A Macroinvertebrate Survey of Sandy Creek in Durham County, NC: A Comparative Study of Post-Restoration and Pre-Restoration Surveys

Abstract

Sandy Creek, located within the Cape Fear watershed within the Triassic Basin of North Carolina, is a first order stream within a tributary watershed that feeds into Jordan Lake reservoir. A biological assessment, following the NCDENR Benthic Standard Operating Procedure, was performed and all macroinvertebrates were identified at three sites over three months within the upper Sandy Creek watershed within Duke University Wetland Center’s Stream and Wetland Assessment Management Park (SWAMP). This was done three years post-restoration in 2008. Mud Creek, Sandy Creek’s reference stream, was also sampled in 2008. This bioassessment was performed as a follow up to the baseline macroinvertebrate survey completed pre-restoration in 2004/2005 and to determine the restoration’s effect on its macroinvertebrates and water quality. The biotic index values calculated from the pre-restoration and post-restoration macroinvertebrate tolerance and abundance levels indicated a decrease in biotic index value or an increase in water quality (6.7 pre-restoration to 6.4 post-restoration). The biotic index values calculated for the three post-restoration sites show a water quality improvement as the water flows through the restoration (6.58 input to 6.434 midpoint to 6.42output) which may indicate that the restoration is increasing stream function. The macroinvertebrate orders and feeding types that were collected provided additional information on the difference between pre- and post-restoration Sandy Creek.