Guidelines for activities affecting Virginia wetlands

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

Coastal Zone
Information
Center
OASTAL WETLANDS OF VIRGINIA

Interim Report No. 3

GUIDELINES FOR ACTIVITIES
MUM AFFECTING VIRGINIA WETLANDS

Gene M. Silberhorn
George M. Dawes
Thomas A. Barnard, r.

AAL 1@-&&

,I A

Special Report in Applied Marine Science and Ocean Engineering No. 46

Virginia Institute of Marine Science
-Gloucester Point, Virginia 23062

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f.Fi .8;

301 JUNE, 1974
V852
no.46

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COASTAL WETLANDS OF VIRGINIA

Interim Report No. 3

GUIDELINES FOR ACTIVITIES AFFECTING VIRGINIA,WETLANDS

Gene M. Si-lberhorn

George M. Dawes
Thomas A. Barnard, Jr.

PrOPerty of CSC Library

Special Report No. 46 in Applied Marine Science and Ocean Engineering

Virginia Institute of Marine Science
Gloucester Point, Virginia 23o62

William J. Hargis, Jr.
Director

June 1974
U DEPARTMENT OF COMMERCE NOAA
COASTAL SERVICES CENTER
2234 SOUTH HOBSON AVENUE
Ca
CHARLES'TON SC 29405-2413

PREFACE

In response to the Legislature's directive "to make a study and report
on all marsh and wetlands in the state" (House Joint Resolution No. 6%
1968) in December, 1969, the Virginia Institute of Maxine Science published
its first interim report on the coastal wetlands of Virginia (Wass and
Wright, 1969). The report emphasized the ecology of wetland areas, their
values to the marine environment, their values to man, and man's relation-
ships with wetlands. More importantly, the report presented recommendations
for a legal definition of wetlands and for the regulation. of activities
detrimental to wetlands. Some specific scientific reseaxch needs were also
cited.

In March, 1972, the Virginia Legislature enacted the Wetlands Act of
1972 which became effective on 1 July 1972 (Code of Virginia, 60.1).
While establishing controls over Virginia's wetlands, as recommended in the
first interim report, the act also assigned additional responsibilities to
the Virginia Institute of Marine Science. In July, 1972, the Virginia
Institute of Marine Science published a second interim report on coastal
.wetlands (Marcellus, 1972). Essentially a progress report, the second
report further identified research needs necessary for effective manage-
ment of wetlands.

This third report primaxily responds to the Legislature's requirement
that the Virginia Institute of Marine Science provide advice and assistance
to the Virginia Marine Resources Commission in the development 'of guide-
lines for evaluating wetlands by type and in identifying conseq@ences of
use of wetlands. This report also identifies continuing research needs.
The.research needs and guidelines set forth herein are based upon the best
knowledge of, and experience with, Virginia wetlands available t this
r
time. VIMS will modify and upgrade the guidelines and researchaneeds as it
becomes possible and necessary.

ACKNOWLEDGMENTS

Much of the research upon which this paper is based was initiated by
Dr. Kenneth L. Marcellus, formerly of this Institute, who also obtained
considerable data reported herein. The authors express their gratitude
for his guidance and contributions and their regret that he was unable to
participate in the final preparation of this report.

Appreciation is also extended to Drs. William J. Hargis, Jr.,
W. Jackson Davis, Michael E. Bender, Robert J. Byrne, Marvin L. Wass,
Messrs. James L. Mercer, Gary Anderson and*Carl H. Hobbs, all of the
Virginia Institute of Marine Science, for their constructive review and
suggestions which have added greatly to the interdisciplinary nature of,
the report.

We wish also to thank the Honorable James E. Douglas, Jr., Cormissioner
of the Virginia Marine Resources Commission, Mrs. Joan C. Skeppstrom and
Mr. James L. Sisson, Jr., Associate Members of the Virginia Marine
Resources Commission, for their review of draft papers and their partici-
pation in joint conferences which have helped shape the direction of the
final report.

The authors have virtual daily contact with members of local wetlands
boards who, along with various staff and members of the Virginia Marine
Resources Commission, will be the ultimate users of the report. We are
particularly grateful for the contributions of the wetlands board members
who have patiently outlined their needs for management information and
whose suggestions have strongly influenced the report.

There are many State and Federal agencies who have interests in appli-
cations for permits to alter the Virginia shoreline. The authors are
appreciative of the responses received from the Virginia Commission on Game
and Inland Fisheries, the State Division of Planning and Conmunity Affairs,
the State Bureau of Shellfish Sanitation, the Virginia Water Control Board,
Region III of the U. S. Environmental Protection Agency, the Annapolis
office of the U. S. Fish and Wildlife Service, and the Baltimore and Norfolk
Districts of the U. S. Army Corps of Engineers.

Much of the research upon which this report is based was supported by
the Research Applied to National Needs (RANN) Program of the National
Science Foundation through the Chesapeake Research Consortium, Inc. The
authors are grateful for this practical support.

Finally, we thank Mrs. Beverly Bennett, Mrs. Judy Hudgins and Miss
Rhonda Rupe for their excellent support in typing many draft papers and the
final manuscript.

TABLE OF CONTENTS

Page
Preface

Acknowledgments iii

Section I - Introduction 1

Section II - Wetlands Types and Properties 3

Type I Saltmarsh Cordgrass Community 6
Type II Saltmeadow Community 7
Type III Black Needlerush Community 10
Type IV Saltbush Community IP
Type V Big Cordgrass Community 14
Type VI Cattail Community 16
Type VII Arrow Arum - Pickerel Weed 18
Community
Type VIII - Reed Grass Community 20
Type IX - Yellow Pond Lily Community 22
Type X. - Saltwort Community 24
Type XI - Freshwater Mixed Vegetation 26
Community
Type XII - Brackish Water Mixed Vegetation 28
Community

Section III - Evaluation of Wetlands Types 29

Section IV - Consequences of Altering Wetlands .32

Section V - Recommended Guidelines When Altering Wetlands 34
General Guidelines
Specific Guidelines 36
Shoreline Defense Structuxes
Dredging and Filling
Sediment Control
Channelling into Marshes or Fastlands

Section VI Status of Research and Marsh Inventory 41

Glossary 48

Literature Cited 51

SECTION I

INTRODUCTION

Article XI of the Constitution of Virginia establishes a policy for
the conservation, development and utilization of natural resources. In
furtherance of this aim the Virginia Wetlands Act of 1972 declared it to
be "the public policy of this Commonwealth to preserve the wetlands and
to prevent their despoliation and destruction and to acccmmodate necessary
economic development in a manner consistent with wetlands preservation."
(Code of Virginia, 62.1-13.1).

There are many types of ecological systems in the coastal zone
Below the low tide limits are found the vast, productive submerged lands
which are vitally important to fish and shellfish as spawning, nursery
and feeding grounds. This area is vegetated by aquatic perennials and
species of benthic algae. Uses of this bottcmland are controlled by the
Commonwealth, with the Virginia Marine Resources Commission serving as
the management agency (Code of Virginia, 62.1-3). Above the low tide
limits and extending up to about mean sea level are found mud or sand
flats which are bare of plants readily discernable to laymen. While
appearing to be lifeless, these flats provide important habitat for crabs,
clams, oysters, worms and other estuarine organisms. Large populations
of algae, bacteria, fungi and microorganisms also inhabit this ar ea form-
ing complex interwoven communities.

Above the sand and mud flats, vegetation occurs which is tolerant to
vet soils as well as periodic flooding. The plants in this area vary in
accordance with salinity, wave action, frequency and duration of tidal
flooding, elevation and soil composition. These lands, usually known as
coastal marshlands, are valuable sources of energy in the aquatic system
since the tons,of,plant material produced per acre-year are the basis of
an important estuarine food web. In addition, ninety to ninety-five
percent of the commercial and sport fishes landed in Virginia waters are
dependent on marshes for food and/or habitat at some stage in their life-
cycles. Marshes,are also habitat for many other species of estuarine
life, particularly waterfowl. They also aid man in protecting fastlands
frcm erosion,-maintaining water quality and buffering coastal flooding and
sea level rise (Redfield,1972). These are some of the reasons why wetlands
are to be conserved and managed. For management purposes, the wetlands
are defined as "all land lying between and contiguous to mean law water
and an elevation above mean low water equal to the factor 1.5 times the
mean tide range ....... and upon which grow one or more specific kinds of
vegetation (Virginia Code, 62.1-13.2(f)). The definition was based on
knowledge developed by many ecologists and on both biological and physical
considerations derived from the research conducted by the Virginia Insti-
tute of Marine Science assisted by the Virginia Marine Resources Commission
(Marcellus, 1972).

Many types of wetlands are*encompassed by the definition established

by the Wetlands Act. Each has characteristic environmental values which
are based on its chemical, biological and physical properties. Intelli-
gent wetlands management requires identification of marsh values and their
relation to the impacts of man's uses. This also is recognized in the
Wetlands Act, which requires that the Virginia Marine Resources Commission
shall, with the advice and assistance of the Virginia Institute of Marine
Science, "from time to time promulgate guidelines which scientifically
evaluate wetlands by type and which set forth the consequences of use of
these wetlands types" (Code of Virginia, 62.1-13.4).

It is the primary purpose of this work to fulfill the legislative
charges and mandate mentioned above. The secondary purpose is to suggest
means by which damaging consequences of wetlands use may be lessened so
that marshes may continue to contribute to the public good and necessary
development may be accomplished in a manner consistent with wetlands pres-
ervation (Virginia Code, 62.1-13-1). Thirdly, the status of wetlands
knowledge is reviewed and weaknesses and gaps identified. After accom-
plishing this purpose, appropriate questions are framed and research needs
axe presented.

SECTION II

WETLANDS TYPES AND PROPERTIES

To pursue the intent of the Wetlands Act, a typing and evaluating
system must be established that is capable of being put to practical field
use by boards or commissions who for the most part do not have comprehensive
training in wetlands ecology. In meeting this objective, it is the judgment
of the Virginia Institute of Marine Science that a classification system is
best resolved by the definition, description and evaluation of natural wet-
lands plant communities.

It is recognized that most wetlands areas, with the exception of the
relatively monospecific cordgrass marshes of the Eastern Shore, are not
homogeneously vegetated. Most marshes are, however, dominated by a major
plant. By providing the manager with,the primary values of each community
type and the means of identification he then has a useful and convenient
tool for weighing the relative importance of each marsh parcel. In Virginia,
many wetlands management problems involve only a few acres or a fraction of
an acre. The identification of plant communities permits the manager to
evaluate both complete marshes and subareas within a marsh.

Each marsh type may be evaluated in accordance with five general values.
These are:

1. Production and detritus availability. Previous VIMS reports have
discussed the details of marsh production and the role of de-
tritus which results when the plant material is washed into the
water column (Wass and Wright, 1969; Marcellus et al, 1972).
The term "detritus" refers to plant material which decays in the
aquatic system and forms the basis of a major marine food web.
The term "production" refers to the amount of plant material
which is produced by the various types of marsh plants. Vegeta-
tive production of the major species has been measured (Wass and
Wright, 1969) and marshes have been rated in accordance with their
average levels of productivity. If the production is readily
available to the marine food web as detritus, a wetlands system
is even more important than one of equal productivity where little
detritus results. Availability of detritus is generally a function
of marsh elevation.and total flushing, with detritus more avail-
able to the aquatic envirornent in the lower, well-flushed marshes.

2. Waterfowl and wildlife utilization. Long before marshes were dis-
covered to be detritus producers, they were known as habitats
for various mumals and marsh birds and as food sources for mig-
ratory waterfowl. Some marsh types are more valuable f@rom this
standpoint.

3. Erosion buffer. Erosion is a common coastal problem. Marshes

can erode but some, particularly the more saline types, erode
much more slowly than do adjacent shores which are unprotected
by marsh. The buffering quality is derived from the ability of the
vegetation to absorb or dissipate wave energy or to establish a
dense root system which stabilizes the soil. Generally, fresh-
water species are less effective than saltwater in this regard.

4. Water quality control. The dense growth of some marshes acts
as a filter, trapping upland sediment before it reaches waterways
and thus protecting shellfish beds and navigation channels from
siltation. Marshes can also filter out sediments that are already
in the water column. The ability of marshes to filter sediments
and maintain water clarity is of particular importance to the
maintenance of clam and oyster production. Excessive sedimenta-
tion can reduce the basic food supply of shellfish through re-
duction of the photic zone where algae grows. It can also kill
shellfish by clogging their gills. Additionally, marshes can
assimilate and degrade pollutants through complex chemical
processes, a discussion of which is beyond the scope of this paper.
Research has shown, however, that marshes act as a natural treat-
ment system that is comparable to artificial tertiary treatmit@nt
of sewage (Pcmeroy, et al, 1972; Sweety 1971; Valiela et al., 197@;
Axelrad, in preparation).
J,
5. Flood buffer. The peat substratum of some marshes acts as a
giant sponge 3.n receiving and releasing water. This character-
istic is an effective buffer against coastal flooding, the
effectiveness of which is a function of marsh type and size.

Research and marsh inventory work acccmplished by VINS personnel
indicate that 10 species of marsh vegetation tend to dominate many marshes,
the dominant plant depending on water salinity, marsh elevation, soil type
and other factors. The term "dominant" is construed to mean that at least
50% of the vegetated surface of a marsh is covered by a single species.
Brackilh and freshwater marshes often have no clearly dominant species of
vegetation. These marshes are considered to be highly valuable in environ-
mental terms. In the following pages twelve distinct marsh types are de-
scribed in detail and a brief outline of the major values of each type is
presented.

3
to
6
f eet
hig h

SALTMARSH CORUGRASS

Sparlina alterniflora

a. Branch of fruiting head.

TYPE I - SALTmARsH coRDGRASS copm-NiTy

Dominant vegetation: Saltmarsh cordgrass (Spartina alterniflora Loisel).

Associated vegetation: Saltmeadaw hay, saltgrass, black needlerush, salt-
wort, sea lavender, marsh. elder, groundsel tree,
sea Qxeye.

Growth habit: Stout, erect grass; long, smooth leaves, often
with attached periwinkle snails,, located at the
waters edge. Tall form 4 to 6 feet tall.along
the water; short form 1 to 2 feet at or slightly
higher than IV2N.

Physiographic position: Ranges from mean sea level to approximately mean
high water.

Aver8@ge density: Usually 20 plants per square foot.- Can range from
10 to 50 plants.

Annual production and Average yield is about 4 tons per acre per annum;
detritus availability: optimum growth up to 10 tons per acre. Daily tides
flux nearly throughout this comnunity. Available
detritus to the marine environment is optimum.
This type of marsh is recognized as an important
spawning and nursery ground for fish.

Waterfowl and wildlife Roots and rhizomes eaten by waterfowl. Stems
utility: used in muskrat lodge construction. Nesting
material for fosters tern, clapper rail and willet.

Potential erosion buffer: Most saltmarshes and brackish water marshes are
bordered by saltmarsh cordgrass along the waters
edge. A marsh/water interface of this type is
highly desirable as a deterrent to shoreline
erosion. The plant stems and leaves tend to
dissipate wave action. Underlying peat with a
vast network of rhizomes and roots is very resist-
ant to wave energy.

Water quality control Marshea of this type can also serve as traps for
and flood buffer: sediment that originate from upland runoff. This
also includes large debris that may accumulate on
the marsh surface. Flood waters are assimilated by
the peat substrate just as water is absorbed by a
sponge.

SLZIMARY: Considering the many attributes of this type of marsh
community, its conservation should be of highest prior-
ity.

aim

a
to to
3 3
feet
high feet
high
b

SALTMEADOW 'MAY ------------- SALr GRASS
or
SALTMEADOW CORDGRASS DIStIckris spicato

SPOrtiftV ROMS
Trqugh-shoped leaves (rolled Inward).
a. Branch with flowers. b. Leaves arranged in one plans.
b. Leaves arranged in 3 or more planes. C. Flowering or fruiting head.
C. Flowering or fruiting head.

TYPE II. SALTMMOW COMMUNITY

Dominant vegetation: Saltmeadow hay (Spartina patens (L.) Greene)
Saltgrass (Distichlis spicata TL.) Greene)

Associated vegetation: Saltmarsh cordgrass, black needlerush, marsh elder,
groundsel tree, saltwort, sea oxeye.

Growth habit: Matted meadow-like stands with swirls or "cowlicks",
individual plants wiry in appearance; saltgrass
1-2 feet high.

Physiographic position: About mean high tide to the limit of spring tides;
saltgrass at lower elevations, saltmeadow hay
predominates at the higher end of the range.

Average density: Mixed populations; 50-150 stems per square foot.

Annualproduction and Ranges from 1-3 tons per acre per annum. Only
detritus availability: small amounts of dead plant material are flushed
out during storms and spring tides.

Waterfowl and wildlife Seeds eaten by birds; provides nesting area.
utility: Habitat for a snail (Melampus) important as food
for birds.

Potential erosion Effective erosion deterrent at higher elevations.
buffer:

Water quality control In many cases, this community represents the oldest
and flood buffer: part of a marsh system. Peat may accumulate to
great depths, making this type of marsh act as a
giant sponge when flood waters wash over it.
Denseness of vegetation and deep peat filters
sediments and waste material.

SUMMARY: This system is an excellent buffer, filtering
out sediments, wastes and absorbing runoff water
originating in the uplands. It may be a better
absorbent than Type I since it is not flooded
daily by tides and its substrate is seldom sat-
urated with water. Production and detritus are
less important to the marine environment than in
Type I communities. Its contributions tend to
favor the upland environment. Its values rank
somewhat below Type I but, nevertheless, a Type II
marsh should not be unnecessarily disturbed.

.3
to
4
f eet r
high

ko b

NEEDLERUSH

Juncus roemerianas

a. Fruiting head.
b. Stem round in cross section.

TYPE III. BLACK NEEDLERUSH COMMUNITY

Dominant v egetation: Black needlerush (Juncus roanerianus Scheele.)

Associated vegetation: Usually pure stands with saltmarsh cordgrass,
saltgrass and saltmeadow hay near the margin.

Growth habit: Dense monospecific stands; plant leafless,
cylindrical hard stans tapering to a sharp pointed
tip; brown to dark green i-n color, 3 to 5 feet
high.

Physiographic position: About mean high water to somewhat below spring
tide limit. Seems to prefer sandy substratum.

Average density: 30 to 50 stems per square foot.

Annualproduction and 3 to 5 tons per acre per annum, decomposes more
detritus availability: slowly than most of the marsh grasses. Not fluxed-
daily by tides.

Waterfowl and wildlife There is no evidence that waterfowl or wildlife
utility: utilize this type of plant directly as a food.
Because of the dense, stiff stands, it has little
wildlife value except for limited cover.

Potential erosion Recent investigations have shown that the dense
buffer: system of rhizomes and roots of black needlerush
are highly resistant to erosion. On sandy shores
and low sand berms which support this community
type, this characteristic is of high value.

Water quality con trol An effective trap for suspended sediments, but
and flood buffer: less effective than the densely matted saltmeadow
community. Provides effective absorbent areas to
buffer coastal flooding.

SUYMARY: As a single monospecific community this type would
support less diversity of wildlife than Type I and
II. It functions quite well as a sediment trap
and erosion deterrent. However, in these categories
it ranks lower than the preceding types. The rhi-
zomes of black needlerush are harder and tougher
than the grasses that dominate Types I and II
ccmmunities;therefore, needlerush is useful as an
erosion deterrent. Overall, the values of this
marsh type rank below Types I and II.

3 to 10 feet high

3 to 10 feet high.

MARSH ELDER GROUNDSEL TREE
/Va frutescefts BOCcharis fiamilifolia,

a. Leaves thick and fleshy. a. Fruiting head.
b. Leaves opposite each other on the stem. h Leaves alternate.

TYPE IV. SfilTBUOH GALLBUOH) COMWITY

Dominant vegetation: Groundsel tree, highwater bush (Baccharis halimifolia
L.), marsh elder, saltwater bus@ (Iva frutescens L.)

Associated vegetation: Saltmeadow hay, saltgrass, wax myrtle, sea oxeye

Growth habit: Shrubs 3 to 10 feet high along the margin of the
marsh and upland plant cormiunities.

Physiographic position- Lower limit is approximately the upper limit of
marsh (marsh-upland ecotone)-

Average density: May provide dense canopy over marsh. Individual
shrub trunks usually spaced 3 to 10 feet apart.

Annual Production and Probably less than 2 tons per acre per annum. De-
detritus availability: tritus of little value.

Waterfowl and wildlife Provides diversity for wildlife in general and
utility: especially as a nesting area for small birds. No
significant food value.

Potential erosion buffer: Although not structurally suited as an assimilator
of sediment and flood waters, it serves somewhat
as a buffer to erosion on sand berms that often
front small pocket marshes. Also functional as
a trap for larger flotsam.

Water quality control of minor consequence, but does trap larger material.
and flood buffer: (See above).

SUMMARY: Useful as an indicator of upper limits of marshes
as defined in the Wetlands Act. Values of this
type rank below that of the preceding types.
However, this community does add diversity to the
marsh ecosystem.

6
to
10
feet
high

BIG CORDGRASS
Spartina cynosuroides

a. Branch of fruiting head.

TYPE V. BIG CORDGRASS COMMUNITY

Dominant vegetation: Big cordgrass (Spartina ynosuroides (L.) Roth.)

Associated vegetation: Usually pure stands

Growth habit: Very tall (6-12 feet), heavily stemmed, leafy
grass with distinct branched fruiting head in
the fall.

Physiographic position: At or slightly above mean high water and extend-
ing to the upland margin. Most common in brack-
ish or low salinity marshes.

Average density: 10 to 15 stems per square foot.

Annual production and 3 to 6 tons per acre per annum. Detritus acces-
detritus availability: sible only on spring or wind tides, however is
rivaled only by saltmarsh cordgrass, which gives
big cordgrass a higher value in the context of
production than other grasses found above mean
high tide. Decomposes more slowly than salt-
marsh cordgrass.

Waterfowl and wildlife Utilized as a habitat by small animals, often
utility: used for muskrat lodges. Geese often eat its
rhizomes.

Potential erosion buffer: The large, coarse rhizomes and intertwining
roots stabilize peat along marsh edges.

Water quality control Usually this community type occupies the older
and flood buffer: parts of a marsh system where peat may be deeper
increasing its capacity as a flood water assimila-
tor. It is also useful in trapping flotsam.

SUMMARY: Although the elevation occupied by this community
type is similar to that of the saltmeadow comnunity,
big cordgrass has a much higher yield of organic
matter which likely contributes to the marine
food web. It is also relatively high in value
as a wildlife food as Well as a buffer to erosion.

NARROW- LEAVED CATTA I L
Typh a angustifolia

COMMON CATTAI L
Typht7 latifolia a b

a. Narrow-leaved cattail (Flower and fruiting head)
b. Common cattail (Flower and fruiting. head)

lllus@trations after Fassett, A Manual of Aquatic Plants.

TYPE VI. CATTAIL COMWNITY

Dominant vegetation: Narrowleaf cattail (Typha angustifolia L.)

Associated vegetation: Broadleaf cattail (Typha latifolia L.), sedges,
bulrushes, arrow arum, pickerelweed, smartweed,
other fresh or brackish water plants.

Growth habit: Characteristic "wiener ona stick" fruiting heads,
long strap-like leaves, somewhat blunted tips. 4
to 6 feet tall.

Physiographic position: Very wet sites, sometimes, in standing water, often
at the margin of marsh and uplands. Does well
in seepage areas resulting from upland runoff.

Average density: 2 to 6 stalks per square foot.

Annual production and 2 to 4 tons per acre. Detritus usually not readily
detritus availability: accessible to the marine environment.

Waterfmql and wildlife Provides habitat for certain birds; roots consumed
utility: by muskrats.

Potential erosion buffer: Because of its preferred habitat and its character-
istic shallow root system, Type VI is only a minor
buffer to erosion.

Water quality control Its usual habitat along the upland margins in soft
and flood buffer: muddy areas ranks this marsh type high as a sed-
ment trap despite its 'shallow rooted condition.
Very few species will grow in these areas either
because of the stagnant condition of the substra-
tun or because they are inhibited by toxin release
of the cattail roots or a combination of the two
factors.

SUNMY: Because of its value as a wildlife food and habitat,
its function as a sediment trap, its relatively
high production and the usual soft substratum,
this type of marsh community should not be in-
discriminately used as a development site. As
far as overall value, is concerned it compares with
a saltmeadaw marsh (Type II).

PICKEREL WEED
pontederig cordato

Blue flower head
ARRoW ARUM
pelfandra viviflica

Flower head
b. Fruiting head
Arrowhead Arrow Arum pickerel
Wood

TYPE VII. ARROW ARUM - PICKEREL WEED COMI=Y

Dominant vegetation: Arrow arum. (Peltandra virginica (L.) Kunth.)
Pickerel weed (Pontederia cordata L.)

Associated vegetation: Sedges, smartweeds, bulrushes, ferns, cattails,
pond lily.

Growth habit: Many broad leaved clumps growing from a thick,
cylindrical rhizome; arrow or heart shaped
leaves. Clumps 2 to 6 feel; tall; average height
3 feet.

Physiographic position: On tidal mud flats from mean sea level to about
mean high tide in low salinity or freshwater
marshes.

Average density: 1 or 2 clumps per 10 square feet.

Annual prodution and
detritus availability: 2 to 4 tons per acre. Detritus readily avail-
able to the marine food wellb because of daily
tide fluxes. In the fall of the year these
species decompose quite rapidly and completely
except for the root stock.

Waterfowl and wildlife Seed3and shoots of both species are eaten by
utility: ducks. Arrow arum seeds float after the pod
decays and are readily available for wood ducks.
Often associated with confirmed spawning and
nursery areas for herring and shad.

Potential erosion buffer: Although this conmmnity type lacks the vast net-
work of rhizomes, roots and peat substratum
typical of a saltmarsh cordgrass community, this
marsh/water interface vegetation is often the
only vegetative buffer to shoreline erosion in
'freshwater areas. The substratum in a marsh
such as this is typically soft, unstable mud.
After the vegetation has decayed in the winter
time, the mud flats are highly susceptible to
erosion due to winter rains.

Water quality control Slows the flow of flood waters, causing some
and flood buffer: suspended sediment to settle out.

SUMMARY: Under natural conditions the marsh of this type
is-relatively stable but it is highly sensitive
to development and activities such as excessive
boat traffic. Because of its many attributes
this marsh ranks similar to that of Type I.

REED GRASS
Phrugmites australls

a. Stand in winter condition, without leaves

TYPE VIII. REED GRASS COMMUMTY

Dominant vegetation: Reed grass(Phragnites australis)

Associated spocies: Switch grass, saltbushes, a few others.

.Growth habit: Tall stiff grass with short, wide leaves tapering
abruptly to a point; soft plume-like seed head.
6 to 10 feet high.

Physiographic position: Usually above mean high tide, drier areas on dis-
turbed sites.

Average density: 3 to 6 stems per square foot.

Annual production and 4 to 6 tons per acre, detritus seldom available
detritus availability: except in storm conditions.

Waterfowl and-wildlife Little direct value to wildlife except as cover.
U@iiity! May have a detrimental effect in that it c an in-
vade areas of a marsh and, compete with desirable
species. It appears to be replacing big cordgrass
and other plants in freshwater marshes of the
Pamunkey River.

Potential erosion buffer: Good erosion deterrent on disturbed sites, especially
on spoil.

Water quality control and Valuable as a buffer to erosion. Potential as
flood buffer: sediment trap and flood deterrent appears to be
minimal.

SUMMARY: This,plant is a relatively recent invader in Vir-
ginia but is spreading rapidly, often displacing
more important marsh plants. It has little or
no value to wildlife in general. Its only impor-
tant value would be its function as a stabilizer
on dredge spoil. This c-cumunity type ranks below
a Type III marsh, the black needlerush community.

*Formally Phragmit@s communis Trinius

YELLOW POND LILY
Naphor adveno

Leaf scar

TYPE DC YELLOW POND LILY CONMUNITY

Dominant vegetation: Yellow pond lily, spatter-dock (Nuphar luteum (L.
Sibthrop and Smith)

Associated vegetation: Pickerel weed, arrow arLmt-

Growth habit: Saucer shaped leaves With a narrow notch, floating
on water; large, leathery yellow flower. 2 to
4 feet high from submerged root stalk.

Physiographic position: Submerged except for floating leaves at high tide.
Found in freshwater areas.

Average density: One plant (cluster of leaves) for every 3 to 5
square feet.

Annual production and to 1 ton per acre; detritus readily available
2
detritus availability: but not a significant contributor to the food
chain.

Waterfowl utility: Excellent cover and attacbment site for aquatic
animals and algae. Feeding territory for aquatic
birds and fish.

Potential erosion buffer: While lacking the stiffness of grasses and sedges,
these plants do reduce wave action from wind and
boats. This has been noted in freshwater streams
and boat channels.

Water quality control Although not a direct assimilator of sediments
and flood buffer: and flo6d waters, the flow of flood water is
slowed somewhat and sediments can settle out.
This function is minimal because the community
is submerged completely :in flood conditions.

SUM02y: Destruction of the community would result in a
decrease in number and diversity of aquatic
animal life in the immediate area. The greatest
value the community has :is its habitat for aquatic
biota. This type should be ranked with or slightly
higher than a Type III (black needlerush) marsh.

SALTWORT
Solicornia s P.

TYPE X. SALTWORT COMMTY

Dominant vegetation: Saltwort, glasswort (Salicornia spp.)

Associated vegetation: Saltmarsh cordgrass, saltgrass, sea lavender.
Growth habit: Leafless green fleshy--stermed @lant, red
in color in fall; 8 inches to 1-@ feet@tall.

Physiographic position: Above mean high tide in pannes or sparsely
vegetated areas.

Average density: 10,to 15 stems per square foot.

Annual production and Less than -1 ton per acre. Exerts very little
2
detritus availability: influence on the marine environment.

Wildlife and waterfowl utility: Some evidence that stems are eaten by ducks.
May be a feeding area for other marsh birds.

Potential erosion buffer: Has very little value as an erosion deterrent.

Water quality control
and flood buffer: Because of the character of the stem, a shallow
root system and the usual small sizes-of the
populations, these community types have little
or no value in this category.

SUMMARY: This community is not high in value. It usually
occupies,small areas within larger more product-
ive marshes and can be used as an indicator of
higher marsh elevations.

FRESHWATER MIXED COMMUNITY TYPE XI
'excluding upland species - pines, cedars, etc.)

BUTTONSUS@H YELLOW POND LILY
BIG CORDGRASS TYPEIX
TYPE V ARROW ARLIM and
PICKEREL WEED
WILD RICE TYPE VII
CATTAIL TYPE V1 SMARTWEED
SWAMP MILKWEED and WATERDOCK
SEDGES

TYPE XI FRESHWATER MDM COMMUNITY

Dominant vegetation: No single species covers more than 50@ of the site.

Associated vegetation: Bulrushes, sedges, waterdock, smartweeds, ferns,
pickerel weed, arrow arum, wi-ldrice, beggar's
ticks, rice cutgrass.

Growth habit; Heterogeneous mixture of' plants.

Physiographic position: From submerged to the upper limits of the wetlands.

Average density: Highly variable.

Annual production and 3 to 5 tons per acre. Iletritus of species such
detritus availability: as arrow arum, pickerel weed and yellow pond lily
would be available in the intertidal zone.

Waterfowl and wildlife A highly valuable marsh for a broad diversity in
utility: wildlife species. Plant; species such as smart-
weeds, waterdock, wi-ldrice and others are prime
waterfowl and sora rail foods. Waters adjacent
to these type marshes are also known as spawning
and nursery grounds for striped bass, shad and
river herring.

Potential erosion buffer: Shoreline erosion protection provided by this type
of marsh is equivalent to Type VII, arrow arum.
pickerel weed community,,

Water quality control This ranks somewhat higher as a sediment trap
and flood buffer: and flood deterrent than an arrow arum - pickerel
weed community. The presence of the stiffer, more
resilient grasses, sedges and rushes and peaty-
type substratum increases the ability of this
type of community over a Type VII marsh as an
assimilator of sediments and flood waters.

SUMMARY: These are very valuable marshes and the aim should
be to keep them in a natural state. This type
of marsh would be ranked equivalent to a salt-
marsh cordgrass marsh (Type I) and an arrow
arum pickerel weed (Type VII) marsh.

BRACKISH WATER MIXED COMMUNITY TYPE X11
(excluding upland species - pines, cedars, etc.)

SALTBUSH TYPE IV SALTMARSH GORDGRASS
BIG COROGRASS TYPE I
TYPE V BLACK NEEDLERUSH
SALTGRASS MEADOW TYPE III
TYPE 11 SALTMARSH BULRUSH
SEA LAVENDER OLNEY THREESQUARE

TYPE XII - BRACKISH WATER MIXED COMKTRITY

Dominant vegetation: No single species coversmore than 50% of the
site.

Associated vegetation: Saltmarsh cordgrass, saltmeadow hay, saltgrass,
black needlerush, saltbushes, three squares,
big cordgrass, cattails.

Growth habit: Heterogeneous mixture of plants in wet areas.

Physiographic position:. Extending from about mean, sea level to the
uplancl margin.

Average density: Highly variable.

Annual productivity and 3 to 4 tons per acre, detritus readily available
detritus availability: in the intertidal zone.

Waterfowl and wildlife Wide diversity of vegetation provides a variety
utility: of wildlife food. Waterfowl foods are plentiful,
such as the generous seed heads of saltmarsh bul-
rush.

Potential erosion buffer: Shoreline erosion protection is the same as that
of a Type I marsh (saltmarsh cordgrass). Most
brackish water marshes axe bordered by saltmarsh
cordgrass.

Water quality control Ranks high in this category, having similar
and flood buffer: attributes as a Type II marsh (saltmeadow).

Subzmy: This marsh is a microcosom of all the communities
found in saline waters. Brackish water marshes
are known spawning and nursery grounds. This
community type contains valuable food and habitat
for awide diversity of wildlife species. Ranks
with a Type I (saltmarsh cordgrass) marsh.

SECTION III

EVALUATION OF WETLANDS TYPES

The Wetlands Act requires the Virginia Institute of Marine Science to
evaluate wetlands by type (Code of Virginia 62.1-13-4). There are several
methods in which -values can be placed on wetlands. One of these methods was
attempted in a recent study (Gosselink, et al.,1973) in which dollar values
per acre of marsh were established based on the natural contributions and
functions of an undisturbed mar'oh- The OaMe report cited another method
in which marsh -values are determined by the commercial market price; pre-
sumably these marshes would be sold for cammercial uses which would ultimately
destroy the natural properties of the marshes. There are also aesthetic values
attributable to marshes but these cannot be effectively evaluated by managers
or scientists in that aesthetic values are an individual judgment.

Establishment of a per acre value of wetlands types in a monetary sense
has not been attempted in this report. One Wetlands Board chairman doubts
that a monetary value would be helpful and suggests that it might lead to poor
decisions based on face value trade-offs which ignore the fact that wetlands
are rarely replaceable (Odom, 1973). An examination of the quality of each
type marsh contained in Section II, however, leads to the conclusion that there
are relative environmental properties which can be assessed on a no unit basis.
Such an assessment can lead to a ranking system which may be of value to managers.

For management purposes, then, the twelve types of wetlands identified
in Section II are grouped into five classifications based on the estimated
total environmental value of an acre of each type._

Group One: Saltmarsh cordgrass (Type I)
Arrow arum - pickerel weed (Type VII).
Freshwater mixed (Type XI)
Brackish water mixed (Type XII)

Group One marshes have the highest values in productivity and wildfowl
and wildlife utility and are closely associated with fish spawning and nursery
areas. They also have high values as erosion inhibitors, important to the
shellfish industry and valued as natural shoreline stabi-lizers. Group One
marshes should be preserved.

Group Two: Big cordgrass (Type V)
Saltmeadow (Type II)
Cattail (Type VI)

Group Two marshes are of only slightly lesser value than Group One marshes.
The major difference is that detritus produced in these marshes is less readily
available to the marine environment due to higher elevations and consequently
less tidal action to fluGh the detritus into adjacent waterways. Group Two
marshes have very high values in protecting water quality and acting as buffers
against coastal flooding. These marshes should also be preserved, but if devel-
opment in wetlands is considered to be justified it would be better to alter
Group.Two marshes than Group One marshes.

Group Three: Yellow-pond lily (Type IK)
Black needlerush (Type III)

The two marshes in the Group Three category are quite dissimilar in
properties. The yellow pond lily marsh is not a significant contributor to
the food web but it does have high values to wildlife and. waterfowl. Black needle-
rush has a high productivity factor but 8 1OW detritus availability value.
Black needlerush has little wildlife value but it ranks high as an erosion and
flood buffer. Group Three marshes are important though their total values are
less than Group One and Two marshes. If develolment in wetlands is considered
necessary,.it would be better to alter Group Three marshes than Groups one or
Two.

Group Four: Saltbush (Type IV)

The saltbush conmunity is valued primarily for the diversity and bird
nesting area it adds to the marsh ecosystem. To a lesser extent it also acts
as an erosion buffer. Group Four marshes should not be unnecessarily disturbed
but it would be better to concentrate necessary development in these marshes
rather than disturb any of the marshes in the preceding groups.

Group Five: Saltwort (Type X)
Reedgrass (Type VIII)

Based on present information Group Five marshes have few values of ary
significance. Whi-le Group Five marshes should not be unreasonably disturbed,
it is preferable to develop in these marshes than in any of the other types.

MARSH VAUJES AS RELATED TO MARSH SIZE

The ranking system thus established is a partial tool for use in making
decisions to alter wetlands for it measures only one marsh type against another.
other factors, involving a wholistic view of the creek or river systems involved,
may be"considered in the decision making process.

For example, acreage is an obviously important factor to consider when
evaluating a specific marsh. A 5 acre marsh is inherently more valuable than
a smaller marsh of the same type. Many creeks and rivers in Virginia however,
have wetlands bordering them which are a series of small separate marshes. The
value of these, when considered in their totality, may be as great as a single
marsh of the sEme type and acreage.

Much is yet to be learned and further research is required to determine
at what point significant values attributable to a marsh ty-Pe or marsh system
cease to exist from a practical managenent viewpoint. Enough is known from
experience gained in the Virginia marsh inventory to date, however, to establish
conservative guidelines for use on an interim basis. These are:

a. Any marsh which is 2 feet or more in average width is considered

----------

to have significant values as an erosion deterrent and in filtering sediments
coming from the uplands. It may also have other values depending upon the
total acreage of the marsh parcel.

b. Any marsh which is greater than 1/10 of an acre in size may have,
depending on type and viability, significant values in terms of productivityy
detritus availability and wildlife habitAt. Depending on its location, it
may also have value as an erosion buffer.

It is emphasized that the foregoing evaluation of marshes is designed for
use by persons involved in managing wetlands in accordance with the Wetlands
Act. There is a need to more accurately evaluate specific marshes, especially
from a wholistic viewpoint. Along with a continuing inventory of wetlands,
so essential to sound management, VIM is continuing research to develop a
formula by which all of the wetlands in the state can be evaluated more effect-
ively.

SECTION IV

CONSEQUENCES OF ALTERING WETLANDS

Sections II and III define and evaluate'wetlands by types. The Wetlands
Act also requires that the consequences of use of the wetlands types be set
forth (Code of Virginia, 62.1-13-4). There are certain uses of and activities
in wetlands which are automatically permitted (Code of Virginia, 62.1-13.5(3)).
Most of the permitted activities are of low intensity in nature, are compatible
with the normal functions of a marsh, and therefore have no significant adverse
consequences. It may have been the legislative intent that all of the permit-
ted uses would be essentially non-degrading to wetlands. In the light of EX-
perience, however, some of the permitted activities, such as govermental
activities in marshes owned or leased by the Commonwealth, should be reexamined
with a view toward bringing them under more positive control. In the meantime,
this report addresses those activities which result in altering marshes and
which require specific permits in accordance with the Wetlands Act. These are
ac+,ivi@ies which inheren@ly degrade or destroy wetlana

Neither we nor anyone else can, at this time, establish the finite amount of
wetlands which can be destroyed or degraded without seriously affecting fish-
eries, wildfowl and animal populations, shoreline stability, water quality
or protection from coastal flooding. It is therefore necessary that activities
in Virginia's wetlands be limited to those which are considered highlyessential.
Loss of wetlands in Virginia through man's activities has been reported for a
fifteen year period commencing in 1955 (Settle, 1969). According to the report,
the average rate of loss in the period 1965-1969 was about 450 acres annually
and the rate of loss was projected to reach about 600 acres annually for the
period 1970-1974. Certainly natural recruitment has not kept pace with losses
to date. The Norfolk District of the Corps of Engineers is attempting to
establish 25 acres of marsh from dredge spoil, but it is too early to say whether
the effort will be successful. Marshes represent only one-half of one percent
of the total ar .ea of the State (Wass, 1969). With such a limited resource and
with a destruction rate far in excess of current recruitment, VIMS concludes
that all uses or activities which destroy or degrade ariy type of wetlands
have consequences which are envirormientally undesirable.

In individual projects, the degree of undesirability can be related to
the size of the project and the amount of marsh destroyed. Because of their
greater potentiality for larger scale adverse effects, big projects obvious-
ly attract attention. However, there should also be a concern for the cumula-
tive effect of mall projects. It was estimated that 271a of the wetlands
lost in the period 1955-1969 were as the result of residential development
and only 17% of the loss waz charged to industrial -projects (Settle, 1969).
Channelization accounted for 47% of the loss but the purposes of the channeli-
zation--whether for residential or industrial purposes-were not specified.
According to VIMS data for calendar year 1973, about 60% of all permit appli-
cations (both subaqueous and'wetiands) were for projects involving single
family residences. VIMS does not have complete data concerning final approval
or modification of permit applications - However, if all applications pertain-
ing to single family residences were approved as received, cumulative altera-
tions to the shoreline (not counting piers and groins) would have amounted

to:
Filling of 27.6 acres of wetlands -
Dredging of 95,232 cubic yards from both wetlands
and subaqueous beds.
Bulkheading of 5 miles of Virginia's shoreline.

It is known that not all applications were approved and that many were
modified in order to reduce adverse effects on the environment. Nevertheless
the figures are significant and take on added importance in the light of a
projected population increase of 1.5 milli-on in Tidewater Virginia by the
year 2,000 (Division of State Planning and Community Affairs, 1972).

It is important that wetlands managers not lose sight of the fact that
a proposal involving a small marsh or ma rsh segment is just one of hundreds
of like nature which, on 0, Statewide scale, account for a really extengive
encroachment on Virginia's finite wetlands inventory.

,33

SECTION V

RECOMMENDED GUIDELINES WHEN ALTERING WETLANDS

The previous sections meet the legislative requirement that VIM provide
advice and assistance to the Virginia Marine Resources Commission in promul-
gating guidelines which scientifically evaluate wetlands by type and which set
forth the consequences of use of the wetlands types (Code of Virginia, 62.1-13.
4). However, VINS is mindful of other legisl 'ative provisions designed to afford
a measure of -protection to wetlands. The legislature established a policy "to
preserve the wetlands and to prevent their despoilation and destruction and to
accomodate necessary economic devplomen-F, in a manner consisfen+, wi@h wetlands
-Preservation I' (Code of Virginia, 62.1-13.1; emphasis added.) This portion of
this report addresses the foregoing policy. It is provided to the Marine Re-
sources Commission as interim environmental guidelines tc apply in evaluating
individual permit applications.

Many of the guidelines have been previously published (Maxcellus et al,
1972) and have been utilized by the VMRC and local wetlands boards. Partial
monitoring of permit actions of the permitting agencies clearly shows that
many proposed uses of the shoreline can be accomodated with little or no loss
of wetlands if,the suggested guidelines are applied. Guidelines which are
included herein but were not previously published have -been developed in the
light of experience gained by investigating and reporting on all wetlands
actions since the effective date of the Wetlands Act,- July,1972.

There are times, of course, when guidelines may not apply in specific
cases. The conscientious application of the guidelines will, however, material-
ly reduce adverse environmental jnpact@ of man's activities on the shoreline
and it is recommended that the Commission, as the management agency responsible,
adopt them and promulgate.them for guidance of local wetlands boards.

GEBERAL GUIDEL=

A. Provided significant marine fisheries, wetlands and wildlife resources
are not unreasonably detrimentally affected, alteration of the shoreline or
construction of shoreline facilities may be justified in order to:

1. Gain access to navigable water by:

a. Commercial and industrial activities for which it has been
clearly demonstrated that waterfront facilities are required.

b. Marinas, camps, boat yards, yacht ciubs and other activities.
which provide broad recreational access to the water.

c. Owners of land adjacent to waters of navigable depth or waters
which can be made navigable with only negligible adverse
impact on the environment.

2. Protect property from significant damage or loss from erosion
or other natural causes.

RATIONALE: These general uses are in accordance with recognized
riparian rights (see United States vs. Smoot Sand and Gravel Corp., 248F.
2nd, 822 (4th cir. 1957) or arp activities which provide benefits to the public
in general. It must also be remembered, however, that Virginia's shoreline
is one of her greatest finite natural resources.

B. Alteration of the shoreline is ordinarily not justified:

I. For purposes or activities which could just as well be conducted
on existing fastlands and which have no inherent requirement
for access to water resources.

2. For purposes of creating waterfront property from lots and sub-
divisions which are not naturally contiguous to waters of 'nav-
igable depth or waters which can only be made navigable by
substantial alteration or destruction of marine resources.

3. When damage to properties awned by others is a likely result
of a proposed activity.

4. When the alteration will result in discharge of effluents which
impair wetlmida) water quality or other maxine resources.

5. When there are viable alternatives which can achieve a given
purpose without adversely affecting marshes., oyster grounds or
other natural resources, or where any adverse effects are
negligible.

RATIONALE: These guidelines reserve the shoreline for those uses or
activities which require water access. They also discourage activities such
as dredging into the fastlands for housing developments which often have a
significant and long term adverse impact on the marine environment through such
effects as changed upland hydrology, sedimentation, changes in water current
patterns near the shor6line, and the introduction of pollutant discharges which
frequently lead to closure of shellfish grounds. The dredging of channels into
fastlands may also lead to deterioration of ground water by sa.1t water intruding
into aquifers.

C. Utilization of open-pile type structures for gaining access to
water is generally preferred over the construction of solid structures or
dredging or filling.

RATIONALE: The construction of solid structures, or the conduct
of dredging and filling operations, often causes irretrievable loss of marsh
through their direct displacement or by indirect effects of sedimentation or
altered water currnets. Open-pile type structures permit continued tidal flow
over existing marsh, avoid potential sedimentation problems, and have less effect
on existing water current patterns.

D. Channels, fills and structures should be designed to meet the special

stresses of the marine environment and to also minimize the frequency of
future maintenance activities.

RATIONALE: Shoreline alterations often change currents, affect
shoreline stability and caus'e biological damage. Unsuccessful structures or
channels generate demands for remedial action which can compound initial -
adverse effects. The lessening of frequency of dredging in chaxmels is par-
ticularly important. Dredging destroys or displaces bottom-dwelJing organisms
of value to the aquatic food web. Organisms can be expected to recolonize
a dredged area after a period of time however too frequent dredging can
inhibit recolonization.

E. High density development in or immediately adjac'ent to wetlands
and/or other flood plains should be discouraged.

RATIONALE: Low-lying development has historical],y created costly
flood control and flood relief problems including claims for indemnification.
Additionally, hydrological changes in upland surface run--off water are caused
by the paving over of formerly absorbent soil, the usual effect being to
increase both the amount amd the rate of surface water flow, thus causing
shoreline erosion and other problems (Leopold, 1968). Finally, high-density
development leads to a concentration of contaminating constituents in urban
surface water runoff which can severly stress receiving waters in the adjacent
marine environment (Burke, 1971). There seems to be a direct relationship
between populations in a watershed and increased coliform levels in adjacent
waters which can lead to long term restrictions in the direct marketing of
shellfish (Wiley, 1974).

SPECIFIC GUIDELINES

The following specific guidelines are recommended for -use in the design,
evaluation or modification of individual projects.

A. Shoreline defense structures.

1. Shoreline defense structuxes are justified only if there is active
detrimental shoreline erosion which cannot be otherwise controlled;
if there is channel sedimentation injurl= to marine life or im-
pairing navigation which can@ot be corrected by upland means; or
if there is a clear and definite need to accrete beaches.

RATIONALE: The location and design of shoreline defense structures
is a highly technical subject and often the precise effects Of Structures on
littoral proc6sses cannot be predicted. A study of one county's shoreline
showed nearly 50% of the existing shoreline defense systems to be ineffective
or poor in performance (Athearn et al., 1974). All defense structures damage
the environment and unnecessary ones may cause greater problems than existed
without them. Solution of an erosion problem requires knowledge of littoral
processes in general plus a knowledge of specific processes of the location in
question. This guideline also clearly precludes the c-onstruction of bulkheads
for purely aesthetic reasons.

2. When bulkheads are deemed to be necessary, they should ordinarily
be placed landward ot, any existing and productive marsh vegeta-
tion. A line of saltbushes,, if existing, can usually indicate
the seaward limit of a bulkhead.

RATIONALE: A bulkhead behind a marsh preserves the marsh for its bio-
logical productivity and utilizes the maxsh's capabilities of aiding water
quality and deterring erosion.

3. Subject to specific analysis of the site, its characteristics
and problems, rock or riprap bulkheads and groins are generally
preferred over vertical structures. Gabions may also be suit-
able. The term "rock or riprap" means carefully placed selected
rock or concrete forms which are especially designed for the
purpose (Thompson, et al., 1972). The term "gabion" refers to
specially designed wire baskets-which are filled with small rock,
rubble or shells to give them necessary weight. Uncontained
broken concrete pavement, cement blocks, and similar rubble are
usually not acceptable due to their small size and light weight.

RATIONALE: Vertical bulkheads reflect energy and often merely transfer
a problem elsewhere. Where wave energy problems exist, whether from natural
causes or from boat wakes, riprap and gabions-are more energy absorbent and
have a longer life span than a vertical structure. In addition, the slope
and nooks and crannies in riprap and gabion structures provide a more suitable
habitat for crabs and small fish. In some cases, sediment is caught in riprap
and gabion structures and is subsequently vegetated with marsh species.

B. Dredging and filling.

1. When filling a marsh is justified, the activity should be confined
to the area inland of the wrack line or any existing saltbush line.
If suitable non-marsh areas are not available and it is necessary
to locate the fill further seaward, locations in Group 3-5 marshes
should be selected if possible (reed grass, saltwort, saltbush,
black needlerush, yellow pond lily). In any event, every effort
should be made to preserve existing saltmaxsh cordgrass (S-2artina
alterniflorja, arrow arum (Peltandra virginica)or pickerel weed
cordata).

RATIONALE: The values of the more important species are preserved thus
scmewhat'lessening the undesirable impact of destroying marshes.

2. When it is found justified to dredge into a marsh, every effort
should be made to select an area in Group 3-5 maxshes (reed
grass , saltwortsaltbush, black needlerush, yellow pond lily).

RATIONALE: The values of the more important species are preserved thus
somewhat lessening the undesirable :Impact of destroying marshes.
3. Dredge spoil should not ordinarily be deposited in adjacent marsh
as a convenience. If it becomes necessary to place spoil on a
marsh, consideration should be given to piling on lower value
portions of the marsh or to scattering the spoil in a

thin layer rather than containing the spoil behind a berm.
Berms in marshes should be used to contain fill only when absolutely
necessary and when they will not cut off tidal flow to wetlands
areas -

RATIONALE: A continuous berm often cuts off water supply to a marsh.
Selective piling allows continued water supply to uncovered portions of a
marsh and may enhance habitat for wildfowl and animals.- Scattering of spoil
in a thin layer can sometimes maintain basic marsh values though it may ultimate-
ly lead to some change in vegetative species if the marsh surface is "significant-
ly raised in elevation. The depth of the soil layer must be.evaluated in each
case.

4. Whenever feasible, displaced marsh vegetation and peat should be used
to reconstitute marsh in the vicinity of the activity site and partic-
ularly along the banks of newly cut canals.

RATIONALE: This procedure will aid to maintain the inventory of marshes
and will deter shoreline erosion and enhance water quality conditions.

5- Overboard disposal of dredge spoil is generall7 undesirable unless the
deposits are basically sand, free of pollutants, the spoil area is
devoid of commercially important bottom organisms, and the deposits
may have a beneficial effect on shoreline erosion problems. There may
be occasions when overboard disposal of silty spoil can be used to
create maxsh however this will probably also entail the planting or
seeding of marsh vegetation under closely controlled conditions.

RATIONALE: Silty soils tend to stay in the water column longer than the
heavier sands and may drift.to other areas causing damage to bottom organisms
outside of the selected spoil area. Pollutants may likewise drift with the
currents. In some cases, good quality sand can be beneficial in nourishing
starved or eroding beaches and this possibility should be considered.

6. Fill material, whether on wetlands or nearby fastlands, should not
contain contaminants -which may leach into adjacent waters.

RATIONALE: Oil or other contaminants can leach off of the surface of
filled areas and travel to adjacent waters via surface runoff. In some instances,
they may also leach downward into the water table. In either case, water
,quality is impaired.

7. Dredging in or hear wetlands for the single purpose of obtaining land
fill is usually not justified.

RATIONALE: The potential adverse effects of dredging, all of which are
not precisely known, do not warrant the risk when upland fill can serve the
purpose. Dredging destroys, at least temporarily, organisms which are directly
useful to man (shellfish) and other organisms, both plant and animal, which
are part of the aquatic food web. The increased water depth after the dredging
will eventually lead to a change'in the existing biota, the effects of which
are not well known.

8. Where feasible, dredging in fresh and near-fresh waters should be

restricted to the months of November through mid-March. In brackish
and saline waters capable of sustaining oysters and clams, the better
months for dredging are mid-March through June and in October and Novem-
ber. Where commerciai dredging for crabs in deeper waters is an import-
ant factor, the better months for dredging are from April through November.

RATIONALE: These times for dredging lessen the possibility of inter-
fering with important commercial fisheries. They avoid the periods of greatest
vulnerability such as times of finfish spawning and migration, shellfish spawn-
ing and extremely cold periods when shellfish.pumping activity is reduced by
cold water temperatures.

C. Sediment Control.

1. Dredging of new channels into marshes or fastlands should be done
"in the dry" if possible; that is, al-1 excavating should be completed
prior to connecting the new channel to an existing waterway. In
existing waterways, sediment curtains should contain the area of
dredging activity if practical.

RATIONALE: Dredging often suspends sediments which drift to other areas
and threaten marine bottom organisms. The suggested procedures either reduce
sediment problems or confine them to a localized area.

2. For relatively small projects (1000 yards or less), dredging by
dragline is usually environmentally preferable to dredging by
the hydraulic method.

RATIONALE: Control of sedimentation is much simpler with the dragline
in that there is a higher ratio of soil to water as the spoil is transferred
from the dredging area. Spoil areas created by dragline dredging can also be
treated and vegetated more quickly than those resulting from hydraulic dredging.
There are times, however, when hydraulic dredging is preferred, particularly.
when spoil is to be placed in an area remote from the dredge site.

3. Dredge spoil disposal areas should meet the criteria contained in
Appendix 4 (pg. 81), VIMS SRAMSCE No.; 35@ Local Management of
Wetlands - Environmental Considerations.

RATIONALE: The material contained in SRAMSOE No. 35 are in use in other
areas and are proving effective in protecting water quality by reducing sediment
loads to waters adjacent to spoil areas.

D. Channel-ling into fastlands or marshes.

1. Where feasible, community piers and launching facilities are
preferable to channelling.into fastlands or marshes for water
access in conjunction with urban development.

RATIONALE: Studies have shown that such channelling leads to water quality
problems CB_e@@_ada and Partington, 1972; Trent et al., 1972). @oor water circulat-
ion and flushing, combined with contaminating constituents and high nutrient
loads from adjacent development often lead to reduced dissolved oxygen levels,
noxious odors, uncontrolled algal growth and fish kills.

2. Even though VIMS strongly objects to the practice, there may be
times when canals through marshes or uplands axe permitted. When
this is the case, the following criteria should be hpplied:

a. Channels should not be dead-ended but should be connected
to a fastland drainage source vhich'will allow a flow-
through of water.

b. Channels should be short in length and preferably no longer
than twice the width.

c. Channels should not be dredged more than 1 foot deeper than
the depth of the waterway to which they are to be connected.

d. Channels should not be box cut but should be dredged with
slopes that approximate the natural angle of repose of
soils of the area, usually on the order of 3 feet horizontal
for every 1 foot vertical.

e. The top banks of channels should be graded to a slight incline
anywhere between mean sea level and mean high tide for an
inland distance of at least 10 feet. This area should then
be planted with marsh vegetation appropriate to the soils
and the salinity of waters in the area.

RATIONAIE: The foregoing criteria reduce the potential adverse impacts
of channelization by providing for better water circulation and bank stability.
The marsh vegetation aids in preventing upland spoils and contaminants from
lowering water quality.

SECTION VI

WETLANDS RESEARCH

In order to more completely understand the function of a wetland
system, researchers at VIMS are involved in wetland studies that in-
corporate the sciences of geological oceanography, chemistry and marine biology.
The staff of the Wetlands Reseaxch Section is grateful for the input from
our colleagues whose wide ranging expertise has enlarged our knowledge of
wetland dynamics and other related problems. The following sections discuss
marsh research and related studies completed or.currently in progress. Many
of these projects are applicable to wetland management problems.

A. Geology of Wetlands and Shoreline Processes.

1. Tidal Creek Flow and Suspended Solid Transport. Given the
twice-daily flooding of marshes during spring tide conditions, coupled with
average tidal periods, a-large amount of water and energy is provided to
transport materials to and from the interior of marsh systems. It appears
that much of this exchange is localized within small channel networks.
Studies of a marsh drainage system on the Eastern Shore of Virginia indicate
that a definite irregularity in the rate of flow prevails during a complete
tidal cycle. This asymmetry appears to result in a net movement of suspended
material exported from the marshes over many tidal cycles (Boon, in press).
Seasonal effects have been observed in the system under study. These
,include a positive correlation between water temperatures and suspended sediment
load levels and a seasona3-ly related distribution of water volume magnitudes
(tidal prisms) entering the marsh.
Levels of suspended sediment concentration are low in winter and high in
the summer months. There is also a variation in tidal prism magnitudes, i.e.,
lower during January and February and higher during September and October.
It can be concluded therefore that active transport capacity of the marsh
drainage system is enhanced during the late summer and early fall and diminish-
ed during the winter months. This pattern should be of interest to workers
studying marsh transport processes and to those contemplating major excavation
and/or fill projects adjacent to marshes.

2. Shore erosion in Tidewater Virginia. In this study, maps of the
1850 period re compared with the series of the 1940's with respect to
shoreline position. The approximately 3,000-miles of shoreline were divided
into about 1,750 segments for which erosion rates were calculated. The re-
sults indicate that over 20,000 acres of land have been eroded in the 100 year
period of which 12,500 acres of that loss occurred on the shore of Chesapeake
Bay proper. The report will be available for distribution in'summer of 1974.

3. County Shoreline Situation Reports. The importance of comprehensive
planning in the utilization of the resources of the coastal zone is gaining
increased recognition throughout the Commonwealth. One central facet of such
considerations is the characteristics of the shoreline, a limited resource.

Although planners frequently have a generalized idea of the importance of
coastal,processes much of the relevant information is generally not avail-
able in useful form.
Our goal is to supply the assessment, and at least a partial integration,
of those important shoreline parameters and characteristics-which will aid
the planners and managers. We have given particular attention to shore erosion
and approaches to correction. In addition we include uses-of the shoreline,
particularly with respect to recreational use since such information could
influence the perception of the coast by potential users. Those characterist-
ics included in the report are: shoreline physiographic use and ownership,
classification, zoning, water quality, shore erosion, existing defenses and
recommendations, potential shore uses, distribution of marshes, flood hazard
levels, and shellfish leases and public grounds.
Reports will be prepared for each Tidewater county within the next two
years.

4. Ocean Shoreline Studies. Recent VIMS studies indicate very high erosion
rates on the barrier islands of the Eastern Shore. Although the erosion rates
along the Virginia Beach-Sandbridge segment are smaller, dramatic shore manage-
ment problem exist in the maintenance of the beach to satisf@j recreational
demands.
Wave refraction studies are underway which will specify where areas
of wave energy concentration exist along the shoreline. This information
has direct bearing on the planning of coastal defenses.

B. Chemistry of Wetlands.

1. Function of Marshes in Reducing Eutrophication of Estuaries of
Virginia. Marshes function in a variety of ways in the estuarine
systems. Some of these are buffering erosion, flood control and providing
wildlife habita't. A more significant value, however, is their,potential to
provide organic matter in the form of detritus and their contributions to t4e
estuarine nutrient budgets. This study involves the relationships between
marsh productivity, detritus flux and nutrient flux of two wetland systems, a
medium salinity marsh (Caxter Creek, Gloucester County) and a low salinity
marsh (Ware Creek, James City County).
Primary Production
This phase of the study was carried out in order to determine the
annual productivity of two Virginia marshes, each in a differ-ejjt salinity
regime, and to attempt to correlate the production with the following
substratum nutrients: nitrogen, phosphorus, calcium, magnesium, potassium,
pH and soil solution itself.
It was found that there were no significant correlations between pro-
duction and soil nutrient concentrations in the marshes with the exception
of a significant positive correlation between potassium and plant production
in Ware Creek Marsh. Thestudy also revealed that low salinity marshes tend
to be more productive than high salinity marshes in Virginia.

Detritus Flux
Carter Creek and Ware Creek had different growing seasons. Ware

Creek, trending toward a freshwater system, began its growing season in
early March with its peak of biological activity in July. By September,
it was again at March levels. Carter Creek, the more saline system, began
its growing season in May, peaked in August and did not decline until October.
Flux calculations indicated a net export throughout the year of "living
material" from both marshes. Therefore, marshes apparently contribute both
autotrcphic (algae) and heterotrophic organisms (bacteria, copepods, ainphipods)
to the river. Much of this material probably consists of microorganisms assoc-
iated with the particulate matter in the water. Also particulate organic
carbon and dissolved organic carbon were found to exhibit net losses from both
marshes during the late summer and fall periods.

Nutrient Flux
The high productivity of estuaries is largely dependent on the amount of
nutrients in the water. Nitrogen and phosphorus, the two nutrients considered
as 11mitirg the Drimary PrOdUetiVity capability of es@uarins, are preren+
largely in their inorganic forms, nitrate and phosphate.
This phase of the study has shown that nutrient rich marsh sediments
help maintain high phosphate concentrations in the estuary.
InfoxTaation gained from this study also suggests that there is a significant
amount of atmospheric nitrogen fixation by marsh plants that is exported frcm
the marshes as nitrate. Nitrogen, in the form of ammonia and dissolved organic
nitrogen, is also received by the estuary from marshes.
The saltmarsh ecosystem thus influences estuarine primary productivity
by converting estuarine produced particulate organic nitrogen and phosphorus
and exporting these nutrients in a dissolved form that can be assimilated by
algae, one of the essential producers in the marine food web.

C. Biology of Marshes.

, 1. Effects of Oil Contamination on Marsh Biota. This project is
designed to study the effects of chronic oil pollution on the fringing salt-
marshes typical of Viriginia wetlands. During the two year course of data
acquisition, parameters of biomass, productivity and community structure are
being monitored in order to indicate both obvious and more subtle changes in
the energetics of the stressed saltmarsh. Field work is presently underway
and laboratory studies are scheduled to begin in the. spring, The ultimate
goal is to provide a basis for predicting the effects of facilities such as
refineries and oil ports on Virginia's wetlands.

2. Marsh Grass Seed Germination and Seedling Success. The 'purpose
of this study is to determine seed germination and seedling development potential
from marsh grasses collected from Virginia's wetlands which can lead to eventual
creation or reconstruction of wetlands.
Marsh grass seeds have been harvested from marshes of three distinct
salinity regimes in the lower Chesapeake Bay.
.Seeds from each of the various salinity regime marshes will be grown
under controlled conditions in order to determine optimal germination and
seedling success for each regime. Further experiments will determine the
effects of salinity and substrate composition on germination and seedling
growth.

.In order to increase our knowledge concerning the use of marsh grasses
as a deterrent to erosion, a study will be conducted ccmparing annual root
and-rhizome production in varying salinities and substrate types.
Seed germination and seedling success in perturbed systems will be
studied as a part of this project-. Using petroleum fractions, fertilizers
and sewage materials as stressors, the germination success of various species
of grass will be investigated. The goal is to indicate some of the effects
of various types of chronic pollution frequently associated with marshes in
Tidewater Virginia.
Phase II of this project will involve the raising of marsh grass in
the greenhouse and the eventual transplanting of these to areas suitable
for the establishment of marshes. Knowledge will be gained concerning es-
tablislunent success and erosion deterrent potential.
3. Community Structure of Freshwater Marshes. The tidal freshwater
marshes of the Pamunkey and the Mattaponi rivers represent one of the most
extensive ecosystems of this type on the eastern seaboard of the United States.
Here may be found as many as 59 different species of flowering plants in
less than one acre. Largely because of the complexity of their vegetation
and inhospitable conditions, the.ecology of freshwater marshes is little
known. In order to inventory and manage these marshes, it is necessary to
systematically define the community types found there.
The Sweet Hall Marsh on the Pamunkey River will be the site for this
study. This project is in its initial stages and will involve standard
ecological methods of sampling and data gathering.
4. Growth Habits and Distribution of Reed Grass (Phramites australis)-

P. australis is considered to be a desirable species in the marshes of
England and Europe. In these environs, it provides a habitat for many
marsh animals including the marsh hawk.
In the freshwater marshes of the Paumunkey and Mattaponi rivers, how-
ever, it is deemed to be a pest as it competes with more desirable grasses
such as wild rice (Zizania aquatica) and big cordgrass (Spartina cnosuroides).
Reed grass frequently invades disturbed areas of a marsh, and often grows
on dredge spoil. It seems particularly successful on sandy dredge spoil and
because of its extensive network of roots and rhizomes, may be useful as a
deterrent to erosion in this situation.
This study will attempt to determine the,biological aspects of this
grass that affect the ecology of marshes, particularly its role
as a.pioneer species in secondary marsh succession.

D. Other Research

Remote Sensinr, Techingues: Textural Signatures for Wetlands Vegetation.
The interpretation of remotely sensed data requires a significant
amount of ground truth data. This is particularly complicated in the case
of freshwater marsh vegetation where the plant communities are relatively
complex and the terrain is inhospitable. Textural features can help provide
the ground truth information necessary to accomplish vegetational mapping
of marshes and can reduce the amount of ground truth data that must be
gathered by traversing a marsh on foot. Texture is defined az the film

density variations that are influenced by factors such as position of leaves,
type of s"tock and position of individual plants with respect to each other
and with respect to their background.
This project, a cooperative effort of NASA/Langley and VINO, was under-
taken with the ultimate aim of providing 7IM3 and similar organizations with
anaother tool to aid in the task of defining the ecological significance of
any wetland area.

Additional Research Needs

A. Shoreline Erosion Problems

Fringing marshes, especially those supporting Saltmarsh Cordgrass
communities and other marsh grass, are known to deter erosion. However,
questions still remain concerning the minimum width of marsh necessary to
effectively buffer erosion.
Other factors, besides width, which need to be studied with respect
to buffering capability are peat depth, nature of substratum and the effects
of boat wakes.
Heavy boat traffic in marshlands and rivers usually accelerates
the erosion rate of marsh edges. This is particularly true in freshwater
marshes where the soft mud substratum and the less resilient cover vegetation
is present. Studies are needed to determine if erosion can be abated in these
areas by replacing the normal soft stemmed, broadleaved vegetation, with more
erosion resistent grasses, sedges and rushes.
Research is also neededto determine alternatives to present shore-
line stablizing structures and construction practices. Questions should be
answered concerning the effectiveness of integrated control of erosion employ-
ing native vegetation and gabions. Other research is needed to.explore the
compatability of vertical bulkheads and natural fringing marshes.

B. Effects of Channelization through Marsh and Uplands.

As more people seek waterfront homes, Venetian type housing develop-
ments and canals have become more prevalent. Complexes such as these have a
deleterious effect on the receiving waters and marshes if they are not care-
fully planned. Some of the direct -problems that researchers need to address
themselves to are what are the effects on water quality of 1) the various
channel depths employed 2) the normal pollutant runoff from canal-side
residences 3) the septic tanks used by canal-side homes 4) various bank
stablizing measures 5) canal length and design 6) various degrees of sediment
control employed.

C. Marsh Creeks-as Fish Spawning and Nursery Area.

In order to more adequately evaluate tidal marsh systems in Virginia,
there is a definite need for an inventory of fish spawning and nursery grounds.
Much of this information, such as species and numbers, is available from the
Icthyology Department at VIMS.
However several needs are still outstanding that would be helpful in

45.

our marsh evaluation program, such as (1) the frequency that spawning and nurse-
ry grounds are associated with marshes (2) correlation of fish species and
numbers with marsh types (3) periodic-sampling (4) and ratio of water area
to marsh area.

D. Marsh Succession.

Marshes are dynamic ecosystems. Wetlands undergo a constant process
of erosion and accretion. Some marsh expansion in tidewater Virginia has
been noted in a series of aerial photographs ranging in years from 1937
to 1971. A study is neededto determine the nature and effect of this type
of recent marsh development.
Problems to be investigated would be (1) serial marsh succession
(2) comparison of developing marshes in various stages of succession (3) phys-
ical processes involved in marsh formation (4) peat depth and age determination
(5) nature of substratum.

Wetlands Inventory

As set forth in the Wetlands Act of 1972, the Virginia Institute of
Marine Science is obligated to inventory the wetlands of tidewater Virginia
in order to better access this resource. This program is planned as a series
of marsh inventory reports of tidewater counties and cities. Two county
reports, Lancaster and Mathews, have been published. The city of Hampton
and York County and town of Poquoson inventory reports are scheduled to be
published by August 1974. In these reports, individual marshes of 1/4 acre
in size-or larger are located and numbered in sequence on maps. Information
such as individual marsh acreage, marsh vegetation percentage and acreage,
and other information are recorded in tabular form. The reports are arranged
primarily according to natural wetland systems organized into sections.
Northumberland, Westmoreland, King George and Stafford counties are
scheduled to be inventoried during the summer and fall of 1974 if present staff
personnel are utilized. If funds are available for additional staff in the
inventory program, several other counties can be inventoried during this time.

GLOSSARY

ALGAE - Simple marine or freshwater phytosynthetic
plants. May be single or multicelled.

AUTOTROPHIC - (organism). Independent of outside sources of
organic substances required for growth. Generally
refers to green plants.

BEYMIC - Pertaining to any plant or animal living in or on
the bottom sediment of a river, ocean, lake or
other aquatic system".

BRACKISH - Pertaining to the waters of bays and estuaries,
salty but of lower salinity than seawater.

BULKHEAD - A structure or partition, usually running paral-
lel to the shoreline, for the purpose of protecting
fastlands, frorn wave action or protecting channels
from upland sedimentation.

COMMUNITY Ecological term for any naturally occurring group
of different organisms inhabiting a common environ-
ment, interfacing with each other especially through
food relationships, and relatively independent of
other groups. Communities may vary in size and
larger communities may contain smaller ones.

DETRITUS Organic matter (primarily marshplants) which
while decaying in the aquatic system forms
the basis of a major marine food web. The organic
matter and its rich growth of microbes are fed
on by many estuarine species.

DOMINANT - For purposes of classifying marshes in this report,'
any organism which makes up at least 50% by volume
of the organisms present in a given area.

DRAGLINE - The method of dredging employing a crane and
large metal bucket to remove accumulated sed-
iment.

DREDGING -"IN THE DRY"- A technique of dredging used where
new channels or canals are being cut. The canal
is dredged from the landward end toward the sea-
ward end and the last step is to open the new
canal to the existing waterway.

DIKE A wall or mound built around a low-lying area
to prevent flooding. Scmetimes called a bern.

ECOIDGY The overall relationships between organisms
and their environment.

ECOTONE The transition area between two adjacent
communities.

EUTROPHICATION The natural process whereby nutrients increase
in concentration in rivers, estuaries-and other
bodies of water. Man's influence has the effect
of speeding up the natural process and causing
problems in many cases.

FASTLANDS, The zone extending from the landward limits of
wetlands to at least 400 feet inland.

FRESH WATER - Waters containing no appreciable salt, usually
less than 0-051o or 0.5 parts per thousand. -

FOOD WEB - The complex interactions of organisms in a natural
community involving organisms feeding on one
another-to obtain energy.

GABION A container filled with stone, brick, shells
or other material to give it a heavy weight
suitable for use in constructing bulkheads or
groins. In the marine environment, usually
made of galvanized steel wire mesh with a FVC
(polyvinyl chloride) coating over the gal-
vanizing.

GROIN A shore protection structure built (usually
perpendicular to the shoreline) to trap sand
and other material moving along the shoreline
and thus retard erosion of the shore.

HETEROGENEOUS - Being composed of many different.forms of
something. Specifically, a heterogeneous
marsh is one composed of marGr different plant species
without any one being dominant.

HYDROLOGICAL - Pertaining to- water, its properties and distri-
bution especially with reference to water on
the surface of the land, in the soil and under-
lying rock.

INTERTIDAL Area on a shoreline between mean high water and
mean low water.

JETTY On open seacoasts, a structure extending into
a body of water designed to prevent shoaling
of a ch=el by sand or other materials.
Usually placed alongside channels at entrances.

LINE OF SALTBUSHES Refers to the characteristic growth of saltbushes.
at the upper limit of the highest high tides.
When present in a line along the inland side
of a marsh it often denotes the upper limits of
wetlands as defined in the Virginia Wetlands
Act.

LITTORAL PROCESSES - Those physical features and characteristics of
the intertidal. axea which determine the type of
shoreline present.

MICROCOSM - A small community regarded as having all the
characteristics of the biosphere or the world.

MONOSPECIFIC - Being composed entirely of one species or one
type of organism. Iii this case a marsh vege-
tated by one type of grass.

MEAN HIGH WATER - The average height of high waters over a nineteen
year period.

MEAN LOW WATER - The average height of low waters over a nineteen
year period.

NITROGEN FIXATION - Conversion of atmospheric nitrogen into
nitrogen compounds which can be more readily
utilized by living organism$.

PERENNIAL - A plant which produces new growth year after
year according to the seasons. In the case of
nonwoody plants the aerial portion dies each
winter and is replaced each spring.

PHYSIOGRAPHIC A description of nature or natural phenomena in
general.

POPULATION All of the members of one species within a
community.

PRODUCTIVITY The rate of energy storage of an.ecosystem or
community in the form of organic substances
which can be used as food materials.

RHIZOMES Underground stems capable of producing new
aerial shoots.

RIPRAP Refers to a bulkhead or groin constructed of
,selected rock or concrete forms carefully
placed so as to dissipate wave energy (bulk-
head) or collect sand (groin) along a shoreline.

SHORE DEFENSE
STRUCTURES A bulkhead or groin intended to deter erosion
of the shoreline.

SPECIATION Pertaining to the numbers of different species
inhabiting a given area, i.e. high speciation
would mean many different species in one area.,

SPOIL -The material rEmoved from a channel bottom or
other body of water during a dredging operation.

SPRING TIDES -Higher hightides which occur twice monthly
due to astronomical conditions.

WRACK LIM A line of debris., above the mean high tide line,
which has been deposited by previous higher
than normal tides.

Literature Cited

Athearn, W.D., G.L. Anderson, R.J. Byrne, C.H. Hobbs III and J.M.
Ziegler, Shoreline Situation Report Northanpton County, Virginia
Institute of Marine Science, Gloucester Point, Virginia, in press.

Axelrad, D.M., M.E. Bender, K.A. Moore and I. Mendelssohn, Function
of Marshes in Reducing Eutrophication of Estuaries of the Middle
Atlantic Region Virginia Institute of Marine Science, Gloucester
Point, Virginia, 1974.

Barada, W. and W.M. Partington, Report of Investigation of the
Environmental Effects of Private Waterfront Canals,Environmental
Information Center, Florida Conservation Foundation, Inc. Winter
Park, Florida, 1972.

Boon, John, Sediment Trans-port Processes in a Saltmarsh Drainage
System Ph.D. dissertation, College of William and Mary, Williams-
burg, Virginia, 1974.

Boon, John, Tidal Discharge Symmetry in a Saltmarsh Drainage System,
Limnology and oceanography (in press).

Burke, Roy III, A Survey of Available Information Describing Expected
Constituents in Urban Surface Runoff; with Special Emphasis on
Gainesville, Florida. Dept. of Environmental Engineering, Univ.
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Clayton, W.D., The Correct Name for the Common Reed, Taxon 17:168-169,
1968.

Code of Virginia, 62.1.

Constitution of Virginia, Article XI.

Fassett, Norman C., A Manual of Aquatic Plants The University of
Wisconsin Press, Milwaukee, Wisconsin, 1957.

Gosselink, James G.j E. P. Odum and R. M. Pope, The Value of the Tidal
Marsh Marine Science Department, Louisiana State University,
Baton Rouge, La., 1973.

Leopold, L.B., 1jydrology for Urban Land Planning - A Guidebook on the
HVdrologic Effects of Urban Land Use. U.S. Geological Survey
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Marcellus, K.L., Coastal Wetlands of Virginia - Interim Report No. 2
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Marcellus, K.L., G.M. Dawes and G.M. Silberhorn, Local Management of
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Mendelssohn, Irving A., Angiosperm Production of Three Virginia
Maxshes in Various Salinity and Soil Nutrient Regimes, M.S.
Thesis, Virginia Institute of Marine Science, Gloucester Point,
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Odom, James E., Chairman, Mathews County Wetlands Board, Mathews
County, Virginia, personal communication, 1973.

Pomeroy, L.R., R.J. Reimold, L.R. Sheuton and R.D.H. Jones, Nutrient
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Redfield, A.C. Development of a New England Salt Marsh Ecological
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Tidal Wetlands of Virginia, 1955-1269, MS Thesis, Virginia Polytechnic
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Sweet, D.C., The Economic and Social Importance of Estuaries U.S.
Environmental Protection Agency, Water quality Office, Washington,
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Trent, W.L., E.J. Pullen and D. Moore, Waterfront Housing Developments:
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Valiela, I., J.M.Teal and W. Sass, Nutrient Retention in Salt Marsh Plots
Experimentally Fertilized with Sewage Sludge Estuarine and Coastal
.Marine Science, 1973.

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DATE DUE

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