Desalination

One way to create new water resources is to reclaim water located in brackish aquifers or the ocean by way of desalination. The technology is available, but costly. Table 4.1 summarizes the costs of desalination for various sources. Over 500 desalination plants, mostly located in California, Florida, Texas, and Arizona, produce approximately 12 percent of the worldwide output of desalinated water (CCC, 1993).

Table 4.1: The typical costs of desalination, 1992 dollars (CCC, 1993)

Desalination Source	Capital Cost ($)	Product Cost ($/ac.ft)
Seawater	20,300,000	1,300
Brackish groundwater	7,000,000-10,000,000	440--500
Municipal wastewater (excludes cost of pretreatment and distribution)	6,400,000	540

Since farmers currently pay only about $70 per acre-foot of water, the high cost of desalination makes it unlikely that agriculture could subsist by using this technology. However, in California desalination has proven useful in providing water during short-term emergency shortages.

Beyond the issue of cost, desalination has a number of other problems:

• Facilities must be constructed near the coasts, which tend to be sensitive environmental areas. Plant and animal habitats could be disrupted by the presence of a desalination plant.
• Facilities must dispose of the salts that are removed from raw water; this highly concentrated brine requires specialized disposal.
• Desalination is a very energy intensive process. For example, before the Santa Barbara reverse-osmosis plant shut down, it used about 6,600 kWh of electricity per acre-foot of water produced. In states already suffering from energy crises, these high electricity demands make desalination a less attractive alternative. (CCC, 1993).