Linking Stream Restoration Success with Watershed and Project Characteristics
Urban Samuel Withers
RES
Nashville, TN
Authors: Withers, U.S., T. Wynn Thompson, E.P. Smith, R. Gamble, W. Paraszczuk, and B. Smith
A synthesis of stream restoration projects within the US estimated that, on average, at least $1 billion was spent annually between 1990 and 2004 on stream restoration (Bernhardt et al., 2005). Increasingly, stream restoration is used in the mid-Atlantic US to address stormwater impacts and to improve water quality as part of the watershed implementation plans for the Chesapeake Bay TMDL, particularly in urban watersheds. However, in comparison to upland best management practices, there is relatively little research on the effectiveness of stream restoration to improve the physical, chemical, and/or biological integrity of stream systems. The goal of this project is to improve our understanding of the conditions under which stream restoration projects are successful in restoring geomorphic function and restoration designs are resilient. Over 50 stream restoration projects in the Piedmont and western coastal plain of Maryland were assessed for geomorphic function and design success using monitoring reports and field assessments. Study projects were selected to represent a range of project completion dates, design techniques, and watershed characteristics. Multiple linear regression analysis was then used to identify correlations and relationships between watershed- and project-level characteristics and measures of stream restoration success. At the watershed scale, land use was most strongly related to functional success, with projects in more natural watersheds exhibiting higher geomorphic function. Design scores correlated negatively with watershed area. At the project level, projects with higher width to depth ratios scored higher on the functional assessment, while particle size was negatively correlated with geomorphic function. Study results suggest stream restoration designs are improving over time, but the ability to determine project success from monitoring reports remains limited.
About Samuel Withers
Samuel Withers graduated from Virginia Tech with a B.S. and M.S in Biological Systems Engineering in 2018 and 2019 respectively.
He is now an Engineer II with RES, LLC in the Nashville area continuing to follow his passion for Ecological Restoration.