California's San Joaquin Valley is one of the most fertile agricultural areas in the world, encompassing almost 5 million acres of productive farmland. A substantial portion of the Valley, about 2.5 million acres, is threatened by saline shallow groundwater which salinizes agricultural lands. The problem occurs mainly on the Valley's west side. Between 1977 and 1991 the area affected by saline shallow groundwater in the west side doubled to about 750,000 acres. The result is waterlogged, saline soil that threatens the economic viability of thousands of acres of farmland.

In addition, the irrigation drainage water is sometimes contaminated with naturally occurring - but elevated - levels of selenium and other toxic trace elements that threaten the water quality, environment, and survival of fish and wildlife. This threat, first noticed in the mid 1980s, resulted in closing several drainage systems in the Valley's west side adding to the drainage water disposal problem.

The Department of Water Resources, with other State and federal agencies, local water and irrigation districts, resource conservation districts, educational and research institutions, growers, consultants, and others, is finding cost-effective ways to manage irrigation drainage water efficiently without harming agricultural production. The goal is to reduce drainage water at the source - the farm - while maintaining a salt balance in the root zone sufficient to maintain productivity. This is being done partly by on-farm demonstration and study projects where state-of-the-art irrigation and drainage management practices are used. As a result, more growers and local agencies are improving their irrigation and drainage management practices to control the drainage problem.