Water quality achievable with agricultural best management practices

ABSTRACT:

Greater emphasis has been placed on controlling nonpoint sources of pollution; however, the quality of water achieved by implementing best management practices (BMPs) remains uncertain. Water quality in runoff from agricultural areas under best management was compared with water quality standards, where appropriate, and with other measures of treated water, thereby defining the water quality achievable by using best management practices. The study draws upon results obtained from 7 years of water quality monitoring in the LaPlatte River and St. Albans Bay watersheds in Vermont of BMPs implemented for manure management, barnyard runoff, and milkhouse wastes. These studies include long-term stream monitoring for sediment and nutrient concentration and load, as well as intensive evaluation of the treatment effectiveness of certain BMPs, such as vegetated filter strips and manure storage, on concentration and export of sediment, nutrients, and bacteria. Results indicate that BMPs may be highly effective in reducing pollutant concentrations and loads, but runoff may continue to exceed water quality criteria. Further development of BMPs is needed to improve the water quality achievable.