Sacramento Region Plans To Store Water Underground As A Climate Change Adaptation Strategy

The Sacramento region is preparing for the long term impacts of the climate crisis when it comes to water supply. Central to the plan is a groundwater storage program with two to three times the space of Folsom Lake. 

As the climate warms it’ll likely become harder to fill up reservoirs, because the snowpack could be small for multiple years. Think of the nearly empty reservoirs across California during the most recent drought.

“We're expecting in the future to have more severe droughts and potential for Folsom Reservoir to not fill up with the frequency that it does,” said James Peifer, executive director of the Regional Water Authority. 

He says the answer is to store water underground: a direct line from the snowpack, down rivers and then pumped or trickled through the ground into the aquifer. It’s a concept he calls a water bank. 

“It allows us to put some water away,” he said. “It's putting a deposit away for a rainy day or a dry day.”

But to make this idea a reality it’s going to take hundreds of millions of dollars and the cooperation of the more than 20 water agencies in the Sacramento region. The authority represents more than 2 million people. 

“A water bank is much like a bank,” he said. “You need to make a deposit first before you can make a withdrawal. So, what we want to do is store water first before we withdraw. That way, it's better for the environment.”

He sees groundwater as a reservoir that could store as much as two times the water found in Folsom Lake. The idea is to capture and store excess water — around 60,000 acre-feet of water in a wet year — when there’s plenty of rain and then to use some of it during dry years. It’s a gentle toggle of not taking too much out of the earth so an aquifer won’t collapse causing subsidence — that’s where land sinks because so much water is removed from under it — which areas of the state are currently going through. 

That’s a big deal because temperatures in the Sacramento area project to increase between 4 and 7 degrees by 2070, according to a 2020 study of the American River Basin by the Placer County Water Agency. But that’s a semi-conservative increase according to California’s Fourth Climate Change Assessment published in 2018.

The entire area between Shasta and the Delta could look and feel more like Phoenix by the end of the century, with maximum daily temperatures expected to increase by 10 degrees Fahrenheit, according to UC Davis’ Benjamin Houlton, one of the authors of the state report.

“We're going to be looking at 40 days per year where the temperature exceeds 104 degrees,” he said. “This is going to be a tremendous challenge on public health."

That amount of warming means more snow will fall as rain earlier every year and could have a huge impact on water supply and flood management. Houlton says it will take innovation to make life tolerable as the region warms. 

In response to the warming trend, water providers four years ago started a Regional Water Reliability Plan to improve water supply for the long term. The plan was completed in 2019 and found a water bank as key to adapting to climate change. 

The institutional side of the Sacramento Regional Water Bank could be operational in a couple years. The project will take local, state and federal buy-in. The plan is expected to cost at least $288 million and will take more than a decade to create. 

“Over the next 18 months, what we're going to do is complete the environmental impact analysis for the water bank … and we hope to be up and running by 2022,” said Peifer.

Some of the infrastructure needed to create this water bank and Water Resilience Portfolio were funded this week through $8.74 million in state grants for 11 projects. The goal of the grants is to help the region adapt to how climate change is expected to alter this part of California by focusing on water.

The Sacramento-area funds are part of $83.9 million in Proposition 1 funds given to communities in the Sacramento, San Joaquin, San Diego, Sierra and Central Coast regions. The grants will address aging infrastructure, flood control, depleted groundwater levels and other critical needs. Around 37% of the funds will benefit disadvantaged and underrepresented communities.

“Water is such a vital resource,” said California Department of Water Resources director Karla Nemeth. “These grants will support agencies and projects to continue local momentum in creating a more diverse water supply portfolio, strengthening partnerships and addressing climate change.”

Some of the other projects include funds to improve wastewater infrastructure in the Oroville area, which is supposed to improve fish habitat along the Feather River. It will also fund $1 million for reducing flood risk brought on by climate change along the Lower Cosumnes River. The money will also fund projects that provide reliable drinking water to communities like Le Grand near Merced.