There's a measurement called an"acre-foot," that not too many people are familiar with -- but which you are more likely to hear about in the coming years, as national and global demand for drinking water grows.
An acre-foot is the amount of water needed to cover one acre of land to a depth of one foot. To put it in more familiar measurements, one acre-foot of water comes to just under 326,000 gallons, or a little more than 43,500 cubic feet of water. One acre-foot is also calculated as the amount needed to satisfy the annual water needs of three average households.
Water utilities spend a lot of their time thinking in acre-feet, especially as they work to meet rising demands for fresh water. Joshua Haggmark, acting water resources manager in Santa Barbara, California, says his city uses about 14,000 acre-feet of water per year.
Like other major urban and agricultural centers in drought-stricken California, Santa Barbara is scrambling to find alternative water sources -- to keep its population hydrated and the state's economically-essential agricultural industry from withering away.
Santa Barbara is unique in one sense: It's currently preparing to refurbish and restart the city's water desalination plant, which has sat idle for nearly two decades. But it won't be cheap, even with the head-start of having much of the facility infrastructure still in place.
The process of desalination, or turning brackish water or sea water into drinking water, has been used worldwide for decades -- and is coming back into economic vogue in the U.S. after earlier outcry about its costs. California in particular has more than a dozen desalination plants in the planning stages.
Desalination has taken root in other traditionally dry parts of the country that are also looking for more dependable sources of water. The Houston Chronicle reports there are currently 46 desalination plants in Texas. And according to the newspaper one utility, the Brazosport Water Authority, has a $60 million project underway to convert the massive saline aquifer under metro Houston into millions of gallons of drinking water.
Given water's rising costs, the new project might even be cost-efficient. The Brazosport Water Authority reportedly estimates it would cost $543 dollars to desalinate one acre-foot of brackish water, compared to the $733 per acre-foot cost of desalinating seawater.
But the underlying reality is, whether from desalination or other sources, the costs of water are going up nationally. In Santa Barbara, Joshua Haggmark says it will cost the city at least $20 million in capital costs to reactivate the local desalination facility, with an additional $5 million in annual operating costs, to eventually produce a capacity of 3,000 acre-feet of drinking water a year, starting several years from now.
But Haggmark says his utility is looking at the possibility, once the desalination plant is restarted, of keeping it operating on a very reduced capacity -- and with lower operating costs -- so it can respond to drought conditions as needed.
People in Santa Barbara "probably pay some of the highest water bills in the country, at $80 to $90 a month," said Haggmark, "but it's still less than people's cell phone or cable bills. The new norm is much higher costs for water, particularly as the resources here become more scarce and we get more water quality issues."