Improving Water Distribution Efficiency in Imperial Valley
Each year, California’s Imperial Valley consumes 977 billion gallons of water from the Colorado River, primarily to produce two-thirds of the vegetables that the United States needs in the winter. Yet when it was discovered that the area was wasting billions of gallons of water, questions were raised about the area’s water management. Specifically, the problem of water wastage put a spotlight on the practices of the Imperial Irrigation District (IID), responsible for water use in the Imperial Valley.
Following several years of hearings and investigations, it was discovered that much of the water loss within IID could be reduced through reasonable conservation measures. Many of IID’s water losses were thought to be due to canal spills and excess tailwater (surface runoff resulting from crop irrigation). Several other factors may have contributed to the loss of water (estimated in the range 35-40 percent), such as maintaining canals in overly full conditions, the absence of regulatory reservoirs, an excess delivery of water to farmers’ headgates, the absence of tailwater recovery systems, the need for an irrigation education program and the need to line main canals and lateral canal.
The lack of reliable information on the sources of water loss within IID, however, impeded the development of a comprehensive water conservation plan. This placed the IID in violation of the California Constitution, more specifically of Article X, Section 2, which prohibits the waste, unreasonable use, unreasonable method of use or unreasonable method of diversion of water. The State of California Water Resources Control Board required that the Imperial Irrigation District take several actions to improve its water conservation program.
In 1988, the IID turned to the Metropolitan Water District (MWD), in an innovative partnership aimed at improving water supply reliability for urban Southern California, and improving the leaky irrigation system in the Imperial Valley. Metropolitan paid the cost of improving Imperial’s distribution system, including such measures as concrete lining earthen canals, constructing local reservoirs and spill-interceptor canals, installing non-leak gates, automating the distribution system, and altering water delivery timetables, as well as the cost of on-farm conservation measures consisting of tailwater pumpback, drip irrigation and linear move irrigation systems.
These measures were great successes – yet with population increases in Southern California, Imperial Valley cannot depend on the status quo. The area must continue to be conscious of its water use, and must continue searching for solutions to improve the sustainability of its water management, while at the same time meeting the agriculture needs of America.