The goal of this project was to create the maximum amount of wetland mitigation possible on a 70-acre parcel located at the southwest corner of Garfield and US-127, in Washington Township, Gratiot County. This wetland mitigation was to be developed as a mitigation bank site to offset wetland impacts incurred during future Michigan Department of Transportation (MDOT) projects occurring in the Maple River watershed. The project included wetland mitigation design, specifications, special provisions, USEPA justification reports, MDEQ mitigation banking approval, and engineering cost estimates required by MDOT.
Niswander Environmental completed a site investigation and developed a mitigation design including earthwork and planting plan, specifications, special provisions for the wetland mitigation site. Niswander Environmental also completed a detailed hydrologic budget to ensure the feasibility of the design. The wetland was designed as surface water driven system and included 30 acres of emergent and forested components. This model was based on site specific characteristics and implemented an innovative design that minimized earthwork and was ecologically self-sustaining. All plans and specifications conformed to MDOT requirements for specifications and special provisions.
Coordination was obtained from the Gratiot County Drain Commissioner since an enclosed County Drain exists along the eastern side of the property. The Drain Commission was in favor of the project since flood storage is needed in this area. The outlet to the mitigation site was incorporated into the existing surface drainage system at this location.
During design of the site, several land use constraints were taken into consideration, such as utility pole locations, inheld properties, and US-127 future right-of-way plans.
The wetland basin was constructed in 2007, and seeding/planting of the mitigation wetland occurred in Spring 2009. Niswander Environmental hand-planted an additional 6,100 bare-root trees into forested sections of the mitigation site in Fall 2010.