Choice of options is driven by data, not obsession

March 13, 2014 

In his March 6 letter to The Cambrian (“Set record straight”), former Cambria Community Services District Director Lou Blanck makes the erroneous claim that the CCSD has ignored cheaper water-supply alternatives in what he calls its “obsession” with desalination.

Describing a water master plan adopted by the CCSD board when he was a member, he lists four “components” of that plan in order of cost, with “emergency, temporary, portable desal” the most expensive. The others were conservation, “dry side-canyon diversion reservoirs” and wastewater recycling.

This water plan was not carried out, but most of its proposed steps have been studied and found to be very expensive for the amount of water they would produce.

The one component that’s hardest to price is conservation. Blanck says this is the cheapest, but the example he gives — “individual home cisterns for reuse of gray water” — would be anything but cheap for homeowners (or for the CCSD ratepayers if this work is subsidized).

Gray water systems require new supply and sewer plumbing within homes, on-site water treatment, and backflow preventers to keep gray water frommigrating back into the CCSD potable water system.

Imagine doing this for thousands of homes and you can see why a massive gray water retrofit has not happened here.

It’s easier to gauge the cost of diversion reservoirs — supposedly the next cheapest proposal — and they come with a high price tag. CDM Smith Engineering studied one such scheme, for three reservoirs off San Simeon Creek, and pegged its cost at $69.7 million. That was more than four times the projected cost of a permanent, fully owned brackish water desal plant then under study.

A new proposal to build a reservoir on the Clyde Warren property is no cheaper. It would cut the needed number of reservoirs to two, but it would require more cut-and-fill over all, at higher cost. The problem with any of these off-stream reservoir plans is that they require large dams, with lots of expensive earth-moving, and deliver little in the way of reliable storage after evaporation is taking into account.

Wastewater treatment, supposedly the third cheapest idea on Blanck’s list, may have a lower price tag than off-stream reservoirs, but it would provide relatively little water for the money spent. In 2004, the CCSD’s Recycled Water Distribution System Master Plan determined that about 50 acre-feet could be supplied for current irrigation use from recycling, along with another 50 acrefeet for future needs, such as irrigation at a new community park.

However, because our wastewater plant does not use an ocean outfall for its effluent, permitting a recycled water system could further reduce the volume available for future needs.

The projected cost for a recycled water system was $5.5 million, for only 50 to 100 acre-feet of non-potable water. That’s less capacity than what is needed and also far more expensive on a unit price basis than water from the CCSD’s wells or, for that matter, from treating brackish water to produce potable water.

Far from being “obsessed” with one solution, the CCSD has been quite willing to look at new ideas for solving Cambria’s chronic water shortage. What we know from past studies, as well as from a series of four public workshops held at the Veterans Memorial Building during 2012, is brackish water treatment, which includes a desalination process, is actually the most cost-effective approach towards securing additional potable water for Cambria.

Jerry Gruber is general manager of the Cambria Community Services District.

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