In the Fall of 2001, the Indiana University Southeast Ecology class continued a bioassessment survey of Blue River initiated in the summer of 1995. Terry Huff, Mark Bostic and the ecology class of the fall of 1995 completed this first survey. The original study, sponsored by the Nature Conservancy and Indiana University Southeast, evaluated 17 sites along the river between Totten's Ford and Wyandotte Lake and at all forks in Washington County.
This fourth order tributary of the Ohio River courses through the hilly unglaciated portion of southern Indiana. Blue River once had a pearl button factory at its confluence with the Ohio River and had several mill dams that have now been abandoned. Despite these impacts, the watershed remained free from major developments and water quality remained high for most of the last century.
In 1975, Indiana designated over 45 miles of the river as a State Scenic River. This protects the river from the potential threat of destruction by public and private projects. The Nature Conservancy is also working to preserve Blue River with an onsite office in Corydon and the funding of studies of the current ecological status of the river. The Indiana Department of Natural Resources and the Blue River Commission work to prevent the removal of the natural vegetation. Blue River is moderately impaired in some upstream areas. The river is constantly affected by silt from erosion and storm discharges that bring excess nutrients and bacteria into the stream flow. Surfacing of existing gravel roads has led to increased development within the watershed. While the effects of these developments are unknown, they are unlikely to be positive.
Blue River is considered to be one of the most biologically diverse areas in Indiana. Several species on the endangered species list, as well as threatened species, call the Blue River home, including three species of darters, the variegate, bluebreast, and spotted darters and fresh water mussels. Darters are an indicator species due to their sensitivity to disruption of water quality. Many endangered and threatened darter species have completely disappeared from other Indiana rivers. Fresh water mussels were collected and eaten by native Americans, were used in the pearl button industry and are currently being exploited by the cultured pearl industry in Japan and Polynesia.
The current study was conducted at three old dam sites on the Blue River, Milltown, Rothrocks, and White Cloud. The Milltown site was located just downstream from the dam while the Rothrocks and White Cloud sites consisted of the area just upstream and downstream of the former dam sites. Riffle fish population estimates, macroinvertebrate bioassessments, habitat assessment studies, riparian vegetation, discharge, water quality and fecal coliform bacteria evaluations were conducted at all three sites. The results were then compared to previous studies conducted at the same sites, as well as data from Mitchell River in North Carolina, a pristine river system untouched by humans. From this study, we hoped to track changes in the Blue River and to determine if the endangered darter populations were being affected.