An Evaluation of the Effects of Stream Restoration on the Benthic and Hyporheic Environments of the Fawn River, IN
Team: Jeffrey White, Todd Royer and Bill Jones
Stream bed sediments are critical habitats for stream-dwelling organisms as well as functional processes of stream ecosystems. This project addresses the effectiveness of a major stream restoration – a clean-up of a massive release of reservoir mud from a DNR Fish Hatchery on the Fawn River in Orland, IN. We will quantify changes in macroinvertebrate diversity and the response in transient storage, and ecological functioning of the stream bed. The benthic and hyporheic zones support a diversity of flora and fauna whose life cycles depend partially or completely on these areas. Benthic macroinvertebrates are often sentinels of stream ecosystem health in that their community composition (diversity and richness) integrates any changes in water quality and stream sediment quality over time. Following disturbance events, changes in numbers and species composition of benthic macroinvertebrate communities are readily measured.
The hyporheic zone (i.e., the 3-dimensional zone of groundwater-surface water interaction beneath the surface channel) is critical to stream functions, including nutrient retention and microbial respiration. Microbial respiration in turn affects dissolved oxygen in the sediment and overlying water. Stream restoration efforts in the Fawn River are likely to affect the size of the transient storage zone and the exchange of water between the surface and the hyporheic sediments. These changes will also influence benthic macroinvertebrate communities. The massive input of fine sediments to the Fawn River is certain to have disrupted, the exchange of water between the surface and subsurface, the size of the transient storage zone, and the overall ecological functioning of the ecosystem. Clean-up activities are intended to restore these processes and functions. We will quantify the response in the ecosystem to the restoration efforts.