Agricultural practices contribute to water pollution by adding nutrients (fertilizers), sediments, and pesticides to the stream through surface runoff. Best Management Practices (BMPs) are strategies designed to improve the quality of a stream by reducing pollution from agricultural areas. These practices range from on-field (planting trees and grasses adjacent to the stream) to in-stream (bank stabilization) approaches. Studies investigating the impact of management practices on improved water quality have concentrated on in-stream strategies and have focused traditionally on physical/chemical characteristics such as nutrient concentrations or sediment yield at a particular location in a stream over a short period of time. Little is known about the responses of aquatic insects, crayfish, and fish to the implementation of BMPs across the entire area that drains into the stream (watershed-wide implementation of BMPs).
The Illinois Pilot Watershed Program is designed to address watershed issues such as erosion, flooding, and deposition of nutrients/sediment in streams and to examine the effects of management practices on improving the entire watershed. As an initial pilot study, four watersheds across the state were selected in areas with several watershed issues or problems and where local interest existed (Fig. 1). Due to the extensive nature of the program, a number of state and federal agencies along with citizen-based groups are participating in the ecological, economic, and social aspects of this program. In each pilot watershed, planning committees and coordinators, which are made up of local watershed interest groups along with local agency personnel from the Natural Resources Conservation Service and the Soil and Water Conservation Districts, identify concerns and evaluate conservation needs in their respective watersheds. These committees also conduct visits with participating landowners to discuss suitability of BMPs and hold local meetings to address landowner questions.
Locations of the four river basins with their corresponding pilot and reference sites.
Funding for installation of BMPs is provided by the Illinois Department of Natural Resources through citizen partnerships with landowners. Additional funding for conservation practices and watershed planning as well as technical assistance in implementing BMPs is also provided by the Illinois Environmental Protection Agency, the Illinois Department of Agriculture, and the Farm Service Agency.
Researcher measuring stream depth.
Assessment of watershed management practices is carried out primarily by the Illinois Natural History Survey (INHS), the Illinois State Water Survey (ISWS), and the Geographic Modeling Systems Laboratory (GMSL) at the University of Illinois. Effects of BMPs on physical stream habitat and aquatic organisms are being evaluated by the INHS, while the ISWS is carrying out the water-quality analysis. GMSL is using stream flow and erosion data to evaluate potential influences of BMPs at reducing pollution and erosion and to assess locations in the watershed where BMPs will be most effective.
The focus of INHS' first year of data collection in 1998 was to determine the similarity of the pilot sampling sites with their corresponding reference or "control" sites. Our aquatic assessment focuses on in-stream habitat, aquatic insects, and fish. Habitat measurements include stream width, depth, flow, and substrate as well as vegetation on stream banks and adjacent land. Aquatic insects are collected from riffles (shallow areas with turbulent flow), runs (moderately deep areas with moderate stream flow), and pools (deep sandy areas with slow flow) based on the proportion of these habitat types within each site. Fish are sampled using an AC electric seine which puts an electric current into the water and stuns the fish. Biologists collect, identify, measure, and weigh the stunned fish. From our 1998 fish data, we found that pilot and reference watersheds were similar in number and types of fish species caught. This suggests that, in general, our pairings are well matched for examining differences in fish composition after BMPs are installed. As BMPs are implemented in the pilot watersheds, we anticipate differences between pilot and reference streams to increase as a result of improved habitat and water quality in the pilots watersheds.
Hope R. Dodd, Center for Aquatic Ecology
Researcher collects water sample for analysis.
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