Across the globe, wetlands are important ecosystems that carry out a variety of functions valuable to our earth's processes. Wetlands provide great water-holding capability, important during flood and drought, and take part in recharging groundwater supplies. They act as filters for pollution, food and habitat for wildlife, and are an important feature for holding carbon dioxide.

Historically, there has been a significant decrease in the number of wetlands as human development has increased. However, during the past 30 years, the federal, state and local governments have been taking a greater interest in the value of wetlands, and the result has been regulated protection of these important natural features. Within the State of New Hampshire, the Department of Environmental Services (DES) has created a Wetlands Bureau that is charged with the task of protecting tidal and fresh water wetlands, as well as surface waters. They officially define a wetland as:

"an area that is inundated or saturated by surface or ground water at a frequency and duration sufficient to support and that under normal conditions does support, a prevalence of vegetation typically adapted for life in saturated soil conditions. Wetlands include, but are not limited to, swamps, marshes, bogs and similar areas." (Administrative rule Wt 101.88)

This is to say, an area with soils saturated by water for periods long enough that they support vegetation suited for extended conditions of wet soil.

Forest Wetlands

Wetlands are not always cattail ponds or a soggy marsh. Because of the large amount of acreage in central New Hampshire that is covered by forest, you will find a large number of forested wetlands. These wetlands may have topographically low areas or depressions, drainages or channels. There may be features known as "pit and mound" where trees appear to be growing on small mounds of soil and are surrounded by depressed topography. A subsurface layer of soil material may be so dense that water permeates very slowly; creating a water table high enough that it seeps through the soil near or at the surface and becomes a "sheet" across a forested landscape. All of these conditions may result in areas of saturated soil in a forest that then support vegetation suited to wet soil conditions, forming a forested wetland.

State Protected Wetlands

All areas meeting the criteria spelled out in the DES definition of wetland is protected by the State of New Hampshire. Any impact or alteration to these areas requires prior approval by the NH DES Wetlands Bureau in the form of a permit. To determine if these areas exist within your property, a wetland scientist certified with the State of NH can be contacted to perform a site inspection and wetland delineation (boundary determination).

Wetland Delineation

Wetland delineation is a process that determines the boundary line of a wetland. It is within this delineated line that approval must be obtained by NH DES before any impact can be made. This line may also be used to determine required state and local setbacks for various development projects.

The 1987 Corps of Engineers Wetlands Delineation Manual outlines the methods used for determining wetland boundaries. Three criteria need to exist within an area in order for it to be determined a jurisdictional wetland: plants requiring saturated soils, soils must be saturated for a specified extended period of time, and there must be evidence of wetland hydrology (topography changes, depressions, channels, etc.).

The Wetland Delineation Process: