Quality Aspects of Agricultural Runoff and Drainage

In this report, the ASCE Task Committee on Agricultural Runoff and Drainage has summarized the literature and research findings with respect to sources of pollutants, nature of downstream impacts, and relationships between pollutant loads and certain physical variables. Agricultural discharges from nonirrigated lands are significant contributors of nitrogen, phosphorus, and pesticides to downstream receiving waters. State-of-the-art knowledge indicates that management practices directed toward control of erosion, control of runoff, and management of fertilizer and pesticide application can reduce total pollutant load carried off-site from agricultural lands. The development of on-site discharge water quality control measures, as contemplated under PL 92-500, must be predicated on detailed surveys of a more specific nature due to the high degree of variability in the factors influencing water-borne pollutant transport.