Breakthrough on Measuring Farm Water Use Bodes Well for New Water Savings in California


This week, a critical milestone that can eventually save a significant amount of water was passed when the California Water Commission gave its unanimous approval to a rule proposed by the Department of Water Resources (DWR) that requires large irrigation districts to measure the water delivered to each of their customers.  California’s landmark Water Conservation Act of 2009 requires large agricultural water suppliers to measure how much water they deliver to individual farmers, both to serve as the basis for volumetric billing of customer water use and to provide more accurate data on the amount of water actually passing through each irrigator’s farm gate. 

In the agricultural sector, measuring water deliveries and charging based on how much water is used is a critical water efficiency tool that can help improve water use efficiency and farm productivity.  Nearly all urban water suppliers across the country measure their water deliveries and bill customers based on how much water is used, and these tools have been shown to improve efficiency by 20%.  Until now, however, most agricultural water suppliers in California were not required to measure how much water they were delivering nor to bill individual irrigators according to their measured water use. 

Thus, although many irrigation water suppliers already measure agricultural water deliveries at the farm gate, a surprising number do not, especially in the rice growing region of the Sacramento Valley, where application rates are enormous.  To place this issue in perspective, California is the #2 rice producing state in the nation, and in 2010, over 550,000 acres of rice were harvested, more harvested acreage than any other crop in the state except hay.  By applying about 5 feet of water to rice fields each year in California’s semi-arid climate, rice production draws nearly 3 million acre-feet of water per year, a staggering amount of water roughly equal to the customer demand of five cities the size of Los Angeles.  So a requirement for water measurement and volumetric billing in rice country could bring new attention to rice production and management practices that might eventually save a significant amount of water – but only if regulations effectively implement the law. 

As recently as January, the California Water Commission approved a muddled rule that was designed to broadly exempt rice-growing districts and many additional districts receiving water from the federal Central Valley Project.  In a highly unusual move, the state’s Office of Administrative Law, which must approve state agency rules for both substance and process, agreed with NRDC and rejected the draft regulation, finding it was not consistent with the 2009 Act.  By the Department’s estimate, fully half the acreage in the Sacramento Valley covered by the Act was not expected to implement farm gate measurement under their initial rule.

The Department reconsidered its approach following the rejection by the Office of Administrative Law in February and at the continued urging of NRDC attorney Doug Obegi and his colleagues at the Sierra Club and the Pacific Institute.  (Urban water suppliers, who know the value of water measurement, were conspicuously absent from this debate.)  The just-approved rule removes the broad exemptions sought by rice-producing districts, and instead establishes performance standards that all water suppliers must meet and lets water suppliers determine the most cost-effective way of meeting them.  The regulation lays out numeric requirements for the accuracy of water measurement devices, and requires that an engineer validate their accuracy.  While the accuracy testing and certification requirements are less rigorous than we would have preferred, the new rule is nevertheless a giant step forward for water conservation in agriculture, an industry that uses 80 % of the state’s developed water supply. 

Making more efficient use of irrigation water will be crucial for maintaining the agricultural economy of the Golden State and the health of its rivers and fisheries in the years ahead.  This rule, by providing more accurate water use information and enabling the introduction of volumetric pricing, begins to align the financial interest of individual farm operators with the broader community interest in making more efficient use of irrigation water.  Innovative district managers are already setting out to find economical ways to measure their deliveries.  And as rice prices, while off of their highs of 2008 and 2009, remain historically strong, there’s no better time than now to upgrade the water delivery systems upon which this crop depends.  And the good news for water managers and consumers throughout the state is that the Water Conservation Act will be enforced even-handedly so that its water-saving purpose will actually be achieved.

As noted above, the Office of Administrative Law must sign off on this rule before it can take effect.  A decision from OAL is expected within the next three to six weeks.  Stay tuned and follow us on Twitter at @NRDCWater for the latest.