PL 92-500 Versus Pollution by Irrigation Return Flow

The need for control of pollutant discharges via irrigation return flows (IRF) is obvious and is required by PL 92-500. The NPDES permits must, by statute and regulation, require that Best Practicable Control Technology Currently Available (BPT) be achieved by July 1, 1977, and that Best Available Control Technology Economically Achievable (BAT) be implemented July 1, 1983. Conventional treatment of IRF is clearly cost-prohibitive. Pollutant discharges by IRF can be controlled through optimum water use, optimum and carefully controlled applications of pesticides and fertilizers, elimination of tailwater discharges, and water reuse. Implementation of such controls through NPDES can be achieved through a program of EPA-funded demonstration plots in each major irrigated area. Optimum practices should be employed upon each plot to ascertain quality of drainage that can be attained by operators within the district or area. BPT and BAT could then be defined for permittees within the district or area. NPDES permit limitations should be based upon the BPT or BAT determinations thus derived.