N.Y. Comp. Codes R. & Regs. tit. 6, § 664.6
(7) Wetland open water, including open water with dead trees and open water that occasionally exposes unvegetated mud flats. Unvegetated open water is part of a wetland as a wetland cover type if it is substantially enclosed by wetland vegetation and is no larger than 2.5 hectares (approximately 6.2 acres). If the body of open water that is substantially enclosed by wetland vegetation is larger than 2.5 hectares (approximately 6.2 acres), then only that portion of the open water that is within 50 meters (approximately 165 feet) of the wetland vegetation is considered to constitute a wetland cover type and to be part of a wetland. When in close conjunction with wetland vegetation, open water can be of considerable value as fish and wildlife habitat.
(b) Ecological associations.
A variety of significant ecological associations may occur in wetlands. Wetlands having an association of substantially different kinds of physical or vegetative structures have special ecological value, especially for wildlife and fish. Association with particular non-wetland features may be important in defining wetland benefits. In addition, the visual diversity provided serves a valuable aesthetic function. The nature and significance of these associations are set forth in this subdivision.
(1) Two or more structural groups. Three groups of wetland vegetative structures can be identified. In order to be significant enough to be considered a factor in classifying a wetland according to this class II characteristic, each structural group must constitute at least a particular minimum percentage of the area of the wetland.
(iii) The water structural group consists of cover types in which the surface of the water is apparent. These submergent and floating vegetation and/or wetland open water cover types, including open water with dead trees and open water that occasionally exposes unvegetated mud flats, must constitute at least 15 percent of the area of the wetland.
For example, a wetland which is 80 percent shrub swamp (woody structural group) and 20 percent submergent and floating vegetation (water structural group) has this class II characteristic. A wetland which is 45 percent deciduous swamp (woody structural group), 35 percent coniferous swamp (also woody structural group), and 20 percent wet meadow (herbaceous structural group) does not have this class II characteristic because, although the woody structural group constitutes well over its minimum 25 percent of the wetland, the herbaceous structural group constitutes less than its minimum 25 percent of the wetland. The physical structure of each of these three groups is substantially different from the structure of each of the other two. The presence of this characteristic increases the value of a wetland as fish and wildlife habitat because each of the different groups can support species not found in the others, thus increasing the variety of species on the wetland as a whole. In addition, those species which need two different structural groups to meet all of their requirements can only exist when both groups are present. The presence of different groups together also provides visual variety, thus enhancing aesthetic benefits.
(6) Island present within wetland. Islands provide nesting habitat and refuge for wildlife. They provide visual variety and interest and can be the focus of recreational and educational activities.
(c) Special features.
Wetlands may contain particularly critical or fragile resources that require special protection. They may also contain other special features which enhance their benefits. Since some of these features are described in relation to major regions of the State, a definition of those major regions is provided in paragraph (1) of this subdivision.
(1) The major regions of the State are shown on the map in Appendix 8-D. More detailed delineations of the major regions shown on that map are available in the regional offices of the department. Where a wetland is near a major region border, the wetland's region shall be considered to extend into the adjacent region(s) to a distance of 15 kilometers (approximately 9 miles) from the wetland. However, this modification of regional borders does not apply to the borders of the metropolitan region. The major regions are:
(5) Vulnerable species. This is a species or subspecies (or botanical “variety”, where “variety” is used as the equivalent of the zoological “subspecies”) of plant or animal (vertebrate or invertebrate):
(iii) whose range is restricted in the State or a major region of the State and it or its habitat has a low tolerance for disturbance.
Vulnerable species shall be identified by the department in additions to this Part after public hearing.
(11) Wetlands adjacent to fertile upland. This characteristic is identified by soil tests or by soils maps. Upland soils in the immediate vicinity of a wetland are an indication of the fertility of the wetland substrate. In general, those soils described by the United States Soil Conservation Service as “high base soils” (pH 5.6 or higher) will be considered fertile for the purposes of this Part. The value of fertile soils is similar to the values described in paragraph (10) of this subdivision: generally, a more naturally fertile substrate will support better habitat for fish and wildlife.
(d) Hydrological and pollution control features.
Some wetlands provide significant hydrological and pollution control benefits. The major features of wetlands providing those benefits are set forth in this subdivision.
(4) Some wetlands are underlain by deposits of pervious earth materials which serve to hydraulically connect them to aquifer systems so that some of the water from such wetlands percolates into the aquifers and recharges them. For infiltration of water from a wetland to be of an amount significant enough to provide a ground-water supply source, and therefore to be either a class I or II characteristic, the pervious earth materials underlying the wetland must be more than three meters (approximately 10 feet) thick. Some of the more important aquifers in the State have already been identified by various agencies, such as the U.S. Geological Survey, the Department of Environmental Conservation, the State Department of Health and various county and regional planning agencies. Preservation of groundwater recharge areas is critical to the protection of the aquifers and the water supply. Recharge to groundwater systems generally takes place during times of the year when little foliage (which discharges water via transpiration) is present. At these times, as well as other times, wetlands can recharge aquifers if the soils at their bottoms are so pervious as to allow infiltration. For example. although the soil types underlying wetlands are usually peat, muck, marl or clay, none of which is very pervious, wetland overflow lands in floodplains may be underlain by sandy or gravelly alluvial soils. These wetlands, even if not very large, can serve to restore significant amounts of water to aquifers, thereby allowing wells to continue yielding water.
(e) Distribution and location.
The distribution and location of wetlands are important considerations in determining the benefits of particular wetlands as open space and for recreational, aesthetic and educational purposes. Nothing in this Part or in the act, however, requires a landowner to open land to public access for such purposes.
(1) Within urbanized areas. “Urbanized areas” are defined by the United States Bureau of the Census, and consist of a central city, or cities, and surrounding suburban areas. According to that definition, the central city must have a population of 50,000 or more, and surrounding closely settled areas are included if these are:
(iv) other similar small areas in unincorporated territory with lower population density when these areas serve to complete urban-suburban community boundaries.
For the purposes of this Part, the urbanized areas of the State are listed by the United States Bureau of the Census as follows: New York -Northeastern New Jersey (the New York State portion), Buffalo, Albany-Schenectady-Troy, Binghamton, Rochester, Syracuse, and Utica-Rome. In addition, incorporated cities not covered by the United States Bureau of the Census definition are included for the purposes of this Part, but only the city proper and not surrounding areas. These are: Amsterdam, Auburn, Batavia, Beacon, Canandaigua, Corning, Cortland, Dunkirk, Elmira, Fulton, Geneva, Glens Falls, Gloversville, Hornell, Hudson, Ithaca, Jamestown, Johnstown, Kingston, Little Falls, Lockport, Mechanicville, Middletown, Newburgh, Norwich, Ogdensburg, Olean, Oneida, Oneonta, Oswego, Plattsburgh, Port Jervis, Poughkeepsie, Salamanca, Saratoga Springs and Watertown. Because of their rarity, their distinctiveness from urban surroundings, and their proximity to large numbers of people, wetlands in urbanized areas can provide unusually important natural, recreational, educational, scientific, open space and aesthetic benefits.
This section describes characteristics and their associated benefits used in classifying wetlands in section 664.5 of this Part.
(a) Cover types.
The different wetland cover types described in this subdivision provide wetland benefits to varying degrees. In order for a wetland to be considered to be of a given cover type and classified accordingly, that cover type should constitute at least 50 percent of the area of the wetland. However, if no single cover type constitutes 50 percent or more of the wetland area, this aspect of the wetland's classification shall be determined by adding up the areas of all the separate cover types in each class and then assigning the wetland to the class that represents the largest proportion of the wetland's area. As listed in section 664.5 of this Part, the only class II cover type is emergent marsh in which purple loosestrife and/or reed (phragmites) constitutes less than two thirds of the cover type; class III cover types are emergent marsh in which purple loosestrife and/or reed (phragmites) constitutes two thirds or more of the cover type, deciduous swamp, shrub swamp, floating and/or submergent vegetation, and wetland open water; and class IV cover types are wet meadow and coniferous swamp. The evaluations of cover types in this subdivision are distinct from the evaluations of structural groups provided in paragraph (b)(1) of this section.