FARM‐LEVEL MANAGEMENT OF DEEP PERCOLATION EMISSIONS IN IRRIGATED AGRICULTURE¹

Abstract

Source control costs for deep percolation emissions from irrigated agriculture are analyzed using a farm‐level model. Crop area, irrigation system and applied water are chosen to maximize the net benefits of agricultural production while accounting for the environmental damages and disposal costs of those emissions. Deep percolation is progressively reduced as environmental and disposal costs are increased. This occurs primarily through the adoption of more efficient irrigation technology and reductions in applied water for a given technology Higher surface water prices, such as through irrigation reform and constrained surface supplies, are additionally considered in light of the drainage problem, as are the effects, both short‐ and long‐term, on ground water use.

A Water Transfer and Agricultural Land Retirement in a Drainage Problem Area

“…In the mid-1980s, elevated concentrations of selenium in ponds at the Kesterson National Wildlife Refuge were attributed to agricultural drainage water that had been used there as a source of water supply (Letey et al 1986;California, 1987;National Research Council, 1989;Posnikoff & Knapp 1997). Subsurface drainage systems served 3,035 ha in Broadview and, since 1983, most of the drain water was discharged into ditches that carried commingled surface and subsurface drainage water from several irrigation and drainage districts into the San Joaquin River.…”