"This Groundwater Replenishment System is an investment; it's an investment in the future of Orange County and it's a step toward a more sustainable and resilient future," Porter said.

On Earth, groundwater makes up the largest reservoir of liquid fresh water and is found in aquifers, explains the paper’s lead author, Francesco Salese, Ph.D., to Inverse.

The system, which has been online since 2008, will be receiving its final expansion this year, which officials say will make about 85% of the city's drinkable water, renewable groundwater.

Groundwater is declining across Eastern Washington’s complex, interconnected aquifer system, as people draw on it for irrigation, drinking and other uses at a pace that threatens its sustainability, ...