The goal of this wetland mitigation project was to restore approximately 33 acres of farmland to historic wetland conditions to create the Clinton River Watershed Mitigation Bank. In 2008, Niswander Environmental began conducting land searches to identify available properties within the Clinton River Watershed that offered suitable conditions for creation of a wetland mitigation bank (Bank). Once located, Niswander Environmental conducted several field assessments over the course of one year to obtain crucial design data. During these assessments, Niswander Environmental installed five automated groundwater level recorders and collected numerous soil borings to ensure a successful project. The wells were used to monitor groundwater levels, determine the existing hydrology patterns, and aid in final design of the Bank.
The Bank property was chosen based primarily on outstanding soil characteristics (i.e., clay) and the presence of an adjacent drain that offered potential for effectively restoring the hydrology on the Property. The design was based on ecological principles and site- specific conditions so that the mitigation wetland will be successful and develop into a self-sustaining ecosystem.
The design consisted of excavation and creation of low head berms, and included the installation of two water control structures so hydrology could be effectively manipulated to ensure success. The presence of forested wetland to the east and southeast suggested that the site was historically wetland, but was effectively drained by an existing ditch when the area was converted to agriculture several decades ago. It was anticipated that once the hydrology was restored, the wetland seed bank would germinate and the upland vegetation would eventually be eliminated due to wetter conditions. Therefore, the Bank was designed to minimize earth excavation in order to maximize the germination of the existing native wetland seed bank.
Niswander Environmental worked diligently with the local and state agencies to obtain necessary wetland, zoning, and SESC permits and to secure a Wetland Banking Agreement. Construction of the Bank was completed by Niswander Environmental in July 2009. In November 2009, Niswander Environmental seeded approximately 29 acres of newly created wetland with a native forested/scrub- shrub wetland seed mix, and the remaining 4 acres was seeded with an emergent seed mix. In May 2010, Niswander Environmental hand-planted 7,500 native trees and shrubs into the basin. Niswander Environmental staff currently monitors and actively manages this Bank, which includes invasive species control (bottom left), annual floristic quality assessments, wildlife surveys, and hydrologic assessments and seasonal water level manipulation.