Submitted to: Book Chapter
Publication Type: Book / Chapter
Publication Acceptance Date: 1/30/2003
Publication Date: 1/15/2004
Citation: Knight, S.S., Welch, T.D. 2004. Evaluation of watershed management practices on oxbow lake ecology and water quality. In: Nett, Mary, Locke, Martin A., Pennington, Dean (Eds.), Water Quality Assessments in the Mississippi Delta, Regional Solutions, National Scope. ACS Symposium Series 877, American Chemical Society, Oxford University Press, Washington, D.C. pp. 119-133. Interpretive Summary: Oxbow lakes are important sports fishery resources that are formed as river channels meander across the landscape. Non-point source pollution from agricultural runoff has impaired water quality and damaged fisheries productivity in many Mississippi Delta oxbows. Combinations of best management practices (BMPs) were tested in three oxbow lake watershed and shown improve fish populations by removing sediment. Water clarity improved, plankton populations increased and sports fish were successfully restocked. This research demonstrates the value of BMP in reducing pollution and improving lake ecology and water quality. This information may be used by the Natural Resources Conservation Service and the U. S. Environmental Protection Agency during the implementation phase of Total Maximum Daily Load development and in farm conservation plans.
Technical Abstract: Much of the worldwide loss of aquatic habitats has been attributed to draining and clearing for agriculture as well as non-point source pollution associated with agricultural runoff. Mississippi Delta Management Systems Evaluation Area (MSEA) project was designed to development and test land and cultural treatments targeted to reduce sediment and associated pollutants entering oxbow lake watersheds. Lake water quality prior to the implementation of best management practices (BMPs) indicated ecologically damaged systems due to excessive suspended sediment. Improvements in water quality were realized through the use of cultural and structural BMPs. Sediments were decreased 34 to 59%, while Secchi visibility and chlorophyll generally increased. Significant improvements in water quality occurred in lakes, which featured cultural practices and combinations of cultural and structural practices respectively. Prior to BMP implementation fish species richness was relatively low and sports fishes were poorly represented. Post-BMP fish sampling indicate successful renovation of lakes with cultural practices and combinations of cultural and structural practices. Bass, lacking in two of the lakes before renovation and restocking, were successfully reestablished in these two lakes. Results indicate that cultural BMPs play a significant role in improving lake water quality and may be needed in addition to structural measures insure improve fisheries.