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Wetlands Primer

By Barbara B. Beall, PWS,

The Chazen Companies
Prepared for a presentation at “Wetlands: Capacity Building for New York Land Trusts”

Wetlands are transitional ecosystems between uplands and open waters.  As such, their boundaries are defined more by regulatory programs than by nature.  The overwhelming characteristic in a wetland is the presence of water.  This water drives the characteristics of the soils in the wetlands and the vegetation in the wetland.  As a result, the federal government and state government utilize specific field indicators for vegetation, soils and hydrology to identify wetlands in the field. 

The NYSDEC regulatory program pre-maps wetlands that they will regulate that are 12.4 acres in size or larger, or other smaller wetlands with significant local importance.  These regulatory maps illustrate where the wetlands are likely to be found, but state regulatory personnel are responsible for establishing the exact boundary in the field.  The regulators typically rely heavily on wetland vegetation for identifying this boundary.  The NYSDEC regulations for Freshwater Wetlands Mapping and Classification are found at 6 NYCRR Part 664.  A 100-foot buffer is established around the wetlands boundary and is also regulated by the NYSDEC.

The federal regulatory program regulates wetlands of any size that are tied to interstate commerce.  The term wetland is defined in the federal regulations as “those areas that are inundated or saturated by surface or ground water at a frequency and duration sufficient to support, and that under normal circumstances do support, a prevalence of vegetation typically adapted for life in saturated soil conditions.  Wetlands generally include swamps, marshes, bogs, and similar areas”.  A standing wetland scientist joke is:  “Everybody knows what swamps, marshes and bogs are…it’s those ‘similar areas” that cause the problems”.

Federal wetlands are delineated in the field using the US Army Corps of Engineers 1987 Manual.  This manual establishes field criteria for three parameters – soils, vegetation and hydrology.  Indicators for all three parameters must be present for an area to be identified as a wetland.  For a good discussion of these parameters, see www.wetlandsforum.org, “Wetland Words and What they Mean” for vegetation, hydrology and soils.

All wetlands are not created equal.  The functions and values a wetland will provide depend upon the wetland’s landscape position, its vegetative community, soil substrate, types of surrounding land use and level of disturbance within the wetland.  Wetland functions are those physical, chemical and biological characteristics of a wetland, or what a wetland does.  Values are those characteristics that are important to society.  Common functions and values that are reviewed for wetlands include groundwater recharge, ground water discharge, flood flow alteration, sediment stabilization, sediment/toxicant retention, nutrient removal/transformation, production export, wildlife diversity/abundance, aquatic diversity/abundance, uniqueness/heritage, and recreation.  There are a variety of assessment methodologies available for evaluating a wetland’s functions and values.  These include WET, HGM, HEP, and others.  Most techniques do a good job of identifying or qualifying the functions and values, but a poor job of quantifying or measuring the amount of function provided.

Under the federal regulatory program, the US Army Corps of Engineers (ACOE) regulates work or structures in navigable waters of the United States, and regulates the discharge of dredged or fill material (broadly defined) in all waters of the United States with an interstate commerce clause connection (i.e., not “isolated” wetlands)[1].

The federal regulatory program basically uses two types of permits to authorize activities in wetlands.  The nationwide permits generally authorize minor types of work in wetlands, generally with impacts less than 0.5 acres.  The individual permits are needed for work with greater than 0.5 acre of impacts.  Under both regulatory reviews, the applicant must demonstrate that the project has avoided, minimized and mitigated impacts to wetlands to the maximum extent practicable, although the stringency of the review is typically stronger under the individual permit review.  The applicant must also demonstrate that they have complied with all associated regulatory reviews including compliance with endangered species review, National Historic Preservation Act, FEMA regulations, Wild and Scenic Rivers, and Section 401 of the Clean Water Act.

The state regulatory program classifies its wetlands into four classes.  Class I wetlands are the highest quality of wetlands.  Again, 6 NYCRR Section 664 discusses the classification of wetlands, and a Class I wetland would be defined as such, for example, due to its large size, variety of cover types, or because it supports important or rare plant communities.  A Class IV wetland, which would be at the other end of the spectrum, is not as valuable a wetland, and would be identified as such, for example, due to its smaller sizes, monotypic vegetative stands, or low value cover types.

Under the state regulatory program, activities are identified and rated for their compatibility with the wetland area and its 100-foot adjacent buffer.  For incompatible activities (and most are defined as such by the regulations), the Applicant must demonstrate compliance with the weighing standards found at 6 NYCRR Part 663.5 (e)(2).  The weighing standards are more stringent for Class I wetlands than for Class IV wetlands.  Unlike the federal regulatory program, where mitigation can only be used to compensate for unavoidable wetland impacts, under the NYSDEC regulatory program, mitigation can be used to “increase the likelihood that a proposed activity will meet the applicable standards for permit issuance”.[2]

[1] The recent US Supreme Court decision in Solid Waste Agency of Northern Cook County v. United States Army Corps of Engineers, ___ U.S.  __, ___ S.Ct. __, 2001 WL 15333 (2001), has determined that certain isolated wetlands are not subject to the jurisdiction of the US Army Corps of Engineers.

[2] 6 NYCRR 663.5(g).



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