Habitat restoration commonly is used in stream improvement and mitigation projects, but its effectiveness rarely is assessed. As mitigation for golf course construction, two 400 m sections of Juday Creek, a 3rd-order cool-water stream in
northern Indiana, were relocated into new channels containing pool-riffle sequences,
large woody debris, and cobble and gravel substrate in 1997. An upstream sediment
basin was installed to protect habitat improvements and stream relocation areas. My
dissertation focuses on the effects of stream restoration and the effect of sediment basins
on the benthic macroinvertebrate community of Juday Creek.
Habitat quality, suspended and deposited sediment dynamics, and macroinvertebrate density and diversity were monitored prior to and for five years after completion of the restoration. The effectiveness of sediment basins and their
maintenance was studied in two locations of Juday Creek in 2001 and 2002. From July 2002 to July 2003, nutrients, physical characteristics, suspended sediment, deposited sediment, fine benthic organic matter, and macroinvertebrates were sampled to examine the relationships among habitat restoration, sediment removal, and secondary production rates of macroinvertebrates.
Habitat quality improved and was sustained for six years in the restored reaches. Macroinvertebrate densities were higher in the restored reaches when compared to unrestored reaches. When properly maintained and designed, sediment basins were effective at reducing instream sediment loads and maintenance had little effect on the stream biota. Restored reaches had better habitat quality and lower amounts of deposited sediment than the upstream control reach. Secondary production rates were 2 to 5 times higher in the restored reach for Baetis sp., Cheumatopsyche sp., Hydropsyche morosa, and H. betteni. Rates of secondary production for Optioservus fastiditus were similar at restored and unrestored reaches.
This study suggests that the restoration improved habitat quality and availability for benthic macroinvertebrates, resulting in increased densities, number of genera, and secondary production rates. The sediment basin protected the restored reaches and greatly improved the success of this project. In addition, this study shows that secondary production rates are a sensitive indicator that may be used to evaluate the effectiveness of stream restoration projects.