Folsom Lake Marina at Folsom Lake, at 17% capacity in February 2014. Photographer: Ken James/Bloomberg
Folsom Lake Marina at Folsom Lake, at 17% capacity in February 2014. Photographer: Ken James/Bloomberg

California's northern rivers are so low that young Chinook salmon have to be trucked on their journey to the Pacific Ocean. Yet to listen to some farmers and their political allies, you would think the fish, shielded by environmental law, are doing fine, while the state's $45 billion agricultural economy is being sucked dry by the epic drought.

Their solution: build huge tunnels, expand big dams (federally subsidized, of course) and pipe more water from the relatively wet north to the dry south. But Mother Nature is sending a different message: California can't count on having bounties of water to meet all the claims on it.

Although some new storage plans make sense -- especially small-scale, local projects and repairs to existing infrastructure -- no new mammoth public works are going to draw more water from the sky. That 20th-century strategy perpetuates wasteful agricultural practices and antiquated water-rights laws. California's water future would be better secured through measures that make the most efficient use of every drop.

Despite the recent rainstorms, the Sierra Nevada snowpack, on which much of the state will depend for water in the dry months to come, is at a quarter of its normal level. The state hopes to rely more on groundwater, but that resource has been dangerously depleted and polluted by previous droughts and overuse. Farmers, who use 80 percent of California's water and produce almost half of all U.S.-grown fruit, nuts and vegetables, are fallowing 500,000 of the 8 million acres cultivated.

Just 38 percent of the state's fields are watered using efficient drip- or precision-sprinkler irrigation systems, according to a 2010 survey. Farmers who have yet to switch from flooding or spraying entire fields need the nudge of loans or rebates.

Incentives are also needed to get farmers to adopt technology to improve irrigation timing. Newer systems can measure the moisture in soil, take the weather into account and even withhold water when a crop is in a drought-tolerant stage of growth. These methods can reduce energy bills and improve crop yields and quality.

If taxpayers subsidize these improvements, farmers in turn will need to refrain from using the water they save merely to expand their operations. The state should end the "use it or lose it" system for water rights that has prevailed for too long. In some cases, it makes sense for municipalities to fund irrigation improvements in exchange for the water that farmers save.

The Pacific Institute estimates that efficiency measures could reduce agricultural water use in California by 15 percent and urban use by 30 percent. The organization calculated that a package of measures producing a savings of 1 million acre-feet of water a year would require an upfront investment of $1.87 billion. By contrast, the proposed Temperance Flat dam and reservoir -- which would be federally financed -- would produce just 158,000 acre-feet of water yearly, at a cost of $3.4 billion. A plan supported by Governor Jerry Brown to build two tunnels beneath the Sacramento-San Joaquin Delta would cost $25 billion.

Farmers complain they are being victimized while few city and suburb dwellers face mandatory restrictions on water use and can still enjoy their lawns and golf courses. This is a fair criticism.

Crazily, water customers in 42 California communities, including Sacramento, the state capital, still pay a flat rate. According to an analysis by the San Jose Mercury News, those places use 39 percent more water per person than the state average. Communities should charge so-called block rates for water, so that the more water a household uses, beyond a reasonable amount, the more it costs.

Localities can expand their supply by recycling more wastewater. Treated wastewater can be used for irrigating fields and landscapes, for industry and for recharging groundwater. The state already recycles about 670,000 acre-feet of treated wastewater yearly, though that's far less than the 3.5 million acre-feet that are discharged into the Pacific.

The California Legislature should add enforcement mechanisms to a 2009 law requiring the installation of high-efficiency toilets, faucets and showerheads in commercial and residential properties by 2019. Water districts should cooperate with energy utilities to offer rebates for clothes washers that use 15 gallons of water per load instead of the 60 gallons that old machines require.

The rest of the state should follow the lead of the Metropolitan Water District, which services southern California, in paying customers to replace their lawns with plants such as salvia and agave that are adapted to the arid climate. About half the water the district sells to residences is used on landscaping.

These changes may sound minor, but in a state with more than 38 million people they add up. And they promote the goal of shared sacrifice. For all the talk of how the drought is inflaming the political divisions between cities and farms, the truth is that Californians are in this one together.

To contact the senior editor responsible for Bloomberg View's editorials: David Shipley at davidshipley@bloomberg.net.