This week the State Water Resources Control Board was briefed on a report prepared by Craig Wilson, the new Delta Watermaster. Although Mr. Wilson’s authority as Delta Watermaster to enforce permits and licenses is limited geographically to the boundaries of the Delta, the Legislature, when creating this new position, also directed the Delta Watermaster to inform the State Board on water issues generally. The Watermaster’s first report (PDF) broadly examines the “reasonable use doctrine”: the constitutional principle that forbids waste and mandates that state water resources be used reasonably and beneficially. This concept is a water rights trump card that applies to all water use in California, but this report was concerned mostly with the politically-loaded topic of agricultural water use efficiency.
Craig Wilson both opens and closes his report with the following statement:
“Inefficient water use is unreasonable water use.”
So bold and elegant in its clean, unclouded simplicity, is it not? The report acknowledges that although the reasonable use doctrine is the “cornerstone” to California water rights, the doctrine is rarely invoked and has not come into its own as an effective enforcement mechanism. Comprehensive study of what it means and how it can be leveraged is overdue. But even as the report outlines certain techniques that conserve agricultural water, it merely hints at the challenges of using this slippery notion to encourage or require substantial improvements in efficiency and conservation.
The 2009 Legislation
It’s simple enough for an appointed Watermaster to make a bold pronouncement in a relatively isolated setting, but it’s quite another matter for elected legislators to do so when drafting a bill. The Legislature turned down the opportunity to do exactly that when passing SB X7 7 as part of the 2009 package of water legislation. SB X7 7 enacts the 20 x 2020 water conservation plan, which requires urban water suppliers to reduce per capita water use at least 10 percent by 2015 and 20 percent by 2020. Although SB X7 7 imposes numeric conservation targets on municipalities, it excuses agricultural water suppliers from achieving similar targets. Instead, the bill requires that agricultural suppliers adopt certain efficient management practices, including measurement of water deliveries, and that they prepare agricultural water management plans by 2012, which will be updated again in 2015 and every five years thereafter, just as municipalities do now.
Although conservation is regarded as a tool to prevent waste, SB X7 7 does not clearly equate a water supplier’s failure to meet these requirements with unreasonable use. Indeed, the legislation shields urban water suppliers from administrative or judicial proceedings based on the failure to achieve their numeric targets. So even if an urban supplier is behind on meeting its target and thus seems to be “wasting” water, its right to the extra water cannot be yanked away just because someone waves a piece of paper crying waste and unreasonable use. All bets are off once 2021 rolls around; but even then, it’s not clear that there would be a finding of unreasonable use.
The bill could have turned out differently. The Legislature had an opportunity not only to create more aggressive conservation requirements for agriculture, but even to declare that categories of inefficiency are unreasonable. It did neither. As it stands now, SB X7 7, if nothing else, serves as a reminder that extracting concessions in the legislative process is never easy. But it may also present an opportunity for the State Board to take a more proactive approach. SB X7 7’s requirements for agricultural conservation are not comprehensive, and the State Board has room to maneuver by establishing a separate but complementary regulatory program involving the reasonable use doctrine. At the same time, though, there are many reasons why the State Board should proceed with care.
Water Conservation in the Agricultural Sector
There is clear value to increasing water conservation efforts in the agricultural sector, particularly given the large share of water in California that is allocated to agriculture. Craig Wilson’s recommendation that the reasonable use doctrine be used more proactively to achieve conservation goals has merit. And yet, Mr. Wilson’s equation of inefficiency with unreasonable use, while offering an elegantly simple principle, does little to simplify the practical complexities inherent to agricultural conservation. Presumably, this is the type of discussion that would take a place at the summit that the report has recommended be convened.
One important concern and source of complication is return flow. Irrigation results in some water being consumptively used through evapotranspiration (ET), which includes both water that evaporates and that which is transpired by crops. Return flow, on the other hand, is not consumptively used and instead joins the stream, either as surface runoff from the field, or as percolation to the aquifer that later discharges to the stream. Even if an upstream grower uses a lot of water to irrigate in a way that’s not particularly efficient, the balance of water that isn’t consumptively used by the upstream grower eventually joins the river as return flow, where it then can be used downstream (although the quality of the return flow may be degraded). This has prompted the observation that the best way to study water use efficiency is at the scale of the whole basin or watershed rather than the individual grower.
Stated differently: in order to successfully achieve conservation in agriculture, there should be a reduction in the quantity of water that is consumptively used at the basin-wide scale. Patching up leaky canals might increase efficiency of the irrigation system, but if it doesn’t reduce the volume of water consumptively used through ET, then it’s reducing return flow without getting to the heart of the conservation question. Consumptive use can be reduced through many different practices.* Ultimately, though, it is difficult to estimate how much water could be conserved in the aggregate because we lack good data as to how much acreage is already being managed using these practices.
Conservation measures that reduce the quantity of irrigation water applied to crops will correspondingly reduce return flow. If the State Board identifies measures that reduce consumptive use, it should also strive to minimize adverse impacts that accompany a reduction in return flow, including impacts to both fish and wildlife and supply. The precise nature and extent of those impacts will likely vary from system to system and depend on local conditions. For example, suppose that an upstream grower uses flood irrigation, which is generally less efficient but generates substantial return flow. The portion of return flow that percolates is delayed before it discharges to the stream, thereby providing downstream growers with water late in the irrigation season. If the upstream grower were to suspend flood irrigation and instead adopt more efficient irrigation techniques, the delayed return flow would diminish. This would, in turn, impact downstream growers, who would lose a once-reliable source of irrigation water. Although it may be tempting to simply declare that flood irrigation is an inefficient — and hence unreasonable — use of water in all situations, that categorical declaration will overlook local conditions. Considering case-by-case details is necessary to understand the impacts but will ultimately complicate the State Board’s task of deciding whether a particular irrigation practice should be deemed unreasonable.
It’s a complicated topic, and we’ve only scratched the surface here. The Watermaster’s report is just an initial effort — but it makes an important statement, and I agree with Mr. Wilson’s basic premise that the reasonable use doctrine can be leveraged as a more proactive enforcement tool for the State Board, provided that adequate administrative resources are allocated to the task. It is both logical and fair to require that the agricultural sector more uniformly pursue best practices in effective conservation. But that doesn’t make it any easier to reconcile broad, constitutional principles with complex, on-the-ground realities, all while attempting to achieve substantial water conservation statewide. It is too soon to say whether this effort will succeed, but it is almost certainly guaranteed to be interesting.
* Management techniques are not limited to fallowing or shifting from field crops to vegetables that require less water (a practice that limits farmers’ flexibility to adapt to market conditions). Other techniques include scheduling irrigation on the basis of daily ET information supplied at weather stations, as well as using regulated deficit irrigation, in which less water is applied during periods when crops can tolerate it, thereby saving water while avoiding negative impacts to yield. Although the State Board could conceivably focus on these techniques as examples of reasonable use, implementation requires capital investment in on-demand irrigation systems, which give growers the flexibility to apply water when and to the extent that it’s needed.