|
Click here for Soil Science
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:
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:
When soil mapping is required within the state of New Hampshire, a soil scientist certified by the State of NH must be hired to perform field investigations of soil properties within a surveyed property. While in the field, he/she will observe such indicators of soil type as color, texture and evidence of a seasonal high water table. Landscape position, rock formations and even vegetation gives further information. Once data from the field has been recorded, it is compared to county soil surveys generated by the United States Department of Agriculture Natural Resources Conservation Service (NRCS), and soil types or soil series are determined for the investigated area. Using a topographical map of the surveyed land parcel, the soil scientist is then able to overlay boundaries of soil series, along with drainage class and slope of each.
One of two types of soil maps are generated, depending on the type of map preferred by the reviewing board to which a map will be submitted:
|
>>> Click HERE for DES Application and Approval Status