Abstract: Session G 3:10 pm (Back to Session G)
Evaluating the Ecological Function of Restored Streams in Piedmont, North Carolina using the Stream Quantification Tool
Sara R. Donatich
Department of Biological and Agricultural Engineering North Carolina State University
Raleigh, North Carolina
The Stream Quantification Tool (SQT), a rapid assessment and spreadsheet tool that quantifies stream function, was developed succeeding 2008 updates to federal compensatory mitigation rules to address the lack of method to evaluate stream function using function-based objective and verifiable performance standards. The SQT is an application of the Stream Functions Pyramid (Harman et al., 2012), which asserts that stream functions are interrelated and build on each other in a specific order, in which hydrologic processes are depicted as the fundamental support for hydraulic, geomorphic, physicochemical, and biological processes. To test the pyramid framework and the ability of the SQT (3.0) developed for North Carolina (NC) to accurately detect and quantify stream function, a functional assessment of 21 function variables was conducted on 19 reference-quality streams and six paired restored and degraded streams in Piedmont, NC (n=31). Natural variability of conditions for reference-quality reaches within the NC Piedmont region were documented and compared to the NC SQT's performance standards. Multivariate relationships between function variables and benthic macroinvertebrate metrics were evaluated to generate significance weights for each variable to ensure the SQT places higher significance on variables that support healthy biota. Principal components regression analysis was conducted to identify site selection (i.e. hydrologic) and design parameters (i.e. hydraulic and geomorphic) that predict “good” biological condition. SQT functional scores for the paired restored and degraded reaches were re-computed with updated performance standards and significance weights derived from this study to evaluate restoration success. The SQT has been adopted into regulation by Wyoming and Tennessee, is under regionalization in Georgia, South Carolina, and Colorado, and is of interest to several other states, including North Carolina. Findings will influence future iterations of the SQT and the adoption of the SQT by the NC Division of Mitigation Services to award function-based credits.