GEOLOGY, GEOMORPHOLOGY, AND NATIVE BROOK TROUT HABITAT FOR THREE MOUNTAIN STREAMS IN GREENVILLE AND PICKENS COUNTIES, SOUTH CAROLINA

Southern Appalachian brook trout are the only trout species native to South Carolina, and reproducing populations are limited and only inhabit small, mountain streams in upstate South Carolina. The stream habitats are very sensitive to external influences such as overfishing and deforestation. Changes in stream habitat could lead to the loss of these native trout populations. This study assesses the in-stream habitat quality of three streams in Greenville and Pickens Counties. By using the Basinwide Visual Estimation Technique (BVET) on approximately 1 mile of each stream along with fish sampling and studies of the geology and geomorphology, we were able to determine which stream had the best trout habitat and which could use improvement. Biotite-quartz-feldspar gneiss forms the bedrock for all three streams, and systematic joint measurements show two dominant trends at N45E and N70W. These prominent joint sets typically control stream flow and along with shallow-dipping foliation and exfoliations surfaces produce alternating riffles and pools. Two essential characteristics of trout habitat are the percent of the stream that is pool habitat and the amount of large woody debris (LWD) present in the stream. Over the mile that we studied on Headforemost Creek we found the stream to have 14% pools and 33 pieces of LWD. On Matthews Creek we found the stream to have 17% pools and 62 pieces of LWD. Finally on Falls Creek we found the stream to have 23% pools and 55 pieces of LWD. Based on the results we determined that each stream was deficient in pool habitat but the best brook trout stream based on the habitat quality was Falls Creek. All three streams are at risk of losing their reproducing populations of native brook trout but this research will help to develop a plan, perhaps to include the addition of large woody debris, to improve the native trout habitat so future generations can enjoy this native species.