Effectiveness of a Stream-Restoration Effort Using Natural Material Instream Structures

The substrata of fluvial systems can be altered by human disturbance in watersheds. This disturbance often results in a reduction of habitat diversity and subsequent reductions in species diversity. Restoration efforts in impacted areas require a thorough understanding of the characteristics of exemplary stream habitat in the region as well as habitat requirements of taxa targeted by specific restoration efforts. The Little Coal River, WV, has historically been disturbed by various land-use practices resulting in near homogeneity of the riverbed substratum such that it is composed almost everywhere primarily of fine-particle or sand-substrate classes. Restoration of an 8-km section of the Little Coal River was attempted with the installation of a series of natural material instream-structures. We monitored the riverbed substratum, including sediment size-class data, prior to and after installation of these structures for a 2-year period to evaluate their effectiveness in restoring overall habitat heterogeneity. Our GIS analysis of the data suggested that approximately 80% of the riverbed substratum was composed of fine-particle or sand substrate classes prior to the natural material structure addition. After 2 years, these 2 substrate classes had decreased by nearly 25%, suggesting that restoration efforts reduced the overall percent composition of fine-particle and sand-substrate classes and increased overall habitat heterogeneity. Our analysis of these data indicate that the natural material instream structures installed in the Little Coal River achieved the objective of promoting downstream movement of some fineparticle and sand substrate that characterized the system (i.e., via sediment transport) and increased substratum heterogeneity.