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America's Debate > Archive > Assorted Issues Archive > [A] Science and Technology > [A] Environmental Debate
I draw my water from a well as do most of my neighbors. We live on the central coast of Calif. where there are a considerable number of farms which also pull water from the water table. The result is we are suffering severe salinity problems in many of the wells due to the replacement affect as water from the ocean steadily replaces the fresh water withdrawn.

In other areas of the country the land is sinking as the inland aquafirs are being steadily depleted. I understand that nationally the aguafirs are being drawn on at a rate that is 25% higher than the recharge rate.

I would be interested to get some discussion going on this subject as I believe eventually it will be an issue that world wide will be more important than oil.
We are experiencing a similar problem on the southeast coast. It doesn't really affect me because I live in downtown Savannah and we get our water from the Savannah River pumped in by the city.

In the outlying areas, particularly in the suburbs of Savannah (if one could call them that), they get most of their water from the Florida Aquifer. My understanding of the Florida Aquifer is that it has three layers. The top is a salt and fresh water mix. The second and third are fresh water. The suburbs draw their water from the second layer and it is getting maxed out. They want to begin drawing from the third but the some experts are saying it will make all three layers unstable - meaning the salt layer will be drawn into the fresh water layers and ruin all the fresh water.

Currently, like most beauractic situations, this one is still "in discussions" to determine what should be done.

I don't know what kind of efforts are being put into desalinization technology, but I think that may be the direction to go. Of course, I know little about science, so I have no real basis for my suggestion. wink.gif
Alan Wood
Being a very dry country, water is our most precious commodity in Australia.
We have been through several years of low rainfall with water restrictions.
A lot of our wheat growing and pastoral areas have been declaired 'disaster' areas because of the drought.
We depend heavily on bore water and, like you, are suffering badly from salinity.
The other problem being chemical fertiliser, specifically those used in the suberbs on gardens. Our soil is mainly sand based with little, if any, nutreants. These are seeping into the bore water and rivers.

Although I live in the Monterey Bay Area I was interested this time in exploring the water situation and history surrounding my original hometown of Santa Barbara, partly because it is more water starved and because up until recently the area seems to have been largely self-sufficient. I was particular interested in their building of a desalination plant and emphasize that a lot in this piece.

The below links are a product of a journey I took this evening covering what it takes to keep one community alive. I will offer a sample from each link to show that at least I did my homework.

The County's residents obtain their potable water from several sources: groundwater withdrawal, storm runoff collected in reservoir systems, the State Water Project, recycled water and desalination. The County's potable water supply is delivered to the public through a variety of water purveyors: incorporated cities, community service districts, water districts, private water companies, conservation districts and others.

The City Council decision to build a desalination plant came at a time when the Santa Barbara south coast was in the midst of severe drought emergency. Gibraltar Reservoir (the source of one third of the City's annual water supply) was empty, and Cachuma Reservoir (source of more than one-half of the City's supply) was projected to empty within two more years. Santa Barbara water users had reduced consumption by 47% and were facing a potential 80% shortage by spring of 1992,with-out significant rainfall or a new supply which would not be dependent on rainfall and which would be large enough to replace up to one-third of the City's normal supply. Based on these conditions, the City of Santa Barbara, the County of Santa Barbara and the Governor of California all declared a drought emergency in Santa Barbara. Santa Barbara City staff determined that a project to desalt seawater would be a feasible solution to the drought emergency.

In the RO process the seawater is filtered at high pressure (800 to 1,000 pounds per square inch) through advanced synthetic membranes which screen out over 99% of the salts and minerals.
Forty-five percent (45%) of the seawater is recovered as fresh water. Fifty-five percent (55%) of the high pressure concentrate passes through an energy-recovery turbine and is pumped back to the City's wastewater outfall and mixed with the City's treated wastewater. The combined effluent is discharged a mile and a half offshore in 75 feet of water. The conditions at the end of the outfall are monitored to observe any effect on the environment.

The drought of the early 1990's showed that the pre-drought water supplies were inadequate. In 1990-1991, an extensive analysis was done to determine which water supply alternatives would best insure adequate water supplies for the future. The analysis showed that either desalination alone, at a capacity of 5,000 AFY, or the State Water Project at an entitlement of 3,000 AFY with a desalination capacity of 3,000 AFY as a drought back-up, were the best alternatives. In June 1991, City voters supported both the State Water Project and desalination as permanent water supplies and the City has included the combined State Water Project/ desalination option in its Long-Term Water Supply Program (LTWSP).

With the Goleta and Montecito Water Districts no longer participating in the facility, the City decided to sell a portion of the capacity. In January 2000, just over half of the pre-filtration capacity and reverse osmosis treatment modules were sold, leaving sufficient capacity to meet the City's anticipated need for approximately 3,000 AFY of production in future droughts.

Is is true the City has a seawater desalination plant?

Yes. In 1990-91, a 7,500 acre foot per year plant was constructed in response to severe drought. It has since been included in the City's long-term water supply plan.

Is the plant operating now?

No. Due to ample rainfall in recent years, cheaper surface water is available and it is not necessary to run the plant at this time. However, during future droughts the plant will be needed to avoid the hardships experienced during the drought of the late 1980's.

How does the cost of desalinated water compare to other available supplies of water?

The annualized cost of water from the desalination plant is approximately $1,500 per acre foot of produced water, which is very close to the cost of water from the State Water Project and the City's Water Reclamation Project, two other recent additions to the City's water supply mix.

Dingo-This gives a pictorial view of Californias many major water projects financed by Federal State and Local agencies.

Dingo-this gives a clearer picture of the hook up of a southern california community like Santa Barbara with a Northern California river like the upper Feather River by drawing off the Calif. Aqueduct.

In my view coastal communities like Santa Barbara should not rely on water drawn from Northern California and the Sierras and should not cut back on their desalination facilities. If these facilities produce extra water they should relieve the wells and enhance the recharge back into the water table and reservoirs. These communities should look to the ocean as a chief source of additional water and also emphasize water conservation and growth limitation.
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