Agricultural Waste Management

Irrigation return flows are agricultural wastes of major significance in the western states. Irrigated agriculture is the largest consumer of water in the U.S., and return flows from irrigation constitute a large portion of the flow in many western streams. The necessity for leaching salt concentrated in the root zone by evapotranspiration concentrates salt in return flows and causes damages downstream. Numerous engineering control measures can be applied to restrict and reduce water pollution from irrigation. These control measures present institutional constraints, and potential management concepts applicable to this agricultural waste are described briefly. In general, present water laws contribute to irrigation return flow quality problems. Irrigators use their full water rights, else they will lose them. Irrigators generally have a negative incentive to internalize the external diseconomies associated with their excessive use of water.