Harvesting the Deluge is an Opportunity for Californians

It doesn’t take a hydrologist to know Californians are getting an unusual amount of rain. Totals in the San Francisco Bay Area are an astonishing 600 percent of normal for this time of year. In almost every watershed throughout the state, total rainfall is well above normal, and in the Sierras, the all important snowpack is now sitting at exactly 200 percent of normal.

With this quantity of water already delivered from the sky, with so much more on the way, one might think that drought restrictions could be lifted. But not so fast. Despite predicting for years that Californians were going to need to rely less on a diminishing snowpack and more on harvesting water from storm runoff, the state has done little to take advantage of the new normal. When the rain stops and the snow melts prematurely, Californians will likely face another year of drought restrictions.

It didn’t have to be this way. In 2014 voters overwhelmingly approved Proposition 1, a water bond that would have funded the sort of water storage projects that we could use right now. But that was over 8 years ago, and not one project has started construction. The proposed Sites Reservoir, an offstream facility originally planned to hold two million acre feet, remains tied up in litigation, endless planning, and only half-hearted and belated efforts by the state to secure matching federal funds. The proposed Temperance Flat Reservoir, which would have held 1.5 million acre feet and which would have been built upstream from an existing reservoir, was killed by state bureaucrats in defiance of the will of the voters.

But even if these reservoirs were built, would they have been filled? In just the first eight days of 2022, over 1.5 million acre feet of runoff has flowed through the Sacramento/San Joaquin Delta, but of that, only 138,000 acre feet has been diverted by the state and federal pumps into the aqueducts we depend on to deliver water to reservoirs in southern and central California. This is less than half what these pumps are capable of moving south.

Californians should be asking why, when levees throughout the Delta region are currently failing from flooding rivers, it isn’t possible for existing infrastructure to be used to move desperately needed water south to badly depleted storage facilities?

The solutions to flooding and the solutions to drought have a compelling symmetry. If you solve one, you have probably also solved the other. New proposals that would permit more fresh water withdrawals from the Delta even during periods of reduced precipitation should be evaluated and fast tracked. For example, the San Joaquin Valley Blueprint proposes to install perforated pipes into engineered channels to divert tens of thousands of acre feet per day without disrupting currents or harming fish populations.

Along with more surface storage, California’s capacious aquifers offer the means to store millions of acre feet of runoff. While percolation basins permit slow recharge of groundwater, recently discovered underground flumes hold the potential to allow rapid diversions of water into underground storage.

Across California’s cities, a recent study by the Pacific Institute claims up to 3.0 million acre feet of storm runoff can be harvested and treated every year, an amount equal to nearly 50 percent of California’s total urban water demand.

There are plenty of ways to solve California’s new set of water challenges, and there is plenty of money to get it done. What is lacking is the will to legislate remedies to the many bureaucratic and litigious obstacles, so Californians can plan and complete these projects in years instead of decades.

This article originally appeared in the print edition of the Orange County Register.

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