Domenigoni: A Dam Site Too Expensive : MWD: A huge new reservoir would cost $2 billion, but water to fill it is problematic and there are cheaper alternatives.

The Metropolitan Water District is undertaking a historic and remarkably open assessment of its water supply and demand projections to determine how best to meet Southern California’s water needs for the next 20 years and beyond.

This assessment has made clear that a $2-billion construction program to build a new reservoir in the Domenigoni Valley in Riverside County is not needed: The water to fill it will not be there. Adequate storage is already available in Southern California to protect against drought and aqueduct failure. There are many underutilized local water supplies that are just now being evaluated.

Domenigoni Reservoir is being designed to store water from Northern California, water that is now in short supply. As the full implications of the Endangered Species Act and the means needed to protect and restore the San Francisco Bay Delta are finally determined, this supply will only shrink further. There may be surplus water during very wet years--one year or two in seven--for the reservoir. MWD may purchase water from agriculture to fill the reservoir, but we already have enormous unused storage capacity in Southern California. And there are no evaporative losses from underground aquifers.

A recent MWD report documents 2.6 million acre feet of storage in our Southern California aquifers, more than triple the proposed storage capacity of Domenigoni. This storage capacity is not evenly distributed beneath member agencies’ communities, and there are insufficient physical connections and no negotiated agreements so that the member agencies could jointly benefit from this capacity. In fact, those who manage our aquifers met together for the first time only this past spring to talk about how to work together. Solving these institutional constraints is much cheaper, though maybe not easier, than the very expensive engineered solution planned.

The cost of Domenigoni, and for some needed water-quality improvements, is tripling the wholesale cost of water this decade. This increase is already causing many member agencies and subagencies to look for alternatives to MWD to meet local needs. Many alternatives are available, starting with using what we have much more efficiently.

Experts say that MWD can easily conserve and reuse more than twice its current projections. Some member agencies are doing a good job of replacing old-fashioned flush toilets that use as much as 7 gallons per flush with 1.6-gallon-per-flush models at a cost lower than the current wholesale cost of MWD water. Some have not begun, just as some are not yet taking seriously the enormous potential for reclamation and reuse. Nor has the impact of the increasing cost of water on people’s choice of landscaping materials been evaluated.

The firm yield that can be developed by using surface water supplies in conjunction with ground water is now under study, as is the potential for developing local ground water that is too high in dissolved solids to be potable. It is much easier to remove these solids than to desalinate sea water.

As the wholesale cost of water continues to escalate, local supplies look better and better. Beverly Hills is drilling new exploratory wells after having closed down its old wells years ago. Burbank is talking about getting off MWD water altogether. Other agencies are working to develop their ground water in conjunction with agencies without ground water who are not even neighbors, demanding that MWD’s pipelines be made available to move the water. These and other creative ideas are just beginning to surface, showing that local water agencies prefer to invest in reducing demand and in their own local supplies.

As these local supplies are developed, MWD will sell less water, causing the fixed costs of an expensive reservoir to be spread over fewer customers, raising the cost of MWD water even higher and stimulating further development of local resources. Since MWD’s member agencies have not yet committed to paying for the huge new dam--what they call an insurance policy--and given the uncertainty about the supply to fill it and the underdeveloped storage and local supplies in Southern California, the only responsible course is to re-evaluate Domenigoni now, before any more money is spent. This project is just too expensive, the supply to fill the dam isn’t there and there are cheaper alternatives.