Marin's water-supply problem

MMWD is weighing a proposal to build an expandable five-million-gallon-per-day desalination plant on the shores of San Pablo Bay.

Because of its unique circumstances MMWD, which serves most of Marin County south of Novato, is the only Bay Area water agency to be considering desalination. Unlike the other large water providers, MMWD gets no water from the Sierra. We rely on local reservoirs for 75% of our water and on the Russian River water for 25%. We have only enough water storage for two consecutive dry winters; a third drought year would force a 65% reduction or more in water use, which could threaten public health and cause severe economic problems to our area.

Fortunately, in recent history the District has had only one severe drought, in 1976 - 77, plus a more modest dry period from 1989 - 94. The winter of 2006 - 07 was extremely dry, however, and the current year started off similarly. At the end of December it appeared that MMWD might face severe rationing for 2008, but a very wet January has removed the immediate threat. Even if this year's rainfall does prove adequate, it reinforces the threat of the drought that will inevitably come to us in the future. The proposed desalination plant would enable the District to better survive future dry periods.

The main problems with a desalination plant are the energy and financial costs. It takes large amounts of energy to push Bay water through reverse-osmosis filters, and so the plant would add significantly to MMWD's carbon footprint - when we have just adopted a pledge to dramatically reduce it. The high costs of construction and yearly maintenance would also increase water bills. Fortunately the energy needed to run a desalination plant has dropped by more than 50% in the last 10 years, and newer nanotechnology is likely to continue that trend. According to experts in membrane technology, energy requirements for desalination are likely to drop another 30 - 50% in the next 10 years, making desalination increasingly attractive in many parts of the world. MMWD is also exploring whether the proposed plant could be run using renewable energy sources such as solar and wind, thus reducing the plant's carbon footprint.

A major problem for most desalination plants is how to get rid of the salty discharge water without environmental damage. MMWD would avoid this problem through a unique partnership with Central Marin Sanitation Agency (CMSA). We plan to mix our discharge with the unsalty treated sewage from CMSA, thus creating an effluent close in salinity to natural Bay water; the desalination plant could actually benefit the Bay. This feature of the MMWD plant helped MMWD secure a $4 million Proposition 50 Grant from the state.

One alternative to desalination is to dramatically reduce outdoor water use. MMWD already has one of the most comprehensive conservation programs in the nation, combined with a steeply tiered rate structure where large water users pay 600% above the basic Tier 1 rate. Nevertheless, watering of landscaping, a large part of which is climate-inappropriate, still accounts for roughly 1/3 of total use. Most of this water is expended during the summer, before we can know whether the following winter will be wet or dry. If enough MMWD customers could be convinced to grow climate-appropriate vegetation, we could save enough water to survive a drought longer than two years. In MMWD surveys, however, the most controversial question was one asking if people would be willing to change their plantings.

MMWD has recently more than doubled its conservation budget; the new expanded program includes:

• generous rebates for ultra-low-flow toilets and water-efficient clothes washers;
• landscaping rebates for more efficient irrigation systems and soil improvements;
• a massive public outreach to schools and community organizations.

It is still uncertain whether these recent measures will be enough to allow the District to survive more than two consecutive dry winters without dangerously low water levels.

Another alternative would be to bring in more water from the Russian River, but this idea is currently not feasible due to legal and environmental problems. By 2012 the environmental and legal difficulties in the Russian and Eel River watersheds may be resolved. If so, the preferred solution for water from the Russian River would be to build a pipeline parallel to Dry Creek to bring water directly from Lake Sonoma, ending our reliance on diversion from the environmentally threatened Eel River. Such a pipeline would also remove the need to move water through Dry Creek itself, so that water needs will no longer override protecting the creek's fish habitat.

The current situation is difficult. We must balance our concern to reduce greenhouse gases with the water-supply needs of more than 180,000 people. Further, if the desalination plant is not built, we must avoid provoking a voter backlash that could undermine the range of green policies of the current Board of Directors.

The Sierra Club's national guidelines on desalination (click on "Water Resources" and then "Desalination Guidelines") state: "Desalination should not be used for water supply needs that can be met by water conservation, water recycling, and other water use efficiency practices." Marin is a situation where we have to make a careful determination whether appropriate alternatives can work.

The greatest amount of discretionary water use in MMWD is for personal irrigation, and it is in this realm that the battle may be fought. How much personal irrigation can we ask our ratepayers to give up to obviate the need for a desalination plant? I as a Boardmember, as well as the Sierra Club Marin Group and other Marin environmental organizations, are now grappling with this question.

MMWD has issued a Draft Environmental Impact Report on the project. Public comments are due by March 7. MMWD extended the comment period to 120 days, rather than the more typical 60 days, to guarantee the highest level of community participation. The DEIR process gives the Sierra Club and our environmental allies a great opportunity to help shape the policy debate on this difficult choice. To find out the current status of the Group's deliberations, visit the web site.

Alex Forman, member of the Marin Municipal Water District Board of Directors (MMWD) since 2000, and co-chair of the Sierra Club Marin Group's Political Committee.