Temperance Flat is linchpin of Valley’s water future. It must be built

One of the primary reasons for building Friant Dam has been dropped from the discussion over time.

Yes, it was constructed to send San Joaquin River water south for farm irrigation and boost the economy. Gov. Earl Warren declared at the dam’s dedication in 1949 that it would help the Valley “become a modern Eden.”

And, yes, its 319-foot tall concrete wall was constructed to reduce flooding. Before Friant was built and the Metropolitan Flood Control District was formed, floods were a fact of life in Fresno.

Largely forgotten is that Friant also was built to reverse the serious groundwater overdraft that was occurring on the Valley’s east side.

By turning water from the Sierra snowpack into irrigation releases, the Bureau of Reclamation reduced agriculture’s dependence on groundwater pumping and significantly raised groundwater levels in those east side areas that had not suffered subsidence.

But there’s one big problem with Friant Dam: It’s much too small to maximize the benefits of the San Joaquin River watershed’s average runoff of 1.8 million acre-feet. An acre-foot is 326,000 gallons.

Now, amid climate change and the lessons we’re learning from California’s historic drought, a fix is in order: A larger dam should be built behind Friant at Temperance Flat.

This location should have been utilized in 1935 when Congress approved initial funding for a dam. But, with the United States suffering through the Great Depression and costs a major concern, the small dam at Friant was built instead.

We know that people overwhelmingly think of the Temperance Flat proposal as simply a “dam.” However, we think of it as the linchpin of the San Joaquin Valley’s water future.

State legislation passed in 2014 emphasizes the important of groundwater recharge. Without Temperance Flat and its 1.3 million acre-foot capacity, as many as 1 million acres of fertile Valley farm land, much of it on the east side, would be fallowed because of future limitations on groundwater pumping.

That would be catastrophic to the Valley economy – putting thousands of people out of work and turning rural communities into ghost towns.

Temperance Flat would capture much more runoff in years of high precipitation and provide its Bureau of Reclamation managers with flexibility to time releases with agricultural needs. As things stand now in wet years, water is let go before spring plantings and summer irrigation simply because Friant’s capacity had been reached.

This new dam also would capitalize on the Central Valley Project’s network of canals to ensure that water is delivered to recharge projects. And it would provide additional water to meet the demands of Valley cities.

People have short memories. As we are in a challenging drought, they forget that there will be wet years ahead. Over the past 30 years, about 30 million acre-feet have been lost to flood releases out of Friant Dam, according to the San Joaquin Valley Water Infrastructure Authority.

It’s important to note, too, that with climate change and warmer temperatures, there is the likelihood of less snowpack, which melts quickly and produces more flooding in the San Joaquin Basin, according to the U.S. Geological Survey.

The simple truth is that a bigger version of Friant would store more precious water and enable that water to be better used for the benefit of people, crops, fish and wildlife. Indeed, it’s impossible to imagine a successful reintroduction of salmon into upper San Joaquin River without the cool water that could be stored at Temperance Flat.

We recognize that the cost to build Temperance Flat is significant; the current estimate is $3 billion. But there is legislation in Congress that would contribute toward the tab.

In addition, California voters passed the Proposition 1 water bond in 2014 that designated $2.7 billion for water infrastructure projects. Those who benefit from the project such as water districts and cities would help pay for construction in exchange for future water deliveries.

Temperance Flat’s proponents are seeking $1 billion from the water bond. Groups backing Sites Reservoir – a proposed 1.8 million acre-foot dam in Northern California that would enhance water supplies to rice farmers in the Sacramento Valley and cities in Southern California – are seeking $2.2 billion.

This editorial board previously backed building Sites Reservoir because it has the potential to improve salmon and Delta smelt populations and serve other environmental needs. We stand by that opinion.

It’s clear to us that California needs both of these projects. In this era of water limits, every drop must be managed and directed to where it does the most good. We urge the California Water Commission to provide funding that helps take Temperance Flat from the drawing board to reality.

This story was originally published December 1, 2016 at 5:39 PM with the headline "Temperance Flat is linchpin of Valley’s water future. It must be built."