A Silver Lining in a Cloud Possibly Looming over the Woodland-Davis Clean Water Agency Water Project

Written by Administrator Monday, 05 September 2011 07:07

By Alan Pryor -

For full disclosure and to allow readers to weigh the merits of the facts later in the article, I have been a long term strong supporter of the Woodland-Davis Clean Water Agency water project. I believe, that we cannot continue to suck more and more groundwater from an aquifer with finite capacity forever.

Since that fateful decision to pass on acquiring Putah Creek surface water rights, we have watched our intermediate aquifer wells deteriorate to the point where they almost unusable for potable purposes without blending with better quality water from deep aquifer wells drilled in the past decade. Now, we may very well see water quality standards tightening in the next few years with respect to hexavalent chromium that may dramatically (by many, many fold) increase the cost of treating that deep aquifer water to meet drinking water quality standards. Combined with the fact that the City is currently in violation of a number of wastewater discharge standards as a result of the deteriorating quality of our current well water, it is clear that the "free-water ride" for Davis is over.

Failure to take aggressive action now to secure a stable future water supply could result in diminishing water quality, restricted availability, and huge increases in our water and waste water treatment costs. Fortunately, another opportunity has presented itself to the City to acquire surface water rights that is now before us and the City has the opportunity to partner with Woodland to take advantage of this perhaps last opportunity.

But there are always a few wrinkles to work out as a project of this magnitude works its way through the regulatory, engineering, and financial analysis maze to completion. As it turns out, one of the biggest wrinkles to surface may, in fact, be able to be turned into an advantage to the cities of Davis and Woodland and result in very substantial near term capital and future operating cost savings for the proposed water project; albeit at the expense of loss of acquisition of senior long term water rights.

One issue involves water supply and the "splitting" of existing senior water rights between the Woodland-Davis Clean Water Agency ("the Water Project") and the Conaway Preservation Group.  The other involves plant capacity and options to balance water needs with water availability at various times during the year.  They are complex, interrelated issues.

The Water Project involves the acquisition of two different types of Sacramento River water rights allowing for the use of the river water by the Water Project. One set of licenses covers junior water rights for the use of up to 45,000 acre-feet per year by the Water Project which is the bulk of the water expected to be drawn from the Sacramento River. This water is free to the project and the only costs are for pumping and treatment. The permit for the rights to this water has already be approved by the State Water Board

However, these are "junior" water rights meaning there is a limitation on their use during normal years when summer water flow is low and water is released from Federal and State dams to allow for required inflows into the Delta. These limitations are known as Term 91 restrictions and prohibit use of the water from the Sacramento River by junior rights holders when low flow conditions exist.

According to the Environmental Impact Report (EIR) submitted by the Water Project to the State Water Board as part of the project evaluation, it was predicted that such water use by the project will only be allowed from 5 to 7 months of the year during the late fall, winter, and early spring. The water obtained under these junior water rights would normally be expected to supply more than 100% of the water needs of Woodland and Davis in normal water years if the use of such water could be spread over the entire year.

Unfortunately, that will not be the case unless some means of storing water pumped during the winter for summer use is employed. In the absence of a such a means to store water drawn during the winter months and held for summer use or obtaining alternate rights to summer water use, the cities would be forced to rely solely on well water separately pumped by each cities' existing wells during the summer.

To partially cover this summer shortage, the water project has also signed an agreement with Conaway Preservation Group (the owners of Conaway Ranch) granting the project "senior" water rights allowing use of up to 10,000 additional acre-feet of water per year which use can be made during summer months even when Term 91 restrictions are otherwise imposed. The term of this agreement was for 24 years after which the water project would hold the senior water rights in perpetuity. The price paid by the water project to Conaway for acquisition of these senior water rights was $2,600,000 per year starting in 2016 and increasing 2% per year - or totaling about $80,000,000 during the 24 year period. That works out to a price of $260/acre-foot in the first year. Project proponents claim this is a very fair and equitable price especially since permanent rights are obtained after 24 years. Project opponents claim this is expensive compared to the cost of pumping groundwater. The later claim is certainly true if groundwater quality could be guaranteed, wastewater discharge standards for selenium are loosened, and new drinking water standards are not imposed for hexavalent chromium.

The State Water Board must also approve this agreement and that is a wrinkle.  The existing licenses covering these senior water rights now held by Conaway Ranch must be split. In June, an application to allow for such a split was made to the State Water Board by Conaway Preservation Group.

Such water transfer applications are subject to protests filed by other parties and during the allowable protest period 5 protests were submitted from the US Bureau of Reclamation, the California Department of Water Resources, the California Department of Fish and Game, the Natural Resources Defense Council jointly with Defenders of Wildlife, and a private individual. Conaway Preservation Group has 180 days to settle these protests through negotiations with the protesters or the protests must be considered and evaluated by the State Water Board when considering the license split application early next year. While it is standard with any water rights applications that many parties will protest, if the protests are not settled in this case, the approval for the license split could be in doubt.

In addition to the lack of proper environmental review and mitigation particularly with respect to impacts to protected species and habitat, the main arguments of the protesters are that the proposed "license splits" are actually nothing more than groundwater substitutions by Conaway Ranch. That is, Conaway is planning on drilling +/- 18 new groundwater wells adjacent to Willow Slough which runs through the Conaway Ranch.  Willow Slough is tributary to the Sacramento River so the argument is made by the protesters that this is like sticking another straw into the River since they are hydraulically connected.

Nor can Conaway Ranch split the licenses without substituting groundwater because they still have to engage in actively farming the property according to the agreement Conaway Ranch signed with Yolo County when the complex series of agreements surrounding the water project were negotiated. Given this dilemma, the approval of the Conaway license split application and the acquisition of these senior summer water rights for 10,000 acre-feet is not yet a done deal.

What happens if the split license is not approved? It would appear that the water project would not get these senior rights and would have to instead rely on the 45,000 acre-feet for generally 5-7 months of the year to which it currently has junior rights and pays nothing. This would also mean that the water project would save $80,000,000 otherwise due to Conaway Preservation Group over 24 years but would lose the free perpetual rights to this water thereafter. But it also means that the water project would also have to figure out how to make the 45,000 acre-feet drawn during the winter months last through the entire year if they wanted to avoid relying entirely on well water during the summer. Of course, the only possible solution is to store the water drawn from the river during the months of plenty for subsequent use during the dry summer months.

This brings us to the next wrinkle which is plant capacity. Regardless of whether or not the water license split is allowed, the water project still faces the dilemma of efficiently treating and delivering the 45,000 acre-feet of junior water rights water that can be drawn during an approximate average of 6 months each year because this amount is far in excess of the combined needs of Woodland and Davis during this period each year. In other words, they can't just pump it and treat it because it has no place to go.

Building tanks for such storage would cost far in excess of the cost of the water itself. The only other viable alternative is to store the water BELOW ground by using aquifer injection. This is a common conservation method now routinely done in Southern California which has been plagued with water shortages for many years. It is a relatively new concept in Northern California because of our relative abundance of water which is rapidly drawing to a close.

Fortunately, the water project has planned for the need for such envisioned conjunctive use of the water and the City of Woodland is now drilling an aquifer storage injection well for test purposes. Even if this aquifer injection model works, there still remains the problem of the water project's treatment plant capacity being effectively utilized.

For example, if the treatment plant treated the entire 45,000 acre-feet during the 6 months of the year when it will be allowed to draw this river water and delivered this water to Woodland and Davis for injection in their own aquifer storage wells, the plant capacity would need to be about 250 acre-feet per day. But after 6 months the plant would only be utilized to treat the 10,000 acre-feet obtained under the senior water rights license split or be mothballed for 6 months until the next wet winter season came when it could again start processing its 45,000 acre-feet during the ensuing 6 months. Paying for such treatment capacity and underutilizing it or idling it 6 months of the year does not make economic sense.

The only viable alternative solution would be for the water project itself to inject 50% (or more) of the raw river water directly into aquifers near to the treatment plant. This raw water could then be drawn back out of the aquifers during the 6 months when water cannot be drawn directly from the river. After recovery from the wells, this water could then be treated in the normal manner and subsequently delivered to the respective cities. If done carefully and properly, the water treatment plant capacity could be then reduced by up to 50% from 250 acre-feet per day to about 125 acre-feet per day. While this will not reduce the treatment plant costs by half because many of the plant costs are fixed, huge savings could still be realized.

Combined with the $80,000,000 saved by not purchasing the senior summer water rights from Conaway Ranch IF the senior water rights license split is not granted, total project capital and operating costs could be easily reduced by well over $150,000,000 and probably much more. That would pay for a whole lot of injection wells.

In addition to the substantially reduced costs associated with this approach, this proposed solution allows a great deal of flexibility to the water project in terms of efficient use of water resources. For instance, it would provide the water project the ability to sell additional treated water it acquired for free to Woodland (allowing greater growth in that City if desired) or sell water to the University of California at Davis (to reduce their own reliance on groundwater) during summer months.

Plus because Davis would not be so reliant on groundwater during summer months (although some blending with groundwater will almost certainly be necessary), it substantially reduces salinity and selenium in the City's wastewater discharge thus satisfying those legal discharge requirements also.

By providing a more uniform, very high quality water supply throughout the entire year, the City could also ban water softeners (because they would be completely unnecessary) thereby reducing salt loading into the waste water system by almost 7,000,000 pounds per year further easing the load on the wastewater treatment plant. 

But there are still a few more wrinkles to work out. For one, although the hydrogeological studies performed by the water project engineers indicate that such aquifer storage is a viable option, we really won't know for sure until the Woodland test well is complete and operating for some period of time.

Another problem is that there has to be adequate aquifer storage capacity near the water project treatment plant itself to store the raw river water for later treatment during the summer. This would mean that envisioned injection wells run and maintained by the cities of Woodland and Davis, respectively, to store treated water within their own municipal boundaries would no longer be necessary. The availability of land for these injection wells local to the planned water project treatment plant itself has not been investigated to my knowledge but it seems plausible that reasonably close locations for the wells could be secured.

Yet another problem is that the initial EIR submitted by the project to the State Water Board did not address such substantial aquifer storage so an entirely new EIR must be prepared and submitted to the State Water Board when applying for a new license allowing for such storage. This, of course, would require a whole range of new engineering analyses to be performed. An additional EIR is being planned for the water project for submission to the Water Board to allow for the water project to construct their own outtake facility in the event funding is not available to Reclamation District 2035 which is currently seeking such funds to construct a joint outtake facility with the water project. It would certainly save many hundreds of thousand of dollars and months of time if such an EIR and subsequent permit application also included the analysis and request to the Water Board for such conjunctive aquifer storage.

Finally, even with such a solution, the City of Davis summer water needs would probably still not be entirely satisfied requiring some use of existing deep aquifer wells by the City. Or in the alternative, the City could finally get serious about summer water conservation and implement a widespread public and private xeriscaping program in the City.

But for potential savings by the water project of $100,000,000 or more, it would seem to be well worth the effort and result in a water delivery system that is a world-class model of efficient, economic use of dwindling water resources and be our legacy gift to the next generation of Davis residents.

Author's Note: This was a very difficult article to research and write because of the complexities of state water laws. After submitting it for review to both water project proponents and opponents, I found that nobody was happy. Proponents of the project claim I am raising issues of tangential importance late in the game, that my article diminishes the importance of the senior water rights acquisition, and that it unfairly casts the water project in a negative light by speculating that substantial savings might accrue if these sublicenses are not approved - i.e. implying they are not necessary. Opponents of the water project claim I am minimizing the importance of the possible loss of the senior water rights water rights and gloss over the other shortcomings they perceive to be inherent in the water project. All I am trying to do is presents facts as they now stand and  propose eventual solutions to vexing water storage problems the water project must overcome whether the senior water rights transfers are approved or not.

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