Dr. Claude M. Epstein1
The water budgets of the wetland environments of the New Jersey coastal plain need a water surplus, especially at the onset of the growing season. However, the source of this surplus varies and serves as a basis for a hydrologic classification of these wetlands. These sources include 1) the ponding and perching of rainfall and surface runoff, 2) the discharge of groundwater into floodplains and depressions, and 3) the recharge of tidal and river flood water onto floodplains.
The sources, and consequently the wetland type, are meant to be identified by simple field methods, such as subsurface borings to locate clay layers and the water table as well as observation of the surrounding topography.
These sources and their resultant wetlands suggest a consistent distribution within the drainage basins of the New Jersey coastal plain. First, wetlands that result from the ponding and perching of precipitation and surface runoff occur at higher elevations away from the floodplains of the drainage basin's stream network. Second, wetlands that result from the discharge of groundwater, by far the most common, occur at the upper margins of floodplains. Third, wetlands that result from inundation by stream flooding occur within the floodplains. Finally, wetlands caused by tidal flood water occur at the lowest elevations at the mouth of the basin's trunk stream.
Knowledge of the wetland type is useful in assessing the nature of possible hydrologic hazards caused by agriculture and can serve as the basis of wetland protection policy.
