Abstract

Irrigation return flows (IRF) are considered the major diffuse or non-point contributor to the pollution of surface and groundwater bodies. Water pollution standards and emerging policies regulating the discharge of the IRF are being implemented in developed countries. The degree of the off-site irrigation-induced pollution depends on the hydrogeological characteristics of the irrigated land and substrata, the agricultural production technologies used, and the water supply and drainage conveyance systems. This entry reviews these issues in IRF, describes the main components and chemical constituents of IRF, and summarizes recommended management practices aimed at reducing the off-site water quality impact from irrigated agriculture.