Submitted to: American Society of Civil Engineers
Publication Type: Abstract Only
Publication Acceptance Date: 8/18/1995
Publication Date: N/A
Technical Abstract: Water quality issues have continued to increase in the Midwest with reports of large loadings of herbicides and nitrate-nitrogen in the Mississippi river. Nonpoint source pollution is a result of decisions made on individual fields and integrated into a collective response for a watershed. There is little understanding of the effect of management decisions within fields and the watershed response that could lead to improved management decisions for the field and watershed. In 1990, a project began on the Walnut Creek watershed south of Ames, Iowa, to investigate the surface and ground water quality response of different farming practices as part of the Management Systems Evaluation Areas (MSEA) program of the USDA Water Quality Initiative. The goal of this project is to investigate the impact of current and emerging farming practices on water quality in the Midwest. Studies are being conducted to relate the herbicide use patterns throughout the watershed to loads and concentrations within the tile drain lines and streams. Through these analyses it will be possible to determine the potential effectiveness of adopting farming practices like conservation tillage, split application of nitrogen, changing herbicide use, and crop rotation. These efforts are being assembled on a watershed scale to link the onsite impact with the offsite movement to determine where within the watershed control structures may be necessary to further enhance and protect water quality.