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Putting desalination into perspective

By Jerry Paul, Santa Cruz Sentinel,  05/06/12

The Santa Cruz City Council’s intention to ensure ample water is much appreciated.

However, engineers have identified options trouncing desalination: less expensive, more energy-efficient, triple lifetimes, keeping lots more money circulating locally.

The facts below show there’s far more water than we need; our actual water problem is the lack of infrastructure to store enough winter river water — our major source — to boost the health of our fish populations and aquifers, while seeing us comfortably through summers and occasional droughts.

Let’s simply call the proposed desal plant’s annual capacity “one desal,” or 2,790 acre-feet. The San Lorenzo River’s average yearly output is 34 desals. Including nearby streams we average 44 desals — 44 times the desalination plant capacity!

Net water use upstream is negligible because septic and irrigation systems eventually return water underground to the rivers. The Santa Cruz Water Department diverts only four desals for human use. So 90 percent of our 44 desals escape us.

We’re in a wet climate. Local mountaintop average annual rainfall comes up to your chin, literally. Our problem isn’t shortage, it’s storage. Santa Cruz Water Department Director Bill Kocher said that another Loch Lomond [the three-desals reservoir near Zayante] would solve the problem.

City and county officials have identified viable storage areas.

The most promising include: Loch Lomond; Hansen and Olympia quarries on Mount Hermon Road; Cemex quarry near Davenport; and especially the aquifers under the Soquel and Scotts Valley areas. If developed, they could collectively store 20 to 90 desals of water.

Furthermore, storing in coastal aquifers is the only way to prevent seawater from shutting down our wells.

In the occasional drought year, Santa Cruz lacks no more than two desals. To completely cover monster two-year droughts, we might want to store four desals, or twice what the desal plant could supply.

Pipelines to/from storage areas run roughly $1 million per mile, far cheaper than the roughly $180 million financed cost of desal — about $3,000 for each of the 60,000 adults served — over and above regular water bills.

Adding renewable energy sources [$10M?] is fine. But why squander those sources on an energy-hog like desalination?

Desalinating any water mass requires an amount of energy that could lift that mass over our heads almost a mile into the sky.

In contrast, the lift from Felton to Scotts Valley is 280 feet; the lift of Loch Lomond spillover to the top of Soquel’s aquifer is 23 feet; or to Scotts Valley’s aquifer it’s downhill. Many of the 25 water alternatives require no energy.

To help fish populations flourish, much water is needed at specific places and times — a situation made far more manageable using capacious storage and water­looping [repeatedly re-using water by pumping it upstream]. We now pump from Felton to Loch Lomond.

City officials have taken a $14 million look at desalination, but no equivalent look at many projects involving other districts’ cooperation [“conjunctive use”], though officially recommended by top-notch consultants. County Water Director John Ricker says he would need $2 million to vet and price the leading water alternatives. Only then will officials be able to fulfill their fiduciary responsibility to prove before EIR hearings in August whether desal is the best choice, and can’t be postponed.

Two things to do immediately:

Sign the petition giving you a desal vote that cannot be overridden by the City Council (Visit rtvod.org or call 419-6441).

Urge officials to commission John Ricker’s studies.

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