Pinyon provided the Wyoming Department of Transportation (WYDOT) with full design services for a wetland mitigation site located in the floodplain of the South Tongue River in the Bighorn National Forest in Sheridan County, Wyoming. Shutts Flats consists of interspersed dry and wet meadow along the South Fork Tongue River. Previous impacts to the system changed the floodplain elevation, disconnecting it from the river. Identified by the US Forest Service (USFS), the project restored over 15 functional units (based on the Montana Wetland Assessment Method) by reconnecting the river to its floodplain.
The four main project elements included low-flow sedge benches, floodplain reconstruction, development of a wetland swale, and increased habitat diversity. In addition to conceptual designs and a full PS&E package (in hardcopy and Microstation and GeoPak formats), Pinyon developed 1D and 2D hydraulic models of the mitigation site using HEC-RAS and a mitigation master plan that included restoration goals and objectives, performance metrics, and a monitoring plan. Within seven months, our staff had permits in hand and had completed conceptual to full designs through a process of multiple review cycles by the Interagency Technical Team. To ensure proper construction, Pinyon staff directly oversaw the project, restoring and creating approximately 2.5 acres of wetland habitat. Additionally, Pinyon restored hydrology to three more acres of decadent scrub-shrub wetland habitat at the north end of the Flats. The project improved the aquatic bed habitat for use by the Columbia spotted frog, a USFS Sensitive Species.
