Reference Wetlands
Wetland regulations are often focused upon determining whether an area is, or is not, a wetland. Accurate delineation of wetlands is needed to ensure that wetlands are appropriately regulated under the law and that non-wetland areas are not unduly regulated. This can be difficult and contentious because most wetlands are not continually wet. There are many factors that can affect shallow groundwater levels including vegetation, soils, surrounding land use and many others The ACD monitors water levels at the edge of 15 wetlands throughout the county that serve as a reference of what various wetland types look like under current conditions. While we can not know for sure if a given area is wetland simply by comparing groundwater levels to nearby similar reference wetlands, the reference wetlands reveal some useful information. The analyses are always site specific and tailored to accommodate the complex and interrelated factors that govern wetlands. The reference wetlands serve as one tool for ensuring accurate wetland regulation.
We monitor water levels of reference wetlands with electronic monitoring wells. We use the WL, Ecotone, and WM series of devices from Remote Data Systems, Inc. Each unit is capable of measuring water levels to a depth of 40 inches on a programmed schedule (we use every 4 hours) with accuracy of plus or minus 3 mm, and resolution of plus or minus 1 mm. These devices are installed in the ground. A hole is augered and a plastic, perforated casing inserted into the hole. The top of the augered hole around the casing is sealed. The electronic device is inserted into the casing. We measure the depth to which the unit is installed at least yearly so electronic readings can be converted into water level depth below the ground's surface. The devices are downloaded periodically throughout the open water season. We also collect other information about the reference wetlands including soils, surrounding land use, vegetation, size, and other factors.
Map of Reference Wetlands
