A project underneath Long Beach Airport that will use stormwater to replenish the water supply received $7.5 million Tuesday, June 19, from Los Angeles County supervisors.

“Every time it rains, we lose millions of gallons of drinkable water by allowing it to run into the ocean,” said Supervisor Janice Hahn. “Innovative projects like this mean we can capture rainwater and use it to replenish our local water supply.”

The project will gather stormwater from the streets of Long Beach and Signal Hill in underground galleries, clean it using machines called hydrodynamic separators and return it to the groundwater. The endeavor had been long talked about, but had not come to fruition until a grant became available in 2015.

Phase 1 of the project, which will have a capacity of 14 acre-feet of water, is underway and is expected to be complete in a few months. That phase cost $11 million and was funded by Caltrans, said Hahn’s spokeswoman, Liz Odendahl.

One acre-foot equals about 326,000 gallons, or the amount used by two small Southern California families in a year.

Tuesday’s infusion of cash will go toward the second phase of the project, which will add 19 acre-feet of water. Signal Hill and Long Beach will provide an additional $4.25 million, according to Hahn’s statement.