In 2009, Niswander Environmental designed, constructed, and planted a 13.5-acre forested mitigation wetland for the Michigan Department of Transportation (MDOT) within the Cass River Watershed located in Saginaw County, MI. In addition, a 9.5-acre emergent wetland was designed immediately adjacent to, but separate from, the mitigation area. The design utilized a low head berm with a water control structure that impedes surface water from leaving the site and one-way flood gates that deliver flood water to the site from the adjacent Cass River. Approximately one foot of excavation was required in the forested mitigation area, resulting in the site experiencing 6 to 12 inches of water seasonally as well as areas of saturated soils. When completing the wetland design, Niswander Environmental took into consideration the completed topography survey, available soils and hydrology information, required vegetation, and MDOT requirements for mitigation construction.
Niswander Environmental provided construction oversight during critical phases, and was forced to make several key alterations while in the field to ensure successful completion. Niswander Environmental provided invasive species control during construction, and hand-planted 5,400 native bare-root trees and shrubs into the wetland basin in 2009. Niswander Environmental currently manages the site for invasive vegetation.