LOS ANGELES (CBSLA.com/AP) — Los Angeles Mayor Eric Garcetti has declared an emergency due to predictions of overwhelming runoff from the eastern Sierra Nevada snowpack that feeds the Los Angeles Aqueduct.

The action Monday is aimed at helping the city Department of Water and Power respond to what it describes as the threat to “the health and safety of the public as well as to protect infrastructure and the environment.”

“The reason we are doing this now is when we see a potentially disastrous situation, a situation that could hurt our economy, our family and our environment, we don’t wait,” Garcetti said at a news conference at City Hall.

The LADWP predicts that the snowpack runoff level from the Eastern Sierra Nevada will be one of the largest in the 100-plus year history of the Los Angeles Aqueduct.

The aqueduct runs hundreds of miles south down arid Owens Valley to Los Angeles.

The city is using aqueduct water to replenish local aquifers and emptying reservoirs to create more capacity but a huge amount will end up in Owens Lake, which dried up when the city channeled its water source into the aqueduct 100 years ago.

Up to a third of Los Angeles’ water supply is from the aqueduct, depending on the year, but has received little from it since 2015 because of the drought. Record levels of rainfall and snow this winter have resulted in the opposite problem, as up to 1 million acre feet of water — or about twice the amount that Angelenos use in a year — is expected to flow through the aqueduct system this spring and summer.

An LADWP official said up to $500 million in damage could occur as a result of the increased water runoff.

(© Copyright 2017 CBS Broadcasting Inc. All Rights Reserved. The Associated Press and City News Service contributed to this report.)