Project Highlights

On behalf of Roane County, S&ME obtained the appropriate state and federal permits for the construction of a distribution center that required impacts to approximately 2.7 acres of wetlands and approximately 3,800 feet of streams.  Compensatory mitigation for stream and wetlands occurred primarily within the Pawpaw Creek watershed located adjacent to the site.  Stream mitigation included the restoration of approximately 3,800 feet of Pawpaw Creek and an adjacent tributary.  Wetland mitigation included the creation and restoration of four wetland areas totaling approximately 10 acres on Pawpaw Creek’s existing floodplain. Because of limited funding, S&ME coordinated on the County’s behalf with the Tennessee Department of Environment and Conservation to implement the mitigation in a phased approach so the project could be funded over time. In support of this phased approach, S&ME prepared bid documents and an engineer’s estimate of construction cost, administered the bid process, and evaluated bids for the County for two contracts, one for stream restoration and one for wetland mitigation.

Prior to construction, excessive sedimentation from adjacent grading activities altered the geomorphology of a proposed design reach. S&ME worked closely with the contractor in the field to alter the proposed design, to address the existing field conditions while minimizing the cost and time lost during construction.

Restoration included streambank stabilization through a multi-pronged application of grading and re-vegetation techniques combined with the installation of stream stabilization structures such as J-hooks, cross vanes, root wads, and combinations.  S&ME performed HEC-RAS modeling including the stream and mitigation area along the stream, prepared written reports and contract documents for the project, and provided construction oversight for the mitigation.  The stream restoration and wetland mitigation are complete, and the site is currently in the monitoring phase. Observations during a 2009 monitoring event performed by S&ME indicate that the mitigation has been successful in creating a vertically and horizontally stable stream channel with improved in-stream habitat, and the adjacent wetlands have developed and maintained hydric soils.