The giant tunnel designed for collecting and storing rainwater will help California cope with prolonged droughts caused by climate change.
In mid-May, the administration of California Governor Gavin Newsom announced a plan to spend over $20 billion to construct the Delta Tunnel to collect more water during rainfall and store it to better prepare for extended droughts exacerbated by climate change, according to Independent.
Aerial view of the Sacramento-San Joaquin Delta. (Photo: Times of San Diego).
State authorities have been planning to build a water storage tunnel system for decades. The most recent version approved by Governor Newsom features a single massive tunnel instead of two separate tunnels as proposed by his predecessor, Jerry Brown. According to Newsom’s administration, California can collect more water from the Sacramento River during significant storms and channel it south for storage. The latest cost estimates from 2020 indicated that the tunnel project would cost $16 billion. New analyses suggest that the tunnel’s cost has risen to $20.1 billion due to inflation. The project will be funded by 29 local public water agencies using revenue from their customers.
Analysis conducted by the Berkeley Research Group indicates that the tunnel will yield benefits of up to $38 billion, primarily due to the increased water supply that helps better respond to natural disasters, such as earthquakes. “The clear benefits justify the costs incurred,” stated David Sunding, a distinguished professor at the University of California, Berkeley, who oversaw the analysis.
The new tunnel will be part of the State Water Project, a complex system of reservoirs, dams, and aqueducts that provides water for 27 million people and irrigates 303,515 acres of farmland. Climate change poses a threat to the state’s water supply. A recent drought caused reservoir levels across California to drop to dangerously low levels, leading to the shutdown of several hydroelectric plants. State officials predict that by 2070, water supply will decrease by 22% due to climate change.
The proposed tunnel will be 72 kilometers long and 11 meters wide, large enough to carry nearly 610 million liters of water per hour. The tunnel will transport water from the Sacramento River around the delta to a reservoir near Livermore.
State authorities stated that this tunnel will allow the state to collect more water when California is impacted by “atmospheric rivers,” major storms that can flood the state for weeks during the rainy season. According to the analysis, the tunnel will help increase the water supply by 17%, nearly offsetting the decline caused by climate change.
