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



                                                        FY 1992 FINAL PRODUCT Task 9
                                                                Permit Compliance & Inspection





                                        Wetlands Guidelines









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                                                     VIRGINIA

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                                                           . I I . . . . . . . .



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                                                         Prepared by

                                             The Department of Wetlands Ecology
                                              Virginia Institute of Marine Science
                                                 College of William and Mary

                                                             and

                                              The Habitat Management Division
                                            Virginia Marine Resources Commission


                                   Developed Pursuant to Chapter 13 of Title 28.2, Code of Virginia



                                                    Reprinted September 1993











































                                      "This reprint was funded, in part, by the Virginia Council on the
                                      Environment's Coastal Resources Management Program through
                                      Grant #NA270ZO312-01 of the Natio'nal Oceanic and Atmospheric
                                      Administration, Office of Ocean and Coastal Resource Management,
                                      under the Coastal Zone Management Act of 1972 as amended."




                                                      Printed on recycled paper.@






                                                                                                Wetlands Guidelines



                                    Table of Contents


                                    Section I      Introduction     . . . . . . . . . . . . . . . . . . . . . . .       1

                                    Section II     Wetlands Types and Properties            . . . . . . . . . . . .     3

                                          Type I          Saltmarsh Cordgrass Community              . . . . . . . .    7

                                          Type II         Saltmeadow Community            . . . . . . . . . . . . .     9

                                          Type III        Black Needlerush Community             . . . . . . . . . .   11

                                          Type IV         Saltbush Community          . . . . . . . . . . . . . . .    13

                                          Type V          Big Cordgrass Community           . . . . . . . . . . . .    15

                                          Type VI         Cattail Community        . . . . . . . . . . . . . . . .     17

                                          Type VII        Arrow Arum-Pickerel Weed Community                . . . . .  19

                                          Type VIII       Reed Grass Community          . . . . . . . . . . . . . .    21

                                          Type IX         Yellow Pond Lily Community          . . . . . . . . . . .    23

                                          Type X          Saltwort Community          . . . . . . . . . . . . . . .    25

                                          Type XI         Freshwater Mixed Community              ..........           27

                                          Type XII        Brackish Water Mixed Community              ........         29

                                          Type XIII       Intertidal Beach Community            ...........            31

                                          Type XIV        Sand Flat Community         ...............                  32

                                          Type XV         Sand/Mud Mixed Flat Community               ........         33

                                          Type XVI        Mud Flat Community          ...............                  34

                                          Type XVII       Intertidal Oyster Reef Community            ........         35

                                    Section III Evaluation of Wetlands Types              . . . . . . . . . . . . .    37

                                    Section IV . Criteria for Evaluating Alterations of Wetlands              . . . .  41

                                    Section V      Wetlands Mitigation-Compensation Policy                 ......      63

                                    Glossary      ................................                                     69






                                Wetlands Guidelines






                                                                             Wetlands Guidelines



                           Section I


                                 Introduction


                                 Virginia's coastal zone is composed of many different but highly
                                 interrelated ecological systems. Below the low tide limits are
                                 found the vast areas of submerged bottomland which are vitally
                                 important as fish and shellfish feeding, spawning and nursery
                                 habitat. These areas not only help support Virginia's highly valu-
                                 able commercial catch but also the myriad of species which the
                                 average Virginian never directly encounters but nevertheless
                                 are as important ecologically as the commercially sought organ-
                                 isms.


                                 Between the high water line and the low water line are found
                                 the nonvegetated intertidal flats and beaches. These areas,
                                 though uncovered and seemingly devoid of life during a portion
                                 of each tidal.cycle, provide important habitat for a host of differ-
                                 ent marine organisms, aquatic birds and many mammals.

                                 Beginning approximately at the elevation we call mean sea level
                                 are found the various vegetated communities known as
                                 marshes. Best known for their high plant production on the or-
                                 der of tons per acre per year, marshes have other valuable func-
                                 tions. They are a buffer between the estuary and the upland;
                                 interacting with both.

                                 With the passage of House Bill 400, which adds nonvegetated in-
                                 tertidal areas to the existing wetlands protection mechanism,
                                 the General Assembly has not only recognized the value of inter-
                                 tidal flats and beaches to the Commonwealth but also the inter-
                                 related and interdependent nature of the vegetated and
                                 nonvegetated wetlands systems. All wetland resources of the
                                 Commonwealth will now be managed under a single, unified pro-
                                 gram. Moving landward from mean low water (the Marine Re-
                                 sources Commission controls the bottomland seaward of mean
                                 low water) wetland jurisdiction now extends to mean high water
                                 where no emergent vegetation exists, and to 1.5 times the mean
                                 tide range where marsh is present. All intertidal areas are now






                                   Wetlands Guidelines



                                        called wetlands and can be managed holistically under a single
                                        permit system.

                                        The purpose of this document is to revise the existing Wetlands
                                        Guidelines, which deal only with marshes, to include beaches,
                                        tidal flats and subaqueous lands as well. Although scientific re-
                                        search has yet to clearly define and quantify all aspects of wet-
                                        lands function and importance within the estuary, there are few
                                        in, the scientific community who would argue that these areas
                                        are not highly significant systems whose conservation is very im-
                                        portant to the Commonwealth. The policy stated by the legisla-
                                        ture when it passed the vegetated wetlands act in 1972 is as
                                        relevant today as it was then:

                                          "Therefore, in order to protect the public interest, promote the
                                          public health, safety and the economic and general welfare of
                                          the Commonwealth, and to protect public and private prop-
                                          erty, wildlife, marine fisheries and the natural enVironment,
                                          it is declared to be the public policy of this Commonwealth to
                                          preserve the wetlands, and to prevent their despoliation and
                                          destruction and to accommodate necessary economic develop-
                                          ment in a manner congistent with wetlands preservation."

                                        In the pages that follow, the value of the wetlands to the Com-
                                        monwealth and its citizens is described. This is followed by a
                                        brief description of each community type and then by an environ-
                                        mental value ranking system. In this section the community
                                        types are ranked relhtive to each other according to their envi-
                                        ronmental values. It should be noted that all wetlands are im-
                                        portant but where management decisions must be made
                                        rIegarding necessary economic development in wetlands, this
                                        ranking system may help in guiding development into the lesser
                                        value wetland communities.


                                        The ranking system is Olowed by the general and specific guide-
                                        lines for wetland disturbing activities. These guidelines have
                                        been expanded to cover the nonvegetated area and to deal with
                                        issues that have arisen since the adoption of the original guide-
                                        lines in 1974. it is intended that these guidelines aid wetland
                                        managers in preserving the wetlands while accommodating nec-
                                        essary economic development along Virginia's 5000 'miles of
                                        shoreline.



                                  2






                                                                             Wetlands Guidelines



                           Section II

                                Wetlands Types and Properties

                                Wetlands, as defined in Chapter 13 of Title 28.2 of the Code of
                                Virginia, fall into two major groupings: vegetated (tidal marshes
                                and swamps) and nonvegetated (intertidal flats, bars and
                                beaches). Although seldom recognized by the general public ex-
                                cept as exhibited in the desire to live on or near the water, wet-
                                lands have a variety of both tangible and intangible values
                                which place them in a position of inestimable importance to the
                                Commonwealth.


                                This section of this document first identifies the primary values
                                of the wetlands, then describes the general wetland types found
                                in "Tidewater" Virginia, and finally ranks these types relative to
                                each other in terms of these primary values.

                                Each wetland type is evaluated in accordance with five general
                                values.


                                These are:


                                A. Production and detritus availability. Marshes and tidal
                                   flats are major sites of primary production in the marine eco-
                                   system. When this plant material dies and begins to decay
                                   (detritus) it becomes the basis of a major marine food path-
                                   way. The productivity of all the major marsh community
                                   types is Well documented and ranges from one to six tons per
                                   acre per year. Generally, the lower the elevation of the
                                   marsh, the greater its contribution of detritus and the
                                   greater its value to the aquatic environment.

                                   Plant productivity on tidal flats is typically less than that of
                                   tidal marshes but higher than the bottom in deeper open
                                   water areas due to the greater supply of light and nutrients
                                   available. Plant productivity in intertidal areas is dominated
                                   by nonvascular plants (bottom-dwelling, one-celled micro-
                                   and macroalgae). Probably the most important function of
                                   the nonvegetated wetlands is that of mediating the break-



                                                                                                3






                                    Wetlands Guidelines



                                            down of detritus produced on the vegetated marshes. Tidal
                                            flats located adjace 'nt to extensive marsh areas may there-
                                            fore be more biologically valuable than more isolated tidal
                                            flats. As mediators of detrital breakdown, nonvegetated wet-
                                            lands are 6ften the sites of large, diverse invertebrate popula-
                                            tions and are often major feeding sites and spawning and
                                            nursery grounds for estuarine organisms of sport and com-
                                            mercial value to man.

                                         B. Waterfowl and Wildlife Utilization. Long before wetlands
                                            were discovered to be detritus producers and feeding areas
                                            for marine organisms, they were known as rich habitats for
                                            various mammals, marine birds and migratory waterfowl.
                                            Some wetland types are more important than others in this.
                                            regard but in many cases distinctions may not be -clear-cut. A
                                            species, for example, may appear to be dependent on vege-
                                            tated marsh for cover and breeding but; without the adjacent
                                            tidal flats may not use a certain marsh at all. Wetlands offer-
                                            ing a variety of habitats and plant types are generally the
                                            more valuable from a habitat perspective.

                                         C. Erosion Buffer. Erosion is a common problem throughout
                                            coastal Virginia and is by no means limited to ocean beaches.
                                            Vegetated wetlands do erode but by virtue of their ability to
                                            establish dense root systems, trap and accumulate sedi-
                                            ments, and baffle wave energy they are buffers against ero
                                            sion and sea level rise. Among the vegetated wetlands the
                                            freshwater communities are less effective in this regard.

                                            Nonvegetated wetlands are also effective erosion buffers al-
                                            though they function in a different manner from the
                                            marshes. For example, a broad, gently sloping sand beach is
                                            an excellent wave energy dissipator and large intertidal bars
                                            and flats serve to "trip" waves as they move shoreward thus
                                            reducing their energy before they strike the shoreline. The
                                            disruption of nearshore intertidal areas may increase wave
                                            energy striking the adjacent shoreline thus accelerating ero-
                                            sion there.


                                         D. Water Quality Control. The dense growth of some marshes
                                            acts as a filter, trapping upland sediment before it reaches


                                   4






                                                                                       Wetlands Guidelines



                                          waterways and thus protecting shellfish beds and navigation
                                          channels from siltation. Marshes can also filter out sedi-
                                          ments 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. Some marshes have been shown to act as sinks
                                          or traps for other pollutants and marsh plants take up nutri-
                                          ents deposited in marsh soils. Excess nutrient levels in an es-
                                          tuary can be a problem but the exact role of marshes in
                                          nutrient removal is not yet fully understood.

                                          Nonvegetated wetlands are also important in the cycling of
                                          nutrients in the estuary and the filter feeding organisms pre-
                                          sent, particularly on tidal flats, remove suspended solids
                                          from the water column in amounts that may significantly af-
                                          fect water clarity.

                                      E.  Flood Buffer. The peat substratum of some marshes acts as
                                          a giant sponge in receiving and releasing water. This charac-
                                          teristic is an effective buffer against coastal flooding, the ef-
                                          fectiveness of which is a function of marsh type and size. The
                                          higher elevation marshes are the more effective flood buffers.
                                          Nonvegetated wetlands, because of their intertidal location
                                          have little value in this regard.

                                      The following descriptions of wetland community types are iden-
                                      tified and presented for management purposes. The first twelve
                                      of these are the vegetated wetlands and of these the first ten are
                                      characterized by a single dominant species of emergent vegeta-
                                      tion. The term "dominant" is defined here to mean at least 50%
                                      of the vegetated surface of the marsh is covered by a single
                                      plant species. Types eleven and twelve are brackish and fresh-
                                      water marshes which have no clearly dominant species of vegeta-
                                      tion.


                                      The five types of nonvegetated wetlands described here are iden-
                                      tified mainly by physiographic position and sediment composi-
                                      tion. No attempt is made to quantitatively separate the
                                      communities by particle size dominance since this is not neces-
                                      sary for value judgements on the level described in this publica-
                                      tipn.



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                            Wetlands Guidelines




                                               SALTMARSH CORDGRASS
                                                  Spartina alterniflora


























                                                                   4
                                                            K

                                                                               A?t:4,
                                                                   7









                                          3 to 6
                                        feet high









                             6






                                                                             Wetlands Guidelines


                            Type 1. Saltmarsh Cordgrass Community


                                  Dominant vegetation: Saltmarsh cordgrass (Spartina alterni-
                                       flora Loisel).
                                  Associated vegetation: Saltmeadow hay, saltgrass, black nee-
                                       dlerush, saltwort, sea lavender, marsh elder, groundsel
                                       tree, sea oxeye.
                                  Growth habit: Stout, erect grass; long, smooth leaves, often
                                       with attached periwinkle snails; located at the waters
                                       edge. Tall form 4 to 6 feet along the water; short form 1 to
                                       2 feet at or slightly higher than MHW.
                                  Physiographic position: Ranges from mean sea level to ap-
                                       proximately mean high water.
                                  Average density: Usually 20 plants per square foot. Can
                                       range from 10 to 50 plants.
                                  Annual production and detritus availability: Average
                                       yield is about 4 tons per acre per annum; optimum growth
                                       up to 10 tons per acre. Daily tides flux nearly throughout
                                       this community. Available detritus to the marine environ-
                                       ment is optimum. This type of marsh is recognized as an
                                       important spawning and nursery ground for fish.
                                  Waterfowl and wildlife utility: Roots and rhizomes eaten by
                                       waterfowl. Stems used in muskrat lodge construction. Nest-
                                       ing material for Forsters tern, clapper rail and willet.

                                  Potential erosion buffer: Most salt marshes 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. Under-
                                       lying peat with a vast network of rhizomes and roots is
                                       very resistant to wave energy.
                                  Water quality control and flood buffer: Marshes of this
                                       type can also serve as traps for sediment that originate
                                       from upland runoff. This also includes large debris that
                                       may accumulate on the marsh surface.
                                  SU'NOIARY: Considering the many attributes of this type of
                                       marsh community, its conservation should be of highest pri-
                                       ority.





                                                                                                7






                              Wetlands Guidelines











                                    SALTMEADOW HAY

                                             or
                                SALTMEADOW CORDGRASS                    SALT GRASS
                                      Spartina patMs                  Distichlis spicata





                                a









                                                                 b



                                 b




                                                 1 to 3                             1 to 3
                                                  feet                               feet
                                                 high                               high


                             a. Flowering or fruiting head.      a. Flowering or fruiting head.
                             b. Leaves arranged in 3 or more     b. Leaves arranged in one
                               planes.                             plane.






                                                                                 Wetlands Guidelines


                             Type 11. Saltmeadow Community


                                   Dominant vegetation: Saltmeadow hay (Spartina patens (L.)
                                         Greene) Saltgrass (Distichlis spicata (L.) Greene).
                                   Associated vegetation: Saltmarsh cordgrass, black nee-
                                         dlerush, marsh elder, groundsel tree, saltwort, sea oxeye.

                                   Growth habit: Matted meadow-like stands with swirls or "cow-
                                         licks," 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.

                                   Annual production and detritus availability: Ranges from
                                         1-3 tons per acre annum. Only small amounts of dead plant
                                         material are flushed out during storms and spring tides.
                                   Waterfowl and wildlife utility: Seeds eaten by birds; pro-
                                         vides nesting area. Habitat for a snail (Melampus) impor-
                                         tant as food for birds.

                                   Potential erosion buffer: Effective erosion deterrent at
                                         higher elevations.
                                   Water quality control and flood buffer: In many cases, this
                                         community represents the oldest 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 filter sediments
                                         and waste material.

                                   SUMNURY: This system is an excellent buffer, filtering out
                                         sediments and wastes and absorbing runoff water originat-
                                         ing in the uplands. Production and detritus are less impor-
                                         tant to the marine environment than in Type I
                                         communities. Its contributions tend to favor the upland en-
                                         vironment. Its values rank somewhat below Type I but,
                                         nevertheless, a Type Il marsh should not be unnecessarily
                                         disturbed.







                                                                                                      9






                             Wetlands Guidelines





                                                     NEEDLERUSH
                                                   Juncus roemerianus







































                                                                        x









                                                        3 to 4
                                                       feet high





                             10






                                                                                     Wetlands Guidelines


                              Type III. Black Needlerush Community


                                    Dominant vegetation: Black needlerush (Juncus roemerianus
                                          Scheele.)
                                    Associated vegetation: Usually pure stands with saltmarsh
                                          cordgrass, saltgrass and saltmeadow hay near the margin.
                                    Growth habit: Dense monospecific stands; plant leafless, cylin-
                                          drical hard stems tapering to a sharp pointed tip; brown to
                                          dark green in color, 3 to 5 feet high.
                                    Physiographic position: About mean high water to some-
                                          what below spring tide limit. Seems to prefer sandy sub-
                                          stratum.
                                    Average density: 30 to 50 stems per square foot.
                                    Annual production and detritus availability: 3 to 5 tons
                                          per acre per annum, decomposes more slowly than most of
                                          the marsh grasses. Not flushed daily by tides.
                                    Waterfowl and wildlife utility: There is no evidence that wa-
                                          terfowl or wildlife 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 buffer: The dense 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 control and t1ood buffer: An effective trap for
                                          suspended sediments, but less effective than the densely
                                          matted saltmeadow community. Provides effective absorb-
                                          ent areas to buffer coastal flooding.
                                    SUMMARY: As a single monospecific community this type
                                          would support less wildlife diversity than Type I and Il. It
                                          functions well as a sediment trap and erosion deterrent but
                                          ranks lower than the preceding types. The rhizomes of
                                          black needlerush are harder and tougher than the grasses
                                          that dominate Types I and Il communities; therefore, nee-
                                          dlerush is useful as an erosion deterrent. Overall, the val-
                                          ues of this marsh type rank below Types I and 11.






                                Wetlands Guidelines













                                      MARSH ELDER                        GROUNSELTREE
                                       Iva frutescens                   Baccharis hamilifolia







                                           V
                                                                             A"", A
                                                                              ,x
                                                                                             a


                                a-                   OV




                                      3 to 10 feet high                      3 to 10 feet high


                                a. Leaves thick and fleshy.            a. Leaves alternate on stem.
                                b. Leaves opposite each other
                                  on the stem.
                                                                                   Awl


                                                                                    tx ff,
































                                12






                                                                                  Wetlands Guidelines


                             Type IV. Saltbush (Gallbush) Community


                                   Dominant vegetation: Groundsel tree, highwater bush (Bac-
                                         charis halimifolia L.), marsh elder saltwater bush (Iva
                                         frutescens L.)
                                   Associated vegetation: Saltmeadow hay, saltgrass, wax myr-
                                         tle, sea oxeye.
                                   Growth habit: Shrubs 3 to 10 feet high along the margin of
                                         the marsh and upland plant communities.
                                   Physiographic position: Lower limit is approximately the up-
                                         per limit of marsh (marsh-upland ecotone).
                                   Average density: May provide dense canopy over marsh. Indi-
                                         vidual shrub trunks usually spaced 3 to 10 feet apart.
                                   Annual production and detritus availability: Probably less
                                         than 2 tons per acre per annum. Detritus of little value.
                                   Waterfowl and wildlife utility: Provides diversity for wildlife
                                         in general and 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 some-
                                         what 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 and flood buffer: Of minor conse-
                                         quence, but does trap larger material. (See above).
                                   SUMAL4,RY: Useful as an indicator of upper limits of marshes
                                         as defined in the Wetlands Act. Values of this type rank be-
                                         low that of the preceding types. However, this community
                                         does add diversity to the marsh ecosystem.













                                                                                                      13






                              Wetlands Guidelines




                                                     BIG CORDGRA.SS
                                                    Spartina cynosuroides



















                                               T.


























                                                                    4j,













                              14






                                                                                     Wetlands Guidelines


                                Type V. Big Cordgrass Community


                                      Dominant vegetation: Big cordgrass (Spartina cynosuroides
                                           (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 extending to the upland margin. Most common
                                           in brackish or lower salinity marshes.
                                      Average density: 10 to 15 stems per square foot.
                                      Annual production and detritus availability: 3 to 6 tons
                                           per acre per annum. Detritus accessible only on spring or
                                           wind tide, 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 saltmarsh cordgrass.
                                      Waterfowl and wildlife utility: Utilized as a habitat by small
                                           animals, often used for muskrat lodges. Geese often eat its
                                           rhizomes.

                                      Potential erosion buffer: The large, coarse rhizomes and in-
                                           tertwining roots stabilize peat along marsh edges.
                                      Water quality control and flood buffer: Usually this com-
                                           munity type occupies the older parts of a marsh system
                                           where peat may be deeper increasing its capacity as a flood
                                           water assimilator. It is also useful in trapping flotsam.
                                      SUMMARY: Although the elevation occupied by this commu-
                                           nity type is similar to that of the saltmeadow community,
                                           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.












                                                                                                         15






                          Wetlands Guidelines











                            COMMON or BROAD-LEAVED NARROW-LEAVED CATTAIL
                                     CATTAIL                    Typha angustifolia
                                   Typha latifolia














                                   X:V,









                                                  j,;
                                      4@ P,
                                                               F@
                                                                A



                                        ilk

                                                   3




                                                04


                                                14







                           16






                                                                                  Wetlands Guidelines


                             Type V1. Cattail Community


                                   Dominant vegetation: Narrowleaf cattail (Typha angustifolia
                                        L.)
                                   Associated vegetation: Broadleaf cattail (Typha latifolia L.),
                                        sedges, bulrushes, arrow arum, pickerel weed, smartweed,
                                        other fresh or brackish water plants.
                                   Growth habit: Characteristie'Viener on a stick"fruiting
                                        heads, long strap-like leaves, somewhat blunted tips. 4 to 6
                                        feet tall.
                                   Physiographic position: Very wet sites, sometimes in stand-
                                        ing 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 detritus availability: 2 to 4 tons
                                        per acre. Detritus usually not readily accessible to the ma-
                                        rine environment.

                                   Waterfowl and wildlife utility: Provides habitat for certain
                                        birds; roots consumed by muskrats.
                                   Potential erosion buffer: Because of its preferred habitat and
                                        its characteristic shallow root system, Type VI is only a mi-
                                        nor buffer to erosion.

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

                                   SUNEMIARY: Because of its value as a wildlife food and habitat,
                                        its function as a sediment trap, its relatively high produc-
                                        tion and the usual soft substratum, this type of marsh com-
                                        munity should not be indiscriminately used as a
                                        development site. As far as overall value is concerned it
                                        compares with a saltmeadow marsh (Type 11).






                                                                                                      17






                             Wetlands Guidelines


















                                  PICKEREL WEED                         ARROW ARUM
                                  Pontederia cordata                  Peltandra virginica




                                               a



                                                                     a
                                           W.,





                                     N







                                                                                          b











                                    a. Blue flower head.               a. Flower head.
                                                                       b. Fruiting head.







                              18






                                                                                    Wetlands Guidelines


                              Type V11. Arrow Arum-Pickerel Weed
                              Community

                                    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 feet 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 production and detritus availability: 2 to 4 tons
                                          per acre. Detritus readily available to the marine food web
                                          because of daily tide fluxes. In the fall of the year these spe-
                                          cies decompose quite rapidly and completely except for the
                                          root stock.
                                    Waterfowl and wildlife utility: Seeds and shoots of both spe-
                                          cies are eaten by 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 community type
                                          lacks the vast network of rhizomes, roots and peat substra-
                                          tum typical of a saltmarsh cordgrass community, this
                                          marsh/water interface vegetation is often the only vegeta-
                                          tive buffer to shoreline erosion in freshwater areas. The
                                          substratum in a marsh such as this is typically often, un-
                                          stable 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 and flood buffer: Slows the flow of
                                          flood waters, causing some suspended sediment to settle
                                          out.
                                    SUAUdARY: Under natural conditions the marsh of this type is
                                          relatively stable but 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 1.


                                                                                                         19






                             Wetlands Guidelines





                                                       REED GRASS
                                                    Phragmites australis



















                                                          i@@    ol















                                               N




























                             20






                                                                              Wetlands Guidelines


                            Type V111. Reed Grass Community


                                 Dominant vegetation: Reed grass (Phragmites australis) for-
                                       merly (Phragmites communes Trinius)
                                 Associated species: 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 disturbed sites.

                                 Average density: 3 to 6 stems per square foot.
                                 Annual production and detritus availability: 4 to 6 tons
                                       per acre, detritus seldom available except in storm condi-
                                       tions.

                                 Waterfowl and wildlife utility: Little direct value to wildlife
                                       except as cover. May have a detrimental effect in that it
                                       can invade 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 dis-
                                       turbed sites, especially on spoil.
                                 Water quality control and flood buffer: Valuable as a buff-
                                       er to erosion. Potential as sediment trap and flood deter-
                                       rent appears to be minimal.
                                 SUAUdARY: This plant is a relatively recent invader in Vir-
                                       ginia but is spreading rapidly, often displacing more impor-
                                       tant marsh plants. It has little or no value to wildlife in
                                       general. Its only important value would be its function as a
                                       stabilizer on dredge spoil. This community type ranks be-
                                       low a Type III marsh, the black needlerush community.











                                                                                                21






                                                                                                        Wetlands Gpidelines






                                                                                                                                                                                        YELLOW POND LILY
                                                                                                                                                                                                   -Naphur luteum






























                                                                                                                                                                                                 7@@    .. .. .... ...

                                                                                                                                                                                                                                                                                                                           ------- ---




























                                                                                                              22






                                                                                    Wetlands Guidelines


                              Type EK. Yellow Pond Lily Community


                                    Dominant vegetation: Yellow pond lily, spatter-dock (Nuphar
                                          luteum (L. Sibthrop and Smith)
                                    Associated vegetation: Pickerel weed, arrow ar       um.
                                    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 detritus availability: To 1 ton per
                                          acre; detritus readily available but not a significant con-
                                          tributor to the food chain.

                                    Waterfowl utility: Excellent cover and attachment 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 and flood buffer: Although not a di-
                                          rect assimilator of sediments and flood 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.
                                    SUAMARY: Destruction of the community would result in a de-
                                          crease 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.











                                                                                                       23






                            Wetlands Guidelines






                                                      SALTWORT
                                                     Salicornia sp.






                                               L




















                                                   A



                                                                              61,

























                            24






                                                                               Wetlands Guidelines


                              Type X. Saltwort Community


                                   Dominant vegetation: Saltwort, glasswort (Salicornia sp.)
                                   Associated vegetation: Saltmarsh cordgrass, saltgrass, sea
                                        lavender.

                                   Growth habit: Leafless green fleshy-stemmed plant, 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 detritus availability: Less than 1/2
                                        ton per acre. Exerts very little influence on the marine en-
                                        vironment.
                                   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 char-
                                        acter 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.
                                   SLTAU4ARY: This community is not high in value. It usually oc-
                                        cupies small areas within larger more productive marshes
                                        and can be used as an indicator of higher marsh elevations.
















                                                                                                25






                            Wetlands Guidelines










                                     FRESHWATER MDCED COMMUNITY - TYPE XI
                                       (excluding upland species - pines, cedars, etc.)






















                                     Buttonbush                             Yellow Pond Lily
                                                                                Type.IX
                                     Big Cordgrass.
                                        Type V                           Arrow Arum and
                                                                           Pickerel Weed
                                           Wild Rice                         Type VII

                                              Cattail                    Smartweed and
                                             Type VI                       Waterdock

                                       Swamp Milkweed                  Sedges








                            26






                                                                          Wetlands Guidelines


                            Type XI. Freshwater Mixed Community


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

                                 Associated vegetation: Bulrushes, sedges, waterdock, smart-
                                      weeds, ferns, pickerel weed, arrow arum, wildrice 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 detritus availability: 3 to 5 tons
                                      per acre. Detritus of species such as arrow arum, pickerel
                                      weed and yellow pond lily would be available in the interti-
                                      dal zone.

                                 Waterfowl and wildlife utility: A highly valuable marsh for
                                      a broad diversity in wildlife species. Plant species such as
                                      smartweeds, waterdock, wildrice and others are prime wa-
                                      terfowl 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 pro-
                                      vided by this type of marsh is equivalent to Type VII, ar-
                                      row arum - pickerel weed community.
                                 Water quality control and flood buffer: This ranks some-
                                      what higher as a sediment trap 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 sedi-
                                      ments and flood waters.

                                 SUMIARY. Th6se 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 saltmarsh
                                      cordgrass marsh (Type I) and an arrow arum - pickerel
                                      weed (Type VII) marsh.





                                                                                          27






                            Wetlands Guidelines










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





















                                      Saltbush                          Saltmarsh Cordgrass
                                       Type IV                                Type I

                                    Big Cordgrass                    Black Needlerush
                                       Type V                             Type III

                                   SaItgrass Meadow                 Saltmarsh Bulrush
                                        Type II
                                                                  Olney Threesquare
                                         Sea Lavender












                            28






                                                                                    Wetlands Guidelines


                                Type XII. Brackish Water Mixed Community


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

                                     Associated vegetation: Saltmarsh cordgrass, saltmeadow
                                           hay, saltgrass, black needlerush, saltbushes, threesquares,
                                           big cordgrass, cattails.
                                     Growth habit: Heterogeneous mixture of plants in wet areas.
                                     Physiographic position: Extending from about mean sea
                                           level to the upland margin.
                                     Average density: Highly variable.
                                     Annual productivity and detritus availability: 3 to 4 tons
                                           per acre, detritus readily available in the intertidal zone.
                                     Waterfowl and wildlife utility: Wide diversity of vegetation
                                           provides a variety of wildlife food. Waterfowl foods are plen-
                                           tiful, such as the generous seed heads of saltmarsh bulrush.
                                     Potential erosion buffer: Shoreline erosion protection is the
                                           same as that of a Type I marsh (saltmarsh cordgrass).
                                           Most brackish water marshes are bordered by saltmarsh
                                           cordgrass.
                                     Water quality control and flood buffer: Ranks high in this
                                           category, having similar attributes as a Type 11 marsh
                                           (saltmeadow).

                                     SUMAURY: This marsh is a microcosm of all the communities
                                           found in saline waters. Brackish water marshes are known
                                           spawning and nursery grounds. This community type con-
                                           tains valuable food and habitat for a wide diversity of wild-
                                           life species. Ranks with a Type I (saltmarsh cordgrass)
                                           marsh.
















                                                                                                        29






                                      Wetlands Guidelines










                                                       DOMINANT BENTHIC SPECIES OF THE
                                                   NON-VEGETATEDNETLAND COMMUNITIES





                                                                                                              IntertidAl Oyster
                                                        Intertidal Teach                 Tidal Flat                 Reef
                                                           Community                     Community               Community

                                      SEDIMENT TYPE SAND                    SAND         SAND/MUD         MUD           SHELL


                                          DOMINANT        Amphipods     . Amphipods      Mud snails Mud snails          Oysters
                                           SPECIES         Mole crabs    Bloodworms      Soft clams Bloodworms Hard clams
                                                          Donax clams     Soft clams     Razor clams Razor clams Curved mussels
                                                                         Razor clams Spionid worms Spionid worms Arnphipods
                                                                         Sandworms Hard clams                         Mud crabs




                                           A. rso B..                                           R

                                                                    D                         G.              K
                                                                                                    Lk




                                      SPECIES      A.  Mole crab (Emer@ita talpoida)     F. Spionid worm (Polydora ligni)
                                       INDEX       B.  Haustorid amphipod                G. Donax clam (Donax variabilius)
                                                        (Parahaustorius)                 H. Mud snail (11yanassa obsoleta)
                                                   C.  Haustorid amphipod                I. Bloodworin (Glycera dibranchiata)
                                                        (Parahaustorius)                 J. Curved mussel (Isochodium recurvus)
                                                   D.  Sandworin (Nereid polycheate)     K. Razor clam (Tagelus plubeus)
                                                   E.  Soft clam (Mya arenaria)          L. Oyster (Crassostrea virginica)
                                                                                              G.R







                                      30






                                                                             Wetlands Guidelines


                             Type X111. Intertidal Beach Community


                                  Dominant species:
                                     Ocean Beach - Mole crabs, Donax clam, Haustorid amphipods
                                     Bay Beach - Haustorid amphipods, oligochaete worms, beach
                                         fleas
                                  Associated species: Ghost crabs, polychaete worms, razor
                                       clams

                                  Growth habit: Most organisms buried just below the sand sur-
                                       face. Constantly being uncovered by waves and burrowing
                                       back into sand. Most species are annuals.
                                  Average density: Highly variable, animals move up and down
                                       beach with tide level. In warmer months densities can aver
                                       age 100 to 5000 individuals/m2 . Annual production is very
                                       high.
                                  Primary production and nutrient cycling: Relatively low
                                       compared to marshes and tidal flats because of high wave
                                       energy.
                                  Habitat value: Very important foraging area for many shore-
                                       birds areas above mean high water are used as nesting
                                       sites by terns and skimmers. Fish utilize area for feeding
                                       during high tide.
                                  Erosion buffer: Beach is an ideal natural wave-energy dissipa-
                                       tor. It interacts with noarshore sand bars and dunes. Its
                                       most important ecological function to man is to buffer the
                                       effects of storm waves.

                                  SLTAUdARY: Beach systems deserve the hig   hest order of protec-
                                       tion particularly when associated with extensive dunes and
                                       nearshore sandbars.

















                                                                                               31






                                Wetlands Guidelines


                               Type XIV. Sand Flat.Community


                                     Dominant species: Sandworm, bloodworm, amphipods, soft
                                          clams, razor clams.
                                     Associated species: Other polychaete worms, hiollusks and
                                          phoronid worms.
                                     Growth habi    t: Most of the inhabitants are surface and deep
                                          burrowing species; some are permanent tube builders.
                                          Most species are annuals,or biannuals, several reproduce
                                          throughout the warm weather period. There is a fairly
                                          rapid turnover of individuals due to predation so the aver-
                                          age size of organisms is small'.
                                     Average densit@: Highly variable with polychaete worms
                                          reaching higher densities than other groups. Densities of
                                          major invertebrate. groups range from 330 to 3000 ind.   /M2

                                     Primar
                                            , y production: Annual production ranges from 100 to
                                          200 g C/n12 . This is lower than that of marshes but only
                                          slightly less than other tidal flats. The primary production
                                          of tl@is community enters the estuarine food web directly
                                          via grazing. This is more efficient than the detrital food
                                          chain where decomposition in an intermediate step. The
                                          large particle size of sand and lower percentage of organics
                                          reduces the role of this community type in nutrient recy-
                                          cling.
                                     Habitat value: Very important as nursery and feeding area for
                                          fishes and blue crabs. Important shorebird feeding area.
                                          May support high shellfish populations.
                                     Erosion buffer: Important in reducing wave energy and thus
                                          erosion potential on adjacent shorelines.
                                     SUNEWARY: Overall, the ecological value of this community
                                          rates only slightly below beaches, oyster reefs and Group I
                                          marshes.













                                32






                                                                               Wetlands Guidelines


                              Type XV. Sand/Mud Mixed Flat Community


                                   Dominant species: Hard clams, parchment worms, Spionid
                                         polychaetes, soft clams, razor clams and mud snails.
                                   Associated species: Other polychaetes, molluscs, crustaceans,
                                         acorn worms, Phoronid worms.
                                   Growth habit: This community is populated in general by
                                         many surface and deep burrowers, and permanent tube
                                         builders. Otherwise similar to sand flats.

                                   Average density: Highly variable but overall higher than sand
                                         flats or mud flats. Densities range from 5300 to 8300 indi-
                                                  2
                                         viduals/m

                                   Primary production and nutrient cycling: Primary produc-
                                         tion in this community is very similar to sand flats. Since
                                         the organic matter content of the sediments is higher than
                                         that of sand flats, secondary, microbial production may be
                                         higher and this augments the primary production. This
                                         community probably interacts with estuarine nutrient cy-
                                         cles to a greater extent than sand flats.
                                   Habitat value: This community is a very important area for
                                         wading birds, shorebirds and other other migratory water-
                                         fowl. It is heavily used by important commercial and sports
                                         fishes for feeding and is important blue crab habitat. The
                                         habitat value may increase in importance when a marsh is
                                         adjacent due to higher organic content in the sediments
                                         and the habitat variety provided by the marsh.
                                   Erosion buffer: Slows wave velocity and thus may reduce
                                         wave erosion impinging on adjacent shoreline.
                                   SUAMARY: Overall this community has very high habitat val-
                                         ues especially if associated with marshes. Ranks only
                                         slightly below beaches and intertidal oyster reefs.












                                                                                                33






                              Wetlands Guidelines


                              Type XV1. Mud Flat Community


                                   Dominant species: Spionid worms, mud snails, razor clams,
                                        bloodworms.
                                   Associated species: Other polychaetes, molluscs and crusta-
                                        ceans.

                                   Growth habit: Surface and shallow burrowing organisms pre-
                                        dominate in this community type. Some permanent tube
                                        builders may be present. Problems with sediment stability
                                        limit species to mainly surface detrital feeders.
                                   Average density: Highly variable; Generally densities are
                                        slightly lower than mixed flats but higher than sand/flats
                                        with a range of 50 to 5000 individuals/m2.
                                   Primary production and nutrient cycling: The areal extent
                                        of mud flats is probably equal to or greater than the total
                                        for marshes. Primary production is probably the highest of
                                        the nonvegetated communities. Mud flats interact signifi-
                                        cantly with adjacent vegetated areas in the cycling of nutri-
                                        ents. Where mudflats and marshes occur together they are.
                                        mutually dependent. Ecologically, each is an extension of
                                        the other.

                                   Habitat value: Highly important foraging area for waterfowl,
                                        sports and commercial fishes and Many other species of
                                        food chain value in the marine ecosystem.
                                   Erosion buffer: Since this community is generally only found
                                        in quiescent areas it has less value in this regard than
                                        sand or mixed flats.

                                   SUAUdARY: The overall ecological value of mud flats is compa-
                                        rable to sand flats and mixed flats. It is probably'most im-
                                        portant in nutrient cycling of the three.













                              34






                                                                                   Wetlands Guidelines


                                Type XVIL Intertidal Oyster Reef
                                Community


                                      Dominant species: Oysters, hard clams, sand worms, am-
                                           phipods, mud crabs.
                                      Associated species: Other polychaetes, mud snails, curved
                                           mussels, barnacles, sponges, hydroids, razor clams, other
                                           molluscs and crustaceans.
                                      Growth habit: Oyster shells provide increased diversity of
                                           habitats for a variety of estuarine species. This community
                                           is characterized by high diversity of attached and associ-
                                           ated organisms.
                                      Average density: Oysters dominate when area managed by
                                           man, Otherwise the reef is dominated by fouling organisms
                                           as listed above. Highly variable density but generally
                                           greater than other flats.
                                      Primary productivity and nutrient cycling: Very little
                                           data are available concerning the primary production of
                                           oyster reefs. Given the high habitat and animal diversity
                                           however, it is probable that primary production is at least
                                           as high as other nonvegetated communities.
                                      Habitat value: Very high; many important food chain organ-
                                           isms associated. This community is heavily utilized by blue
                                           crabs and fishes during high tides. Very high diversity and
                                           secondary productivity.
                                      Erosion buffer: Shells cemented together may be important in
                                           dissipating waves and may resist shoreline erosive forces.
                                      SUNBURY: Overall ecological value very high. This coramu-
                                           nity is an excellent habitat with high diversity.













                                                                                                     35






                             Wetlands Guidelines































































                           .  36






                                                               Wetlands Guidelines



                        Section III

                            Evaluation of Wetlands Types

                            For management purposes, th'e twelve types of vegetated wet-
                            lands (marshes) and five types of nonvegetated wetlands (tidal
                            flats and beaches) identified in Section II are grouped into five
                            classifications based on the estimated total environmental value
                            of an acre of each type. The reader is cautioned however that
                            these groupings are based on average values and case-by-case
                            analysis may yield differing results. One must also exercise re-
                            straint when comparing vegetated vs. non-vegetated communi-
                            ties.


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


                                           Nonvegetated communities
                                           Intertidal beaches (Type XIII)
                                           Intertidal oyster reef (Type XVID

                            The vegetated community types in Group One have the highest
                            values in productivity and wildlife utility and are closely associ-
                            ated with fish spawning and nursery areas. They also have high
                            values as erosion inhibitors, are important to shellfish popula-
                            tions and are important factors in nutrient cycling.

                            Intertidal beaches and sand bars have the highest relative val-
                            ues as buffers to shoreline erosion. In addition, they rank very
                            high as marine habitat and in secondary productivity. Intertidal
                            oyster reefs, which occur primarily on the seaside of the Eastern
                            Shore, have their highest values in terms of productivity, habi-
                            tat and commercial importance.

                            All of the communities in the Group One classification merit the
                            highest order of protection.



                                                                             37






                               Wetlands Guidelines



                                    Group Two;         Vegetated communities
                                                       Big cordgrass (Type V)
                                                       Saltmeadow (Type II)
                                                       Cattail (Type VI)


                                                       Nonvegetated communities
                                                       Sand/flats (Type XIV)
                                                       Sand/mud mixed flats (Type XV)
                                                       Mud/flats (Type XVI)

                                    The marshes in Group Two are only slightly less valuable than
                                    those in the Croup One classification. The major -differences be-
                                    ing the reduced availability of detritus from the Group Two
                                    marshes due to physiographic factors. The detritus produced on
                                    the Group Two marshes is more likely to accumulate in the
                                    marsh and is less available to marine organisms. Group Two
                                    marshes have high values in maintaining water quality, buffer-
                                    ing coastal flooding, and as habitat.

                                    The Group Two, nonvegetated communities have high general
                                    productivity values and play an essential role in nutrient cycling
                                    in the estuary. They are very important foraging areas for ma-
                                    rine birds and many mobile marine organisms of commercial
                                    and recreational importance. They have less value than the
                                    Group One communities from an erosion and flood buffering
                                    standpoint.

                                    Group Two wetlandscommunities rank only slightly below
                                    those of Group One in overall environmental importance. They
                                    deserve an order of protection only slightly below that of the
                                    Group One wetlands. Since there are many variables involved in
                                    any evaluation scheme, it is highly likely that some Group Two
                                    wetlands may on occasion outrank some Group One communi-
                                    ties. This may be particularly true of the nonvegetated communi-
                                    ties which exhibit a great deal more variability than the
                                    vegetated communities.








                               38






                                                                   Wetlands Guidelines



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

                              The two marshes in the Group Three category are quite dissimi-
                              lar in properties. The yellow pond lily marsh is not a significant
                              contributor to the food web but it does have high values to wild-
                              life and waterfowl. Black needlerush has a high productivity fac-
                              tor but a low detritus availability value. Black needlerush has
                              little wildlife value but it ranks high as an erosion and flood buff-
                              er. Group Three marshes are important, though their total val-
                              ues are less than Group One and Two marshes. If development
                              in wetlands is considered necessary, it would be better to alter
                              Group Three marshes than Group One or Two.

                              Group Four:    Saltbush (Type IV)

                              The salthush community is valued primarily for the diversity
                              and bird nesting habitat 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 only a
                              few values of significance. While Group Five marshes should not
                              be unreasonably disturbed, it is preferable to develop in these
                              marshes than in any of the other types.

                              The ranking system above is only a partial tool for use in rnak-
                              ing decisions to alter wetlands for it measures only one wetland
                              type against another. Other factors, involving a total view of the
                              creek or river system involved, should be considered in the deci-
                              sion making process.

                              Acreage is obviously one important factor to consider when
                              evaluating a specific wetland. A large wetland is inherently
                              more valuable than a smaller wetland of the same type. Many



                                                                                   39






                               Wetlands Guidelines



                                    creeks and rivers in Virginia however, contain vegetated and
                                    nonvegetated wetland areas which are quite small and/or frag-
                                    mented. The cumulative value of these small areas may be as
                                    great or greater than that of a single wetland of the same type
                                    and acreage.

                                    Any marsh which is   *2 feet or more in average width i's consid-
                                    ered to have significant values as an erosion deterrent and in fil-
                                    tering sediments coming from the uplands. It may also have
                                    other values depending upon the total acreage of the marsh par-
                                    cel. 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 productivity, detritus availability and wildlife habitat.
                                    Depending,on its location, it may also have value as an erosion
                                    buffer.


                                    In Virginia wetlands represent a little over 1% of the total acre-
                                    age in the state yet they play a vital role in sustaining the impor-
                                    tant commercial and recreational fisheries which millions of
                                    east coast citizens enjoy. Population and development pressures
                                    in the tidal portion of Virginia pose a subtle but constant threat
                                    to these marine resources. Habitat losses are generally counted
                                    in small portions rather than catastrophic leaps. It is very impor-
                                    tant to'note that althoughIthe large scale projects attract
                                    greater publicity, the total resource loss due to many small pro-
                                    jects may be of equal or greater importance from an environ-
                                    mental viewpoint.

                                    Because of the essential functions performed by wetlands in the
                                    marine environment and the limited extent of this resource, it is
                                    necessary to limit the activities which adversely affect wetlands
                                    to those considered highly essential. If the activity proposed can
                                    be accommodated while preserv   ing all or most of the wetlands
                                    involved, a proper balance has been struck. In cases where devel-
                                    opment and preservation are mutually exclusive the necessity of
                                    the activity must be weighed against the value of the resource
                                    involved and the degree of adverse impact the, activity will have
                                    on the wetland.








                               40






                                                                                 Wetlands Guidelines



                              Section IV

                                   Criteria for Evaluating Alterations of Wetlands

                                   The legislature established a policy "to preserve the wetlands
                                   and to prevent their despoliation and destruction and to accom-
                                   modate necessary economic development in a manner consistent
                                   with wetlands preservation". This section addresses the forego-
                                   ing policy. Many proposed uses of the shoreline can be accommo-
                                   dated with little or no loss of wetlands if the following criteria
                                   are applied. There are times, of course, when these criteria may
                                   not apply in specific cases. The conscientious application of
                                   these criteria will, however, materially reduce adverse environ-
                                   mental impacts of man's activities on the shoreline.

                                   The individual criteria contained in this section are supported
                                   by brief statements explaining the basic reasons behind adop-
                                   tion of the particular criterion. It is emphasized that these ra-
                                   tionale are of necessity very brief and do not encompass all
                                   aspects of the given subject. Persons desiring further details
                                   should contact either the Virginia Marine Resources Commis-
                                   sion, Habitat Management Division or the Virginia Institute of
                                   Marine Science, Department of Wetlands Ecology.

                                   General Criteria


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

                                       1 Gain access to navigable waters by:


                                           a.  Commercial, industrial, and recreational interests
                                               for which it has been clearly demonstrated that wa-
                                               terfront facilities are required.

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



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                               Wetland.@ Guidelines



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


                                     B. Alteration of the shoreline is ordinarily not justified:

                                       1. For purposes or activities which can be conducted on exist-
                                          ing fastlands and which have no inherent requirement for
                                          access to water resources.


                                       2. For purposes of creating waterfront property from lots and
                                          subdivisions which are not naturally contiguous to waters
                                          of navigable depth or waters which can only be made navi-
                                          gable by substantial alteration or destruction of marine.re-

                                          sources.


                                       3. When damage to properties owned by others is a likely re-
                                          sult of the proposed activity.

                                       4. When the alteration will result in discharge Qf efhuents
                                          which impair wetlands, water quality or other marine re-

                                          sources.


                                       5. When there are viable alternatives which can achieve the
                                          given purpose without adversely affecting marshes, oyster
                                          grounds or other natural resources.

                                          Rationale: These criteria recognize riparian rights and re-
                                          serve the shoreline for those uses or activities which re-
                                          quire water access. These criteria also point out that
                                          activities such as dredging into the fastlands for housing
                                          developments often have a significant and long term ad-
                                          verse impact on the marine environment through such ef-
                                          fects as changed upland hydrology, sedimentation,
                                          changes in water current patterns near the shoreline, and
                                          the introduction of pollutant discharges which frequently
                                          lead to closure of shellfish grounds. The dredging of chan-
                                          nels into fastlands may also lead to deterioration of
                                          ground water by salt water intrusion into aquifers.




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                                                                                    Wetlands Guidelines



                                    C.  Utilization of open-pile type structures for gaining access to
                                        adequate water depths is generally preferred over the con-
                                        struction of solid structure, dredging or filling.

                                        Rationale: The construction of solid structures, or the con-
                                        duct of dredging and filling operations, often causes irretriev-
                                        able loss of wetlands through their direct displacement or by
                                        indirect effects of sedimentation or altered water currents.
                                        Open-pile type structures permit continued tidal flow over ex-
                                        isting wetlands and subtidal areas, avoid potential sedimen-
                                        tation problems, future maintenance dredging, and have less
                                        effect on existing water current patterns.

                                    D.  Channels, fills and structures should be designed to with-
                                        stand the maximum stresses of the marine environment and
                                        also to minimize the frequency of future maintenance activi-
                                        ties.


                                        Rationale: Shoreline alterations o  ften change currents, af-
                                        fect shoreline stability and cause biological damage. Unsuc-
                                        cessful structures or channels generate demands for
                                        remedial action which can compound initial adverse effects.
                                        Designs which minimize the dredging frequency in channels
                                        are particularly important. Dredging destroys or displaces
                                        bottom-dwelling 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 adjacent to wet-
                                        lands and/or other flood plains is discouraged.

                                        Rationale: Development in low-lying areas and on high en-
                                        ergy coastlines has historically created costly flood control
                                        and flood relief problems including claims for indemnifica-
                                        tion. Additionally, hydrological changes in surface run-off
                                        patterns are caused by the paving over of formerly absorbent
                                        soil. The usual effect is an increase in both the amount and
                                        the rate of surface water-flow, often contributing to shoreline
                                        eros'ion and other problems. Finally, high-density develop-
                                        ment leads to a concentration of contaminating constituents



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                                 Wetlands Guidelines



                                          in urban surface water runoff which can severely stress re-
                                          ceiving waters in the adjacent marine environment. There ap-
                                          pears to be a direct relationship between population density
                                          in a watershed and increased bacterial levels in adjacent wa-
                                          ters. This may lead to the imposition of long term restric-
                                          tions on the direct marketing of shellfish.

                                       Specific Criteria

                                       The following specific criteria are established for use in the de-
                                       sign, evaluation or modification of individual projects.

                                       A. Shoreline Protection Strategies

                                          1. Shoreline protection structures are justified only if there
                                             is active, detrimental shoreline erosion which cannot be
                                             otherwise controlled; if there is rapid sedimentation ad-
                                             versely affecting marine life or impairing navigation
                                             which cannot be corrected by upland modifications; or if
                                             there is a clear and definite need to accrete beaches.


                                             Rationale: The'design and placement of shoreline protec-
                                             tion structures is, a highly technical subject and often the
                                             precise or long-term effects of such structures on littoral
                                             processes cannot be predicted. A study of one county's
                                             shoreline shows that nearly 50% of the existing.s'horeline
                                             protection systems are ineffective or poor in performance.
                                             Shoreline protection structures disrupt natural forces and
                                             drive a shoreline away from a natural equilibrium state.
                                             In short, all protective structures have the potential to ad-
                                             versely affect marine resources directly or through indi-
                                             rect means. Needless shoreline modification is therefore
                                             discouraged.


                                          2. For shorelines experiencing mild to moderate erosion, the
                                             planting of marsh grasses is a preferred means of stabiliza-
                                             tion, Note: The planting of marsh grasses is not appropri-
                                             ate on all shorelines and  requires some technical
                                             expertise. Free advice is available from the Virginia Shore-



                                  44






                                                                                   Wetlands Guidelines



                                           line Advisory Service and the Virginia Institute of Marine
                                           Science.


                                           Rationale: Fringing marshes buffer erosion through their
                                           dense root systems and ability to collect sand and sedi-
                                           ments moving along the shoreline. When a fringe marsh is
                                           established, it not only provides food and habitat for ma-
                                           rine birds and other organisms but also minimizes the ad-
                                           verse effects to adjacent shoreline properties which are
                                           often associated with other types of erosion control meas-

                                           ures.


                                       3.  When an erosion control structure, such as a bulkhead or
                                           seawall, is deemed necessary, it should ordinarily be
                                           placed landward of any existing and productive marsh
                                           vegetation. A line of saltbushes, if existing, can usually in-
                                           dicate the seaward limit of the vertical structure. Along
                                           shorelines where no marsh vegetation exists, the retaining
                                           structure should ordinarily be placed far enough landward
                                           of mean high water so as to minimize exposure to wave ac-
                                           tion.


                                           Rationale: A vertical retaining structure behind a marsh
                                           not only preserves the marsh for its biological productivity
                                           but also utilizes the marsh's capabilities of aiding water
                                           quality and deterring erosion.


                                           Placing a vertical retaining structure landward of mean
                                           high water minimizes its exposure to wave action and re-
                                           duces erosion or scour along the toe which could jeopard-
                                           ize the integrity of the structure. Landward placement
                                           also preserves intertidal bottom, maintaining habitat di-
                                           versity and associated functions of this area within the ma-
                                           rine ecosystem.

                                       4. Sloped rock or riprap revetments and gabions are gener-
                                           ally preferred over vertical structures.





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                                 Wetlands Guidelines



                                            Rationale: Vertical retaining structures tend to reflect
                                            wave energy and often transfer a problem to neighboring
                                            properties. Coastal waves, whether from natural causes or
                                            from boat wakes, are better absorbed or dissipated by
                                            riprap revetments or gabio'ns. In addition, the slope and
                                            open spaces in riprap or gabion structures may provide
                                            suitable habitat for crabs and small fish. In some cases,
                                            sediment may be trapped in riprap or gabion structures
                                            and subsequently become vegetated with marsh species.

                                         5. The placement of offshore breakwater or submerged, near-
                                            shore sills parallel to a portion of shoreline in order to at-
                                            tempt to elevate the height of a beach or dampen wave
                                            energy is generally acceptable only in areas with a good
                                            sand supply in the nearshore zone or where there is active
                                            detrimental erosion. Sill structures are usually con-
                                            structed of properly filled sandbags, gabions or mortar
                                            filled bags. Although not a general rule, the sill is usually
                                            most effective when placed at or near the mean low water
                                            line. Both breakwaters and sills must be specifically de-
                                            signed for the shoreline segment in question.

                                            Rationale: The placement of sill structures where there is
                                            an insufficient supply of sand to the beach may cause
                                            harmful effects to the shorelines of adjacent downdrift
                                            properties. Placing the sills at, or near the mean low water
                                            line will usually ensure sufficient backshore height; Place-
                                            ment of the sill structure too far offshore may result in in-
                                            sufficient filling and ultimately failure of the system. Sills.
                                            may also not be suitable for high use beaches because of
                                            the potential hazard to swimmers.

                                         6. The placement of a groin or series of groins on eroding
                                            shorelines in an effort to trap sand and build up a beach is
                                            justified only when there is sufficient sand in the littoral
                                            drift system or if properly functioning groins Already exist
                                            in the section of shoreline in question.




                                 46







                                                                                Wetlands Guidelines



                                         Rationale: Groins are designed to trap sand and build
                                         beaches. When they function properly, they necessarily de-
                                         prive downdrift shorelines of sand and thus may acceler-
                                         ate erosion to adjacent properties particularly if there is
                                         only a small amount of sand available in the system.

                                     7.  When groins are considered justified they should be low
                                         profile in design and only as long as is necessary to trap
                                         sand drifting in the littoral zone. Ideal groin length can be
                                         determined by examining the sand fillets in existing
                                         groins along the same shoreline reach or can be based on
                                         the width of the local beach.


                                         Rationale: The low profile groin is designed to resemble
                                         the natural beach slope and allow sand to by-pass and
                                         thus nourish downstream properties once the groin has
                                         filled. Groins which are too long for the existing beach
                                         may shunt sand out to deeper water thus making it un-
                                         available to downdrift properties.

                                      8. The use of jetties at the entrance of a channel in order to
                                         maintain navigable depths or protect the entrance from
                                         wave attack is justified only when there is a clear and dem-
                                         onstrated need for such a structure and adjacent proper-
                                         ties will not be significantly adversely affected.

                                         Rationale: jetties attempt to prevent the littoral drift
                                         from entering the channel by trapping sediment moving
                                         along the shoreline. Sand tends to accumulate on the up-
                                         drift side of a jetty and sediments are transported away
                                         from the jetty on the downdrift; side. This can often result
                                         in accelerated erosion of the downdrift shoreline.


                                   B. Filling and Dredged Material Disposal.

                                      1. Filling in wetlands or subaqueous areas for the singular
                                         purpose of creating waterfront upland property is gener-
                                         ally undesirable.




                                                                                                  47






                                 Wetlands Guidelines



                                            Rationale: Marine resources are finite, provide many
                                            valuable services and products and are delicately balanced
                                            in an intricate web of biological and physical interactions.
                                            Permanent loss of these resources and unnecessary altera-
                                            tions jeopardize this delicate ecological balance.

                                         2. When filling along a shoreline is necessary, the activity
                                            should be confined to the area landward of any wetlands.
                                            If suitable non-wetland areas are not available and it is
                                            necessary to locate the fill further seaward, locations in
                                            Group 3;-5 wetlands should be selected if possible (reed
                                            grass, saltwort, saltbush, black needlerush, yellow pond
                                            lily). Every reasonable effort should be made to preserve
                                            existing Group 1 and 2 wetlands communities. In nonvege-
                                            tated wetlands, fill should be contained at or above the
                                            mean high water line. in cases where some encroachment
                                            beyond mean high water is justified (e.g. where an eroding
                                            -bluff is being graded down to stop erosion), the encroach-
                                            ment,channelward of mean high water should be limited
                                            to the minimum required to achieve the desired goal.

                                            Rationale: The values of the more important wetland
                                            communities are preserved, thus somewhat-lessening the
                                            undesirable impact of destroying marshes and in the case
                                            of nonvegetated areas, minimizing encroachment con-
                                            serves these shallow areas to- function as described in Sec-
                                            tion II of this document.


                                         3. Fill material, whether on wetlands or nearby fastlands,
                                            should not contain contaminants which may leach into ad-
                                            jacent waters. Upland source material is generally prefer-
                                            able to dredged material for use as fill.


                                            Rationale: Oil or other contaminants can leach off 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 qual-
                                            ity is impaired. Most dredged material is composed of silts



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                                                                                     Wetlands Guidelines



                                           and clays which when dry and compacted do not allow the
                                           free flow of water and thus may cause hydraulic flow prob-
                                           lems behind a bulkhead.


                                       4.  Where feasible, controlled disposal of dredged material on
                                           highland property is the preferred method.

                                           Rationale: There are many difficulties inherent in control-
                                           ling dredged material in the marine environment. Marine
                                           resources are finite and subject to significant disruption
                                           from such activities since the water column can act as a
                                           vector carrying sediments well beyond the immediate dis-
                                           posal point.

                                        5. Dredged material disposal areas should meet the following
                                           criteria:


                                             a. Disposal by the bucket or dragline method:

                                                   (1) Build an earth-tight bulkhead along the perime-
                                                       ter of the disposal area sufficient to confine the
                                                       dredge spoil. The bulkhead or dike (berm)
                                                       should have a top elevation at least 3 feet above
                                                       the average upper limit of spring tides.

                                                   (2) Earthen dikes (berms) should be compacted as
                                                       they are constructed, have side slopes no
                                                       steeper than 1 horizontal to 3 vertical, a top
                                                       width of at least 3 feet, and the toe of the slope
                                                       should be at least 15 feet from existing marsh
                                                       grasses. Spillway boxes or release pipes should
                                                       be provided to prevent water from eroding or
                                                       over-topping the dike. As soon as possible after
                                                       completion of the project, the disposal area
                                                       should be graded and vegetative cover estab-
                                                       lished.








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                                 Wetlands Guidelines



                                                    (3) In some projects involving small volumes of gen-
                                                        erally sandy material, a double line of staked
                                                        straw bales may provide suitable containment.

                                               b. Disposal by hydraulic methods:

                                                    (1) Earthen dikes should be constructed by
                                                        dragline or land fill methods to the specifica-
                                                        tions as described in 3 (1) above. The volume of
                                                        the disposal area lying below the elevation of
                                                        the spillway crest should, at all times during
                                                        the dredging, be sufficient to provide a retention
                                                        time long enough to clarify the discharge water
                                                        to meet applicable water quality standards. The
                                                        spillway should be placed as far as possible
                                                        from the discharge end of dredging pipes.

                                                    (2) The dredge pipeline should have tight joints to
                                                        prevent leaks. Grading and vegetative cover
                                                        ,should be accomplished as soon as possible. (It
                                                        is recognized that hydraulically filled areas may
                                                        take many months to dry sufficiently for people
                                                        or equipment to move across them. Seeding may
                                                        have to be delayed for periods possibly as long
                                                        asa year. The spillway should therefore be
                                                        maintained until the area is permanently
                                                        seeded and vegetation is well established and
                                                        providing adequate ground cover to retain the
                                                        soil).


                                                        Rationale: Control of sedimentation is accom-
                                                        plished if the above criteria is maintained dur-
                                                        ing the entire dredging period.

                                         6.  Dredged material should not ordinarily be deposited in ad-
                                             jacent marsh as a convenience. if it becomes necessary to
                                             place spoil on a marsh, consideration should be given to
                                             placing it on those portions of lower value or to scattering
                                             the material in a thin layer rather than containing it be-


                                 50






                                                                                       Wetlands Guidelines



                                            hind a berm. Berms in marshes should be used to contain
                                            fill only when absolutely necessary and when they will not
                                            impair tidal flow to other 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 dredged material
                                            in a thin layer can sometimes maintain basic marsh val-
                                            ues though it may ultimately lead to changes in vegetative
                                            species if the marsh surface is significantly raised in eleva-
                                            tion. The depth of the soil layer must be evaluated in each

                                            case.


                                        7.  Whenever feasible, displaced marsh vegetation and peat
                                            should be used to reconstitute marsh in the vicinity of the
                                            activity site and particularly along the banks of newly cut
                                            canals. The practice of compensating for marsh loss in one
                                            area by building marsh in another is theoretically viable
                                            but because of significant technical difficulties is not al-
                                            ways recommended.

                                            Rationale: This procedure, when successful, aids in main-
                                            taining marsh inventory and will deter shoreline erosion
                                            and enhance water quality conditions.

                                        8.  When under specific case by case analysis it is determined
                                            that marsh creation is an acceptable means of compensat-
                                            ing for an unavoidable marsh loss, one marine habitat
                                            (e.g. tidal flats) should ordinarily not be sacrificed to cre-
                                            ate another (marsh). Resource compensation through
                                            marsh creation is not a panacea and should be limited to
                                            cases where the loss of existing marsh is unavoidable and
                                            significant and there is a high probability of success.

                                            Rationale: There is at present no conclusive evidence
                                            that the trading of one marine habitat for another results
                                            in a net gain for the environment. The creation of marsh
                                            from upland or other habitat is technically feasible in


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                               Wetlands Guidelines



                                          many cases. It is however a complex activity that gener-
                                          ally cannot be successfully accomplished without technical
                                          knowledge and expertise.

                                       9. Overboard disposal of dredged material is generally unde-
                                          sirable unless the deposits are basically clean sand, the
                                          disposal area is devoid of comme'rcially important bottom
                                          organisms, and the deposits will have a beneficial effect on
                                          shoreline erosion problems. There may be occasions when
                                          overboard disposal of silty spoil can be used to create
                                          marsh. This will probably also entail the planting or seed-
                                          ing of marsh vegetation under closely controlled conditions.

                                          Rationale: Silty soils tend to stay in the water column
                                          longer than the heavier sands and may therefore drift to
                                          other areas resulting in damage to bottom organisms out-
                                          side 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,

                                       10. Whenever overboard disposal is permitted, the operation
                                          should be located and conducted so as to minimize impacts
                                          on commercially important bottom dwelling (benthic) or-
                                          ganisms such as clams and oysters, submerged aquatic
                                          vegetation, and other unique or highly productive habitats.

                                          Rationale: Because water is the link which ties all differ-
                                          ent marine habitats together and can transport pollutants
                                          ,over large areas, care must be taken to localize the im-
                                          pacts of overboard disposal to the maximum extent practi-
                                          cal.


                                       11. The overboard disposal of good quality sand in order to re@-
                                          plenish beaches is generally acceptable so long. as the
                                          beach sand and dredged sand are size-compatible.

                                          Rationale: The placement of material of smaller particle
                                          size than that found on the natural beach will only serve



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                                                                                 Wetlands Guidelines



                                         to increase turbidity since it will be resuspended by wave
                                         action and carried away very quickly resulting in little
                                         benefit for the sand-starved beach.


                                  C. Dredging

                                     1.  When possible, open pile piers should be lengthened to
                                         reach necessary water depths in order to minimize the
                                         amount of dredging required.

                                         Rationale: Open pile piers have a minimal adverse im-
                                         pact on the marine environment. Dredging is a significant,
                                         though temporary, disruption which must be repeated in
                                         order to maintain water depths. Every dredging project,
                                         whether new dredging or maintenance requires an ap-
                                         proved disposal area and this can be a major problem par-
                                         ticularly in developed areas.

                                     2.  Dredging for the singular purpose of obtaining fill is ordi-
                                         narily not justified.

                                         Rationale: Although dredged areas are repopulated to a
                                         degree by organisms after cessation of dredging, they gen-
                                         erally never return to their predredge productivity levels if
                                         water depths are greatly increased. The result is a chronic
                                         degradation of habitat quality and reduction in system pro-
                                         ductivity.

                                     3.  For relatively small projects (2000 c.y. or less), dredging
                                         by dragline or bucket method is generally preferred.

                                         Rationale: Control of sedimentation is much simpler with
                                         the bucket dredge in that there is a higher ratio of soil to
                                         water as the dredged material is transferred from the
                                         dredging area. Dredged material disposal is less compli-
                                         cated and more easily subject to productive use. Hydraulic
                                         dredging is preferred for large dredging projects particu-
                                         larly when the dredged material is to be placed in an area
                                         remote from the dredged site.


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                                 Wetlands Guidelines



                                         4.  The practice of "double handling" dredged material in a
                                             waterway is generally undesirable.

                                             Rationale: This activity, which involves the interim place-
                                             ment of dredged material in the waterway effectively dou-
                                             bles the adverse effects of bottom disruption and turbidity
                                             associated with dredging activities.

                                         5.  Dredging in shellfish areas, beds of subaquatic vegetation
                                             and other areas of singularly high productivity should be
                                             avoided if possible.

                                             Rationale: These areas generally have very high values
                                             to both commercial and sport fisheries and to the organ-
                                             isms that support them. In addition their recovery period
                                             from dredging is measured in years rather than months as
                                             is the case for other bottom types. In many cases the new
                                             depth involved after dr edging may preclude any recovery
                                             of these particular biotic communities.


                                         6.  In oyster and clam growing areas (brackish and saline
                                             water) dredging should be avoided during the months of
                                             July, August, September, December, January and Febr-u-
                                             ary, whenever possible. This is particularly important
                                             when the dredging is to be performed within 500 yards of,
                                             or overboard disposal is within one mile of, productive pub-
                                             -lic or privately leased oyster ground. In anadromous fish
                                             spawning and nursery areas (i.e. freshwater), dredging
                                             and overboard disposal operations should be avoided,
                                             when possible, during the period of mid-March through Oc-
                                             tober. Particularly critical is the actual spawning period,
                                             mid-March through June. Concern is heightened when
                                             overboard disposal is involved.

                                             Rationale: The majority of oyster spawning and S'patfall
                                             occurs during the months of July, August and September
                                             in most areas of Virginia. Higher than normal suspended
                                             solids levels, which can occur in proximity to large dredg-
                                             ing and disposal activities', can interfere with the develop-


                                 54






                                                                                   Wetlands Guidelines



                                          ment and survival of oyster larvae. Resultant sedimenta-
                                          tion can also adversely affect the setting of oyster larvae
                                          by covering clean hard substrates thus making them un-
                                          available to the larvae. During the coldest months of the
                                          year, oysters are more susceptible to siltation because
                                          their pumping activity is reduced and they are less able to
                                          clear away rapidly accumulating silt. During the spring
                                          spawning run (mid-March through June) anadromous fish
                                          eggs and larvae can be adversely affected by higher than
                                          normal levels of suspended sediments. Adult migrations
                                          can be impeded especially in narrow streams and rivers
                                          where turbidity may reach from bank to bank. The period
                                          July through October is the nursery period when the lar-
                                          vae develop into juveniles before beginning their migra-
                                          tion back to the ocean. Note: This guideline is not subject
                                          to blanket application in the salinity regimes where it is
                                          applicable. Careful case-by-case analysis is required.

                                       7. In relatively large water bodies, overdredging to reduce
                                          the frequency of maintenance dredging, should not exceed
                                          an additional two feet and this should be based on the an-
                                          ticipated sedimentation rate. In narrow canals and other
                                          water bodies subject to poor flushing, the dredged depth
                                          should not exceed one foot below that of the connecting wa-
                                          ters.


                                          Rationale: This guideline balances the benefits of re-
                                          duced maintenance frequency and thus environmental dis-
                                          turbance with the creation of stagnant or' "dead" water
                                          which can occur when artificially deep holes are created.

                                    Specialized Structures and Activities


                                    D. Channeling into Fastland or Marshes

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




                                                                                                       55






                                Wetlands Guidelines



                                            Rationale: Studies have shown that such channeling
                                            leads to water quality problems. Poor water circulation
                                            and flushing, combined with contaminating constituents
                                            and high nutrient loads from adjacent development often
                                            leads to reduced dissolved oxygen levels, noxious odors, un-
                                            controlled algal growth and fish kills.

                                        2.  While environmentally objectionable, there may be times
                                            when channels into marshes or uplands are permitted.
                                            When this is the case, the following criteria should be ap-
                                            plied in order to reduce adverse effects:

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

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


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

                                              d. The top banks of channels should be graded to a
                                                 slight incline anywhere between mean sea level and
                                                 mean high tide f6r 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.


                                              e. Channels should be significantly shallower at their
                                                 heads than at their mouths in order to promote bet-
                                                 ter exchange with the natural waterway.

                                              f. Channel curves and angles should be avoided.

                                                 Rationale: The foregoing criteria reduce the poten-
                                                 tial adverse impacts of channelization by providing



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                                                                                 Wetlands Guidelines



                                             for better water circulation and bank stability. The
                                             marsh vegetation aids in preventing upland spoils
                                             and contaminants from lowering water quality.

                                  E. Dams and Impoundments

                                     1. Dams and impoundments should ordinarily not be located
                                        in tidal wetland areas. If some encroachment into such ar-
                                        eas is deemed necessary every effort should be made to
                                        limit the encroachment as much as possible and restrict
                                        marsh loss to Group 3-5 marshes.

                                        Rationale: Impounding an upland area generally involves
                                        a tradeoff of one set of upland habitat values (e.g. hard-
                                        wood forest) for another set (lake or pond). When tidal wet-
                                        lands are lost to this same type of development, the loss to
                                        the marine environment can be severe and is generally ir-
                                        replaceable.

                                     2. When a dam or impoundment is constructed in, or adja-
                                        cent to, a tidal stream, provisions should be incorporated
                                        into the design to maintain a flow of freshwater into the es-
                                        tuary.


                                        Rationale: Maintaining a flow will minimize the up-
                                        stream movement of salt water in the stream and thus re-
                                        duce large scale aquatic habitat changes due to salinity
                                        shift.


                                     3. Dams should incorporate the use of fish ladders in order to
                                        minimize the loss of upstream spawning and nursery
                                        grounds for marine species.

                                        Rationale: Many commercial and sports fishes are
                                        spawned and develop to adult stages above the tidal estu-
                                        ary. These areas are critical to the maintenance of popula-
                                        tion levels in these species.





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                                  Wetlands Guidelines



                                         4. Techniques which will minimize the possibility of mud-
                                            wave creation adjacent to the dam site should be imple-
                                            mented when wetlands are present.

                                            Rationale: This guideline limits wetland losses due to im-
                                            poundments to that immediately in and upstream of the
                                            dam site. A mudwave effectively destroys wetlands in its
                                            path by raising the substrate elevation above the range of
                                            tide.


                                         5. Whenever possible, impoundments should be designed to
                                            incorporate shallow water areas capable of supporting
                                            emergent vegetation and water tolerant timber.

                                            Rationale: Shallow water habitat within the impound-
                                            ment can help offset the loss of tidal wetland habitat due
                                            to dam construction.


                                       F. Marinas


                                         1. Dry storage type facilities are encouraged in preference to
                                            wet slip complexes.


                                            Rationale: Such facilities minimize adverse impacts to
                                            the marine environment and do not occupy space in the
                                            water which could be used for recreation by all citizens of
                                            the Commonwealth.


                                         2. When siting and designing a marina facility in a coastal
                                            'waterway, the following should be considered:

                                              a. All structures should be open-pile or floating with
                                                  any permanent loss of aquatic habitat limited to that
                                                  which is absolutely necessary.


                                              b.  If sited in a small tributary or other poorly circulat-
                                                  ing body of water,the marina should be situated
                                                  near the mouth rather than the headwaters.





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                                                                              Wetlands Guidelines



                                         c. The structures should encroach no more than one
                                            third the distance across the waterway except in un-
                                            usual channel configurations.


                                         d. Marinas should be sited away from productive or ac-
                                            tively worked oyster and clam grounds.

                                         e. Consideration should be given to the size and depth
                                            of the existing waterway and to the number of boats
                                            already housed in the vicinity.

                                         f. Slips for deep draft vessels should be located in the
                                            naturally deeper waters of the marina.

                                         g. If the site involves a marsh, all structures except
                                            those needed for access (ramps, railways, etc.) should
                                            be located landward of or channelward of marsh vege-
                                            tation.


                                         h. Design of any necessary breakwaters should permit
                                            adequate water circulation within the facility to help
                                            prevent an accumulation of pollutants. Floating tire
                                            or other non-permanent type breakwaters should be
                                            considered.


                                            Rationale: The foregoing criteria reduce the poten-
                                            tial adverse impacts of marinas by providing for bet-
                                            ter water circulation, minimizing marine habitat
                                            loss, and reducing initial and maintenance dredging
                                            requirements.


                                 G. Drainage and mosquito ditches

                                    1. Drainage and mosquito ditches should be designed accord-
                                       ing to a master plan which will maximize their effective-
                                       ness while minimizing their extent as much as possible.

                                    2. Ditches designed along conventional grid patterns are dis-
                                       couraged in favor of ditches which link identified mosquito



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                                    Wetlands Guidelines



                                                producing areas within the marsh with tidal waters.
                                                Drainage ditches should also be designed to connect to spe-
                                                cifically identified, areas of poor drainage.

                                             3. Depths should be limited to no more than 1 foot deeper
                                                than the connecting waters.

                                             4. Depending on the size of the ditch, dredging should be ac-
                                                complished "in the dry" Gandside to seaward).

                                             5. If dredge spoil must be placed in the marsh, it should be
                                                spread or broadcast as thinly as possible over a broad area
                                                with no effective elevation change on the marsh surface. If
                                                this is not possible, the dredged material should be placed
                                                in small widely separated mounds creating plant diversity
                                                and allowing water to circulate over the remaining marsh.

                                             6. Where maintenance dredging is to be accomplished, the
                                                dredged material should be placed, to the maximum ex-
                                                tent possible, on the old spoil area. If this is in the form of
                                                a continuous berm paralleling the ditch, the berm should
                                                be breached periodically to promote inundation of the re-
                                                maining marsh.

                                             7., Rotary ditchers are the preferred means of constructing
                                                mosquito ditches and small drainage ditches.

                                                Rationale: Adherence to the above procedures will maxi-
                                                mize the effectiveness of the ditches while minimizing ad-
                                                verse impacts to the wetlands.

                                          H. Submarine pipeline crossings

                                             1. Whenever feasible,' pipelines should be placed on piles or
                                                attached to existing structure.

                                             2. When a pipeline must be buried in the river bottom, the
                                                st ockpiling of excavated material adjacen   t; to the trench
                                                should be avoided.




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                                                                              Wetlands Guidelines



                                   3.  When a pipeline must be buried in a marsh, material may
                                       be temporarily placed along side the trench if upon comple-
                                       tion all excess material is removed from the marsh, the
                                       original elevation is restored, and all denuded areas are
                                       sprigged with appropriate vegetation.

                                       Rationale: These guidelines minimize construction im-
                                       pacts to the wetlands and allow for the fastest possible re-
                                       covery of the natural system after the disturbance.





































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                             Section V. Wetlands
                             Mitigation-Compensation Policy

                                   Definitions


                                   The following words, when used in these guidelines, shall have
                                   the following meaning unless the context clearly indicates other-
                                   wise:


                                   "Compensation" means actions taken which have the effect of
                                   substituting some form of wetland resource for those lost or sig-
                                   nificantly disturbed due to a permitted development activity; gen-
                                   erally habitat creation or restoration. Compensation is a form of
                                   mitigation.


                                   "Mitigation" means all actions, both taken and not taken,
                                   which eliminate or materially reduce the adverse effects of a pro-
                                   posed activity on the living and nonliving components of a wet-
                                   land system or their ability to interact.

                                   Policy

                                   In spite of the passage of the Virginia Wetlands Act and the Fed-
                                   eral Water Pollution Control Act in 1972, the pressures to de-
                                   velop lands, including wetlands along Virginia's shoreline, have
                                   continued to accelerate as evidenced by the increasing number of
                                   permit applications being submitted. At the same time scientific
                                   research has demonstrated that certain wetlands can be estab-
                                   lished or re-established in areas where wetlands are not found at
                                   present. This has led to an increasing number of proposals call-
                                   ing for the destruction of wetlands in one area in order to accom-
                                   modate development, and the creation of wetlands in another
                                   area in order to offset the loss of the natural wetland resource.


                                   Although compensating for the loss of a wetland by establishing
                                   another of equal or greater area sounds very attractive in theory
                                   and has been regarded as successful in a few specific cases, in
                                   general, this form of mitigation has proven difficult to success-
                                   fq1ly implement. Many questions regarding the ecological sound-



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                                    Wetl ands Guidelines



                                          ness and feasibility of substituting one habitat for another re-
                                          main to be answered.. In addition, a number of studies have dem-
                                          onstrated that for various reasons the created habitats either
                                          never attain the level of productivity or diversity of the natural
                                          systems they replace or simply are not capable of performing the
                                          ecological functions of the undisturbed habitat.

                                          Although California and Oregon now require compensation for
                                          lost wetlands on all projects, states such m North Carolina and
                                          New Jersey have taken a much more limited approach to the
                                          mitigation-compensation question. In general, these latter two
                                          states rely on wetland compensation only as a last resort to re-
                                          place *wetlands whose loss is highly justified and unavoidable.
                                          Virginia to this point has also taken a very conservative tack
                                          with regard to the use of wetland compensation as a manage-
                                          ment tool.


                                          The Commission,     and these guidelines, do not require that all
                                          wetlands losses be compensated. They do recommend, however,
                                          that compensation be required on a limited basis to replace un-
                                          avoidable wetlands losses. There are three main reasons for this
                                          recommendation.


                                          First, a'literature survey and experience with implementing com-
                                          pensation on a day-to-day basis reveal a number of significant
                                          problems with the concept itself that remain to be resolved.

                                          Second, there are general philosophical and technical questions
                                          regarding compensation which have not been answered by the
                                          scientific community to this.point in time.-

                                          Third, and most important, a reading of the Wetlands Act
                                          clearly indicates that the General Assembly intended for the
                                          Commonwealth's wetland resources to be preserved in their
                                           natural state," and emphasized through its declaration of pol-
                                          icy, the importance of an overall ecological approach to wetlands
                                          mana  gement.

                                             "The Commonwealth of Virginia hereby recognizes the unique
                                             character of the wetlands, an irreplaceable natural resource
                                             which, in its natural state, is essential to the ecological sys-



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                                                                                 Wetlands Guidelines



                                     tems of the tidal rivers, bays and estuaries of the Common-
                                     wealth." (Emphasis added)

                                  The General Assembly also stated that where economic develop-
                                  ment in the wetlands is clearly necessary and justified it will be
                                  accommodated while preserving the wetlands resource.

                                        it is declared to be the public policy of this Commonwealth
                                     to preserve the wetlands and to prevent their despoliation
                                     and destruction and to accommodate necessary economic de-
                                     velopment in a manner consistent with wetlands preserva-
                                     tion." (Originally adopted under Section 62.1-13.1 of the Code
                                     of Virginia) (Emphasis added)

                                  In Section 28.2-1308 of the Code of Virginia the General Assem-
                                  bly mandated the preservation of the ecological systems within
                                  wetlands of primary ecological significance and then stated:

                                     "Development in Tidewater, Virginia, to the maximum extent
                                     possible, shall be concentrated in wetlands of lesser ecological
                                     significance, in wetlands which have been irreversibly dis-
                                     turbed before July one, nineteen hundred seventy-two, and in
                                     areas of Tidewater, Virginia, apart from the wetlands."

                                  The General Assembly has spelled out clearly that "necessary
                                  economic development" is to be accommodated in Tidewater, Vir-
                                  ginia, but that the emphasis is on wetlands preservation in their
                                  natural state.


                                  General Criteria


                                  It shall remain the policy of the Commonwealth to mitigate or
                                  minimize the loss of wetlands and the adverse ecological effects
                                  of all permitted activities through the implementation of the
                                  principles set forth in these Wetlands Guidelines which were
                                  promulgated in 1974 and revised in 1982. To determine whether
                                  compensation is warranted and permissible on a case-by-case ba-
                                  sis, however, a two-tiered mechanism will be implemented. This
                                  dual approach will consist first of an evaluation of necessity for
                                  the proposed wetlands loss (See Specific Criteria). If the pro-
                                  posal passes this evaluation, compensation will be required and




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                                     Wetlands Guidelines



                                          implemented as set forth in the second phase, the Supplemental
                                          Guidelines.


                                          The primary thrust of combining the existing Wetlands Guide-
                                          lines with the two-tiered compensation guidelines is to preserve
                                          the wetlands as much as'possible in their natural state and to
                                          consider appropriate requirements for compensation only after it
                                          has been proven that the loss of the natural resource is unavoid-
                                          able and that the project will have the highest public and private.
                                          benefit. Commitments to preserve other existing wetlands shall
                                          not ordinarily be an acceptable form of compensation.

                                          Specific Criteria

                                          In order for a proposal to be authorized to destroy wetlands and
                                          cornpensate for same in some prescribed manner, the three crite-
                                          ria listed below must be met. If the proposal cannot meet one or
                                          more of these criteria, the activity shall be denied, or must occur
                                          in areas apart from the wetlands. Should it satisf3i all three crite-
                                          fia, however, compensation for the wetlands lost is'required.

                                          1. All reasonable mitigative actions, including alternate siting,
                                              which would  eliminate or minimize wetlands loss or distur-
                                              bance must be incorporated in the proposal.

                                          2.  The proposal must clearly be water-dependent in nature.

                                          3.  The propos al must demonstrate clearly its need to be in the
                                              wetlands and its overwhelming public and private benefits.

                                          Supplemental Guidelines

                                          If compensation is required, then the following guidelines should
                                          be given due consideration and, if appropriate, may be included
                                          as conditions of the permit:

                                          A. A detailed  plan, including a scaled plan view drawing, shall
                                              be submitted describing the objectives of the wetland compen-
                                              sation, the type of wetland to be created, the mean tide range
                                              at the site, the proposed elevations relative to a tidal datum,
                                              the exact location, the. areal extent, the method of marsh es-



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                                                                  Wetlands Guidelines



                              tablishment and the exact tim e frame from initial work to
                              completion.

                           B. Once the grading is completed at the planting site, it should
                              be inspected by a competent authority to insure that the ele-
                              vations are appropriate for the vegetation to be planted and
                              that the surface drainage is effective.

                           C. The compensation plan and its implementation must be ac-
                              complished by experienced professionals knowledgeable of
                              the general and site-specific requirements for wetland estab-
                              lishment and long-term survival.

                           D. A performance bond or letter of credit is required and shall
                              remain in force until the new wetland is successfully estab-
                              lished; a minimum of two growing seasons.

                           E. The compensation marsh should be designed to replace as
                              nearly as possible, the functional values of the lost resource
                              on an equal or greater basis. In general this means creating a
                              marsh of similar plant structure to that being lost. This may
                              not be the case where a lesser value marsh is involved (i.e.
                              Group 4 or 5 wetlands). A minimum 1:1 areal exchange is re-
                              quired in any case.

                           F. The compensation should be accomplished prior to, or concur-
                              rently with, the construction of the proposed project. Before
                              any activity under the permit may begin, the permittee must
                              own all interests in the mitigation site which are needed to
                              carry out the mitigation.

                           G. All reasona ble steps must be taken to avoid or minimize any
                              adverse environmental effects associated with the compensa-
                              tion activities themselves.


                           H. On-site compensation is the preferred location alternative
                              with off-site in the same watershed as a consideration when
                              on-site is not possible. Locating a compensation site outside
                              the river basin of the project is not acceptable unless it is
                              done as part of a state-coordinated program of ecological en-
                              hancement.




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                                  Wetlands Guidelines



                                        L  In selecting a compensation site, one aquatic community
                                           should not be-sacrificed to "create" another. In cases where
                                           dredged material must be placed overboard, the area may be
                                           used to create marsh, oyster rock or improve the resource
                                           value of the bottom.


                                        J.. The type of plant community proposed as compensation must
                                           have a demonstrated history of successful establishment in or-
                                           der to be acceptable.

                                        K. The proposed activity should stand on its own merits in the
                                           permit review. Compensation should not be used to justify
                                           permit issuance.

                                        L. Manipulating the plant species composition of an existing
                                           marsh community, as a form of compensation, is unaccept-
                                           able.


                                        M. Nonvegetated wetlands should be treated on an equal basis
                                           with vegetated wetlands with regard to compensation and
                                           mitigation, unless site-specific information indicates one is
                                           more valuable than the other.


                                        N. Both short- and long-term monitoring of compensation sites
                                           should be considered on a case-by-case basis. For unproven
                                           types of compensation the applicant will be responsible for
                                           funding such monitoring as is deemed necessary.

                                        0. Where on-site replacement for noncommercial projects is not
                                           feasible, compensation for small wetland losses (less than
                                           1,000 sq. ft.) should be avoided in favor of eliminating loss of
                                           the natural marsh to the maximum extent possible.

                                        P. Conservation or other easements to be held in perpetuity
                                           should be required for the compensation marsh. Easements
                                           accepted by the Commission will be processed in accordance
                                           with the provisions of Section 28.2-1301 of the Code of Vir-
                                           ginia.

                                        Q. All commercial projects which involve unavoidable wetland
                                           losses should be compensated.



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                                                                               Wetlands Guidelines


                            Glossary

                                  ALGAE - Simple marine or freshwater photosynthetic plants.
                                       May be single or multicelled.
                                  ANNUALS - Invertebrates which generally spawn once a year
                                       and live about a year.
                                  BENTHIC - Pertaining to any plant or animal living in or on the
                                       bottom sediment of a river, ocean, lake or other aquatic sys-
                                       tem.

                                  BERM - A wall or mound built around a low-lying area to con-
                                       tain a spoil material.
                                  BIANNUALS - Invertebrates which generally spawn twice a
                                       year and live less than a year.
                                  BRACKISH - Pertaining to the waters of bays and estuaries,
                                       salty but of lower salinity than seawater.
                                  BULKHEAD - A structure or partition, usually running parallel
                                       to the shoreline, for the purpose of protecting fastlands
                                       from wave action or protecting channels from upland sedi-
                                       mentation.

                                  COMMUNITY - Ecological term for any naturally occurring
                                       group of different organisms inhabiting a common environ-
                                       ment, interfacing with each other relatively independent of
                                       other groups. Communities may vary in size and larger
                                       communities may contain smaller ones.
                                  DETRITUS - Organic matter (primarily marsh plants) which
                                       while decaying in the aquatic system forms the basis of ma-
                                       jor 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 re-
                                       port, 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 sediment.
                                  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 seaward end and the
                                       last step is to open the new canal to the existing waterway.



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                                   Wetlands Guidelines



                                         DIKE - A wall or mound built around a low-lying area to pre-
                                              vent flooding-
                                         ECOLOGY - The overall relationships between organisms and
                                              their environment.
                                         FASTLANDS - The zone extending from the landward limits of
                                              wetlands to at least 400 feet inland.
                                         FRESH WATER - Waters containing no appreciable, salt, usu-
                                              ally less than .5 parts per thousand.
                                         FOOD WEB - The complex interactions of organisms in a natu-
                                              ral 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 con-
                                              structing bulkheads or groins. In the marine environment,
                                              usually made of galvanized steel wire mesh with a PVC
                                              (polyvinyl chloride) coating over the galvanizing.
                                         GROIN - A shore protection structure built (usually perpendicu-
                                              lar to the shoreline) to trap sand and other material mov-
                                              ing 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 many- different species without any one being
                                              dominant.

                                         HYDROLOGICAL - Pertaining to water, its properties and dis-
                                              tribution especially with reference to water on the surface
                                              of the land, in the soil and underlying rock.
                                         INTERTIDAL - Area on a shoreline between mean high water
                                              and mean low water.

                                         JETTY - On open seacoast, a structure extending into a body of
                                              water designed to prevent shoaling of a channel by sand or
                                              other materials.@ Usually,placed along side channels at en-
                                              trances.

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




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                               LITTORAL PROCESSES - Those physical features and charac-
                                    teristics of the intertidal area 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. In this case a marsh vegetated 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.
                               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 phenom-
                                    ena in general.
                               POPULATION - All of the members of one species within a coni-
                                    munity.
                               PRIMARY PRODUCTION - Biomass produced directly from
                                    sunlight by plants.
                               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 aer-
                                    ial shoots.

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

                               SECONDARY PRODUCTION - Biomass produced by animals
                                    grazing on plants or other organic matter.
                               SHORE DEFENSE STRUCTURES - A bulkhead or groin in-
                                    tended to deter erosion of the shoreline.







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                                 Wetlands Guidelines



                                      SPECIES DIVERSITY - Pertaining to the numbers of different
                                           species inhabiting a given area, i.e. high species diversity
                                           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 high tides which occur twice monthly
                                           due to astronomical conditions.

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
















































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