National Water Quality Goals and Irrigated Agriculture

The 1972 Federal Water Pollution Control Act Amendments (P.L. 92-500) have an important but often overlooked impact on the irrigated agricultural community of the western United States. The specific goals of P.L. 92-500 are unrealistic because of the lack of both knowledge and funds to develop effective control technologies in regard to irrigation return flows. Surface and subsurface return flows should be differentiated for purposes of study, treatment, and management. Treatment and salt disposal require expensive and complicated technologies. Some states have been granted the authority to oversee the issuance of National Pollution Discharge Elimination System permits; irrigation entities in both California and Washington have formed large return flow groups to facilitate the collection of water quality data and to assist the farmer in developing the best practical control technology. The agricultural user also needs information on the relationship between crop yield and irrigation water quality; the ASCE Task Committee was formed to study the salinity hazards faced by the irrigator.