The state of California is struggling through the third year of a serious drought, but even in "normal" years Californians use far more water than is really available. And if we made four basic, common-sense changes in the way we use California water, we'd have enough to go around even in drought years, which is good for us and wildlife.
That's the gist of a report released today by the Natural Resources Defense Council (NRDC) and the Pacific Institute, which says that four straightforward initiatives to reduce water use and increase supply could save as much as 13.8 million acre-feet of water per year -- well over the amount used by all of California's cities.
That would be a big change from the status quo, in which we currently overtap California's rivers and groundwater by around 6 million acre-feet per year, and we'd get there by using water more sensibly, taking advantage of currently available technology already being used by many Californians.
The report, The Untapped Potential of California's Water Supply, finds that Californians take about 5 million acre-feet per year more from the Sacramento-San Joaquin watershed than can be taken sustainably, while groundwater pumping takes somewhere between 1 and 2 million acre-feet more from aquifers each year than comes back into those aquifers through natural recharge.
That's the inevitable result of a Twentieth Century water policy that focused almost entirely on building new dams and canals and drilling new wells, with only the slightest lips service paid to conservation.
But that can't continue. "We've hit the wall in California," said report co-author Peter Gleick of the Pacific Institute, during a press phone call to announce the release of the report. "We've passed Peak Water."
The good news, according to the report, is that a combination of agricultural and urban water use efficiency, reusing water, and capturing urban rainwater to recharge aquifers is expected to free up between 11 and 14 million acre-feet per year. That's more than 20 times the annual water use of Los Angeles, and it's equivalent to building and filling up three new reservoirs the size of Lake Shasta.
According to the report, water conservation in the agricultural sector, which used 80 percent of the state's water, could free up 5.6 to 6.6 million acre-feet per year without fallowing acreage or changing to more water-efficient crops. That's about 20 percent of the sector's current water use. The report recommends abandoning flood irrigation for drip or efficient sprinkler irrigation, along with scheduling irrigation to encourage more droughty crops and conserving soil moisture through mulching or other means.
Conservation in urban areas, including replacing inefficient appliances, fixing leaks, further encouraging property owners to rip out their lawns, and other efficiency measures would conserve up to 5.2 to 7.1 million acre-feet per year, about equivalent to urban Southern California's annual water use.
Reusing water from municipal and other sewage systems for landscape and crop plant irrigation, industrial use or other applications could mean reducing demand for 1.2 to 1.8 million acre-feet of "unused" water, freeing that up for other uses -- including leaving it in the river or aquifer. And the stormwater that now falls in our cities and towns and is dumped at sea through storm drain systems could instead be captured and used to replenish aquifers, the way it used to before we paved over all the porous surfaces that used to soak up the precipitation. Homeowners can also capture their rooftop runoff in rain barrels for later use to water their gardens. The report's authors estimate that could provide between 400,000 and 600,000 acre-feet of water a year for groundwater replenishment, roughly in the ballpark of Los Angeles' total annual water use.
During Tuesday's press event co-authors Gleick and the NRDC's Kate Poole demurred on estimating what the cost of these measures would be, pointing out that costs vary widely from region to region within the state. There's also the complexities involved in figuring out the greater cost of not using our water more sensibly. How many dollars have been lost to our economy due to closures of fisheries, loss of tourism revenues, and slumps other industries dependent on a healthy landscape?
The report's authors claim that these programs would free up enough water to restore the Sacramento Delta and end the mounting issue of groundwater overdrafting. They may be optimistic, but given that their recommendations are all things we should be doing anyway, that hardly matters.