Sites Reservoir: California's largest new reservoir project in decades moves forward

California is moving forward with a plan to build the state's largest new reservoir in 50 years.

This comes after a Yolo County judge dismissed a lawsuit last week from the Sierra Club, Center for Biological Diversity, Friends of the River and other environmental groups that were aiming to block the project, the Mercury News reported. 

The 4.5-billion project, known as Sites Reservoir, would be located about 70 miles northwest of Sacramento and provide water to millions of people between the Bay Area and Los Angeles.

It's named Sites for the town it's in -- a tiny community with just a handful of residents nestled in a valley of the coastal range mountains in rural Colusa County. 

The project had to clear several regulatory processes before construction, including an environmental review, and it has faced fierce resistance. 

Unlike most reservoirs, the Sites project wouldn't be connected to a river or stream for water to naturally flow into the lake. Instead, operators will have to pump water from the nearby Sacramento River.

Environmental groups, including the Natural Resources Defense Council, have said the project will take too much water from the river, harming endangered salmon. Plus, they say the water from the Sites project will be more expensive for customers because of high pumping costs.

It takes a lot of water to run California, which has nearly 40 million residents. The state has a robust agricultural industry that supplies the bulk of the nation’s fruits, nuts and vegetables and a diverse — but fragile — ecosystem that is home to endangered salmon species.

Until recently, California had been mired in years of drought, with nearly all precipitation coming during the winter months and early spring. California has a vast system of reservoirs that capture and store water from rain and melted snow in the Sierra Nevada mountains. The reservoirs then release water throughout the year for drinking, agriculture and environmental purposes while also offering recreation for local residents and tourists.

But the drought has drained those reservoirs to alarmingly low levels, forcing state and federal officials to release a lot less water. That’s been bad for the environment and forced farmers to fallow thousands of acres of crops.

When it does rain in California, it rains a lot. 

So-called "atmospheric rivers" that suck moisture from the Pacific Ocean can dump tremendous amounts of rain on the state in short periods. The Sites Reservoir, project officials say, would capture that extra water when it’s available.

The reservoir would hold enough water to supply about 3 million households for one year — although much of the water would be for agricultural purposes. It would be nearly twice the size of the most recent reservoir built in California, but still much smaller than some of the state’s better known lakes like Shasta and Oroville.

The project is on track to break ground in 2026 and finish by 2032.

The Sites Reservoir would be the eighth largest in California.

Adam Beam from the Associated Press contributed to this report.