Site Evaluation and Design Plan for a Created Forested Wetland

The Michigan Department of Transportation (MDOT) is at a deficit for wetland mitigation credit in the Maple River Watershed due to construction of the St. Johns Bypass on US 127. MDOT requested design plans for the creation of a forested wetland that are cost effective, innovative, and fit within the landscape.

Project sponsor

Through ArcGIS mapping and field surveys, the construction site was characterized to determine hydrology, topography, and soil classification. In order to determine the hydrologic regime of the system a water balance excel model was developed to predict inundation period and daily water height. Site design was optimized to minimize excavation, maintain wildlife usage, and ensure vegetative establishment.

Lab scale soil percolation rate testing by constant head method

Results of the water balance indicate sufficient water for a forested wetland ecosystem. Stop-log control structures and an earthen berm constructed from on-site soil are utilized to facilitate the necessity for precise water depths. The design includes small areas of emergent and scrub-shrub wetland to promote ecological diversity.

Overview of site location, 50 acres

AutoCAD design drawings depict plan, cross-sectional, and structural component views. Specifications are provided for construction of the site with details on required grading, vegetation planting, wildlife structures, and long-term monitoring.

Design Team from left to right; Alyse, Mike (MDOT), Kevin, and Hanna

The project is currently being finished by MDOT. They took our design and drawings and expanded on the specifications in order to create a bid proposal. The total implementation cost will be around $500,000 and is slated to begin construction in the Spring!

- Kevin