On average, rain and snow storms drop about 200 million acre-feet of water on California each year – 65 trillion gallons of the life-giving liquid.
Nearly two-thirds of it either evaporates, sinks into the ground or is absorbed by trees and other plants while the remainder, 70-plus million acre-feet, finds its way into rivers flowing either to the Pacific Ocean or several inland “sinks.”
Californians divert more than half of that runoff to drink, irrigate farms, water lawns, brush teeth, remove bodily dirt and myriad other uses. Agriculture accounts for about three-quarters of the human diversions.
When you include millions of acre-feet of water pumped from underground aquifers each year, you have California’s water supply, and were we able to count on that 65 trillion gallons of precipitation each year, we wouldn’t have a water problem.
However, we can’t, and as we deal with the third year of severe drought and consider the potential effects of climate change, we are beginning to rethink how we manage water in terms of both supply and reliability.
The water bond that Gov. Jerry Brown and the Legislature placed on the Nov. 4 ballot recognizes – belatedly – the need for managerial changes to become more efficient in water use, especially in agriculture, to upgrade water quality and to place more water in storage during wet years to offset volatility of precipitation.
There’s renewed interest in charting and regulating the uses of groundwater because aquifers are being drawn down sharply due to the drought, causing land to sink in some regions, perhaps to the point of making aquifers incapable of regeneration during wet years.
Finally, we are seeing the beginnings of what could be, politically, the most difficult of all water policy changes – recasting water rights that date back, in some instances to when Spain controlled California.
Last week, two University of California researchers published a study finding that just since 1914, California has allocated water rights equal to five times the 70 million acre-feet of annual runoff from precipitation, mostly to federal, state and local government water agencies, and about nine times current diversions.
The study implies that our structure of water rights is completely nonsensical, particularly since, as it notes, the Water Resources Board, which supposedly regulates supply, has absolutely no idea who is taking what under those rights.
Bringing some managerial logic to the situation would be extremely difficult, but not impossible. As the UC study points out, both Australia and South Africa have reformed their water rights in recent years.
Dealing intelligently with long-term water supply reliability will become more difficult if climate change affects precipitation patterns, but will be impossible without rational groundwater regulation and water rights reform.