Effects of Channel Catfish Farming on Water Quality and Flow in an Alabama Stream

摘要

Big Prairie Creek, Hale County, Alabama, receives overflow and draining effluent from about 5.000 ha of channel catfish, Ictalurus punctatus, ponds. Tributary streams receiving effluent directly from ponds were higher in concentrations of suspended solids, turbidity, nutrients, and biochemical oxygen demand than Big Prairie Creek, and these variables increased from upstream to downstream stations in Big Prairie Creek. Nevertheless, water quality in Big Prairie Creek was good at the last downstream station, and concentrations of variables did not exceed water quality criteria required by the stream classification system. Six reference streams in the same eco-region as Big Prairie Creek, but without channel catfish farms on their watersheds, had concentrations of most water quality variables similar to those found in the downstream reaches of Big Prairie Creek. Findings suggest that channel catfish farming has not had a great impact on water quality in Big Prairie Creek. Although catfish farms occupy7.5% of the area of the Big Prairie Creek watershed, stream flow has not decreased as a result of impoundment of runoff by ponds. Use of best management practices (BMPs) to reduce the volume and improve the quality of pond overflow and draining effluents should be adequate to prevent negative downstream water quality impacts in catfish farming areas of Alabama.