http://www.capoliticalnews.com/s/spip.php?breve1984
Map of Pittsburg, California here:
http://maps.yahoo.com/maps.py?&addr=&csz=Pittsburg,CAContra Costa Times, 06/11/2007
EVERY YEAR for at least the past two decades, California has added a half million people to its population. But during that time the only significant reservoir to open was Las Vaqueros. No new major water conveyance system has been constructed and there are none planned.
Thanks to successful conservation efforts and that there have been no severe droughts in 30 years, California has been able to meet its demands for fresh water. That may not be the case in the future unless some major changes in water policy are made.
More can be done with conservation and reuse, but these efforts are not likely to be enough as California continues to grow. The state will have to increase water storage above and below ground, and it needs to find other new sources.
There is only one new source of water available to California, and it is inexhaustible: the Pacific Ocean and its bays and estuaries.
However, tapping that source is not yet financially feasible, but it may well be in the years ahead. What is required are economic desalination plants to convert salty sea water into fresh water.
Getting fresh water from the ocean has long been a dream. But it could become a reality in the not too distant future.
New technology has cut the cost of desalination in half since 1990. Continued progress could reduce the cost even more as the cost of water from traditional sources increases or simply is not available.
Taking the salt out of water requires considerable energy, which is why it is so expensive. Converting sea water to fresh water now costs about $2,500 per acre-foot, enough to supply a family of five for a year.
By comparison it costs the Santa Clara Valley Water District $300 to $400 an acre-foot to buy and treat water from state and federal agencies.
There are 20 desalination projects in the planning stages along California’s coast. One of the most ambitious and promising ones is being considered for Pittsburg.
The four largest Bay Area water agencies plan to hire a firm by next month to build a $1.9 million pilot desalination project in Pittsburg. If all goes well, a large plant will be constructed by 2012 to provide 71 million gallons of fresh water a day. It would be among the largest desalination projects in the world.
Building a plant in Pittsburg has several advantages. Most important, it would extract water with salinity levels far below those in the ocean. The plant would use existing intake and outfall structures and be close to economical energy sources and electric transmission facilities.
As a result, the plant would be able to produce fresh water for $500 to $1,200 per acre-foot, depending on salinity levels.
There are other hurdles besides cost to overcome. Desalination plants need to make sure they do not harm wildlife with their intake pumps, and brine must be discharged in an environmentally sensitive manner.
Desalination alone is not going to solve California’s water problems. More conservation, reuse and storage will be required. But once the cost and environmental hurdles are cleared, desalination can become an important source of fresh water, particularly in droughts, when other sources dry up and reservoirs are low.
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