Title
Resolution to Approve a Contract with TSP Environmental to Perform Maintenance and Restoration of the Wetland Mitigation Area, Sediment Basin and Steep Slopes at the Ann Arbor Maintenance Facility ITB-4192 ($331,589.00)
Memorandum
Attached for your review and action is a resolution to approve a $331,589.00 contract with TSP Environmental to make corrections to the wetland mitigation area at the Ann Arbor Maintenance Facility (Wheeler Service Center) to comply with Michigan Department of Environmental Quality (MDEQ) requirements, repair erosion, and improve storm water conveyance systems.
The Wheeler Service Center was constructed under a 2005 MDEQ permit and Pittsfield Township Commercial Site Plan that required the creation of 2.59 acres of new wetland, including 2.23 acres of forested and 0.16 acres of scrub/shrub wetland. The wetland types that have established are wetter than planned, consisting of emergent and wet meadow wetland, and the required number of trees and shrubs did not survive the original planting. In order for trees to survive in the constructed wetland mitigation area, topsoil mounds will be added in order to provide a root zone that is only semi-saturated rather than permanently inundated. Trees and shrubs will be planted on these mounds. In addition, sediment that has eroded into the wetland from a failing storm water conveyance swale will be removed, and the swale will be armored to prevent further erosion and sedimentation in the regulated wetland area.
Correction of several other bank erosion problems, removal of sediment from a sediment basin, re-installation of storm water pipe end sections, and installation of new drainage channels and culverts will also be included in this project. The new drainage structures will address ice formation on the main service access drive due to drainage problems. Access routes to the work areas are being planned to accommodate future maintenance needs. The additional storm water improvem...
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