Assessing changes to in-stream turbidity following construction of a forest road in West Virginia

Two forested headwater watersheds were monitored to examine changes to in-stream turbidity following the construction of a forest haul road. One watershed was used as an undisturbed reference, while the other had a 0.92-km (0.57-mi) haul road constructed in it. The channels in both are intermittent tributaries of the Left Fork of Clover Run in the Cheat River watershed of West Virginia. To meet the objectives of another part of the study, silt fence was installed continuously along the banks of the streams from sampling stations at the catchments' mouths to the headwaters of each stream network; however, the silt fence became ineffectual at and near stream crossings during road construction, thereby allowing substantial amounts of sediment to reach the channel. Daily and stormfiow sampling began in fall 1999 using automatic collectors and continued through and beyond the period of road construction which began in July 2002 and ended in September 2003. Turbidity (NTU) was measured from those samples. Following road construction, treatment watershed turbidities increased significantly for both daily and stormfiow samples. However, the increases in stormfiow turbidities were much greater than those occurring for daily samples. Turbidity values for both daily and stormfiow samples appear to be decreasing exponentially, but neither returned to pre-construction levels by the end of the study period.