Professor University of Tennessee Knoxville, Tennessee, United States
Abstract Submission: The Federal Compensatory Mitigation Rule (2008), under Clean Water Act (CWA) Section 404, requires assessments determining mitigation credits to replace loss of stream functions due to unavoidable impacts to aquatic resources. To provide consistency with these compensatory mitigation requirements, the U.S. Army Corps of Engineers and the U.S. Environmental Protection Agency have promoted the development of a Stream Quantification Tool (SQT) in which several states have adopted. These SQTs identify stream functions establishing standard protocols to quantify potential stream function impacts that may result from proposed projects, and estimate the potential benefits (lift) from stream restoration. Assessment protocols are based on metrics within five categories: hydrology, hydraulics, geomorphology, physiochemical, and biology. State SQTs have the potential to promote best engineering practices for restoration, and their use is reasonable for single-thread stream types. However, practitioners have found its use to be problematic in more complex geomorphic settings and highly altered watersheds such as urbanizing catchments. A tool founded in a one-size-fits-all approach may not accurately reflect lift and loss, and may result in inappropriate use as an assessment tool. Incorporating metrics of active physical and ecological processes, and the linkages between functions within the SQT is critical to gaining a full understanding of system dynamics and to accurately determine debits and credits of restoration projects. The Tennessee SQT have been technically reviewed by a broad consortium of practitioners, leading to a revision to address some of the issues with its implementation. The revised Tennessee SQT version is presented.
