Guest commentary: Using the Reasonable Use Doctrine to restrict riparian water use

Commentary by Craig Wilson, the first Delta Watermaster and former Chief Counsel to State Water Board:

The Governor recently stated that we need to step it up regarding responses to the epic drought that continues in California.  He then issued an unprecedented Emergency Order mandating urban water use reductions.   Yesterday the state Water Board issued an Order to implement this mandate.
The Order did address agricultural water use, but did not mandate any additional water use cuts for this sector. Since the issuance of the Governor’s Order, many have commented on the agricultural water use issue. Some have stated that agriculture has already done more than its fair share in cutting back on water use. They point to the drastic cuts in water allocations that agricultural customers of the major water projects have endured, the water use curtailments that have been imposed on junior water right holders, and the fact that agriculture is using less water per acre to grow crops due to efficiency improvements. On the other side of the debate there are comments that, since agriculture water use is many times that of urban water use, mandatory cuts in agricultural water use are appropriate.Since junior water right users and customers of the major water projects have already been cut, any major additional  agricultural water use restrictions would have to come from senior water right users, either persons who began diverting water to storage for later use prior to 1914 or persons who divert water pursuant to riparian water right. Riparian water rights are the rights of persons who own land along a watercourse to use water from that watercourse on their land.

It has been suggested that these two types of water rights can and should be curtailed pursuant the the state’s existing water right priority system. But, while that system is suitable to curtail water use by pre-1914 appropriators, its use to curtail riparian water right holders is problematic. Riparian water right holders are legally entitled to divert natural and abandoned (water that has been diverted but returned to the watercourse via runoff) water. Even in times of drought there is some natural and abandoned water in watercourses. Under these conditions, it is difficult to curtail riparian water use.

This is particularly true in the Delta, where there are many riparian water users. These users argue, not without persuasive merit, that there is always natural water flow in the Delta due to tidal action. While others can argue that most of the water entering the Delta during times of drought is not natural flow, but rather stored water being released upstream, any attempt to impose cuts on Delta and other senior riparians is likely to be resisted. Water wars could be ignited that would last for years without any water use restrictions.

There is another way to reduce water use by senior riparian water users, most of whom use water to irrigate crops. That way is to make more aggressive use of the state’s Reasonable Use Doctrine. In 2011, as part of my duties as the first Delta Watermaster, I submitted a Report to the State Water Board and the Delta Stewardship Council entitled” The Reasonable Use Doctrine & Agricultural Water Use Efficiency”. In that Report, I stated that the Doctrine is the cornerstone of California’s complex water rights laws. All water use must be reasonable regardless of the type and seniority of the underlying water right and what is reasonable can change based on the circumstances.

Applying the Reasonable Use Doctrine to agricultural water use the Report stated: ‘Practices that reduce consumptive water use can result in true water savings. There are proven measures and technologies available now to make agricultural water use more efficient. Many are already being employed in California and studies have shown that they work to reduce water use. Persons who do not employ some or all of these technologies where they are economically justifiable, locally cost effective and not harmful to downstream agriculture and other environmental needs are simply using water unreasonably.’

So how can the Reasonable Use Doctrine be used to restrict water use by senior riparian water right holders? The State Water Board has ample authority to issue Orders to implement the Doctrine. It can order senior riparian water users to reduce their water use by making efficiency improvements in their irrigation practices. Reducing unproductive evaporation and transpiration during the growing season will save water.

There are many proven techniques to to reduce water losses due to excessive evaporation and transpiration. Evaporation losses can be greatly reduced by prohibiting flood irrigation. Water delivery system improvements, weed control projects, and use  of soil moisture probes can all reduce evaporation. Projects to reduce transpiration water use by crops include fallowing land, planting crops that use less water, and growing the same type of crop, but with a variety that uses less water. A combination of such measures can make a significant dent in consumptive water use and can done this year.

 Conservatively, senior water rights attach to at least 4 million acre feet of water. A 20 percent reduction would save some 800,000 acre feet. This amount is nearly two-thirds the amount of water estimated to be saved by the drastic urban water use cuts imposed yesterday by the Water Board.  Orders developed by the State Water Board could require senior riparian water right holders to prepare and implement water use reduction programs within 30 days with a ten (or twenty) percent reduction goal. The water users’ program could rely on a combination of some or all of the above- mentioned measures.  Let the water users choose what best works for them. The Orders could require monitoring of actual water use and a final report documenting the water use reductions achieved. Use of the Reasonable Use Doctrine in this manner  is appropriate during this time of drought and can reduce water use by the last segment of major water users that have not been required to cut back: the senior riparian water users.  A result would be a true ” all hands on deck” approach where all segments of California’s water community play a major role in reducing water use during our epic drought.
Note:  This commentary was written by Craig Wilson, the first Delta Watermaster and former Chief Counsel to State Water Board.  The views and opinions expressed in guest commentaries are those of the authors and do not necessarily reflect the official policy or position of Maven or Maven’s Notebook.

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