Wetland Identification
Because protection of wetlands depends on accurate and consistent identification methods, the NJ wetlands legislation requires use of a single wetlands identification methodology. To facilitate the wetlands identification and boundary delineation process, the Freshwater Wetland Act authorizes the DEP to provide verification for the presence or absence of wetlands, for delineations, and other provisions, by issuing Letters of Interpretation (LOI). Only the DEP can determine that an area is a regulated freshwater wetland through the LOI process.
The DEP offers three types of LOI's:
- A presence/absence LOI
- A line delineation LOI for sites under 1 acre
- A line verification LOI for sites greater than 1 acre.
An LOI application requires details about the property including Bergen County Soil Survey Maps and National Wetland Inventory maps. When a wetland site is over 1 acre, a NJ certified engineer or surveyor initially flags the delineation. The DEP performs on-site inspections to verify the delineation line for accuracy[1]. The method of determining the wetland line includes deep digging to measure hydrology of the soil. The process is well defined so line variation is minimal if properly performed.
In an effort to insure accurate, consistent and repeatable wetlands identifications and determinations, the NJ legislature directed the DEP to adopt and use the federal methodology that has been developed by the four federal agencies primarily involved in wetlands identification and delineation: the U.S. Army Corps of Engineers, the U.S. Fish and Wildlife Service, the U.S. Environmental Protection Agency, and the U.S. Department of Agriculture Soil Conservation Service. It provides direction on identifying various site-specific wetland indicators and using them to establish a wetlands boundary that is accurate, consistent, and repeatable. The federal methodology uses a three-parameter approach to identify wetlands. Characteristics of the soils, the vegetation and evidence of hydrology are used to determine the presence, absence, or extent of wetlands.[1]
For most instances, a routine on-site determination is all that is necessary to determine the existence of wetlands. This approach may be conducted by assessing the soils or by evaluating the plant communities.
For more difficult sites, an intermediate-level on-site determination is required. This approach is necessary on sites where the determination of wetlands vegetation requires more detailed analysis, especially when the boundary between the upland and wetlands is not clearly defined.
The third approach, a comprehensive on-site determination is designed on those sites that are extremely large or complex or when detailed information is necessary to support legal challenges. In applying this approach, use of a team of specialists is recommended so that accurate and detailed information may be compiled on the soils, vegetation, and hydrology of the property.
The last approach presented is for disturbed area and problem area determinations. Disturbed areas are those where filling, damming, clearing, or other human activities have impacted the wetlands. Wetland determinations on these sites require research into the past history of the site as well as investigation into existing conditions. Identification problems on these areas can occur because vegetation usually common to upland situations exist or the wetlands are unique to very limited geographical regions. An evaluation of other site characteristics or familiarity with the region is helpful in defining these wetlands.
* Some of the prior information is courtesy of the Association of New Jersey Environmental Commissions
[1] See the: Federal Manual for Identifying Jurisdictional Wetlands, Superintendent of Documents, Washington DC