/grass 401o 25-year, 24-hour storm simulation
Feedlot runoTf Fescue 201o Settling basin, then through 60 m of grass
buffer
Dairy manure Forest/scrub 35-40% Gravely, silt-loam soils
Liquid dairy waste Fescue 3.4%

Natural, mixed
Feedlot effluent Fescue 201o Moved through 2 consecutive 30m VFS
Fertilizers Grass
Bermuda grass

Forested
Forest/wetland 79.6 ha undisturbed watershed

Fertilized field Man-made gravel
runoff
Sewage spray Forested pine

occurs at about sixty meters of buffer width, beyond -buffer width and nitrate removal is simply inappro-
which improved removal efficiency is slight with priate. Considering that nitrate removal predomi-
increased buffer width. For TSS removal, an ap- nantly occurs through biological rather than physi-
proximate increase in buffer width by a factor of 3.0 cal or chemical means., site-specific variables, such
provides a 10 percent increase in removal efficiency. as denitrification potential, may need to be consid-
The greater vegetated buffer widths required for ered in order to better estimate nitrate removal in
TSS removal, compared to sediment removal, may vegetated buffers.
be due to smaller-sized particles and a greater
amount of particulate matter, which in general Removal of total phosphorus
requires greater buffer width to b e adequately The data given in Table 4 and modeled in Figure
removed from surface water runoff. As with sedi- 8 suggest that the removal efficiency of phosphorus
ment removal, the few included forested buffer in vegetated buffers is quite variable, and relatively
values are high for the removal of TSS from runoff. low at very narrow buffer widths. Buffer efficiency
increases rapidly to twelve meters of buffer width,
Removal of total and nitrate-nitrogen where approximately sixty percent phosphorus
The removal efficiency of vegetated buffers for removal is achieved. Buffer efficiency improves
nitrogen varies considerably, particularly within the with added buffer width, until approximately eighty
range of narrow buffer widths. This is very evident percent removal is achieved in an eighty-five-meter-
from both Table 4 and Figure 6. Removal efficiency wide vegetated buffer. Greater phosphorus removal,
of nitrogen in a nine-rrieter-wide vegetated buffer as with other pollutants, is achieved only with large
is expected, from the modeled relationship, to be additions of buffer width after this point. Overall, an
about sixty percent. Removal efficiency increases approximate increase in buffer width by a factor of
with increasing buffer width to about 80 percent 2.5 is required to achieve a 10 percent increase in
removal at sixty meters of buffer width, after which phosphorus removal.
point the rate of removal of nitrogen per unit in- Although phosphorus is reported to be typically
crease in buffer width slows. An approximate bound to sediments, it is generally bound to smaller-
increase in vegetated buffer width by a factor of 2.6 sized sediment particles (Karr and Schlosser, 1977).
is required to achieve a 10 percent inc rease in Since smaller-sized particles and particulates are
nitrogen re m-oval efficiency. typically not as effectively filtered out by vegetated
The nitrogen removal efficiency data used in buffers as coarse-grained sediments, this may result
Table 4 and Figure 6 are mainly from studies. in the differences noted'between sediment and
performed in grassed buffers, and therefore may not phosphorus removal efficiencies, as seen when
adequately portray removal efficiencies of forested comparing the removal patterns in Figure 4 and
buffers. However, the scatter in the forested buffer Figure 8. The forested buffer data given in Figure 8
data included in Figure 6 appears as wide and as appear to be as variable and scattered as those for
variable as that noted for grassed buffers. grassed buffers.
Nitrate removal, is variable, but generally low,
according to'the data give ni in Table 4 and shown in Performance standards
Figure 7, for all buffer widths. The modeled nitrate From the values given in Table 4, and the
removal-to-buffer width relationship shown in modeled relationships seen in Figure 4 through
Figure 7 suggests that approximately 50 percent of Figure 8, an estimated removal standards matrix
the nitrate present will be removed in buffers of one was constructed (Table 5). Other than for nitrate, the
hundred meters in width. The modeled relationship matrix suggests that, on average, 50 percent overall
for nitrate'removal suggests that increased removal pollutant removal can be expected to occur in
will only occur given enormous increases in veg- vegetated buffers five meters wide. Seventy percent
etated buffer width. It is unclear if the low removal removal efficiency can generally be expected to oc-
efficiency of nitrate in vegetated buffers provided cur in vegetated buffers of about thirty-five meters
by this model is due to the data being generally in width, while eighty percent removal efficiency
from grassed buffers, which are often less than ideal might b e expected in buffers of about eighty-five
denitrification sites, or if the relationship between meters in width. Vegetated buffer widths between

Figure 4.

Figure 4. Relationship of percent 100- 0
removal to buffer width for the -0 00
treatment of sediments contained in 80- P
surface water runoff. An approximate > 0
0
increase in vegetated buffer width by a E
4) 60-
factor of 3.5 is required to achieve a 10
percent improvement in removal of
E 40-
sediment. The most efficient vegetated
buffers, based upon width-to-removal
ratios, will be about 25 meters in width, 0-0 20-
after which large additions of buffer - N = 4 (forested) 0
width are required to achieve only small N = 15 (grassed) 0
increases in sediment removal efficiency. 0 1 1
0 50 100 150 200 250 300
The modeled line is: % removal = [(7.613 Buffer Width (m)
* In(width in meters)) + 55.8]. Data are
taken from Table 4. [1 meter = 3.28 feet]

Figure 5.

Figure 5. Relationship of percent 100-
removal to buffer width for the treat- 0
ment of TSS contained in surface water 'as
runoff. An approximate increase in 80-
vegetated buffer width by a factor of 3.01 is >
0
required to achieve a 10 percent improve- E 60- 0
ment in removal of TSS. The most efficient
vegetated buffers, based upon width-to- 40-
removal ratios, will be about 60 meters in -IR -0
width, after which large additions of buffer 20- 0
width are required to achieve only small N = 3 (forested) 0
increases in TSS removal efficiency. The 0 N = 15 (grassed) 9
modeled line is: % removal = [(8.34 * 04 . 1.111-1111 1 1 1 1 1 1 1 1 1 1 1 1
In(width in meters)) + 45. 1 ]. Data are 0 50 100 150 200 250 300
taken from Table 4. [1 meter 3.28 feet] Buffer Width (m)

250 and 550 meters will be needed to achieve 90 - Decreased disturbance from neighboring
99 percent overall pollutant removal effectiveness. areas
The matrix given in Table 5 may be useful in Decreased predation: wider buffers further
estimating the potential overall removal of a veg- reduce predation
etated'buffer for a given buffer width, or for estimat-
ing the removal of a given buffer width for a spe- It is difficult to be specific about the value to
cific pollutant of concern. These values should be wildlife of vegetated buffers as habitat, since the
held in light of the site-specific conditions in and vegetative makeup of the buffer area will often
around the actual buffer area, and buffer width determine what species will use it, as well as how
adjusted according to best professional judgment for they use it. The habitat value of vegetated buffers
best estimating a buffer width to achieve the desired for different animal and plant species will also be
removal efficiency. determined by width of the buffer, proximity to
other required habitat types, proximity and density
M Wildlife Habitat Protection of predators and competitors, and proximity of each
For the purposes of this review, the term "wild- organism to others of its species. Furthermore, noise
life" refers to both animal and plant species. The use disturbance from developed or developing areas
of the term wildlife, with regard to its animal affects habitat quality and use. The greater the
component, is generally meant to encompass all disturbance, the greater the buffer required to reduce
except large mammals. This is particularly. true at the impact upon the use of adjacent environments
narrow buffer widths, but large mammals may by wildlife. In some instances, buffers may need to
become part of the vegetated buffer complex as the be established around habitat areas in order for them
width of the buffer increases,. providing more to be successfully utilized by wildlife. This will be
suitable conditions and space for large mammals. most critical in areas that are highly developed and
The vegetated buffer concept has reached its create a lot of disturbance noise, for instance.
greatest application for wildlife habitat protection in The value of narrow buffers as habitat will therefore
the development of "gre* enway ... .. stream corridor," be directly related to the amount of disturbance they
and "habitat corridor" management programs. These receive from adjacent areas.
practices generally set aside vegetated strips along Table 6 provides a summary of buffer widths
rivers and streams to promote good water quality, reported in the literature considered to provide
maintain wildlife habitat, and provide wildlife travel habitat for various broad wildlife categories: this
corridors. Current paradigms suggest that increased summary is presented graphically in Figure 9.
environmental diversity and complexity promote Several authors (for example, Tassone, 198 1; Cross,
increased biodiversity (see Wilson, 1988). There- 1985; Triquet et al., 1990; Groffman et al., 1991b)
fore, the establishment of vegetated buffers can be note that vegetated buffers that are contiguous to
viewed as one step in maintaining local ecosystems areas of natural vegetation are likely to support, or
and promoting regional biodiversity. The following be used by, a greater number of species. Even sinall
highlights some of the potential benefits to wildlife vegetated buffers can be enhanced in value by being
of vegetated buffers, as.noted by Groffman et al. close to undisturbed areas that more fully satisfy
(1991b): - species-specific resource requirements.'
- Increased species diversity: mixed habitat From the reported values in Table 6, which
types promote greater diversity range from 15 to 200 meters, it is difficult to deter-
- Increased foraging sites; mixed vegetation mine a "best size" buffer width for general wildlife
provides greater food availability habitat. It has been noted that 15-meter buffer
- Wildlife dispersal corridor: wider buffers widths provide habitat under certain conditions, and
@ provide a better travel corridor it may be that widths much less than that will not
- Escape from flooding provide adequate space - bird nesting sites for
- Hibernation sites instance - for resident species. Buffers less than 15
- Breeding and nesting sites: wider buffers meters wide, however, may provide adequate habitat
reduce nest parasitism for the temporary activities, such as resting'or
feeding, of both resident and transitory' species.

Figure 6.

Figure 6. Relationship of percent removal loo- 0 0 0 0 0
to buffer width for the treatment of nitro- 0
gen contained in surface water runoff.
An approximate increase in vegetated buffer >
0
width by a factor of 2.6 is required to achieve S 0
0 60-
a 10 percent improvement in removal of
nitrogen. The most efficient vegetated buffers, 401,
2 40-
based upon width-to-removal ratios, will be
about 60 meters in width, after which large z
additions of buffer width are required to 20- 00
- N 5 (forested) 0
achieve only small increases in nitrogen 0 14=211,ra, I!,
removal efficiency. The modeled line is: % 0111, - II "@ _4,
removal = [(10.5 * ln(width in meters)) + 0 110 .... 210 .... 310 .... 510 610 710 80
37.4]. Data are taken from Table 4. Buffer Width (m)
[I meter = 3.28 feet]

Figure 7.

Figure 7. Relationship of percent 100-
removal to buffer width for the treat-
ment of nitrate contained in surface
water runoff. Unlike the other modeled 80-
pollutant removal-to-buffer width relation- 0
E 60- 0
ships, that for nitrate is suggested to be
inappropriate. Nitrate is typically removed
by biological processes rather than 40-
through physical and chemical means, and
the variables that control denitrification 20
may better determine the removal of N = 1 (forested) 0
nitrate in vegetated buffers than does N = 10 (grassed) 0
buffer width. Data are taken from Table 4. 0 . . . I I I I I I IT . . . IT." I I
[I meter = 3.28 feet] 0 5 10 15 20 25 30 35 40 45 50
Buffer Width (m)

Figure 8.

Figure 8. Relationship of percent removal 100- 0 0 0 0
to buffer width for the treatment of
phosphorus contained in surface water
80-
runoff. An approximate increase in vegetated0
buffer width by a factor of 2.5 is required toE
60-
achieve a 10 percent improvement in removal 9)
a. -
of phosphorus. The most efficient vegetated0
buffers, based upon width-to-removal ratios, CL 40-0
0
0
will be be about 75 meters in width, after
which large additions of buffer width are 20-
required to achieve only small increases in - b N 5 (forested) 0
N 11 (,@sd"
phosphorus -removal efficiency. The modeled 0 41 "" ,
line is: % removal = [(10.3 * ln(width in 0 10 20 30 40 50 60 710 80 90
meters)) + 34. 1 ]. Data are taken from Table 4. Buffer Width (m)
[1 meter 3.28 feet]

Table 5. Estimated removal standards matrix for specific pollutants as taken from the modeled relationships shown in
Figure 4 through Figure 8 for vegetated buffers. In general, greater than 50 percent removal standards can be met with
vegetated buffers about 5 meters wide. The 80 percent removal category generally marks the optimal width-to-removal ratio
boundary, above which the increase in removal efficiency for a given increase in buffer width is small. [I meter 3.28 feet]

Buffer Width (m)
% Removal Sediment TSS Nitrogen Nitrate Phosphorus
50 0.5 2 3.5 >100 5
60 2 6 9 - 12
70 7 2D 23 - 35
8D 25 6D 6D - 85
90 90 200 150 - 250
99- 300 700 350 - 550
@0_

Many studies have determined buffer widths for rather than providing a sharp contrast between
wildlife habitat by determining species-specific habitat types. In some cases where no buffer exists,
needs - such as those for rare, threatened, or a sharp contrast may be unavoidable, and transient
endangered species - and then applying them to wildlife may be the major users of the vegetated
buffer width requirements. Few studies, however, buffer area. Wider buffers will provide less contrast,
have determined overall needs for multiple-species since they will produce a larger gradient between
use of buffers, and fewer still have studied use habitats, and will become habitat themselves. Some
patterns of wildlife for existing or newly established routine assessment and maintenance practices may
vegetated buffers that are part of a multiple-use be required to maintain habitat value and keep in-
resource management program. It is therefore vading species from overtaking implemented buffers.
difficult to determine how buffers of various widths
and vegetative makeup, once implemented, will be 0 Erosion and Flood Control
used by wildlife. Vegetated buffers employed as erosion controls
However, if current paradigms are correct, then are generally applied as best management practices
with regard to value of vegetated buffers to wildlife, to mitigate the off-site impacts of development and
bigger is better, and some is better than none. Large construction activities. However, by their very
buffers may be required in areas where species nature, vegetated buffers can assist in reducing
preservation is a major focus of vegetated buffer erosion even when not specifically designed for that
development, while smaller buffers may be ad- purpose. Since vegetated buffers slow the velocity
equate in other areas, particularly where more of runoff flow, as well as dissipate flow and reduce
contiguous stretches of habitat are nearby. Larger channelized flow, they will reduce the probability of
buffers will provide a greater diversity of resources erosional problems downstream of buffer areas.
over the long term for wildlife in general, while It was previously noted, however, that vegetated
small patches will provide "island" habitats in the buffers can become clogged with sediment removed
larger mosaic. The greater the diversity of available from surface water runoff. Vegetated buffers that are
resources, the greater the potential for the long-term employed specifically for erosion control - for
survival of the targeted or intended wildlife species, instance, to control sediment movement from
as well as for incidental users. construction sites - may need to be rehabilitated
Some caution, however, is noted in a summary after construction work if they are intended to
by Groffman et al. (1991b) of vegetated buffers as continue functioning as a multiple-use buffer.
wildlife habitat. The authors note that sharp con- Vegetated buffers also have value for flood
trasts between habitat types, such as engineered control, and have been employed for this purpose.
buffers, may promote the growth of weed species. They control flooding by reducing flow velocity,
The weed species could invade nearby natural areas, allowing absorption and storage of water in soils,
replacing resident vegetation with opportunistic and and by moving water from surface to subsurface
transient species. This was reported by Dillaha et al. watercourses. Vegetated buffers also mitigate
(1986a) to be a common problem in vegetated property destruction by maintaining some undevel-
buffers assessed in the state of Virginia. Weed oped land along waterways and keeping developed
species have been known to invade nearby habitats, or developing areas back from floodwaters, storm
thereby reducing the habitat value of the buffer. This surges, and extreme high tides.
is a most important consideration if the vegetated The capacity of the buffer area to provide flood
buffer is established for the protection of rare, control will depend on rainfall and runoff intensity,
threatened, or endangered species, and may also be soil characteristics, hydrologic regime, and slope of
a consideration in the development of small buffers both the buffer and the source of runoff water. Even
that represent island patches. under ideal conditions, the ability of a vegetated
This suggests that care should be taken in buffer to control flooding will be related to the
designing and designating vegetated buffers next to water source area. A buffer that is small relative to
sensitive areas, or where rare or endangered species the water source area will have only limited ability
live. In these cases, the vegetated buffers could be to control flooding. When buffers are applied with a
developed to graduate into the sensitive habitat, primary intent of flood control, water-holding

Table 6. Recommended buffer widths for wildlife habitat. The reported widths are generally intended as minimu rn values
to provide the desired habitat requirement to meet the given objective. [I meter = 3.28 feet]

Author(s) Width W Objective Specifics
Triquet et al., 1990 15-23 General avian habitat Riparian wooded area
Shisler et al., 1987 15-30 Protect wetland habitat from low- Densely growing mixed species buffer
intensity disturbances
Tassone, 1981 30 Wildlife travel corridor
Shisler et al., 1987 30-45 Protect wetland habitat from high- Densely growing mixed species bufTe-r
intensity disturbances
Howard and Allen, 1989 60 General wildlife habitat
Tassone, 1981 60 Breeding sites for fragment-sensitive bird
species
Groffman et al., 199 1 b 60-100 General wildlife habitat
Cross, 1985 67 Small mammal habitat Wooded riparian area
Groffman et al., 199 1 b 91.5 Protect significant wildlife habitat Natural vegetation
Brown et al., 1990 178 Wetland habitat protection
Scheuler, 1987 200 Diverse songbird community
U.S. ACE, 1991 <9W For all but large mammals Riparian forest

Figure 9.

Figure 9. Ranges of buffer widths
noted in the literature to provide Avian-
effective habitat for several broad, Wildlife Travel Corridor
categories of wildlife. Thexanges Breeding Bird - 40
of categories represented by a circle All .Except -
arise from one study, and therefore 200---C;-
Large Mammals -
may not be very representative of General Wildlife
that particular category. Two -
reported values make up the range Rare Species
shown by each of the horizontal
bars. Data are taken from Table 6. 0 20 40 60 80 100
H meter 3.28 feet] Range of Buffer Widths (m)

capacity of the buffer area will need to be deter- general guidelines can be developed for the use of
mined, and proper width applied to the buffer in vegetated buffers. Table 7 provides a generalized
order to store the water received during a given overview of the pollutant removal effectiveness -
storm event. taken from the modeled relationships and as pre-
sented in Table 5 - and wildlife habitat value,
E Historical and Cultural Preservation taken from Table 6 - for a range of buffer widths
While vegetated buffers are best known for their for multiple-use vegetated buffers. The effectiveness
use in preserving and protecting water quality and of vegetated buffers for pollutant removal, as well
wildlife habitat, application of coastal buffer zones as for wildlife use, is presented as increasing steps
may also have value in preserving and protecting of buffer width.
historical and cultural sites. In Rhode Island, for Using the generalized set of buffer widths
instance, many of the important archaeological sites presented in Table 7 for developing and implement-
pertaining to Native Americans such as summer ing a vegetated buffer policy requires that local
encampments and trading sites are within 200 conditions and intended uses be taken into consider-
feet of the coast. The same may be true for other ation. The buffer widths listed in Table 7 are meant
coastal states. If so, establishing coastal vegetated to be useful in a general sense for planning pur-
buffers can preserve potentially important sites for poses. For example, the table values may be overly
future archaeological study. large if removal of sediment is the intended effect,
and if the area of buffer implementation is very
N Scenic and Aesthetic Enhancement conducive to sediment removal. Similarly, the table
Aesthetic and scenic qualities of vegetated values may be too small if the removal of metals is
buffers often provide an "extra" value or benefit to the intended effect and the proposed buffer area
the major purpose for which the vegetated buffer overlies impermeable soils on steep slopes.
was designed. As noted in Mann (1975), Simeoni From the values presented in Table 7, a mul-
(1979), and Forman and Godron (1986), landscapes tiple-use vegetated buffer of five meters could be
with high visual diversity are generally more ap- considered a reasonable minimum-buffer-width
pealing than nondiversified landscapes. Designed standard. A five-meter-wide vegetated buffer will
planting of trees and shrubs within the buffer area provide approximately 50 percent sediment and
can enhance visual diversity and thus aesthetic nutrient removal (except for nitrate). While a
appeal. As the vegetated buffer attracts wildlife, vegetated buffer of this width may not provide good
such as songbirds, visual and biological diversity overall wildlife habitat, it may be sufficient to
are both enhanced. In areas previously cleared of provide resting and feeding areas for both resident
vegetation, reestablishing native species can assist and migratory species. A five-meter-wide multiple-
in rebuilding the sense of "wilderness" often associ- use vegetated buffer can be practically imple-
ated with coastal expanses. It is this sense of isola- mented, except in areas of very dense development,
tion and wilderness that makes coastal regions and these exceptions could be reviewed as a vari-
attractive to those who visit. ance to general buffer policy. A five-meter-wide
The aesthetic value of vegetated buffers is, how- vegetated buffer could be established as a minimum
ever, mostly based on subjective factors, and there- goal for the restoration of already developed areas.
fore not fully transferable in implementation prac- Establishing a minimum buffer width will also
tices. Although no criteria for aesthetic values of maintain or improve the scenic and aesthetic quality
vegetated buffers exist, aesthetics will continue to be of the area, and will act as nondestructive, natural
included as an intrinsic value of vegetated buffers that fencing between public waters and private uplands.
are implemented for natural resource management. It should be kept in mind, however, that a five-
meter-wide vegetated buffer removing approxi-
0 General Guidelines for Multiple-use mately 50 percent of pollutants and sediment
Vegetated Buffers contained in surface waters may not meet minimum
Although the conditions determining the actual performance standards in all instances. If an ap-
effectiveness of a multiple-use vegetated buffer will proximate performance criterion of 80 percent
be of a local and/or site-specific nature, some removal is desirable, then a 75-meter-wide ve97

etated buffer may be the acceptable minimum. This many areas, however, a 25-meter vegetated buffer
buffer width will also provide minimum general may make some developable lots unusable due to
habitat value. If protection of habitat for significant site constraints, and may not give sensitive re-
species is to be the main purpose of the vegetated sources adequate protection. Shifting the fixed
buffer, then 200 meters may be the minimum accept- width to higher or lower values alleviates problems
able buffer width. This width will also provide on one end while creating them at the other. This
approximately 90 percent removal of sediment and approach has many limitations, but has been used by
pollutants. As minimum buffer width increases, how- resource managers in vegetated buffer programs.
ever, conflict may arise in areas where small-sized A variation of the fixed-width vegetated buffer
land parcels or extensive development already exists. approach is that recommended by the U.S. Forest
For general-purpose buffers that will provide Service in a recently published booklet describing
some value as wildlife habitat, a minimum width of riparian buffers (see Welsch, 1991). In this case, a
15 meters is suggested. A vegetated buffer of this vegetated buffer has a minimum width of 28 meters,
width should be implementable in most areas that and consists of three zones. The zone closest to the
are only moderately developed. Vegetated buffers of water is of a fixed width (five meters) and allows
15 meters should provide some water quality for no alteration of the buffer. The second, or
protection for most waterways (e.g., approximately middle, zone has a minimum width (17 meters) but
60 percent pollutant removal); will offer minimal can be expanded based upon local or site-specific
wildlife habitat value and greater visual and aes- conditions or to achieve a given effect (e.g., rare
thetic appeal; and can provide a natural physical species protection). Limited use, such as selective
barrier between public and private properties. 'harvest of timber, may be allowed in this zone of the
For areas that are undeveloped, or are character- buffer area. The third, or most inland zone, abuts a
ized by large lot sizes, buffers of 50 meters or more developed or disturbed area and possesses a mini-
could be applied to ensure that some areas are mum width (6 meters) that can also be expanded
providing general wildlife habitat. Buffers of this based on local conditions. This inland zone might
width could be applied to all publicly owned lands, consist of lawn in a residential setting or hay field in
such as state parks, recreation areas, and conserva- an agricultural setting. This approach alleviates some
tion areas. For areas that are considered critical, or problems by allowing greater buffer widths to be ap-
provide habitat for rare, threatened, or endangered plied as needed, but still may be restricted in its
species, the buffer width could be extended to 100 applicability in areas where small lot sizes are conunon.
meters or more to ensure sufficient habitat diversity A further modification of the fixed-width
and isolation from disturbance, and to promote the approach to vegetated buffer implementation is
long-term survival of these species and their eco- setting a realistic minimum vegetated buffer width
system. The minimum acceptable width will be based upon lot size or land use. A minimum width
determined by the function or functions of the vege- could be established for small lots or high-density
tated buffer. Resource managers may need to define residential areas so the buffer will provide some
present and future uses for the regions under their benefit for pollutant removal and/or habitat while
purview, and then develop minimum multiple-use not inordinately restricting use of property. The
vegetated buffer widths for the goals and uses desired. minimum vegetated buffer width could then be
expanded as lot size and/or land use changes to
M Implementation Approaches to Multiple- provide greater benefits of pollution removal and
use Vegetated Buffer habitat provision, while not overly restricting use of
One approach to multiple-use buffer implemen- private or public lands. One example of this ap-
tation is applying a fixed vegetated buffer width proach is that developed by the state of Rhode Is-
along all waterways. For instance, a vegetated land, which is provided in full detail in Appendix A.
buffer of 25 meters in width could be required An alternative to a fixed-width vegetated buffer
bordering all waterways. This approach, according is a vegetated buffer tailored to each site, using a
to Table 7, would provide approximately 70 percent model to generate a buffer width based upon a
overall removal of sediment and pollutants, and variety of data, but dependent upon site-specific
provide minimal general wildlife habitat. Along conditions. This approach is often data-intensive,

Table 7. A summary of pollutant removal effectiveness and wildlife habitat value of vegetated buffers according to buffer
width. The stepwise increments are adapted from Table 5 and Table 6, and reflect changes in pollutant removal effectiveness
and wildlife habitat value according to width of the vegetated buffer. [ I meter = 3.28 feet]

Buffer Width (m) Pollutant Removal Effectiveness Wildlife Habitat Value
5 Approximately 50% or greater sediment and Poor habitat value; useful for temporary activities of
pollutant removal wildlife
10 Approximately 60% or greater sediment a7d- Minimally protects stream habitat;poor habitat
pollutant removal value; useful for temporary activities of wildlife
15 Greater than 60% sediment and Minimal general wildlife and avian habitat value
pollutant removal
20 Approximately 70% or greater sediment and Minimal wildlife habitat value; some value as avian
pollutant removal habitat
30 Approximately 70% or greater sediment and May have use as a wildlife travel corridor aswell as
pollutant removal general avian habitat
50 Approximately 75% or greater sediment and Minimal general wildlife habitat value
pollutant removal
75 Approximately 80% sediment and pollutant Fair-to-good general wildlife and avian habitat value
removal
100 Approximately 80% sediment and pollutant Good general wildlife habitat value; may protect
removal significant wildlife habitat
200 Approximately 90% sediment and pollutant Excellent general wildlife value; likely to support a
removal I diverse community
600 Approximately 99% sediment and pollutant Excellent general wildlife value; supports a diverse
removal community; protection of significant species

but does result in a given buffer width that will Despite its limitations, the modeling approach is
better approximate a specific performance standard. often considered the most accurate and dependable
The modeled approach, however, will only be as method of delineating vegetated buffer widths, and
good as the site-specific data from which the model is commonly used by regulatory agencies. A strictly
is run. High quality data for use in a model will modeled approach, because it is based solely upon
often be expensive (e.g., time put into collecting it), "real" data, leaves less room for argument of re-
which may limit its overall practicality for general quired buffer widths (other than whether or not the
use in resource management programs. Further- input data or the actual model is appropriate) and is
more, most modeled approaches only consider one therefore generally viewed as more "justifiable."
vegetated buffer benefit - pollutant removal, for Since a strictly modeled approach is very "black-
instance - and neglect other potential benefits. and-white," it is generally inflexible, and may limit
Many of the existing buffer delineation models were full implementation of multiple-use vegetated
developed to mitigate construction impacts, and buffers by resource managers. Using a modeled
therefore may not be readily applicable in establish- approach to determine buffer widths to achieve a
ing multiple-use vegetated buffers in already devel- given pollutant removal standard, and then review-
oped or undeveloped areas. A further limitation to ing the modeled buffer width using best professional
the site-specific modeled approach is that regulatory judgment to achieve other benefits (e.g., provision
staff will be required to delineate vegetated buffers of wildlife habitat) may provide more flexibility and
on a case-by-case basis, which could become time a better multiple-use vegetated buffer program.
consuming. Furthermore, permit applicants will not Each approach to the application of vegetated
be able to incorporate vegetated buffer widths buffers as a management tool has both good and bad
during the initial design process. This will add cost points, and it will be up to the implementing author-
to all development requiring a permit, and the cost ity to determine what trade-offs are the most reason-
will be bome by both the permit applicant and the able and the most acceptable. Costs and benefits
pen-nitting agency. will have to be weighed and examined in light of the

uncertainty, restrictions, and flexibi lity inherent in canopy. Wherever possible, wetlands both
each of the different approaches. coastal and inland -- would be incorporated into the
buffer area. These areas most often provide the
The "Ideal" Buffer conditions that are conducive to denitrification, as
Although it is not possible to develop- a "one well as often providing valuable habitat. Further-
best" vegetated buffer for all purposes, it is possible more, upland buffers would be designated around
to describe the components of an "ideal" vegetated wetland areas to provide habitat for the in any
buffer for multiple use. If the vegetated buffer is animals that use wetlands as feeding and foraging
intended to reduce pollutant inputs -to waters from areas but rely upon the uplands for breeding sites
nonpoint sources, provide wildlife habitat, and and refuge from predators.
establish a visual and physical barrier, it is possible Vegetation species growing in the buffer would
to develop a general description of an ideal veg- be native, or species that are known to grow in
etated buffer. This description may prove useful in similar habitat and climate. Ornamental species may
creating vegetated buffers that will perform within be appropriate, provided they will not exclude or
expectations and provide the results for which they outcompete *native species. Many state agencies or
were established. nongovernmental organizations - land trusts,
universities, and botanical societies - have put
Contour together pamphlets that list and describe plant
The ideal multiple-use vegetated buffer for the species native to a region. These publications would
removal of pollutants, regardless of width, would be be consulted when planning a vegetated buffeT to
relatively flat in contour in order to promote shallow best e'nsure an indigenous cover within the buffer
sheet flow through the buffer. This would increase area.This is important for ensuring the longevity of
residence time, allow greater absorption of water the vegetation in the buffer, for providing adequate
into the soil layer, and reduce the probability of cover and forage for resident species, and for
channelized flow. The v(-,getated buffer would not preventing problems associated with invasions of
have any gullied or channelized areas within it. nonnative species. - 'I I
Similarly, the landscape surrounding and leading To provide greatest value to wildlife, the ideal
into the buffer would not promote channelized flow buffer would contain a mix of vegetation that fruits
into the buffer area, and would have adequate on a progressional schedule in order to provide a
vegetation or engineered design to reduce sedimen- variety of feed types over the greatest length of
tation at the leading edge of the buffer zone. Engi- time. Vegetation in the buffer would be as randomly
neered designs might include the installation of distributed as possible- woody vegetation inter-
level spreaders, or mechanical grading of the soils to spersed with areas of grass - to provide increased
produce a less steep slope, and/or alteration of the diversity within the buffer habitat landscape. W-g-
"preferred" direction of surfaceflow to promote etation of various heights and canopy thickness
shallow sheet flow into the buffer. would provide the greatest diversity to avian wild-
life, and would promote use by the greatest diversity
Vegetation of birds, as well as other fauna. Some bird species
Ideally, the vegetation within.the multiple-use herons and osprey, for example - require. large
vegetated buffer would consist of a mix of species. trees as nesting sites, and providing some large trees
The leading edge of the buffer might consist of a in the- vegetated buffer would promote the nesting
thickly growing grass maintained at a height of activities of these and other species.
about four inches. Beyond the grassy area would For aesthetic appeal, a mix of vegetation would
grow a mix of trees, brush, and possibly native provide visual diversity. Although some tall trees
grasses. The species of trees would have well- within the buffer area would be kept to provide
developed root systems capable of exploiting canopy habitat, short trees and brush would be
nitrogen stores traveling in groundwater, particu- dispersed throughout the buffer to allow water
larly in areas that are serviced by septic systems. views from areas landward of the leading edge of
Brush or woody-stemmed understory species would the buffer. Based upon vegetation type and pollutant
also provide a well-developed root system. and uptake rates, the buffer area would be determined to

remove a given portion of those pollutants of Although the ideal vegetated buffer may not be
concern, and then aesthetically fit into the landscape realized under most circumstances, the concept of
based upon development patterns and paths of the ideal buffer is useful as a reference or goal
surface water flow. during design and implementation phases. It can
The ideal multiple-use vegetated buffer would help ensure that the buffers that are eventually
be designated in existing natural areas. Designating implemented will contain the most desirable traits
vegetated buffers composed of existing vegetation possible, given natural limitations and site restric-
assures the habitat value of the buffer to the support tions, and thereby be the most practical. The closer
of native species. Designation of preexisting veg- to the ideal a given buffers becomes, the more
etated areas as buffers is also more economical since closely it will serve its intended purpose and pro-
the costs of design and engineering are avoided. vide the anticipated results.

jvol

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71-

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17.

111. Use of Vegetated Buffers in area of vegetated buffer. If estimates of pollutant
input to the vegetated buffer can be arrived at -
the Coastal Zone through nonpoint source loading models, for in-
stance - an estimate of removal efficiency can be
N Application and Approach obtained for a given buffer area. Given the rapidity
Vegetated buffers hold the promise of being an of the growth and sophistication of nonpoint source
effective multiple-use management tool for sustain- loading models and computerized geographic
ing the diverse uses of the coastal zone. The range information systems, it is not unrealistic to imagine
of multiple-use vegetated buffer widths, five to 200 calculating pollutant loadings to the coastal zone,
meters (or more; see Table 7), provides resource locating sensitive habitat areas or especially scenic
managers with a set of tools that can be applied or otherwise "special" areas, deten-nining the
according to developmental conditions along the vegetated buffer area required to provide expected
coast. It also allows flexibility with regard to pur- benefits, and then designing the location, extent, and
pose and use of the multiple-use vegetated buffer configuration of the vegetated buffer.
area. Adopting some form of vegetated buffer Some coastal areas, such as historical seaports
program that applies minimum buffer widths ac- and coastal villages, gain much of their charm and
cording to existing or potential development and ambiance by their location directly on the water. In
density, as well as applying wider buffer zones such instances, a vegetated buffer may be inappro-
around areas of critical concern, can result in the priate, and other ways to mitigate nonpoint source
development of a contiguous, or nearly contiguous, pollution impacts and create wildlife habitat, if
band of vegetated land bordering the coast. Such a possible, may need to be considered. Resource
program will assist in reducing the nonpoint source managers will have to evaluate the various uses of
contribution of pollutants flowing into coastal their coastal zone, decide on a vegetated buffer
waters, provide a diversity of wildlife habitats, approach, and then define where and how to imple-
provide for the protection and enhancement of ment the vegetated buffer program.
scenic and aesthetic appeal of the coastal zone,
promote flood and erosion control, and provide a 0 Public Perception
visual and physical transition zone between public It is important to acknowledge that humans are a
and private coastal properties. Development of such species that utilizes the coastal zone for a variety of
a program is realistic, equitable, and feasible. purposes. This must be not only considered, but
A coastal zone buffer policy can be readily incorporated into vegetated buffer policy. Design
4 established using a variety of available resources. and implementation of a coastal vegetated buffer
11
4 U.S :Geological Survey topographic maps, town zone program that disregards human use of the
J zoning maps, aerial photographic survey results, or coastal zone is bound to meet both resentment and
Geographical Information Systems (GIS) databases resistance, which could potentially be great enough
can readily be used to interpret conditions along the to force the abandonment of the use of this impor-
A coast, and then to establish vegetated buffer widths tant management tool for preserving and protecting
4 for a given region. Habitat for rare, threatened, or coastal resources.
endangered species; areas particularly prone to Establishing a program that utilizes vegetated
erosion and/or flooding; areas bordering poorly buffers for multiple use - pollution control, wild-
flushed estuaries or significant shellfish beds; and life habitat, scenic improvement - would help in
areas of particular historic or scenic significance making the program more appealing to a wider aud-
may be identified as critical resource areas by ience. Furthermore, a multiple-use approach to a
coastal managers, and larger buffer widths imple- coastal vegetated buffer program would make the
mented to provide for a greater degree of protection results of its implementation more "real" in the eyes
and/or preservation, of many. Increased scenic improvement, or greater
Although the removal rates presented in Table 2 wildlife sightings, are both very tangible, very visi-
cannot be used directly to provide a required width ble, and very real public "benefits" of a multiple-use
for implementing a vegetated buffer, they can be buffer program. Certainly they are more tangible
used to estimate annual removal rates for a given than increased pollutant removal, which is often in-

visible to, and misunderstood by, the general public. access to the water's edge, and the trails would be
The ideal buffer -program, however, would be checked and maintained on a regular basis for
one that is acceptable to the landowner who is being erosion -or promotion of channelized flow through
requested to-"donate" the fringe of coastal acreage the buffer area. An occasional picnic table, gazebo,
for the benefit of the public. Certainly the private or similar use structure might be suitable within
landowner will gamer some benefit from the pro- some vegetated buffers, provided it promotes
gram - increased wildlife sightings and the pres- neither a loss of effectiveness nor overuse of the
ence of a natural barrier between his personal lands buffer as a travel zone to and from the structure.
and those of the public, for instance - but resent- Areas that have buffers established to protect critical
ment due to land use limitations is often -felt by habitat or significant wildlife may not be suitable
private landowners. Given some leeway,for manipu- for any manipulation for recreational use. Such
lation and use of the buffer area, most landowners manipulation will have to be assessed on a case-by-
will feel less threatened by the program's infringing case basis in order to ensure that the original intent
upon their rights of ownership and use.. for which the buffer was established is not jeopar-
dized. Appendix B provides an example of a mul-
0 Management and Maintenance tiple-use vegetated buffer management and mainte-
Regulatory agencies should develop a vegetated nance program. This example is taken from the
buffer use, maintenance, and management booklet Rhode Island Coastal Resources Management
that outlines to abutting landowners what is permis-" Program (CRMP), and was developed to comple_
sible within the buffer, information sources for the ment the vegetated buffer policies for the state of
proper maintenance and management of the buffer Rhode Island CRMP (Appendix A@.
area, and a calendar and schedule of recommended All woody-stemmed species of vegetation
or required maintenance procedures. An assessment would be pruned and trimmed on a schedule to pro-
of implemented buffers by Castelle et al. (1992) mote vigorous growth and utilization of nutrients.
reported that 95 percent of the assessed buffers As trees and brush mature, or as individual plants
showed signs of alteration after their implementa- succumb to natural causes, selective harvesting
tion. In all cases where the buffer was part of a would maintain a vigorously growing and diverse
resident'ial lot, the buffer was eventually replaced plant community. Leaf litter and other organic debris,
with lawn by the homeowner. The authors suggest providing that it does not present a hazard or limit
that a lack of clear'use and management objectives other intended uses of the buffer area, would not be
for the buffer, as well "as a lack of buffer monitoring, removed from the buffer area. The breakdown of
resulted in the high alteration rate. A strong public leaf litter provides a natural source of carbon to the
education program implemented with the adoption soil layer, which is one requirement for the process
of the buffer policy into the regulatory framework of denitrification. Considering that coastal waters
will go a long way toward helping landowners Are generally nitrogen-sensitive, and nitrate is a
understand why the buffers were established and readily usable form of nitrogen in marine waters, the
how.landowners can use and maintain these areas. promotion of denitrification in coastal zone veg-
This is supported by the findings of Castelle et al. etated buffers should be considered a priority. G
Irass
(1992), who note that buffers on the property of clippings may or may not be removed from the buf- -
landowners who understood the purpose of the fer area, and worn or thin spots may be overseeded.
buffers were less affected by homeowner manipula- -Although neither fertilizatio 'n nor watering of the
tion and impact than those buffers on property of buffer area would be needed as a regular maintenance
landowners who had little or no understanding of activity, either or both might be appropriate in estab-
buffer purpose. lishing new buffer areas or restoring existing ones.
The management of coastal zone multiple-use
vegetated buffers will need to balance landowners' 'N An Example: Rhode Island's Coastal
rights to use of their property with maintenance of Buffer Program
the purpose for which the buffer was originally An example of multiple-use vegetated buffer
implemented. Winding trails and footpaths would be policies that have been developed for use in the
allowed within the vegetated buffer to provide coastal zone of Rhode Island. is provided in Appen-

dix A. It applies various-sized, fixed-width veg- are applied on small lots so as not to cause the lots
etated buffers, based on the summary given in Table to become unusable, and with the realization that
7, for residential lands; a fixed-width buffer on areas pollutant removal will be limited and habitat value
of concern or significance; and a case-by-case minor. As lot size increases, wider buffers are
approach to other development, such as industrial, implemented, increasing their value for pollutant
residential subdivisions, and commercial uses. removal, wildlife habitat, and visual appeal.
The Rhode Island example institutes vegetated I In all cases, and for all lot sizes, wider buffers
buffers along the entire coastline of the state, while are implemented where they border waters whose
taking into consideration land parcel size and primary use has been designated Type I - Conser-
existing coastal development patterns. The program vation, or Type Il - Low Intensity Boating. The
strives to strike a balance between land use by the reasoning is that these types of waters require a
homeowner and protection of coastal resources. The higher degree of protection and preservation in or-
widths of the established buffers are determined der to maintain their designated primary uses. Wider
according to lot size and Coastal Resources Man- buffer widths are also applied when the area receiv-
agement Council (CRMC) water type. The CRMC ing the buffer abuts an area of critical concern, special
water type is a designation of the predominant use significance, or scenic or historical importance.
of coastal waters (i.e., I-Conservation Areas; 11-Low The actual regulatory program, as adopted by
Intensity Boating; III-High Intensity Use; IV- the state of Rhode Island, is included in Appendix A
Multipurpose Waters; V-Commercial and Recre- exactly as it appears in the state's regulatory coastal
ational Harbors; VI-Industrial Waterfronts and program documentation. Appendix B includes a
Commercial Navigation Channels). Special mea- complementary vegetated buffer maintenance and
sures (e.g., wider buffers) are applied along areas management document created as part of the veg-
that are considered critical or sensitive, such as etated buffer program implemented by the Rhode
wetlands or habitat that is used by rare, threatened, Island CRMC.
or endangered species.
The vegetated buffer policies and regulations E State Coastal Buffer Programs:
are limited to residential areas (existing and infill) A Summary
and allow for limited use of the buffer areas so that This review of coastal states' programs, poli-
homeowners are not unduly denied use oftheir cies, and/or regulations that could be used to estab-
coastal property. These policies and regulations are lish vegetated buffers along the coastal zone con-
used as guidelines for other types of development cerns itself only with those that are a part of the
(commercial/industrial), but the final determination states' Coastal Zone Management Programs. Poli-
of buffer width for development other than single cies and regulations applied by other state agencies
family residential is performed on a case-by-case are mentioned when the state CZMP defaults to
basis by CRMC staff engineers and biologists to other programs to avoid replication, or when no
mitigate any potential impacts to the coastal zone. CZMP has been established for a given state.
The Rhode Island vegetated buffer program was Finally, despite the fact that the shores of the Great
developed to provide for multiple uses and multiple Lakes are considered under the federal coastal zone
benefits. During development of the program, it was management program, this review restricts itself to a
quickly realized that implementing vegetated description of those states bordering saltwater
buffers that would provide both high pollutant coastlines'*
removal and high quality habitat was not practical in Table 8 provides an overview and summary of
all coastal areas. Attempting to implement such the differences among states' policies, regulations,
buffers would either lead to the proposed program's and requirements for the establishment of vegetated
not being adopted, or to requests for variances on buffers along the coastal zone. A similar description
nearly all permit applications. of state buffer policies has been put together in
Given this, a program was developed that Castelle et al. (1992), but pertains strictly to wet-
balances the landowners' rights and the CRMC's lands and buffers around wetlands. Readers with a
mandate to "preserve, protect, and where possible, particular interest in wetlands may want to review
restore ecological systems." Narrow buffer widths that document. The program descriptions given here

are based on a* review of published state programs leaving vegetation along coastal areas being logged,
and/or discussions with state agency personnel. Any but the actual vegetated width preserved is deter-
errors, omissions, or misinterpretations are those of mined on a case-by-case basis. On city- and state-
the authors. owned lands, a 100-foot no-cut zone is required,
Of the twenty-three state programs reviewed, while on private property there is a 66-foot no-cut
four had buffer programs applying to the entire zone. This relates to timber harvest areas only, and
coastal zone as an element of their state coastal zone as noted above, is subject to modification on a case-
management programs. Two other states had buffer by-case basis. No statewide coastal zone program
elements that pertained only to a certain portion of buffer requirement currently- exists.
their coastal zone. Nearly all states had some fon-n
of mitigation procedure that could be applied during Californ *ia
the permitting process to establish vegetated buffers The state of California buffer program focuses
in the coastal zone. Construction or septic system on wetland habitat protection. The program requires
setbacks, which could be used to establish vegetated a minimum 100-foot buffer around coastal wetlands,
buffers, were reported by most states, although with additional width required if adjacent lands. are
many reported those to be established by town biologically significant, if sensitive wildlife inhabit
rather than state regulations ' the buffer, if the area is highly susceptible to ero-
The various setbacks and buffer policies being sion, or if proposed development poses significant
used by state coastal zone management programs potential impact. The 100-foot buffer@ however, is
that could establish vegetated buffers range from 20 used -as guidance only, and may be negotiated on a
feet to 300 feet of buffer width (excluding the case-by-case basis. Buffer regulations may exist at
possibility of no buffer). This represents a range of local levels of government, and may be more or less
buffer effectiveness (from Table 7) from fifty stringent than the 100-foot buffer guideline sug-
percent pollutant removal and poor habitat 'Value to gested by the state coastal program. Vegetated
eighty percent pollutant removal and good general buffers may be applied to riparian areas when
wildlife habitat value. No state program had policies coastal program jurisdiction is extended into water-
or regulations that provided greater than 80 percent sheds that drain into sensitive coastal areas.
pollutant removal, and none provided buffer widths
that were in the category (from Table 7) considered Connecticut
excellent as wildlife habitat, although either or both The state of Connecticut coastal zone program
could potentially be achieved during case-by-case has policies that promote preservation of vegetated
buffer development. coastal areas but has no statewide requirements.
Implementation of vegetated buffers or construction
Alabama setbacks along the coast may occur through zoning
The state of Alabama has a 40-foot construction regulations and requirements at local levels of gov-
setback requirement, but it is only applicable to land ernment. Construction setbacks that do exist in local
along-the shoreline areas immediately on the Gulf zoning ordinances may vary by town throughout the
Coast; it does not include back bays and coves. coastal zone of the state. New vegetated buffer
The application of the 40-foot setback is meant to policies and regulations are being drafted by state
protect beach dune systems and is measured regulatory agencies. While these new policies are
from the dune crest. Vegetated buffers may be estab- generally focused on riparian systems, their applica-
lished through local zoning regulations of coastal tion may be extended into the state's coastal zone.
districts but are not a requirement of the state
coastal zone program. Delaware
In the state of Delaware, establishment of
Alaska vegetated buffers in the coastal zone is not a re-
In the state of Alaska, separate requirements for quirement of the coastal zone management program
coastal vegetated buffer areas may be established but may occur at the local level, according to local
through local government mandates for each re- zoning regulations. State CZMP staff may require
gional borough. Regulations exist that require the establishment of a vegetated buffer during the

Table 8. A listing of buffer and setback widths that coastal states have established through their coastal zone manage-
ment programs. M denotes the. width is mandated, while R denotes that the width is recommended only. [I foot = 0.305 meters]

State Buffer Width Status Setback Width Status Comments
Alabama 40% Applies to Gulf M Primarily for dune protection and
Coast only preservation
Alaska 10Y city/state lands; M Applies only to tim r harvest
66' private property operations
California 100' around wetlands R Mainly for habitat preservation
Connecticut Through local ordinances
Delaware 50'from mean high M Also through local ordinances
water mark
Florida Through local ordinances
Georgia No CZMP at present
Hawaii 40' from shoreward M Applies to all islands in the
vegetation line; 20' if Hawaiian islands group
hardship shown
Louisiana Through local ordinances
Maine 75' along entire coast; M Also has a buffer management
250' along sensitive program
wetland areas
Maryland 100' along Chesapeake M Case-by-case on non-Chesapeake Bay
Bay shore shores
Massachusetts in process of development
Mississippi Rarely; case-by-case
New 100' along wetlands M The definition of wetlands includes
Hampshire the entire NH coast
New Jersey 0-300'on a case-by-case R Only along sensitive areas; local
basis zoning supersedes state
New York 75' from wetlands (30' M Vegetation not required in the
in New York City) setback
North 30' around significant M Vegetation not required in buffer
Carolina waters
Oregon Through local ordinances
Rhode Island 0-200' on a case-by-case R 50' from the coastal M New buffer program being
basis feature reviewed
South Carolina Variable, according to R Only applicable in coastal
erosional rates dunes; vegetation not required
Texas CZMP being developed
Virginia 100' along Chesapeake M Not required along other state
Bay shore coastal areas
Washington Through local ordinances

permitting process on a case-by-case basis. Further- Florida
more, a 50-foot construction setback from the edge In the state of Florida, vegetated buffers may be
of a water body or wetland is required, and may act established in the coastal zone as part of the permit-
as a vegetated buffer. The state coastal zone pro- ting process on a case-by-case basis, or as mitiga-
gram also requires the use of vegetation for shore- tion requirements due to proposed development
line stabilization as a first choice during the pen-nit- impacts. Furthermore, requirements for vegetated
ting process. Rip-rap or other engineered shoreline buffers may exist at local levels of government
stabilization structures may be allowed where through implementation of construction setback
vegetation proves inefficient or impractical. A major regulations for development along the coast. State-
focus of the program is the creation of wetland areas mandated setbacks in the coastal zone relate only to
as the shoreline stabilization structure of choice. requirements for the setback of septic systems from
coastal wetlands.

Georgia years. Pruning and other maintenance procedures
The state of Georgia has, no statewide require- are allowed, but complete removal of grasses or
ments for the establishment of vegetated buffers, understory in the buffer is prohibited. A vegetated
and at present is not a participant in the federal buffer 250 feet wide is required along areas border-
coastal zone management program. A Marshland ing sensitive wetlands. The larger buffer width is
Protection Act may create vegetated buffers in the implemented to provide added protection to wild-
coastal zone adjacent to protected marshes (or as the life, especially waterfowl, while the minimum
marsh itself), but the primary purpose of the Act is buffer width of 75 feet is implemented for protec-
to protect marshlands, not create vegetated buffers. tion of water quality and visual appeal.
The Shoreline Protection Act gives'state regulatory The buffer applies to new construction only., and
agency staff some discretionary power to establish preexisting lots are exempt from the 75-foot buffer
vegetated coastal buffers through the permitting and requirement. Preexisting Jots may not expand by
review process. greater than 30 percent, may not expand toward the
water's edge, and if outside the 75-foot buffer zone,
Hawaii may not extend into the buffer area during expari-
The state of Hawaii has policies and regulations sion. Local zoning ordinances may require a greater
within the state coastal zone program to establish buffer width than the minimum 75-foot buffer
vegetated buffers along the coast. For all of the mandated by the state program.
Hawaiian island group, a 40-foot shoreline setback
is requiredi beginning at the shoreward edge of the Maryland
coastal vegetation line and extending inland. The It is the policy of the Maryland coastal zone
buffer is generally intended to remain in an undis- program to promote the establishment of vegetated
turbed state, but certain uses are allowed, and vari- buffers along the coast, and buffers may be required
ances may be sought for limited development within on a case-by-case basis,, particularly around wetland
the buffer. In cases in which hardship can be proven, areas. As part of the Chesapeake gay Program, all
the mandatory 40-foot setback buffer can be reduced, land 1000 feet inland of the shoreline of the Chesa-
to 20 feet. Each of the islands in the Hawaiian island peake Bay and its tributaries is subject to a 100- foot
group may develop its own regulations with. regard buffer requirement. The buffer requirement may be
to the shoreline setback, but the width may not be waived if "good conservation practices" are em-
less than the 40 feet mandated by state regulations. ployed at the shoreline site. Furthermore, the buffer
requirement is only applicable to new development
Louisiana - existing development and previously plattedlots
The state of Louisiana has no statewide policies are "grandfathered" to p, reexisting requirements.
or regulations that establish vegetated buffers in the Other state programs share the cost of buffer strip
coastal zone. Vegetated buffer areas may be estab- implementation with farmers actively using land.
lished on a case-by-case basis as part of the -state bordering the Chesapeake.Bay and its tributaries.
permitting process. When established, buffers are The major emphasis of this policy has been in
used to protect significant habitat or resources by tidal tributaries of Chesapeake Bay. The emphasis in
moving. development activities away from the non-Chesapeake Bay portions of the Maryland
resource to a region of minimal im -pact. coastal zone has been on stabilization of the coast
by promoting planting and preservation of vegetated
Maine areas. Vegetation within,the buffers along the coast
The state of Maine, as part of its Shoreline has focused on grass species, while woody-
Zoning Act, has implemented a coastal vegetated stem med species have received greater emphasis
buffer establishment program. The coastal zone along tidal tributaries.
program mandates a 75-foot minimum vegetated Plummer (1993) provides a more comprehen-
area, measured from mean high water, along the sive review of Maryland buffer policies and regula-
entire Maine coast. The buffer must be kept in a tions, as well as a review of implementation within
vegetated state, with no more than 40 percent of the coastal zone program.
existing trees in the buffer being harvested every 10

Massachusetts Jersey buffer policy and regulations, as well as
The state of Massachusetts coastal zone pro- implementation examples.
gram does not currently have policies or regulations
that establish vegetated buffers along the coast. New York
Establishment of vegetated buffer areas may occur The general policy of the state of New York
at local levels of government through zoning ordi- coastal zone program is to protect significant coastal
nances and regulations, or may be established on a resources and habitats, and therefore vegetated
case-by-case basis through the coastal zone program buffer areas may be established during the permit-
permitting process. The state coastal zone program, ting process on a case-by-case basis. The state
however, is in the process of developing a buffer coastal zone program encourages the protection and/
zone program, which is presently being drafted. or planting of vegetation along the shoreline, but
does not require it as part of the program mandate.
Mississippi Through the regulatory program of the Depart-
The state of Mississippi coastal zone program ment of Conservation, a construction setback
has no statewide policies or regulations that estab- regulation exists that may establish vegetated buffer
lish vegetated buffers in the coastal zone. During the areas. The regulations require a setback from
permitting process, however, vegetated buffers that wetland areas of 75 feet (30 feet in New York City).
consist solely of tidal wetlands may be established The setback regulation does not require that the
to protect significant resources and habitats. The buffer area be vegetated, but encourages the use of
establishment of vegetated buffer areas applies only vegetation. Local government may develop and
to tidal wetland environments, and does not apply to implement vegetated buffer policy and regulations
upland areas adjacent to the coast. according to local zoning ordinances.

New Hampshire North Carolina
The state of New Hampshire coastal zone In the state of North Carolina, the portion of the
program, through state wetlands regulations, re- coastal zone that lies within 75 feet of the water's
quires the establishment of a 100-foot vegetated edge is subject to permit approval for development
buffer around coastal wetlands, beginning at the purposes. Vegetated buffers may be established
mean high tide mark. Although the buffer area is a through the permitting process on a case-by-case
requirement, activities can still be conducted basis. When buffer areas are established, they need
within the buffer, provided that proper permits have not be vegetated as a requirement, but vegetation is
beenissued. encouraged. A 30-foot buffer is required around
waters that are classified as high quality and/or of
New Jersey high significance, but the buffer need not be veg-
The state of New Jersey has a coastal zone etated. The 30-foot buffer requirement is most
program element that may be used to establish typically used to protect public water supply water-
vegetated buffers along the coast. The program shed areas. Local zoning ordinances may require the
element requires a buffer width of 0 to 300 feet, establishment of vegetated buffers along the coast.
determined on a case-by-case basis, and is depen- Phillips (1989d) reviews some local-level buffer
dent on the potential impact to water resources from requirements in North Carolina.
the proposed development activity. The buffer
program applies to private property, and to all Oregon
activities conducted in the coastal -zone by any state The state of Oregon has several statewide
agency. The buffer program, however, is only policies that require local governing bodies to be
applicable to those areas of the shoreline designated consistent in their planning and zoning efforts.
as significant or sensitive areas. Furthermore, local Statewide policies to preserve and protect signifi-
plans and zoning ordinances supersede the state cant coastal habitats, cultural and historic resources,
coastal buffer program, and do not have to be and scenic qualities may result in the establishment
consistent with state coastal zone policy. Plummer of vegetated buffers along the coastal zone through
(1993) provides a more detailed review of New local adoption and implementation. Areas marked

for preservation and/or restoration in estuaries may program deal with the concept of vegetated (and
also be viewed as vegetated buffers. nonvegetated) buffers.

Rhode Island Virginia
The state of Rhode Island coastal zone program The state of Virginia has a buffer program
has a policy for the establishment of vegetated applicable to the shoreline of the Chesapeake Bay
buffers, but it is implemented on a case-by-case under the Chesapeake Bay Preservation Act, but the
basis under the purview of program staff. When program does not apply to other coastal areas in the
applied, the buffer is measured from the inland edge state. The coastal zone program recommends the use
of the coastal feature (as defined by the program), of vegetation and vegetated buffer areas for shore-
with buffer width based on potential impacts of line stabilization and other uses, but it is accom-
development and the sensitivity and use of the plished on a voluntary basis by property owners.
adjacent land and water. The state coastal zone Along the shores of the Chesapeake Bay, the
program also requires a minimum 50-foot construc- Chesapeake Bay Preservation Act requires a 100-
tion setback, but local zoning ordinances or regional foot vegetated buffer along all shoreline that drains
Special Area Management Plans may require the to or is adjacent to the Chesapeake Bay. The pro-
establishment of a buffer area, or require a greater gram does provide for limited use within the veg-
setback distance. etated buffer, and variances may be sought to utilize
The state of Rhode Island has developed a more lands within the buffer area. No variances will be
complete vegetated buffer program, a final version provided that result in less than a 50-foot vegetated
of which is included in Appendix A. Adoption of the buffer remaining along the shoreline (except for
program occurred during early 1994. Appendix B agricultural uses).
contains a copy of the vegetated buffer management Water-dependent uses - such as marinas and
and maintenance document that accompanies the docks - are generally allowable within the 100-
state's buffer program. foot buffer area. Agricultural land uses that abut the
shoreline may seek a smaller vegetated buffer width
South Carolina of 50 feet, and a 20-foot buffer may be allowed for
In the state of South Carolina, -vegetated buffers agricultural purposes, provided that a management
may be established on a case-by-case basis along or plan has been developed and is actively being
within critical or sensitive areas, such as salt implemented. Plummer (1993) provides a more
marshes. Typically, the program regulates activity complete review of the Virginia Chesapeake Bay
within the critical or sensitive areas, rather than Preservation Area Program, as well as implementa-
establishing buffers around them. The coastal zone tion examples.
program also has jurisdiction within a setback area
inland of coastal dune systems. The setback width is Washington
determined by erosional rates, and although veg- The state of Washington coastal zone prograrn
etated buffers could be established within the recommends the use of vegetated areas for shoreline
coastal setback, the focus of the program is to stabilization and other purposes, but does not
regulate activity in the setback area rather than to require their use. Each of the coastal counties in the
establish it as a buffer area. The overall intent of the state is required to develop its own master plans and
setback.is to protect property by removing structures zoning ordinances, which may, but are not required
from erosional zones along the coast. to, include regulations for the establishment of
Texas , vegetated buffers at a local level.
The state of Texas is in the process of develop-
ing its coastal zone program, and therefore at
present has no policies or regulations that establish
vegetated buffers along the coast. The program that
is in development recognizes the value of coastal
buffer zones, and several policies within the draft

Alp

@np- n

Aq@4

IV. Selected Bibliograph Adams, L.W. and L.E. Dove. 1984. Urban wetlands for
Y stormwater control and wildlife enhancement. National
Institute for Urban Wildlife. Columbia, MD. 15 pp.
This bibliography represents a search of the Adams, L.W. and D.L. Leed (eds.). 1987. Integrating man
literature for works that relate to vegetated buffers. and nature in the metropolitan environment. National Institute
The selected bibliography presents a wide range of for Urban Wildlife. Columbia, MD. 249 pp.
subjects, ranging from pollutant removal research to
the aesthetic and scenic value of vegetated buffers. Adams, L.W., T.M. Franklin, L.E. Dove, and J.M.
The selected works are definitely biased towards Duffield. 1986. Design considerations for wildlife in urban
research on pollutant removal efficiency of veg- stormwater management. Transactions of the North American
etated buffers. The reason for this is twofold: (1) the Wildlife and Natural Resources Conference 51:249-259.
bulk of the published literature is the results of Ahola, H. 1990. Vegetated buffer zone examinations on
research with this as their focus, and (2) in light of the Vantaa River basin. Aqua Fennica 20(l):65-69.
the recent emphasis on control of nonpoint source Allen, H.H. 1979. Role of wetland plants in erosion
pollutants, this portion of the literature is extremely control of riparian shorelines. In: P.E. Greeson, J.R. Clark, and
valuable in pursuing the use of vegetated buffers as J.E. Clark (eds.), Wetland Functions and Values: The State Of
a nonpoint source control mechanism. However, Our Understanding. American Water Resources Association
the selected references presented here represent a Technical Publication No. TPS79-2. pp. 403-414.
reasonable introduction to the diversity of uses of Ambus, P. and R. Lowrance. 1991. Comparison of
vegetated buffers as a multiple-use resource man- denitrification in two riparian soils. Soil Scientist Society of
agement tool. America Journal 55:994-997.
Several bibliographies, some annotated, are Anacostia Restoration Team. 1992. A current assessment
given in the following list of literature references. of urban best management practices: Techniques of reducing
One of special note, however, is that compiled by nonpoint source pollution in the coastal zone. Metropolitan
Dr. David Correll at the Smithsonian Environmental Washington Council of Governments. Washington, DC.
Research Center (Correll, 1993). This bibliography Anderson, B.W. and R.D. Ohmart. 1985. Riparian
is specific to the literature regarding forested buff- revegetation as a mitigating process in stream and river
ers, and is indexed according to the parameters restoration. In: J.Gore (ed.), The Restoration of Rivers and
researched in each citation given. The bibliography Streams. Butterworth Publishers. Boston, MA. pp. 41-80.
also contains references culled from international Anderson, M.P. 1984. Movements of contaminants in
sources, and provides 'a robust compendium of groundwater: Groundwater transport, advection, and disper-
research in forested buffers. sion. In: National Academy of Sciences, Groundwater
Contamination. pp. 37-45.

Abell, D.L. (ed.). 1989. Proceedings of the California Asmussen, L.E., A.W. White, Jr., E.W. Hansen, and J.M.
Riparian Systems Conference: Protection, Management, and Sheridan. 1977. Reduction of 2,4-D load in surface runoff
Restorationfor the 1990s. Pacific Southwest Forest & Range down a grassed waterway. Journal of Environmental Quality
Experiment Station Technical Report No. PSW- I 10. Berkeley, 6:159-162,
CA. 115 pp. Aubertin, G.M. and J.H. Patric. 1974. Water quality after
Aber, J.D., K.J. Nadelhoffer, P. Stendler, and J.M. clearcutting a small watershed in West Virginia. Journal of
Melillo. 1989. Nitrogen saturation in northern forest ecosys- Environmental Quality 3:243-249.
tems. BioScience 39:378-386. Ault, G.H., T.L. Loudon, and I.B. Gerrish. 1979. Crop-
Adam, R., R. Lagace, and M. Vallieres. 1986. Evaluation land, buffer, and stream: A field study. American Society of
of beef feedlot runoff treatment by a vegetative filter. Ameri- Agricultural Engineers Paper No. 79-2010. St. Joseph, MI.
can Society of Agricultural Engineering Paper No. 86-208. St. Baker, D.E. and L. Chesnin. 1975. Chemical monitoring
Joseph, MI. of soils for environmental quality and animal and human
Adams, L.W. and L.E. Dove. 1989. Wildlife reserves and health. Advances in Agronomy 27:305-367.
corridors in the urban environment: A guide to ecological Barfield, B.J., E.W. Tollner, and J.C. Hayes. 1979.
landscape planning and resource conservation. National
Institute for Urban Wildlife. Columbia, MD. 91 pp. Filtration of sediment by simulated vegetation. 1. Steady state
flow with homogeneous sediment. Transactions of the Ameri-
can Society ofAgricultural Engineers 22(3):540-545; 548.

Barker, J.C. and B.A. Young. 1984. Evaluation of a Broderson, J.M. 1973. Sizing buffer strips to maintain
vegetative filter for dairy wastewater in southern Appalachia. water quality. Master's of Science thesis, University of
Water Resource Research Institute, North Carolina State Washington. Seattle, WA. 84 pp.
University. Raleigh, NC.
Brown, K.W., K.C. Donnelly, J.C. Thomas, and J.F.
Barnes, K.B. 1988. Cartographic modeling of nonpoint Slowey. 1984. The movement of nitrogen species through
pollutant surfaces for a coastal drainage area. In: Lyke and three soils below septic fields. Journal of Environmental
Hoban (eds.), Proceedings of the Symposium on Coastal Water Quality 13:460-465.
Resources. Technical Publication Series of the American Water
Resources Association, MD. pp. 133-145. Brown, K.W. and J.C. Thomas. 1978. Uptake of N by
grass from septic fields in three soils. Agronomy Journal
Bartlett, M.S., L.C. Brown, N.B. Hanes, and N.H. 70:1037-1040.
Nickerson. 1979. Denitrification in freshwater wetland. soil.
Journal of Environmental Quality 8:460-464. Brown, M.T. and J.M. Schaefer. 1987. Final Report: An
evaluation of the applicability of upland buffers for the
Barton, D.R., W.D. Taylor, and R.M. Biette. 1985. wetlands of the Wekiva Basin. Center for Wetlands, University
Dimensions of riparian buffer strips required to maintain trout of Florida. Gainesville, FL. 163 pp.
habitat in southern Ontario streams. North American Journal
of Fisheries Management 5:364-378. Brown, M.T., J.M. Schaefer, and K.H. Brandt. 1990.
Buffer zones for water, wetlands and wildlife in cast central
Beaulac, M.N. and K.H. Reckhow. 1982. An examination Florida. Center for Wetlands Publication No. 89-07. Florida
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Bulletin 18:1013-1024. 71 pp.

Best, L.B. 1983. Bird use of fencerows: Implications of Bubenzer, G.D., J.C. Converse, and J.W. Patoch. 1989.
contemporary fencerow management practices. Wildlife Downward movement of water below grass filter strips --
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University of Wisconsin. Madison, WI.
Bingham, S.C., P.W. Westerman, and M.R. Overcash.
1980. Effect of grass buffer zone length in reducing the Budd, W.W., P.L. Cohen, P.R. Saunders, and F.R. Steiner.
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342. Management 11:587-507.

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Appendix A 2. Vegetated buffer zones have been applied as best
management practices within the fields of forestry and
The Rhode Island Coastal Zone agriculture since the 1950s to protect in-stream habitats from
degradation by the input of sediment and nutrients (Desbonnet
Buffer Program et al 1993). More recently, vegetated buffer zones have gained
popularity as a best management practice for the control and
abatement of nonpoint source pollutants (contaminated runoff)
Adopted April 1994, RI CRMP and are routinely applied in both engineered and natural
settings (Desbonnet et al 1993; EPA 1993).
Section 140 Setbacks 3. Coastal Buffer Zones provide multiple uses and
Amend Section 140. C to read as follows: multiple benefits to those areas where they are applied
(Desbonnet et al 1993). The multiple uses and benefits of
11C. Setbacks shall extend a minimum distance of either Coastal Buffer Zones include:
fifty (50) feet from the inland boundary of the coastal feature (a) Protection of Water Quality: Buffer zones along the
or twenty-five (25) feet inland of the edge of a Coastal Buffer perimeter of coastal water bodies can be effective in trapping
Zone, whichever is further landward. In areas designated by sediments, pollutants (including oil, detergents, pesticides,
the Council as Critical Erosion Areas-(Table 2), the minimum herbicides, insecticides, wood preservatives and other .
distance of the setback shall be not less than 30 times the domestic chemicals), and absorbing nutrients (particularly
calculated average annual erosion rate for less than four nitrogen) from surface water runoff and groundwater flow.
dwelling units and not less than 60 times the calculated The effectiveness of vegetated buffers as a best management
average annual erosion rate for projects proposing more than 4 ractice for the control of nonpoint source runoff is dependent
dwellings units. P
upon their ability to reduce the velocity of runoff flow to allow
"SECTION 150 COASTAL BUFFER ZONES for the deposition of sediments, and the filtration and biologi-
cal removal of nutrients within the vegetated area. In general,
A. Definition the effectiveness of any vegetated buffer is related to its width,
1. A Coastal Buffer Zone is a land area adjacent to a slope, soil type, and resident species of vegetation. Effective
Shoreline (Coastal) Feature that is, or will be, vegetated with buffers for nonpoint source pollution control, which remove at
native shoreline species and which acts as a natural transition least 50%, and up to 99%, of sediments and nutrients entering
zone between the coast and adjacent upland development. A them, range from 15 feet to 600 feet in width.
Coastal Buffer Zone differs from a construction setback The removal of pollutants can be of particular importance
(Section 140) in that the setback establishes a minimum in areas abutting poorly flushed estuaries that are threatened
distance between a shoreline feature and construction activi- by an excess of nutrients or are contaminated by runoff water,
ties, while a buffer zone establishes a natural area adjacent to a such as the South Shore Salt Ponds and the Narrow River.
shoreline feature that must be retained in, or restored to, a Large, well flushed water bodies, such as Narragansett Bay,
natural vegetative condition (Figure 2). The Coastal Buffer are also susceptible to nonpoint source pollutant inputs, and
Zone is generally contained within the established construc- can be severely impacted by nonpoint source pollutants as has
tion setback. been documented in studies completed for the Narragansett
Bay Project.
Figure 2 An example of the application of a Coastal (b) Protection of Coastal Habitat: Coastal Buffer Zones
Buffer Zone. provide habitat for native plants and animals. Vegetation
within a buffer zone provides cover from predation and
Boundary of climate, and habitat for nesting and feeding by resident and
Construe tion Area migratory species. Some species which use coastal buffer
zones are now relatively uncommon, while others are consid-
Inland Edge of the Buffer ered rare, threatened or endangered. These plants and animals
Coastal Feature- Boundary are essential to the preservation of Rhode Island's valuable
coastal ecosystem.
The effectiveness of vegetated buffers as wildlife habitat
is dependent upon buffer width and vegetation type. In
Coastal Lawn
Feature 50' Vegetated Buffer general, the wider the buffer the greater its value as wildlife
75'CRMC Setback Septic habitat. Larger buffer widths are typically needed for species
d Field that are more sensitive to disturbances (e.g., noise). Further-
CRNIC 200'Jurisdiction more, those buffers that possess vegetation native to the area
provide more valuable habitat for sustaining resident species.
Ita'
tur@e

B. Findings A diversity of plant species and types (e.g., grasses, shrubs
1. The estab;ishment of Coastal Buffer Zones is based and trees) promotes biodiversity within the buffer area, and the
upon the CRMC's legislative mandate to preserve, protect and, region overall.
where possible, restore ecological systems.

(c) Protection of Scenic and Aesthetic Quality: One of managed in accordance with the standards contained in this
the primary goals of the Council is to preserve, protect, and section. In cases where native flora (vegetation) does not exist
where possible restore the scenic value of the coastal region in within a buffer zone, the Council may require restoration
order to retain the visual diversity and unique visual character efforts which include, but are not limited to, replanting the
of the Rhode Island coast as seen by hundreds of thousands of Coastal Buffer Zone with native plant species.
residents and tourists each year from boats, bridges, and such
vantage points as roadways, public parks, and public beaches 4. Coastal Buffer Zones shall remain covered with native
(Section 330). Coastal Buffer Zones enhance and protect flora and in an undisturbed state in order to promote the
Rhode Island's scenic and visual aesthetic resources along the Council's goal of preserving? protecting, and restoring
coast. Coastal buffers also preserve the natural character of ecological systems. However, the Counciltray permit minor
the shoreline, while mitigating the visual impacts of coastal alterations to Coastal Buffer Zones that facilitate the continued
development. Visual diversity provides for both contrast and enjoyment of Rhode Island's coasta( resources. All alterations
relief between the coastal and inland regions, leading to to Coastal Buffer Zones or alterations to the natural vegetation
greater aesthetic value of the landscape. (i.e., areas not presently maintained in a landscaped condition)
within the Council's jurisdiction shall be conducted in
(d) Erosion Control: Coastal Buffer Zones provide a accordance with the standards contained in this section as well
natural transition zone between the open coast, shoreline as all other applicable policies and standards of the Council.
features and upland development. Natural vegetation within a In order to -ensure compliance with these requirements, the
Coastal Buffer Zone helps to stabilize the soil, reduces the Council may require applicants to submit a Buffer Zone
velocity of surface water runoff, reduces erosion of the soil by Management Plan.
spreading runoff water over a wide area, and promotes
absorption and infiltration through the detrital (leaf) layer and
underlying soils. The extensive root zones often associated Table 2a.
with buffer zone vegetation also help prevent excessive Coastal Buffer Zone designations for residential
shoreline erosion during coastal storm events by stabilizing development.
underlying soils. Water Use
(e) Flood Control: Coastal Buffer Zones aid in flood Residential Lot Type Category Type,
control by reducing the velocity of runoff and by encouraging Size 3, 4, 5 & & 2
infiltration of precipitation and runoff into the ground rather (sq. ft.) 6 Required Buffer
than allowing runoff to flow overland and flood low -lying (f t)
areas. In addition, Coastal Buffer Zones often occupy the .<10,000 15 .................... 25
flood plain itself and thus add to coastal flood protection. 10,000 - 20,000 25 .................... 50
20,001 - 40,000 50 .................... 75
40,001 - 60,000 75 ......... .......... 100
(f) Protection of Historic and Archa .eological Resources: 60,001 - 80,000 100 .................... 125
80,001 - 200,000 125* .................... 150
Coastal Buffer Zones protect areas of cultural and historic >200,000 150 .................... 200
importance such as archaeological sites by helping prevent
intrusion while protecting the sites' natural surroundings.

5. In order to enhance conservation, protect water quality,
C. Policies and maintain the low intensity use characteristic of Type I and
2 waters, greater buffer widths shall be applied along the
1. The establishment of a Coastal Buffer Zone i's based coastline abutting these water types.
upon the CRMC's legislative mandate to preserve, protect and,
where possible, restore ecological systems. The determination 6. In critical areas and when the property owner owns
of the inland boundary of the Coastal Buffer Zone must adjoining lots, these lots shall be considered as one lot for the
balance this mandate with the property owner's rights to purposes of applying the values contained in Table 2a and
develop and use the property. ensuring that the appropriate'buffer zone is established.

2. The Council shall require Coastal Buffer Zones in
accordance with the requirements of this section for the D. Standards
following: a) new residential development; b) commercial and
industrial development; c) activities subject to Section 300.8 1. All Coastal Buffer Zones shall be measured from the
and Section 300.13; and d) inland activities identified in inland edge of the most inland Shoreline (Coastal) Feature.
Section 320. For existing residential structures, the Councir
shall require a Coastal Buffer Zone for category "A'; and "B" 2. Coastal Buffer Zone Requirements for New Residential
activities when the RIDEM requires the modification or Development: The minimum Coastal Buffer Zone require-
expansion of an existing septic-system or when the footprint of ments for new residential development bordering Rhode
the structure is expanded. Island's shoreline are contained in Table 2a. The Coastal
Buffer Zone requirements are based upon the size of the lot
3. The vegetation within a buffer zone must be either and the CRMC's designated Water Types (Type I - Type 6).
retained'in a natural, undisturbed condition, or properly Where the buffer zone requirements noted above cannot be

66@

met, the applicant may request a variance in accordance with variance to these requirements in accordance with the burdens
Section 120. 1 A variance to 50% of the required buffer width of proof contained in Section 120.
may be granted administratively by the Executive Director if
the applicant has satisfied the burdens of proof for the granting 6. All property abutting Coastal Natural Areas (Section
of a variance. Where it is determined that the applicant has 210.4) shall have a minimum vegetated Coastal Buffer Zone
not satisfied the burdens of proof, or the requested varriance is of 25 feet from the inland edge of the coastal feature. The
in excess of 50% of the required width, the application shall Executive director shall have the authority to grant a variance
be reviewed by the full Council. to these requirements in accordance with the burdens of proof
contained in Section 120.
3. Coastal Buffer Zone Requirements for Existing
Residential Structures that Expand the Footprintofthe 7. All property located within the boundaries of a Special
Structure andfor Structures Required by the RIDEM to Modify Area Management (SAM) Plan approved by the Council shall
or Expand an Existing Septic System: When an existing meet additional buffer zone requirements contained within
residential structure does not meet the Council's Coastal these SAM plans. When a SAM plan's buffer zone require-
Buffer Zone requirements contained in Table 2a (e.g., the ments apply, the buffer width values contained in this section
existing structure does not have a buffer zone or has a buffer will be compared to those required by the SAM plan, and the
zone with a width less than the value contained in Table 2a), larger of the buffer widths applied.
the following Coastal Buffer Zone requirements shall apply to
each modification of the residential structure until the 8. The setback (Section 140) for all new residential,
property's Coastal Buffer Zone equals, but does not exceed, commercial, and industrial structures shall exceed the Coastal
the value contained in Table 2a: Buffer Zone requirement by a minimum of 25 feet for fire,
safety, and maintenance purposes. Where the 25 foot separa-
(a) Where alterations to a residential structure result in tion distance between the inland edge of the buffer and
the expansion of the structure's footprint (square footage of construction setback cannot be obtained, the applicant may
the ground floor area encompassed by the structural founda- request a variance in accordance with Section 120. The
tion of an existing building), the Coastal Buffer Zone require- Executive Director shall have the authority to grant variances
ment shall be established with a width equal to the percentage to this requirement. However, a vegetated Coastal Buffer
increase in a structure's footprint as of April 15, 1994 multi- Zone shall not directly contact any dwelling's footprint.
plied by the value contained in Table 2a ([square foot increase
of footprint/square footage as of April 15, 1994] X value
contained in Table 2a = Coastal Zone Buffer Requirement); E. Buffer Management and Maintenance Requirements

(b) Where alterations to a residential structure result in an 1. All alterations within established Coastal Buffer Zones
increase in flow to the Individual Sewage Disposal System or alterations to natural vegetation (i.e., areas not presently
(ISDS) and the RIDEM has required the modification or maintained in a landscaped condition) within the Council's
expansion of the existing ISDS, the Coastal Buffer Zone jurisdiction may be required to submit a Buffer Zone Manage-
requirement shall be established with a width equal to 25% of ment Plan for the Council's approval that is consistent with the
the value contained in Table 2a (0.25 X value contained in requirements of this section and the Council's most recent
Table 2a = Coastal Buffer Zone requirement). edition of Buffer Zone Management Guidance. Buffer Zone
Management Plans shall include a description of all proposed
These requirements only apply to category "A" and "B" alterations and methods of avoiding problem areas such as the
assents. In addition, the Executive director shall have the proper placement and maintenance of pathways. Applicants
authority to grant a variance to these requirements for category should consult the Council's most recent edition of Buffer
A" assents in accordance with the burdens of proof contained Zone Management Guidance when preparing a buffer manage-
in Section 120. ment plan.

4. Coastal Buffer Zone Requirements for all Commercial 2. In order to promote the Council's goal to preserve,
and Industrial development and activities subject to the protect and, where possible, restore ecological systems,
requirements of Section 300.8, Section 300.13, or Section 320: Coastal Buffer Zones shall be vegetated with native flora and
Coastal Buffer Zones shall be determined on a case-by-case retained in a natural, undisturbed condition, or shall be
basis by the Council. Table 2a may be used as appropriate properly managed in accordance with Council's most recent
pidance. However, depending on the activity proposed and edition of Buffer Zone Management Guidance. Such manage-
its potential impacts on coastal resources, the Council may ment activities compatible with this goal include, but are not
require a Coastal Buffer Zone with a width greater than that limited to:
found in the Table 2a.
(a) Shoreline Access Paths: Pathways which provide
5. All property abutting critical habitat areas, as defined access to the shoreline are normally considered permissible
by the Rhode Island National Heritage Program or the provided they are less than or equal to 6 feet wide and follow a
Council, shall possess a minimum vegetated buffer zone of path that minimizes erosion and gullying within the buffer
200 feet between the identified habitat and any development zone (e.g., a winding, but direct path). Pathways should
area. The Executive director shall have the authority to grant a avoid, or may be prohibited in, sensitive habitat areas,

including, but not limited to, coastal wetlands. Pathways may (d) Safety and Welfare: Selective tree removal, pruning
be vegetated with grasses and mowed or may be surfaced with and. thinning of natural vegetation within a Coastal Buffer
crushed stone or mulch, Zone may be allowed by the Council on a case-by-case basis
for proven safety and welfare concerns (e.g., removal of a
(b) View Corridors: Selective tree removal and pruning damaged tree in close proximity to a dwelling). In order to
and thinning of natural vegetation may be allowed within a promote child safety and manage pets in areas harboring ticks,
defined corridor in order,to promote a view of the shoreline. fences along the inland edge of a Coastal Buffer Zone and
Only the minimal alteration of vegetation necessary to obtain a along shoreline access pathways may be permitted.
view shall be acceptable to the Council. Shoreline access
paths shall be located within view corridors to the maximum (e) Shoreline Recreation: The CRMC recognizes that
extent practicable in order to minimize disturbance of Coastal shoreline recreation is one of the predominant attractions for
Buffer Z ones. View corridors shall be prohibited in sensitive living on, or visiting the Rhode Island Coast. In order to allow
or critical habitat areas. for such uses, minor alterations of buffer zones may be
permitted along the shoreline if they are determined to
(c) Habitat Management: Management of natural consistent with Council's requirements. These alterations may
vegetation within a buffer zone to enhance wildlife habitat and include maintaining a small clearing along the shore for picnic
control nuisance and non-native species of vegetation may be tables, benches, and recreational craft (dinghies, canoes, (Jay
allowed. Homeowner control of pest species of vegetation sailboats, etc.). Additionally, the CRMC may allow small,
such as European bittersweet and nuisance species such as non-habitable structures including storage sheds, boat houses
poison ivy is normally considered acceptable. However, the and gazebos within Coastal Buffer Zones, where appropriate.
indiscriminate use of herbicides or the clear-cutting of However, these structures may be prohibited in sensitive or
vegetation shall be prohibited. The use of fertilizers is critical habitat areas. Due to the potential for these structures
generally prohibited within the Coastal Buffer Zone except to impact values provided by Coastal Buffer Zones, the
when used to enhance the replanting of native vegetation (e.g., Council shall exercise significant discretion in this area.
hydro-seeding) approved by the Council. However, the
clearing or outright elimination of natural vegetation for such
purposes as controlling ticks or pollen shall not be permitted.

B. Management options within coastal buffer zones:
Appendix B
Rhode Island Coastal Buffer 1. Shoreline Access Paths - Pathways which provide
access to the shoreline are normally considered appropriate.
Zone Management Guidance Pathways may be 6' wide or less and follow a winding, but
direct path that does not promote erosion within the buffer
zone. Shoreline access paths must be designed to minimize
Revised January 7, 1994 disturbance and may be prohibited in sensitive habitat areas,
including but not limited to, coastal wetlands. Pathways may
CRMC Coastal Buffer Zone Management Guidance be vegetated with grasses and mowed or may be surfaced with
crushed stone or mulch. Fertilizers may only be allowed for
A. Guidelines for preparing an application for Coastal the initial establishment of grassed pathways. Proper site
Buffer Zone Management: plans must be submitted which show the location of the
proposed path through the buffer zone. Applicants may also
1. All proposals for buffer zone management must be be required to delineate the path on site for CRMC staff
designed with respect to the one or more of the "Management inspection.
Options" identified in Section "B" of these guidelines and 2. View Corridors - Selective tree removal and pruning
must utilize appropriate techniques for managing vegetation as and thinning of natural vegetation may be allowed within a
defined in Section "C". defined corridor in order to promote a view of the shoreline.
2. Photographs and site plans must be submitted for all Only the minimal alteration of vegetation necessary to obtain a
applications in order to minimize the need for on-site inspec- view shall be considered acceptable (clear cutting is not
tions. Actual field inspections will only be performed when allowed). Shoreline access paths (if proposed) should be
deemed necessary by CRMC staff. All applications should be located within a view corridor to minimize disturbance within
complete, clear and concise. Applications which are unclear or the buffer. Applicants proposing a view corr idor must prepare
imprecise will be returned. a plan showing the view corridor's location within the Coastal
Buffer Zone with respect to view points from a dwelling or
3. Applications which propose acceptable alterations other viewing area. View corridors are typically trapezoidal in
within Coastal Buffer Zones (as determined by CRMC staff) shape, being narrow at the inland edge and expanding toward
will be processed as a "Category "A" and will receive the shore. On residential lots of 2 acres or less, only one view
administrative approval. In cases where CRMC staff deter- corridor is typically considered acceptable. View Corr idors
mines the application to be unacceptable, an effort will be may not affect more than 25 % of the length of the Coastal
made to negotiate a resolution with the applicant. If a Buffer Zone as measured along the shoreline feature. View
favorable resolution cannot be reached, CRMC staff will make Corridors may be prohibited in sensitive or critical habitat
a recommendation to the Executive Director that the applica- areas.
tion be processed as a Category "B" review requiring final 3. Habitat Management - The management of natural
decision by the full Coastal Council. vegetation within a Coastal Buffer Zone to either enhance
4. All proposals for Coastal Buffer Zone management wildlife habitat or control nuisance and/or non-native species
should involve minor alterations which do not depreciate the of vegetation may be allowed where it is demonstrated that the
values and functions of Coastal Buffer Zones as defined by existing environmental conditions will be improved for native
Section 150 of the RICRMP. At a minimum, at least sixty plantlife and wildlife. Additionally, homeowner control of
(60%) of a buffer zone shall remain completely unaltered. nuisance species of vegetation such as European Bittersweet
Typically, Coastal Buffer Zone Management Plans which and poison ivy are considered acceptable within managed
affect 25% or less of a buffer zone are more likely to be portions of Coastal Buffer Zones. However, the indiscrimi-
approved. Areas to remain unaltered should be clearly nate use of herbicides is prohibited and fertilizers may only be
identified on the pfoposed plans. An exception to this used to enhance the replanting of native vegetation. In
requirement is allowed for "Suburban Coastal Buffer addition, maintaining a buffer zone in a "landscaped condi-
Zones" - see Section B.6 of this Guidance material. tion", or establishing lawn are not considered appropriate
habitat management activities and are prohibited. In Coastal
5. Where appropriate, Coastal Buffer Zone management Buffer Zones encompassing one acre or more, clearing may
ay be applied to Coastal Banks. However, the CRMC may be allowed to establish field conditions which contain native
impose greater restrictions on alterations affecting coastal grasses and herbaceous plants. In such cases, clearing for
hanks. field establishment shall not affect more than 25% of the
Coastal Buffer Zone. All Buffer Zone Management plans
6. Tree damage and removal - in cases where a small involving habitat management within a Coastal Buffer Zone of
number of dead, diseased, or storm damaged trees need to be one acre or more, or in sensitive or critical habitat areas (as
removed from a buffer zone, the applicant may request an determined by CRMC staff) shall submit a buffer zone
expedited review. In such cases, a description of work and a management plan prepared by a qualified environmental
photograph of the area may be sufficient for CRMC review. professional or biologist.

4. Safety and Welfare - Selective tree removal and 2. Selective Pruning - Pruning as defined for CRMC
pruning and thinning of natural vegetation within a Coastal purposes involves cutting branches from trees, tree saplings
Buffer Zone may be allowed on a case-by-case basis for and shrubs. For certain Coastal Buffer Zone Management
proven safety and welfare concerns (e.g., removal of a options, pruning the tops of shrubs and forest undergrowth
damaged or diseased tree in close proximity to a dwelling). In (topping) may be appropriate to discourage growth in height.
order to promote child safety and manage pets in areas On level ground, shrubs and forest undergrowth should be
harboring ticks, fences along the inland edge of a Coastal pruned to a height of not less than 4'-5'. In areas where the
Buffer Zone and along shoreline.access paths or shoreline ground surface descends toward the shoreline, topping should
recreation areas may be permitted (fences must be of an only be perfonned to a height that allows a view of the water.
"open" type construction to permit the passage of wildlife, e.g, Applicants proposing pruning must describe in detail the work
split rail or similar). Coastal Buffer Zone management plans proposed, provide photographs and a'site plan, and/or mark
shall include methods of avoiding problem areas such as the -those portions of the Coastal Buffer Zone where vegetation
proper placement and maintenance of paths. will be pruned on-site. The species of vegetation to be pruned
should be identified since some species of vegetation cannot
5. Shoreline Recreation - The CRMC recognizes that tolerate excessive pruning or topping. Selective pruning is
shoreline recreation is one of the predominant attractions for often a preferred technique for the establishment of a view
living on, or visiting the Rhode Island coast. In order to allow corridor.
for. such uses, minor alterations of Coastal Buffer Zones may
be permitted along the shoreline if they are determined to be 3. Selective Thinn - Thinning as defined for CRMC
consistent with CRMC's goals and policies as noted in the purposes involves the selective removal of tree saplings,
Rhode Island Coastal Resources Management Program (RI shrubs and vines occurring in brush areas and in the under@
CRMP). Appropriate alterations typically include maintaining growth of forested buffer zones. Applicants proposing
a small clearing along the shore for picnic tables, benches, and thinning must describe in detail the work proposed, provide
recreational craft (dinghies, canoes, day sailboats, etc.). photographs And a site plan, and/or mark areas to be thinned
Additionally, where appropriate, the CRMC may allow small on-site. The species of vegetation to be removed from a
(200 sq. ft. total floor space, or less), non-habitable structures Coastal Buffer Zone man -agement area must be differentiated
including storage sheds, boat houses, and gazebos within from those species which are to be retained and encouraged.
Coastal Buffer Zones. Due to the potential for these structures Selective thinning is often a'preferred technique in areas
to impact natural values provided by Coastal Buffer Zones,,the where habitat management will be performed.
Council shall exercise significant discretion in this area.
4. Restorative Planjing - For purposes of Coastal Buffer
6. Suburban Coastal Buffer Zones - Where the Coastal Zone Management, restorative planting shall be strictly
Buffer Zone requirement is 25' or less (as per RICRMP defined as the planting or replanting of natural vegetation
Section 150, Table 2a), the CRMC shall consider such buffer native to the Rhode Island shoreline. However, naturalized
zones "Suburban Coastal Buffer Zones". Suburban Coastal species such as Rugosa Rose may be allowed, as determined
Buffer Zones may be managed in their entirety (100%) by by CRMC staff. The planting of non-native, landscape and
selective tree removal, s 'elective pruning, selective thinning exotic species, in most cases, shall not be considered appropri-
and restorative planting. However, the CRMC may require ate in Coastal Buffer Zones.
thatseveral trees be maintained or planted to protect scenic
quality. 5. Mowing - In most cases, mowing of vegetation within
a Coastal Buffer Zone shall be prohibited unless associated
with the establishment and maintenance of shoreline access
C. Appropriate techniquesfor managing vegetation path or approved shoreline recreation area. However, for
within a coastal buffer zone: certain habitat management options, annual or biannual
mowing may be allowed to maintain field vegetation where
1. Selective Tree Removal - In cases where the applicant such vegetation is considered valuable to wildlife and other
wishes to remove a few select trees, trees proposed to be cut natural values. In such cases, mowing shall be confined to
must be specifically identified for CRMC staff review. In 25% of the Coastal Buffer Zone area, or less.,
most cases, photographs of the buffer area may be sufficient
provided-the affected trees are clearly shown in relation to the 6. Clearing - Clearing or clear-cutting of vegetation
surrounding buffer and shoreline. Trees may also be marked within a Coastal Buffer Zone shall only be allowed for the
on-site to allow inspection by CRMC staff. In order to establishment of shoreline access paths, shoreline recreation
minimize disturbance and allow monitoring by CRMC staff, areas and in certain cases, habitat management options which
tree stumps of fallen trees shall not be removed. CRMC staff are designed to maintain a field of native grasses and herba-
may make a follow-up inspection to verify that only marked ceous plants. Clearing shall not affect more than 25% of the
trees were cut based upon stump counts. Should the applicant Coastal Buffer Zone area. Clearing for habitat management
wish to remove a fallen tree from the buffer zone, this must be shall not be allowed in Coastal Buffer Zones of less than one
performed in a manner which does not disturb remaining acre.
vegetation. Selective tree removal is often a preferred
technique for the establishment of a view corridor.

7. Filling and grading - Minor filling (10 cubic yards or
less) and grading shall only be allowed in Coastal Buffer Zone
areas for the establishment of shoreline access paths and
shoreline recreation areas. Certain minor cutting and filling
activities may also be allowed on a case-by-case basis to
promote these uses. Filling and grading shall not be allowed
for habitat management options,

Figure 10. Example of an adequate buffer,zone management plan drawn by owner.

- View corridor to be maintained by pruning bru�h to a height of 4-5'

- View corridor at shore 507200' of buffer length at coastal feature 25%

River Road

Driveway

Dwelling

40'

View 100'setback
Corridor

6'wide Buffer area
Buffer area path to remain 75'buffer
to remain undisturbed
undisturbed F-I O'x 10' gazebo
50' 200' buffer
length at
coastal wetland

Edge of wetland

Edge of Narrow River

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