Ringside: When it Comes to Water, California Needs to Think Big Again

For most of the previous century, Californians successfully designed and built big water infrastructure. In sixty years, from 1910 through 1970, we built the most impressive system of interbasin transfers in the world. The Los Angeles Aqueduct, Hetch Hetchy Aqueduct, Colorado River Aqueduct, Delta Mendota Canal, Friant-Kern Canal, and California Aqueduct. Altogether these conveyances are over 1,500 miles in length and every year they move millions of acre feet from where water is found to where water is needed.

For more than a half-century since then, progress has slowed. The proposed Delta Conveyance – a 45 mile long tunnel under the Sacramento-San Joaquin Delta, with an internal diameter of 36 feet – regardless of its virtues or detriments, has been mired in controversy. If it were built and run nonstop at maximum capacity, it could move over four million acre feet per year.

With or without a tunnel, how the Sacramento-San Joaquin Delta is managed needs an urgent upgrade.

Here is a list of solutions, each of which deserves serious evaluation. An assortment of them combined and implemented would restore water abundance to California.

The opportunity is huge. In 2023, a very wet year, 5.2 million acre feet (MAF) was pumped south from the Delta, while 27.2 MAF flowed to sea. The delta pumps (state and federal) only operated at half their capacity in that year. What if there were safe ways to remove more water from the delta during wet years?

Starting upstream, improved weather forecasting could mean less water would have to be released from major reservoirs to leave vacancy for unexpected late spring runoff. At the same time, California’s aging major reservoirs could be dredged, with the rich silt made available for habitat restoration and levee upgrades. Completing off-site reservoirs like the embattled Sites project, or an off-stream reservoir on the Consumnes River, would also add storage for release later in the summer, as would upstream aquifer recharging. Extending the 26 mile Folsom South Canal another 20 miles to connect to the aqueduct pumps at the Clifton Court Forebay is another way to store and manage delta bound runoff from the American, Cosumnes, Mokelumne, and Calaveras rivers.

Millions of acre feet of additional upstream storage would be feasible by taking these steps, but the ability to rapidly and safely withdraw water from the delta requires additional projects. Of immediate urgency is to dredge about 85 miles of channels in the south delta in close proximity to the pumps. With five decades of silt accumulation that gets worse every year, if these channels aren’t deepened to historical depths, the pumps will have to be shut off even more frequently in order to prevent them from drying up. If they are deepened, it is likely the pumps could be operated more often, moving more water south.

To address the challenge of fish getting trapped in the pumps, there are prime locations in the delta that have been identified for fish friendly diversion projects, infiltration beds where perforated pipes buried in gravel collect gravity fed water at a velocity of one inch per minute. Such a facility would not entrain fish, and could be located in the central delta only a few miles from the Clifton Court Forebay with a collection pool and connecting aqueduct only about five miles long. One might also be constructed immediately adjacent to the Clifton Court Forebay, as a much improved way to avoid trapping fish.

Downstream from the delta, there are ways that tidal energy might be redirected, diminishing the quantity of salt water that enters the delta at high tide. Further downstream, major cities need to upgrade their wastewater treatment plants to remove nitrogen and phosphorus from the effluent. Both of these steps would reduce the volume of delta flow required to maintain ecosystem health in the estuary and in the bay, allowing for more pumping.

These are big projects, but there’s much more. Why not build an aqueduct from the Atchafalaya River to Lake Powell? Taking 3 MAF/year (or more) out of the Atchafalaya wouldn’t even put a dent in its greater than 160 million acre feet per year average flow. The distance is only 1,200 miles, less than the length of California’s major aqueducts, and the elevation of Lake Powell, 3,500 feet, is roughly equal to the lift required to move water into Los Angeles over the Tehachapi Mountains.

Or what about an 80 mile long tunnel from the California coast through the mountains to drop some of the ocean into the Salton Sea? Just the 230 foot drop into the below sea level basin could generate about 10 percent of the hydroelectricity required to completely desalinate the incoming water, or treat a much higher percentage of that water if the goal is to more gradually bring down and maintain the lake’s salinity at a level that supports a healthy ecosystem.

While we’re at it, why not build desalination plants on a massive scale, emulating maritime nations from the Middle East to Singapore? Lower Colorado Basin states might be induced to pay a significant portion of the construction cost in exchange for equivalent shares of Colorado River water that currently flows into California. As for the energy, it only takes 3,500 gigawatt-hours for desalination to produce a million acre feet of fresh water. That should be our initial target per year, and it would consume barely one percent of California’s total electricity consumption. Moreover, the day of cheap and abundant electricity is not far away. SMRs and enhanced geothermal are going to change the electricity game forever. And, hardly an afterthought, note that robotics is going to significantly lower the cost of major infrastructure projects.

Californians should be exploiting these emerging technologies to produce abundant water. We have constructed a luxuriant civilization atop an arid landscape. We should embrace and enhance this marvelous transformation. With forty million people loving life here, and the most fertile farmland on earth, our job isn’t to return the state to its desert origins. Our job isn’t to impose water scarcity on a rationed, frustrated populace, and condemn our farm economy to a consolidated, corporatized, shrunken footprint. Our inspiration should be to set an example to a thirsty world by maintaining and expanding the magnificent systems that irrigate our farmland and hydrate our cities.

We must think big again.