Delta Watermaster Craig Wilson talks to the Delta Stewardship Council about expanding "Term 91"

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After the conclusion of the public hearing on the rulemaking package on January 24, the Delta Stewardship Council held their regular monthly meeting.  The sixth item on the agenda was Delta Watermaster Craig Wilson, who presented his latest report, Term 91: Stored Water Bypass Requirements.

California Water Code directs Mr. Wilson to submit regular reports on water issues to the State Water Board and the Council.  His most recent report describes how Term 91 is currently being imposed on some junior water right holders, how expanding Term 91 could improve Delta water quality, and recommends expanding Term 91 requirements on a phased basis in accordance with water right priorities.

Mr. Wilson began with a brief history of the events that led up to the creation of a Term 91, the “stored water bypass requirement.”  The State Water Board was created in 1967 to merge two separate agencies, a water rights board and a water quality board.  “The idea was that water quality issues affected water rights matters and vice versa,” he said, “and nowhere is that more apparent than in the Delta, and I think the efforts of the water board over the years to deal with beneficial uses in the Delta is a perfect example of how those two functions have been merged.”

Since the 1970s, the water board has adopted a series of water quality control plans to protect beneficial uses in the Delta.  The plans state water quality objectives and standards, including flow standards, and also contain implementation plans on how to achieve those standards, Mr. Wilson explained:  “Term 91 is an example is how the water board has used its water rights authority to implement some of the standards in the water quality control plan.”

Term 91 is basically a subset of an introduced and well-understood water rights principle, Mr. Wilson explained:   No water right holder has a right to use water that was previously stored or imported by another water right holder upstream and then released into the water course for use downstream. Such water has already been appropriated and is not natural or abandoned flow.

As an example, Mr. Wilson said that in the spring, summer and fall, there’s a lot of stored water being moved around the state, so on any given watercourse, stored water is basically comingled with natural and abandoned flow. While the natural water flow is subject to the state’s water right system and priorities, in the case of stored water, billions have been spent to create a water project to store and release the water later for beneficial use, so that water is not subject to the normal water rights situation.  Those who developed that supply have a right to the water; even senior water right holders are not supposed to be diverting stored water, whereas they have the complete ability to do so for natural and abandoned flows, he explained.

There are two key water right principles that have an impact on stored water bypass requirements, Mr. Wilson explained.  The first is the rule of priority in the water right system, which completely and validly applies to natural and abandoned flows.  The rule against diverting stored water is not implicated for natural flows, he pointed out, and persons must bypass natural flows to senior water right holders when they need it.  The second principle that has an impact is the principle of area of origin.  With ‘area of origin,’ people can establish water rights to divert natural and abandoned flows, even if they are junior to the projects and other people who are outside the area of origin.  It is a sort of flipping of priorities, he said: “Regarding stored water, area of origin still has a role to the extent that stored water bypass requirements are applied on a priority basis, and if people want to contract for stored water, they may have some sort of leg up in that process.” To further clarify, he added: “If an area of origin type of entity wanted to create a project, come to the water board and seek an appropriate permit to do that, they may be able to go to the head of the line because they are located in an area of origin.”  He noted that the issue is currently pending before the federal courts right now and the outcome is uncertain, but there is some legal support for an argument that the area of origin people have some type of priority to stored water flows.

The State Water Project and the Central Valley Project store large amounts of water in the winter and spring, and then release that water for transport south either for their customers or to meet downstream needs and requirements of the water board.  When the water board adopted Delta water quality control plans in the 1970s, they required the water projects to meet certain water quality objectives, including flow requirements.  The effect of these water right conditions is to actually require the projects to release from storage or to curtail diversions when flow of water entering the Delta would otherwise be insufficient to meet some of the water quality standards, Mr. Wilson explained.

After those requirements were put on the projects, they started protesting subsequent water right applications in order to protect their water supply, so Term 91 was developed to share the allocation of who was responsible for meeting these flow objectives.  Term 91 basically specifies that certain permittees are prohibited from diverted stored water which is being released by the major projects to meet water quality standards or other in-basin requirements.  This basically applies to post-1965 permittees and licensees; they cannot divert project water when natural flows are insufficient to meet water quality standards and the projects are releasing water to meet the standards, Mr. Wilson noted.  When it was originally adopted, it was intended to be an interim solution but instead, it has become a long term method of attempting to allocate the responsibility for meeting water quality standards in the Delta.

Only 120 permittees have Term 91 conditions, and these are permittees that are junior in water right priority to the projects.  “These were the applications that were protested by the projects after their obligation to meet water quality standards was imposed and the water board decided to impose a stored water bypass requirement on those junior permittees and licensees,” he said.

When the water projects are going to  release stored water to meet water quality standards, they notify the water board.  It can be early in the year or later in the year, depending upon how much flow is in the system.  “For instance, if the curtailments and restrictions apply May through August, about 90 of these permittees and licensees are asked to curtail their water use.  If it’s been a wet year and the obligation to meet standards doesn’t kick in until later in the year, it can be as few as 25 or 30 permittees, and there actually have been three years in the past decade where flows have been sufficient that none of these junior water right holders were required to curtail their water use,” Mr. Wilson said.

After the water board is notified, it issues a “notice of curtailment” to the 120 (or less) permittees that are subject in a given year.  The permittees then have to file a certification that they either ceased or curtailed their diversion, purchased water, or had an alternative source such as another water right they held such as a riparian or 1914 water right.  The State Water Board does some sporadic compliance checking, Mr. Wilson noted.

In 2012, the board was notified in June that they would be releasing water to meet water quality standards, and so curtailment letters were sent to 27 permittees in July.  The curtailment period was in the month of August, and eventually compliance certifications were received from all 27 permittees that were subject to Term 91 that year.  “There were some compliance checks done, some field work, office reviews, and no instance of violations were found.  Everybody that was subject to the curtailment requirement complied with it as far as we could tell,” he said.

Mr. Wilson’s report recommends a possible expansion of Term 91, based on the general legal principle that downstream water right holders should not be diverting stored water, and term 91 is only a subset of that, he said:  “The law is perfectly capable of allowing an expansion of Term 91 should it be necessary.  And in fact, a wider application of the curtailments could spread the obligations to meet water quality standards more fairly, and requiring a broader group of people to comply could help achieve standards and increase the likelihood that they will be met.  So for the Delta, the expansion of the term could be very important for protecting the Delta’s beneficial uses.”

The State Water Board is currently revisiting flow standards, Mr. Wilson noted:  “We don’t know how that’s going to come out.  The revisions could require a more natural hydrograph type of approach, or they could revise the standards, and if they are, then the implementation phase of achieving those standards they could possibly be looking at expansion of Term 91 as one method to achieve them.”

Currently, Term 91 applies only 120 post-1965 permittees, but it could be expanded to more senior appropriators and be phased in based on priorities.  Back in the 1990s, the water board considered possible expansion of Term 91, looking at it in quite some detail, Mr. Wilson noted, but at the time, the water projects and other entities came to the water board with their own agreements to allocate responsibility.  “The Department [of Water Resources] and the Bureau of Reclamation came back to the board and said don’t expand it, we have these agreements worked out, we will be the backstop, we will guarantee that they are met, and we have these agreements with these other entities,” Mr. Wilson said, noting that several agreements were entered into at the time and Term 91 was not expanded.

Mr. Wilson acknowledged that the same thing could happen this time, however “the alternative to that would be actually using an expansion of Term 91 and not having actually agreements between the projects and the entities, but actually curtailment requirements imposed upon more senior water right holders regarding stored water.  Again, I want to emphasize this has nothing to do with natural flow or abandoned flow; the water right priority system fully applies in that situation,” he said.

The term could be expanded to those who are not regulated directly by the water board, go all the way down to the pre-1914 appropriators and even riparians, he acknowledged, but even in the dry periods of the summer, “in-Delta diverters, I can’t imagine a situation where they are brought into this , although I guess it would be theoretically possible,” he noted.  In order to expand Term 91, there would need to be some type of proceeding to impose the term on other permittees and licensees of the board.

To wrap things up, we’re trying to ramp up and do a better job of enforcing and applying the existing term 91 requirements and the recommendation of this report is to consider expansion of term 91 requirements more broadly to apply to stored water bypass obligation, or as an alternative to that, go through the process where agreements are achieved between the project operators and other entities to more fully and fairly allocate this responsibilities,” Mr. Wilson concluded.


  • Click here to view the video of the meeting (Agenda Item 6).
  • Click here for Delta Watermaster Craig Wilson’s power point.
  • Click here for the report, Term 91: Stored Water Bypass Requirements
  • Click here for Maven’s Notebook Report Summary for Watermaster’s report on Term 91.
  • Click here for the Delta Watermaster, in his own words, on the roles and responsibilities of his office.
  • Click here to visit the Delta Watermaster online.



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