Effects of Stream Restoration on In-stream Water Quality in an Urban Watershed

The purpose of this on-going project is to provide information to Municipal Separate Storm Sewer System (MS4s) operators and states on the performance of selected best management practices (BMPs), specifically, stream restoration techniques, on improving biological and instream water quality within an urban watershed. Accotink Creek in Fairfax City, Virginia was selected as the study location. This project involves monitoring before and after restoration of 1,800 linear feet of degraded stream channel in the North Fork of Accotink Creek from Lee Highway to Old Lee Highway in the City of Fairfax, Virginia. Restoration, which was completed in June 2006, included installation of native plant materials along the stream and bioengineering structures to stabilize the stream channel and bank. These actions were intended to restore the stream channel to a stable condition, thereby reducing stream bank erosion and sediment loads in the stream. In-stream samples were collected and analyzed for physical, chemical, and biological (macroinvertebrates, bacterial indicators) parameters to document the changes in stream quality as a result of the restoration. The preliminary results of the sampling and monitoring are summarized in the paper.