Irvine Lake begins draining for $470 million dam upgrade

Irvine Lake started its mass draining process to prepare for upgrades to the 93-year-old reservoir that provides water to 1.5 million people in Orange County, CBS News Los Angeles reported.

The draining is part of the Irvine Ranch Water District's $470 million Santiago Creek Dam improvement project to enhance seismic safety and replace the outlet tower and spillway, according to a district spokesperson.

Currently about 23 feet deep, the lake's water level is expected to drop to five feet in three weeks, with complete draining planned once contractors are ready to work on the dam.

The California Department of Fish and Wildlife noted they cannot enforce protections for the lake's non-native fish species, suggesting residents contact the water district or Orange County Parks for fish relocation or fishing events.

Local anglers expressed concern about the impact on the lake's trophy-class fishery, which includes largemouth bass, catfish, trout, and others, fearing restocking may not restore the same fish population.

The project is expected to be completed by summer 2032, with plans to restock the lake after upgrades are finished.