Chesapeake Bay Watershed development policies and guidelines

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

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Development Policies and Guidelines

U. S. DEPARTMENT OF CC ,! ERCE NOAA
COASTAL SERVICES CENTER
2234 SOUTH HOBSON AVENUE
'CHARLESTON' SC 29q.05-2"4 l

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P:-op-utr or age >

COUNCIL ON THE ENVIRONMENT

Richmond, Virginia
QH October 1989
104.5
.C45
C46
1989

This document was developed by the Baywide Population Growth and Development
Commitment Team in response to a commitment made in the 1987 Chesapeake Bay
Agreement. It was reviewed by state agencies, local governments, regional planning
agencies, the Local Government Advisory Committee, and private groups. It was originally
printed as an Agreement Commitment Report from the Chesapeake Executive Council
with funding provided through Virginia's Coastal Resources Management Program
(VCRMP). VCRMP funding comes from the Coastal Zone Management Act of 1972, as
amended, and administered by the Office of Ocean and Coastal Resources Management,
National Oceanic and Atmospheric Administration. (Grant Number NA87AA-D-CZ092).

Reprinting was undertaken under a second VCRMP grant from NOAA,
NA88-D-CZ091.

COMMONWEALTH of VIRGINIA
KEITH J BU1TLEMAN Council on the Environment 903 ,INTH STREE- C:.CE BUILDING
ADMINISTRATOR I CHMO.NO 232' 3
aC1- 786-45,O

To the Reader:

This document was created jointly by the Commonwealths of Virginia and Pennsyl-
vania, the State of Maryland, the District of Columbia, and the Federal Government to
provide guidance to their agencies in the development of projects which they undertake or
S fund. The Chesapeake Executive Council, recognizing the ever increasing consequences of
population growth and development on the environment of their jurisdictions, wanted a
method for assuring that their governments would provide leadership in this important
arena.

Virginia has provided copies of these Policies and Guidelines to all state agencies
and is institutionalizing them statewide into the Commonwealth's construction procedures.
They are available upon request by calling the Council on the Environment at
(804) 786-4500.

Sincerely,

Keith J. Buttleman

TABLE OF CONTENTS

Introduction

Impacts of Development on Water
Quality and Living Resources 4

Development Policies and Guidelines 8

Sediment 8

Toxics 12

Nutrient 14

Hydrologic Cycle 17

Habitat 19

Environmental Resources 21

~~ CHESAPEAKE BAY WATERSHED DEVELOPMENT POLICIES AND GUIDELINES

INTRODUCTION

I ~~Background

Population projections prepared by Pennsylvania, Maryland, Virginia, and the Dis-
I ~ ~trict of Columbia indicate that the Chesapeake Bay watershed will experience a 20 percent
population increase amounting to more than 2.6 million new residents in the next 30 years.
I ~~Further, the majority of this population will settle in areas on or near the Bay or its more
* ~~important tributaries and their sub-basins. The provision of housing, places to work and
shop, and the water, waste treatment, roads, power, and landfills to support this growth will
bring enormous change to the landscape. The housing, employment, infrastructure, and
recreational facilities needed to accommodate this new population must be accomplished
with far greater sensitivity to the environment than has been the case in recent decades.
I ~ ~Otherwise our air, land, water, and wildlife resources will suffer increasing degradation,
and our costs will continue to accelerate. For both environmental and economic reasons,
we must build on what is already in place before disturbing new land. When new areas are
I ~ ~developed, it must be with much greater efficiency and forethought than is reflected in our
present practices.

S ~~~~To protect the water quality and living resources of the Bay, selection of the most
suitable location for development is of utmost importance. Some areas are more con-
ducive to development than others, and some lands are not conducive to development at
all. It is critical that land use change and economic development take place onhy within
suitable locations. In addition, the appropriate siting, design, construction, and operation
and maintenance of devel-opment and its associated utilities, and facilities are critical to
protect the Bay's resources. This must take place not just along major tributaries and the
Bay shoreline but upstream and in the smaller watersheds of the region. These actions are
I ~ ~essential to prevent direct, indirect and cumulative adverse impacts on the environment
from land use change. If this is done, not only will the Bay benefit but every community
throughout the watershed will have improved its streams and rivers, protected its habitat
areas, and enhanced its quality of life.
Without an increased commitment to undertaking development in an envi-
I ~ ~ronmentally responsible manner, the hundreds of millions of dollars that have been and
will be spent to restore and protect the Bay will not accomplish their purpose. Farther-
more, future residents of the watershed will experience a vastly reduced quality of life. Tile
Chesapeake Executive Council is firmly convinced that prevention of environmental degrada-
tion is a far more successful strategy titan the mitigation of adverse impacts and the reclama-
tion of resources.

Therefore, in drafting the 1987 Chesapeake Bay Agreement the Council expanded
p ~~considerably upon previous interstate Bay restoration activities and recognized the sig-
nificant impacts that population growth and development have on the water quality and

living resources of the Bay. The Population Growth and Development section of the4

Agreement mandates that state and federal governments "assert the full measure of their
authority to mitigate the potential adverse effects of continued growth" while recognizing
that local jurisdictions are responsible for many of the day-to-day decisions affecting the
Bay. Further, local governments must be given the support of state and federal resources
and the benefit of a state/local partnership in the implementation of environmentally sen-
sitive development.

The goal of the Population Growth and Development section of the Agreement is
to: "Plan for and manage the adverse environmental effects of human population growth
and land development in the Chesapeake Bay Watershed." This document is a response toI
that commitment of the Agreement which promises:

By January 1989, to adopt development policies and guidelines designed to reduce ad-
verse impacts on the water quality and living resources of the Bay, including minimum
best management practices for development and to cooperatively assist local govern-
ments in evaluating land use and devel- opment decisions within their purview, consis-
tent with the policies and guidelines.

In response to this Commitment, the Chesapeake Executive Council adopts this
document and agrees that these Chesapeake Bay Development Policies and Guidelines:

o will be required for all development projects undertaken by their govern-I
ments' agencies and institutions and for all projects receiving their govern-
ments' financial support;

o will be applied throughout the Chesapeake Bay watershed of their jurisdic-
tions; and

o will be considered by state and federal regulatory agencies in their decision
making, as they are able under law.

Further, the Chesapeake Executive Council members agree that they must:

o encourage local governments to use these Policies and Guidelines in review-
ing and evaluating public and private projects within their jurisdictions;I

o provide technical assistance and financial support for this purpose; and

o disseminate this document and additional educational materials to private
sector development interests and others and assist them in understanding its
contents in order that they might better contribute to improving the Bay.

Finally, given the differing legal histories of the several participating jurisdictions,
barriers to the use of some of these Policies and Guidelines may exist. The Chesapeake
Executive Council members agree to identify barriers that hinder the initiation of an effec-
tive development strategy within their jurisdictions and to act to remove them.
Any endeavor of this kind must be evaluated regularly both as to compliance and ef-
I ~ ~~fectiveness. It is critical that the activities undertaken as a result of this initiative be as-
sessed as follows:

1 o~~~~~~ the extent to which the signatory jurisdictions have implemented the
adopted policies;

U o~~~~~~ the degree to which the Policies and Guidelines appear to be benefit-
ing water quality and living resources; and

o the appropriateness of the recommended guidelines and practices,
given advances in knowledge and changes in technology.

These evaluations will be undertaken and a report made to the Chesapeake Executive
b ~~Council by December 1991.

I~~~~~~~~~~~~~~~

IMPACTS OF DEVELOPMENT ON WATER QUALITY AND LIVING RESOURCES

The relationship between land and water is clear. By the natural forces of wind,
rain, and gravity, what is on the land will enter the water unless barriers and filters are
I ~ ~present. Within the Chesapeake Bay watershed, land uses therefore can be divided into
two basic categories: those that tend to protect the Bay's waters and living resources and
those that cause them to deteriorate. Forests, permanently vegetated fields, and wetlands
are examples of the former; they retain or filter natural runoff. Most uses associated with
human activities to some degree or another fall into the latter category. These activities
(paving, digging, clearing, and grading, for example) can alter the natural water retention
characteristics of the land, causing excessive amounts of polluted water to reach ground
water, streams and rivers, and the Bay. The extent of degradation depends on many factors
including proximity to the Bay or its water sources, type of activity, and the characteristics
of the disturbed land.

Conseuuences of Develomnent
I ~~~~Development projects, which include housing, shopping centers, office parks, street
and highway projects, recreational facilities, and other activities, alter the natural vegeta-
tion, slope, and water retention characteristics of the land, and produce three major types
of pollutants: sediments, nutrients, and toxics.
All too often, development practices strip the land of the absorbing capacity of its
natural vegetative cover and replace it with impermeable surfaces which preclude water
from seeping into the soil. This prevents the pollutants in the runoff from being filtered
out before they enter the waterway. It also causes the water to flow in large volumes and
with increased speed into storm sewers or streams. Fast moving water scours the surface of
the land- scape, increasing stream bank erosion, gouging open gullies, and carrying along,
I ~ ~soils; it flushes toxics, decaying materials, and animal wastes from urban surfaces and may
deposit these materials directly into water courses. In addition, when a large volume of
storm water enters urban sewer systems, it may overwhelm the capacity of a facility causing
the storm water to combine with the sewer water, bypass the sewage treatment facility, and
overflow directly into rivers and the Bay.

I ~~Sediments

into Sediments are eroded soils and other materials that are transported from the land
intorvers and the Bay or which are subsequently resuspended in the water from river beds
or the Bay bottom. It is the presence of sediments in the water that gives it an unclear
I ~ ~(turbid) appearance. Turbid water blocks sunlight which is needed in the growth of sub-
merged aquatic vegetation (SAV) whose beds constitute important habitat for young crabs
and many finfish. In addition, the small pieces of material in such water (particulates) can
P Z~~og the gills of small fish and invertebrates. Turbidity can also cause water temperature
to rise to the point where it is no longer an appropriate environment for some sensitive

I ~~~~~~~~~~~~~4

species. When sediment settles out of the water, it changes the character of the river bed
or Bay bottom. By covering the natural bottom it can prevent adequate oxygen exchange 4
or inhibit the movement of bottom dwelling species. Further, sediment deposited on oyster
beds not only smothers the oysters, it also eliminates the hard, clean surfaces on which the
young oysters (spat) set.

Toxics

Toxic substances--chemicals and heavy metals that are released into the Bay and its
tributaries--can severely damage life forms, especially in their immature stages. Benthic
diversity, abundance, and community structure are all harmed by toxic contamination in
sediments. The concentration (bioaccumu-lation) of heavy metals and toxic organic comn-
pounds in the tissue of shellfish and finfish is closely related to the high concentration of
those materials in Bay waters and sediments. This bioaccumulation increases in higher or- I
ders of the food chain and in older individuals within a species, thus posing a potential-
health hazard to those consuming them. In addition, toxic chemicals pose an additional lo-
calized threat to SAV beds. (A separate commitment of the 1987 Chesapeake Bay Agree-I
ment, the Toxics Reductibn Strategy, addresses the overall issue of toxics in the Bay.)

NutrientsI

Nutrients such as nitrogen and phosphorus are essential for plant growth. However,
in excess, they can degrade water quality and destroy living resource habitats. This is just
what occurs in a variety of direct and indirect ways when too many nutrients spur the
growth of algae which interfere with light penetration of the water, contribute to low
oxygen levels, and alter the food and resources available to other organisms. This in turn
impacts submerged aquatic vegetation, fish, oysters, and waterfowl, among other or-
ganisms. Reducing these impacts through the control of nutrients into the Chesapeake Bayv
watershed is a major objective of The Baywide Nutrient Reduction Strategy, another comn-
mnitment in the 1987 Chesapeake Bay Agreement.3

Potentially Polluting Land Develonment Activities

Clearinv Land

Increased nonpoint source pollution results from essentially all intense land uses,I
including development. The conversion of land from less intensive to more intensive uses
can cause changes in soil stability and the contours of the land, vegetative cover, site
hydrology and point source discharges.

Problems of soil erosion and compaction are often experienced on land cleared for
development. Erosion causes loss of topsoil, sedimentation, and the transport of whatever
nutrients and toxics cling to the soil. Further, the loss of topsoil leaves the ground less able
to support new vegetation and increasingly subject to further erosion. Compaction, which

5 I

is frequently caused by construction equipment, compounds this problem by leaving the soil
~~ ~too dense for adequate water and oxygen supplies to support the growth of soil-stabilizing
plants.

Another form of disturbance caused by development is the recontouring or filling of
land. From a water quality perspective, this activity is especially serious when the land
which is filled is a wetland or marsh. Such lands, while frequently thought of as worthless,
I ~ ~are in reality rich habitats for a wide variety of living resources. They nurture finfish and
shellfish and are an important source of food for waterfowl. Decaying wetland vegetation
provides food for aquatic organisms, and wetland communities serve as buffers to wave ac-
I ~ ~tion against the shoreline. Wetlands are especially important below areas of upland
ground disturbance as they slow rushing waters, allowing sediments to fall out, and their
soils and vegetation filter draining waters before they reach water courses. It should be
recognized, of course, that wetlands are limited in their assimilative capacity; they, too, can
be degraded by too much sedimentation and too many nutrients.

U ~~~~Vegetation helps to protect water quality in a variety of ways. By dispersing and
slowing water flow, vegetation limits soil erosion and the movement of sediments down
I ~ ~slope. Its removal for purposes of development aggravates this erosion. In addition, it al-
ters habitat. New vegetation, generally lawns and transplanted trees and shrubs, often re-
quires extensive use of fertilizers and pesticides. This vegetation is also less successful at
S ~~retarding runoff than the natural vegetation which was there prior to development. This is
especially true for forested cover, which is extremely important in regulating the movement
of nutrients from the landscape into streams.

The removal of natural vegetation also alters habitat, and habitat loss changes the
nature of the remaining habitat as well as its size. Forested areas and edges are eliminated,
and the continuity of woodlands is lost; for some species, habitat range becomes too limited
and the species can no longer survive in the area.

U ~~Impervlous Surfaces

3 ~~~~An increase in the amount of impervious surfaces --- materials through which water
will not pass --- is a natural consequence of land development. Surfaces such as roofs,
sidewalks, roads, and parking lots, collect water and speed its movement instead of permit-
I r~~ing it to percolate through the earth, eliminating the filtering effect of naturally vegetated
soil on water. Roads and parking areas accumulate nutrients, toxic materials such as lead,
copper, zinc, asbestos, and deicing chemicals, oil and grease from the operation of motor
vehicles, and decaying vegetation and animal wastes. Laden with these contaminants,
water flows from impervious surfaces into nearby streams, contaminating both local water
and, subsequently, the Bay.

* ~~~~~~~~~~~~~~~6

Wastewater Treatment

The treatment of sewage is a necessary part of development. On-site systems, even
when well designed and properly installed, can release nutrients to ground water that even-
tually drains to streams, rivers, and the Bay. Failing septic systems, a fairly common
problem,4 can contaminate shellfish grounds, closing them to productive uses. Off-siteI
sewage systems, while preferred to on-site treatment, may fail to remove all nutrients prior
to discharging wastewater. In addition, many chemical substances are not removed by
treatment and some, chlorine, for instance, may be added to the discharge.
Toxic Materials

In addition to automobile-related toxic pollution, development provides many other
opportunities for toxic contamination; pesticide use, accidental chemical spills from in-I
dustrial and commercial sources, and paints, solvents, and fuel often are disposed of in
sewers and frequently end up in local water courses causing their contamination. Construc-
tion and maintenance activities associated with changing land uses are a source of pes-I
ticides used to control weeds and insects. Whether accidentally spilled or intentionally ap-
plied to the land's surface, these substances can attach to soil particles or drain into local
ground and surface water, making them unfit for many local uses and increasing the con-I
tamnination of the Bay's water as well.

Given the anticipated development within the watershed, improving development
practices is a critical element in protecting the future of the Chesapeake Bay. Both water
quality and living resources will suffer if we continue to assume that we can build nearly
anywhere and in almost any manner. Moreover, it is important to make clear in encourag-
ing the use of these Policies and Guidelines that not only will they protect the Bay, they
also will provide an improved environment throughout the watershed, especially if they are I
used consistently across jurisdictions.

Therefore, the Chesapeake Executive Council has adopted the following develop--
ment and resource protection Policies and Guidelines to accommodate land use change
and development while protecting the water quality and living resources of the Chesapeake
Bay watershed.

ThEVELOPMENT POLICIES AND GUIDELINES FOR THE~

The oliiesandguidelines that follow are intended to guide the location, design,
contrutin, pertin, ndmaintenance of new developments in such a manner as to
preserve the quality of the Chesapeake Bay and its tributaries. Each policy is accompanied
by guidelines and representative practices from which an effective strategy for implement-
U ~ ~ing the policy may be developed. Not all guidelines and practices will be appropriate for
every construction project, and use of alternatives to accomplish the desired environmental
I ~~objectives is certainly warranted.

Evaluation measures, printed in italics, have been suggested for each policy in order
that design and construction strategies can be tailored to the preferences of each jurisdic-
tion and the characteristics of specific projects.
Policy 1 - Design, locate. and construct new developments in a manner that controls the
amount of sediment enterin2 the ChesaDeake Bay and its tributaries.

The control of sediments is central to strategies for maintaining water quality and
the plant and animal life of the Bay and its tributaries. Effective control of sediments is ac-
complished through the careful location of land disturbing activities in order to avoid steep
I ~ ~slopes and those soils having a high potential for erosion. Careful design of projects is also
necessary to prevent erosion and block sediments from entering surface waters.

I ~~~~Forests and other types of vegetation are effective in controlling erosion and should
be incorporated into project designs. The leaves of trees, shrubs and ground covers com-
bine with the decaying litter on the ground reducing the impact of rainfall and storing the
water for gradual release. In addition, roots bind soil particles making them harder to dis-
lodge, and decaying vegetation contributes to open, porous soils.

Floodplains and wetlands adjacent to streams and rivers are natural sediment traps.
By allowing storm water to spread out and slow down, these areas can settle out suspended
I ~ ~materials washed off upland areas. Effective project design can incorporate on site the
same principles to reduce erosion and minimize the transport of sediments into the Bay
* ~~~and its tributaries.

In general, new development should be undertaken in a manner that limits erosion and
sediment transport to quantities that would be expected if tile site were maintained in a
naturally vegetated state. This suggests that the following guidelines should be considered in
p ~~project planning:

3 ~~~~~~~~~~~~~~8

Guideline I.1I. Use location. design. and construction Dractices that prevent or minimize

Design projects to avoid grading, clearing, or building on hhly erodable soils and
topsoil, and breaking up the root mat that holds soil in place. For instance,

Use vegetated slopes as buffers between dissimilar uses.
Cluster structures on existing flat areas.I
Design road networks in new developments to run with the natural topog-
raphy rather than running across steep slopes.I
Design subdivisions to use natural contours and site topography in order to
reduce the need for massive grading.

Plan for future needs in order to reduce dredging. For example,

Identify sites that are appropriate for boat access by virtue of proximity to
deeper waters, among other factors, and reserve those sites for that purpose.
Designate those areas on local comprehensive plans and plan for compatible.
uses on surrounding parcels, thus avoiding the development of conflicting ac-
tivities that may prevent the use of suitable sites for marine access.
Reserve those areas through public acquisition and appropriate zoning.

Maintain vegetation wherever possible. The root mat binds soil particles whileI
leaves and forest litter help reduce the impact of rain water. As vegetation decays,
it maintains porous soils to absorb storm water runoff. For instance,

Leave forest litter and underbrush on densely shaded slopes.
Limit the use of lawns and newly established ground covers to areas with
good exposure to the sun..
Keep machinery away from slopes, trees, and forested areas during construc-
tion to avoid compacting roots.I
Limit clearing of forested areas.

Avoid development in floodplains and tidal and non-tidal wetlands.
Reduce the velocity of storm runoff to prevent scouring of soils. For example,

Avoid development on steep slopes. If such slopes must be cleared, incor-
porate terraces or gradual slopes to stabilize soils for revegetation.
If slopes are cleared, revegetate immediately.

Build access roads at an angle to slopes.

Avoid concentrating runoff into channels if sheet-flow can be maintained or
developed.
Maintain forest fringes to act as forested buffer strips.
I ~~~~~~Direct sheet-flow through vegetation.
Use velocity reducers at the end of pipes.

Reinforce steep channels. For instance,
Use baffles to interrupt flows.
Where baffles alone are impractical, use stabilizing mechanisms to Prevent
scouring if this will not increase downstream erosion.
Restore or preserve aquatic and shoreline vegetation to help dissipate the energy of
waves breaking against the shore. For instance,
I ~~~~~~Insure effective erosion and nutrient control throughout the watershed to
prevent adverse effects on submerged aquatic vegetation
I ~~~~~~Avoid dredging, filling, diking, ditching, excavating, clearing, or other prac-
tices that destroy wetlands.
Encourage non-structural shoreline erosion control practices.
Locate marinas and other water dependent activities ad~jacent to areas of
deeper water which are less suitable for aquatic vegetation.
Regrade and replant eroded banks to allow sunlight to reach shallow inshore
areas and to reduce the angle at which waves strike the bank.
Guideline 1.2. Where orevention of erosion is not comp~letely effective. trap) and remove
u ~~sediments before they reach rivers. streams. or the Bay.
Install erosion and sediment control measures prior to land clearing.
Design sites with features that reduce the velocity of runoff to allow soil particles to
I ~ ~~~settle out. For example,
Interrupt drainage channels with baffles, and direct flows to wetlands created
expressly for storm water management purposes where particles can settle
out before the runoff enters streams and rivers.

Incorporate settling basins in project designs.
Locate and design settling basins to insure that scouring does not occur
during heavy storm flows.
Direct sheet flow runoff across-vegetated areas.
p ~~~~Designate and maintain streamnside management zones on either side of perennial
streams to filter out sediment and nutrient runoff.

* ~~~~~~~~~~~~~~10

Guideline 1.3. Reduce activities that alter the natural transport and deposition of sedi-
ments to the Bay and its tributaries.4
Build docks and marine facilities in areas which minimize the need for dredging.
Discourage the construction of private piers and docks in areas that require dredg-
ing in order to gain access.I
Reduce the need for shore hardening by siting new structures and infrastructure
where they are safe from historic rates of erosion.
Where shore erosion must be controlled in order to protect valuable capital assets,
design solutions for entire reaches of shoreline rather than single parcels. Construct
or establish those solutions prior to subdivision and sale of property, and provide for I
their maintenance by future property owners.

Where structural shore-erosion measures must be used, promote the use of rip-rap
rather than bulkheads because it limits bottom scouring and provides aquatic
habitat.
For existing sites, use homeowner associations to recommend uniform protection
measures.

Guideline 1.4. Plan for future needs in order to reduce sedimentation.
Identify sites that are suitable for water dependent uses by virtue of proximity to
deeper waters, among other factors, and reserve those sites for that purpose. For
example,
Designate those areas on local comprehensive plans and plan for compatible
uses on surrounding parcels, in order to avoid the development of conflicting
activities.
Reserve those areas through public acquisition and appropriate zoning.
In areas where some dredging will be necessary, identify suitable sites for disposal of
dredged material and acquire or reserve those sites.

Guideline 1.5. Protect sand. vravel and other mineral deposits and orovide for their use in
an environimentally sensitive-manner.-

Identify important deposits of minerals such as sand, gravel, and other non-
renewable resources, and give priority to the use of those deposits that are outside
of floodplains.
Undertake mining practices in ways that present the least potential for sedimenta -
tion or the degradation of wildlife habitats and water quality both during and follow-
ing extraction. Stripping existing natural vegetation always degrades existing
habitat.�

Reclaim mined sites so that erosion and sediment transport is no greater than that
which took place before mining occurred.
Site future development well away from economically important deposits of
minerals and other resources to assure that those deposits can be used without ad-
verse impact on neighboring activities. This will reduce pressures to use deposits
which may be located on sensitive lands.
Policy 2 - Desiin. locate. and construct new develonments in a manner that controls the in-
troduction of toxic comnounds into the Chesaueake Bay and its tributaries.

The benefits of eliminating toxic compounds from the the Bay, its tributaries, and
local water bodies are clear. Living resources are protected, as are the consumers of those
resources. Control of toxics requires a three part program which includes minimizing the
use of toxic compounds, removing them from proximity to Bay waters and pathways to
those waters, and providing for effective control of spills resulting from accidents and
natural disasters.
Manufacturing and production processes that support modem styles of living
depend on the use and manufacture of compounds that are toxic to living organisms.
Maintenance of the quality of the Chesapeake Bay and its tributaries cannot be based on
the premise that production and use of these substances will be eliminated. Rather, em-
phasis will be placed on using them efficiently and responsibly. Point source emissions of
toxic compounds are regulated under the authorities of the various jurisdictions and the
Federal government. The emphasis of the Development Policies and Guidelines is on con-
trolling non-point toxic sources that are influenced by the manner in which communities
are developed.
Many persistent compounds are already present in the waters of the Bay and will be
eliminated gradually through its natural flushing action. Other toxics, however, will be
deposited on the bottom of the Bay and its tributaries and subsequently covered by clean
sediment. Practices such as dredging that cause the resuspension of sediments from these
deposits should be avoided. In this regard, the control of erosion and sedimentation is im-
portant to the control of toxic substances because it reduces the need to dredge existing
channels or open new ones.
Jurisdictions should strive to accomplish new development in a manner that prevents
the introduction of toxic compounds through the movement of water across the surface or un-
der the ground. Practices that result in transport by air or precipitation should be minimized.
Guidelines for achieving this include the following:
Guideline 2.1. Reduce the use of toxic compounds in the construction. oreration. and
maintenance of new development.
Select building sites that minimize the need for certain pesticides and fungicides.
For instance,

Select dry, well-drained sites for structures in order to reduce the potential
for termite infestation and prolong the life of termiticide and other pesticide
applications.

Locate residential structures well away from wetlands since concentrations of

mosquitoes and other insects may be prevalent in those areas, resulting in
pressure for chemical controls.

Minimize and control the use of toxic substances in construction. For example,0
Construct buildings using sheet or batten rather than foaming or spray-on in-
sulation, since the latter pose a higher risk of introducing toxics into the at-
mosphere.
Avoid careless disposal of construction materials. Separate toxic substances
from general building debris and dispose of toxic substances in a legally ap-I

Design and construct landscaping for new development that is adapted to local con-
ditions. For instance,
Use native plants in landscaping since they are usually better adapted to local
growing conditions and require fewer applications of pesticides to maintain a I

Substitute degradable materials for persistent ones.
Guideline 2.2. Site new activities that use. store. or manufacture significant Quantities of
toxic substances away from oroximitv to the Bay and its tributaries.
Reserve specific waterfront locations for those potentially polluting activities that
must be near water to accomplish their basic purpose. For example,
Locate port facilities and large marinas in already urbanized areas.
Locate uses that do not require a waterfront location for proper operation, such as
fuel and material storage facilities, well away from the waterside.
Locate transportation facilities, such as major arterial roads and large parking lots,
away from the shorefront and floodplains.
Select sites that minimize the risks of transport through ground water. For example,
Evaluate the suitability of septic systems on the basis of wet season percola-
tion rates.

Locate storage facilities for fuels, pesticides, and other toxic substances on
clay or other impermeable soils, and as far away from the water as possible.
Avoid karst and seismic zones where accidental releases may be transported
rapidly through subsurface channels.
Site landfills on dense soils, well above the existing water-table to avoid both
short- and long-term ground water contamination.
Avoid sites where steep slopes, rapid erosion, and proximity to rivers, streams, and.
drainage channels present high risks for transport of accidental releases or spills.

II ~~Guideline 2.3. Trap snills before they reach the Bay or its tributaries.
Where groundwater levels and soils are appropriate, detain or infiltrate the first
flush of storm water, containing the most contaminants, on site. For instance,

I ~~~~~~Infiltrate the first flush of storm water from small parking lots and other im-
pervious surfaces where large contaminant loads are not present.
Where heavy concentrations of contaminants may be present, channel the
first flush of storm water to detention basins where it may be cleaned prior to
release.
I ~~~~~Establish vegetated areas above storm water management measures to trip
sediments and contaminants.
I ~~~~Control the movement of toxic substances to provide opportunities for clean-up and
treatment. For example,
Avoid the location of septic systems on very porous soils. When they must be
used, maintain adequate space to assure sufficient time for binding or
decomposition of substances.
I ~~~~~~Install pavement with curbing and channeling devices wherever large quan-
tities of toxic substances are handled or stored, such as in industrial areas.
Construct containment structures around areas where toxic substances are
stored or used.

U ~~Policy 3 - Design, locate. and construct new developments in a manner that controls the in-
troduction of nutrients into the Bay and its tributaries.
I ~~~~The lowering of current levels of nutrients in the Bay watershed is essential if the ef-
fort to restore the abundance of the Bay's living resources is to succeed. In a naturally
functioning system, the primary sources of nutrients are decaying plant and animal tissue,
I ~ ~deposits from the atmosphere, and the wastes of animals and micro-organisms. Erosion
adds trace elements as well. Nutrient movement off the land is best manag'ed by maintain-
ing a natural vegetative cover to reduce soil and water flow and to increase the nutrient up-
take by plants.
As development activity increases in the Bay watershed, many additional nutrient
sources are introduced. At the same time, the changes which take place on the land sur-
I ~ ~face, particularly soil disturbance, the removal of natural vegetation, and the creation of
impervious surfaces, take up nutrients and carry them to local streams and rivers. Both ad-
ditional nutrient sources and changes in the landscape contribute significantly to increasing
nutrient loads from development.
Human wastes may be a major additional nutrient source in developing areas. They
may be handled as point sources in centralized treatment plants, or through on-site dis-
posal, which represents a nutrient source to the developed landscape. Animal wastes and
p ~~fertilizers can be managed through a variety of management practices.

I ~~~~~~~~~~~~~~14

Appropriate development strategies can greatly reduce the overabundance of
nutrients, especially those that are introduced from non-point sources such as storm water
and ground water. Fortunately, the process is enhanced by the ability of plants and micro-
organisms to absorb nitrogen and phosphorous, and indeed, some of the strategies for con-
trol are based on this fact.
In general new developments should be undertaken in a manner that restricts the intro- I
duction of nutrients to levels that would be expected from the site if it were in its naturally
vegetated state. Guidelines for development include the following:
Guideline 3.1. Preserve and re-establish wetlands. both inland and adiacent to the shore. to
intercen)t nutrient and sediment inputs from urDland sources thereby reducing the amount of
these materials released into the Bay and its t/'ibutaries.
Maintain or re-establish tidal and non-tidal wetlands in and adjacent to developed
areas. For example,
Incorporate protection of tidal and non-tidal wetlands as elements of site
design.
Preserve a buffer of naturally vegetated land between wetlands and
developed areas, including lawns and impervious surfaces to prevent wetland
degradation.
Where water dependent activities are constructed in or adjacent to wetlands,
minimize dredging, impervious surfaces, filling, and the release of sediments
and toxic substances.
Minimize the rate and volume of runoff entering wetlands from developed areas to
provide effective pollution retention in the wetlands and preserve the wetland
biological community. For instance,
Limit the extent of impervious cover and lawn area near wetlands while
retaining vegetative cover.
Avoid consolidation of channelized runoff into wetlands.

Guideline 3.2. Design landscapes that restrict the need for chemical fertilizers.
Incorporate forested areas into landscape designs, and allow the normal cycle of leaf
fall and decay to maintain nutrient balances. This is especially important in buffers
and along shorelines and slopes.
I
Avoid extensive plantings of grasses and other groundcovers that require frequent
applications of fertilizers and intensive maintenance.

Guideline 3.3. Provide for the uptake of fertilizers and animal wastes through the use of
best management t)ractice before they are washed into local waterways. -
Allow storm water from fields, lawns, and other areas where broadcast fertilizers
may be used to filter through vegetated areas before it reaches the bay and its
tributaries.

15~~~~

Install filter strips adjacent to fields where broadcast chemical fertilizers may be ap-
plied in order to control water containing dissolved nutrients.
Avoid excessive application of fertilizers by soil testing to determine appropriate
amounts needed

I ~ ~~~Manage land application of sewage sludge to obtain the least risk of contamination
to water quality.

I ~~Guideline 3.4. Establish and use a set of Driorities for storm water caualitv management on
development sites.
Do not limit storm water quality management to on-line facilities designed to con-
trol peak storm discharges.
Preserve or establish forested buffer strips on freshwater streams and other water
I ~ ~~~bodies.
Where erosion and sediment movement is anticipated, provide for sediment
I ~ ~~~removal upgradient of water quality management facilities.
To the extent possible, control infiltration of rainfall on-site, upgradient of forested
S ~ ~~~buffers, wetlands, and artificial storm water marshes.
Encourage sheet-flow of storm water into artificial storm water marshes to increase
retention time and vegetative uptake, and to reduce channel scouring.
Avoid the use of natural wetlands for the management of high rates or volumes of
runoff, relative to pre-development conditions.
Use retention and extended detention basins as on-line facilities where management
of runoff, volume, and water quality occurs within a single facility.

Guideline 3.5. Incoroorate storm water oualitv management considerations in the earliest
stages of Droiect desi2n.
Consider on-site space requirements for water quality management before estab-
lishing the overall distribution and number of building units, their floor area, and
the extent of impervious surfaces on the site. For example,
Reserve space for necessary structural water management facilities, avoidingn
their placement in environmentally critical areas.
Incorporate forested and other natural vegetative covers into initial
* ~~~~~~landscape designs.

* ~~~~~~~~~~~~~~16

Guideline 3.6. Prooerlv treat human wastes before they are introduced into the Bay and itsJ
tributaries.,
Upgrade existing waste treatment plants and collection systems before demands
equal or exceed their capacity.
Locate conventional and innovative on-site disposal systems and potable water sup-I
plies according to a set of criteria designed to maximize their effectiveness and
nutrient retention. For instance,
Test and evaluate soils to determine their ability to transmit and clean ef-
fluent from on-site disposal areas.
Use only unsaturated, unconsolidated soils beneath disposal trenches or pits,
to insure containment of effluent.
Insure that proposed on-site systems are sized and located in designated andI
approved sewage disposal areas.
Develop and use innovative technologies to enhance treatment of effluentI
where water table conditions do not permit adequate treatment in the soil.
Do not locate septic fields near the crown of slopes, where the potential for
system failure and surface water contamination is increased.
Where shore erosion rates are high, site fields where they will remain at an
acceptable distance from the water throughout their expected life.
Insure adequate spacing and water flows for proper dilution of effluent from
small, on-site treatment systems.I
Locate septic tanks and wells in areas with good soils and provide adequate
space between septic systems and the seasonal high water table.I
Consider using two compartment septic tanks and alternating drain fields
Develop guidelines to prevent the failure of on-site sewage treatment facilities. ForI
example,
Regularly review operation and maintenance of septic systems and other on-
site treatment facilities to minimize introduction of nutrients or toxic sub-
stances.
Investigate the long-term maintenance and effectiveness of package treat-
ment plants before allowing such systems to be used.

Policy 4 - Design, locate. and construct new develoiiments to minimize alterations of the
natural hydrologic cycle.
Alterations in hydrology resulting from development impair water quality and affect
the stability of stream habitats. Extensive development has the potential to alter the0
characteristics of freshwater in-flow by increasing peak storm flows, aggravating low flows N
during periods of drought, and changing the circulation pattern of water in the system.

Salinity in parts of the estuary is a direct function of the quantity of fresh water flowing into
the system through rivers and streams, ground water, and rain water. If the development
involves the removal or alteration of forested areas or non-tidal wetlands, these changes to
the hydrologic cycle will be greatly increased.
The natural hydraulic cycle for any area is a function of soils, groundwater condi-
tions, vegetative cover, and topography. It will usually involve both percolation of rain into
the soil and direct runoff into streams. Water that enters the soil emerges in surface chan-
I ~ ~nels at different times and places depending on local conditions.
Strategies for development should focus on maintaining and, where necessary,
replicating natural hydrologic conditions. Effective site designs emphasize retention of
natural vegetative cover and uses storm water management measures that produce a flow
similar to pre-construction runoff characteristics. In general; new development should be
designed to minimize the amount of the rainfall on a site that is shed as surface runoff.
I ~ ~Remaining storm water should be infiltrated to maintain ground water or should be returned to
the atmosphere by evaporation and transpiration~ As well; the movement of tides, streams, and
rivers should not be impeded by new structures. Development guidelines that can help to
achieve these standards include:
Guideline 4.1. Incornorate storm water management Dractices into design and location
criteria for new development.
Infiltrate storm water runoff from impervious surfaces close to where it falls as rain
in order to reduce the need for expensive control and channeling structures and to
avoid concentrating impurities to levels that overwhelm the ability of natural sys-
tems to assimilate those impurities. For example,
Break large areas of impervious surface into several smaller areas.
Maintain natural vegetation as open space buffers between adjacent uses and
to provide privacy where desirable.
Direct runoff from impervious surfaces across filter strips and through
naturally vegetated areas.
Avoid concentrating storm water into channels, favoring sheet-flow instead.
Use porous surfaces to allow direct infiltration of storm water.
Where immediate infiltration is impractical, direct storm water runoff to detention
or retention facilities. In this way, excess runoff can be detained long enough to per-
I ~ ~~~colate into the ground or can be released at a rate that more nearly approximates
natural release rates. This helps to maintain normal, cyclic high and low flow
characteristics. For instance,
Use storm water extended retention and detention structures to accomplish
both sediment control and toxics removal objectives.
Create storm water management wetlands, and employ them to slow the
movement of storm water and provide nutrient uptake.
p ~~~~Regularly inspect and maintain infiltration structures to insure their effectiveness.

Guideline 4.2. Avoid locating new structures where they will alter the flow of tides. streams.
and rivers.
Elevate roads on bridges rather than on compacted fill material that blocks or chan-
nels water flows.
Do not construct instream structures that block or impede the movement of
migratory fish.
Avoid constructing, expanding, and rebuilding structures in flood plains and wet-
lands.

Avoid the use of bulkheads and riprap for control of shorelines where biological or
nonstructural means (such as beach nourishment or grass planting) are appropriate.

Policv 5 - Desigm. locate. and construct new develooments in a manner that minimizes
destruction and degradation of imnortant habitats for oiants and animals.

Aquatic and terrestrial plants and animals are integral elements of the Chesapeake
Bay watershed. Plant and animal communities play essential roles in maintaining the
quality of water in the system and are valued resources in their own right. By its very na-
ture, development alters and destroys habitat, and therefore it is essential that a priority be
placed on assuring that the impacts that do occur are limited to those habitats of least
economic and biological importance.
Rare and endangered species present a special problem in that their preservation
often precludes any alteration of their habitats and in some instances may require reversal
of previous actions that place stress on those habitats. Location and design criteria can of-
ten contribute to efforts to preserve habitats.
It should be recognized as well that while some species are not sufficiently rare on a
statewide basis to warrant official designation as threatened or endangered, they may be
considered worthy of protection by a local jurisdiction because they are locally uncommon.

The protection of high quality habitats and the inter-relationships between biologi-
cal communities can be incorporated into location and design criteria for new develop-
ment. Appropriate site-related criteria are important, as are regional approaches that con-
sider protection strategies for entire biotic communities.

New development in the Bay watershed should restore or preserve the habitats of rare or
endangered species and should avoid the disruption of economically and biologically important
habitats. Guidelines for new development include the following:
Guideline 5.1. Design. locate. and construct new development in a manner that oreserves
rare and endanerea d srecies.
Locate new development where it will not affect rare biological communities. For
instance,
Survey sites prior to acquisition for development to identify rare and endan-
gered plants and animals and to determine if the site is suitable for the
proposed use.

Acquire sufficient land for proposed projects so that important habitats can
be preserved without precluding the achievement of development objectives.
Design sites to preserve rare biological communities. For example,
Isolate noise-generating activities and areas of intense activity from sensitive
habitats using buffers, open space, and less intense activities.
Avoid subdividing sites in a manner that fragments important habitats or that
I ~ ~~~~~creates parcels that cannot be developed without altering important habitats.
Maintain corridors of natural vegetation linking habitat areas in order to
avoid genetic isolation of species in those areas, and to provide for the free
movement of wildlife between habitat areas.

Use construction practices that prevent impacts on sensitive habitats. For instance,
Keep machinery out of sensitive areas.
I ~~~~~~Clearly mark sensitive areas before and during construction.
Do not use sensitive areas for disposal of debris from construction or site
I ~ ~~~~~preparation.
Preserve a vegetated buffer around sensitive areas.
S ~ ~~~~~Prevent sediments, silts, and toxic substances from being washed into sensi-
tive areas.

Guideline 5.2. Design. locate. and construct new developments to avoid the loss of im-oor-
tant habitats.
Design sites in a manner that preserves and restores native biological communities.
For instance,
Cluster developments on less sensitive areas of a site.
Incorporate wetlands and other important habitat areas into site designs.
Protect common but nevertheless important habitat areas--such as wetlands
and riparian forests.
!Design landscaping plans that avoid large-scale, intensively managed plant-
ings and favor preservation of natural vegetation.
I ~ ~~~~~Where agricultural sites are developed, preserve adjacent natural areas and
replant cleared areas with native species.
I ~~~~~~Where forested areas are modified by development, locate construction
along the edge and maintain a canopy cover wherever possible to maintain
maximum habitat value.

* ~~~~~~~~~~~~20

Locate new development where it will have the least impact on existing habitats.
For example,�
Acquire and develop sites within and adjacent to areas of existing develop-
ment in order to achieve compact development forms that minimize clearingU
and paving.
Avoid developing on prime agricultural soils in order to reduce clearing of
less desirable areas for agricultural use.

Reserve shorelines for water dependent uses and set other activities backI
from the waterfront, particularly where shellfish beds, fish spawning areas,
and other aquatic resources are present.

Policy 6 - Manage 2rowth within the jurisdictions of the Chesaneake Bay watershed in aI
manner that urotects ininortant environmental resources.
The protection of the water quality and living resource habitats of the Bay requires
care in the way we build communities that goes beyond simple questions of the design,
location, and construction of individual developments. Through effective community
design, we assure efficient use of land, energy, and physical and living resources. Manage-
ment of the collective impact of multiple, individual development decisions is a proper
function of government, and wise management by local, state, and federal authorities can
do much to assure the future of the Bay and its tributaries.

Cooperative action by and among all levels of government is required in order to
achieve effective community design. Action by elected officials of the towns, cities, and
counties of the Bay watershed is an immediate and necessary part of effective governance ,
since it is at this level that individual development decisions may best be related to local
conditions. As well, effective regional planning is necessary to address those impacts that
transcend single jurisdictions. Finally, state and federal participation is warranted because
of the jurisdiction and authorities that are incumbent within those levels of governmrent.
Community development that includes the preservation of water quality and natural
habitat can provide for efficient use of common resources and help balance resource useI
among competing demands. In addition, effective community design can help to prevent
excess financial burdens on private individuals, developers, and local governments that may
arise from incompatible or inappropriate developments in environmentally sensitive areas. I
In order for such management to be effective, governments should include preservation of
the quality of the Bay and its tributaries as they prepare long-range plans, and they should
employ a wide range of innovative implementation and management tools as they camr out
those plans.II
Federal, state, and local development decisions should preserve the water quality and
living resources of the Chesapeake Bay. As well, new or existing regulatory techniques thatI
provide incentives for development consistent with these goals should be used. Guidelines for
action include:

Guideline 6.1. Reserve the waterfront for water-dep~endent uses.
Reserve the waterfront for activities that must be near water to accomplish their
basic purpose. For example,�

Locate port facilities and large marinas in urban areas and less intense
water-dependent uses in less developed areas.
Encourage the cooperative use of docking, parking, cargo-handling, and
storage facilities in waterfront industrial areas to limit waterfront demand.
Locate commercial and residential uses that are enhanced by, but not de-
pendent on water access, close to the water, but maintain open spaces be-
tween those uses and the waterfront.
Locate uses that do not require a waterfront location for proper operation,
such as fuel and material storage facilities, well away from the waterside.
Locate transportation systems and utility corridors serving ports and
waterfront industries upland to reduce pressure on waterfront sites.

Restrict waterfront residential and commercial development in urban areas to sites
where such historic development patterns have previously existed.
Encourage cluster development away from the water's edge in order to leave the
land nearest to the water as common open space and to reduce the impacts of
development on water quality and living resources of the Bay and its tributaries.

Guideline 6.2. Construct/extend infrastructure in areas most suited for develooment.
rather than areas with high concentrations of wetlands. steep) slooes. significant plant and
wildlife habitat. valuable resources. or other environmentally sensitive characteristics.

Locate new development near or within the existing service areas of public sewage
treatment plants in order to avoid the premature extension of infrastructure and to
reduce new infrastructure needs.
Plan for and construct new treatment facilities to serve higher densities of develop-
ment in suitable areas accessible to, but not directly on, the shore.

Guideline 6.3. Encourage compact development forms to minimize the amount of paved
areas necessary to serve expected population growth.

Incorporate mixed uses within a development site to minimize the need for new
roads, parking facilities, and other impervious surfaces. For example,

Incorporate a range of community and commercial services in the site design
to limit the need for automobile trips.
Locate areas of residential development near employment centers to reduce
commuting volumes and distances.

Develop high density housing near community centers and near high quality
transportation facilities.

Develop sites adjacent to areas of existing development rather than leapfrogging
into undeveloped areas.4
Plan infrastructure improvements to encourage compact development. For ex-

amlEncourage the development of infill sites where feasible to reduce the needI
for paving previously undisturbed areas or creating new infrastructure.
Redevelop or rehabilitate existing structures.I
Develop on vacant parcels within cities, towns, and'communities.

Guideline 6.4. Locate development away from sensitive resources.
Locate development to avoid the loss of important habitats. For example,I
Reserve shorelines for water dependent uses and set other activities back
from the waterfront, particularly where shellfish beds, fish spawning areas,I
and other aquatic resources are present.
Locate marinas and other water dependent activities adjacent to areas of
deeper water, which are less suitable for the growth of aquatic vegetation.
Avoid developing on prime agricultural soils and in significant forested areas. Such
development may result in the clearing of less desirable areas for agricultural useW
and the loss of important plant and wildlife habitat.

23~~~~~~~