Agricultural and forest land runoff in upper South River near Waynesboro, Virginia

Abstract

Sources and yields of organic matter, suspended solids and nutrients in the Upper South River Basin were investigated during the summer low flow period of 1974. Parameters monitored at sampling stations in the basin included chemical oxygen demand, total suspended solids, turbidity, specific conductance, total phosphorus, total Kjeldahl nitrogen, nitrate, and iron. These data were used with flow and drainage area data to determine the relative magnitude and daily yields of materials from various sources.

Sources of organic matter, suspended solids, and nutrients entering the South River included agricultural, forest and urban land drainage as well as domestic and industrial wastewater effluents. The yields of materials from the various sources were computed during an intense storm in May, wet weather flow in June, and dry weather flow in July.

During the short term period of high storm flows, land runoff was the primary source of all pollutants. On the long term basis, however, wastewater effluents were the major contributors of all parameters except total suspended solids. Industrial effluents contributed the greatest proportion of chemical oxygen demand and total nitrogen. The Waynesboro sewage treatment plant supplied the greatest phosphorus loading.

In comparison with forest drainage, agricultural land drainage was found to be a greater source of all materials monitored. Urban runoff was not analyzed separately, but it appears to contribute significant pollutant loads.

It was found that reduction of phosphorus in the Waynesboro sewage treatment plant effluent may reduce excessive algal production in the South River below the city of Waynesboro.