Impact of best management practices on water quality in the Nomini Creek Watershed

The Nomini Creek Watershed project was initiated in 1985 as Virginia's action in dealing with the water quality problems of the Chesapeake Bay. Nomini Creek was selected because it was an agricultural watershed with few best management practices in place at the beginning of the study and was a representative watershed for the Coastal Plain of Virginia. The watershed is located in Westmoreland County, Virginia.

The goal of the project was to provide data needed to quantify the water quality impacts of cropland BMP implementation in a watershed with a complex landuse. The data collected during the project included landuse, hydrologic, water quality, soils, and geographical data.

The goal of this study was to conduct a detailed analysis of the data collected from the Nomini Creek watershed in order to evaluate the effectiveness of a system of BMPs on the quality of surface water. The specific objectives of this study were: 1) to compile the landuse data and determine if any significant changes in cropping practices occurred during the study period, 2) determine if any changes occurred in the monthly rainfall, and runoff values over the study period, and 3) determine if any changes occurred in the monthly total suspended solids, nitrogen, and phosphorous loadings from the watershed over the study period.

The analysis indicated no significant change in the rainfall and runoff amounts over the study period. The BMPs implemented during the study target surface runoff. Sediment bound nutrients such as ammonium and total kjeldahl nitrogen reduced during the study period and soluble nutrients such as ortho-phosphorous and total phosphorous increased during the study period.