A 45-mile, $16 billion tunnel that would mark California’s largest water project in nearly 50 years took a step closer to reality this week, with Gov. Gavin Newsom reaffirming his support for the ambitious proposal.

The Delta Conveyance Project would wind through the Sacramento-San Joaquin River Delta, connecting the water-rich north to the arid south. It would benefit 27 million residents, according to the California Department of Water Resources.

Why a tunnel? In addition to supplying water to population-dense southern California, the proposal would provide a detour around the state’s wetlands and water infrastructure.

Endangered species, brackish water and outdated infrastructure restrict the state’s ability to deliver water from the Sacramento River’s estuary, according to the San Francisco Chronicle.

The pipeline would instead take water from the delta, transporting it underground in an attempt to bypass current roadblocks.

The draft environmental impact report, which entered a public comment period on Wednesday, lays out four objectives:

  • Address the impacts of rising sea levels and climate change.
  • Bolster earthquake resiliency by minimizing water disruption.
  • Provide flexibility for conservation projects in the delta.
  • Strengthen the state’s ability to deliver water.

According to the Chronicle, the project could also increase the amount of water delivered to the Bay Area, southern California and surrounding farmland.

“Delta conveyance remains essential for our water future,” Wade Crowfoot, California’s natural resources secretary, told the Chronicle.

Project faces criticism: Some iteration of the project has been discussed for years, dating back to Newsom’s predecessor, Gov. Jerry Brown, who had initially proposed two pipelines.

The pipeline has been met with pushback from critics who say it’s a water grab, according to the Chronicle, and warn the project would take much needed water from the delta and farmers.

The Chronicle also notes the construction could also displace homes and require state land acquisitions.

“It’s not a good thing,” Glenn Burgin, who grows alfalfa, corn, wheat and rice on the delta, told the Chronicle.