PASADENA, Calif. (KABC) -- The Los Angeles County Flood Control District has begun making room for rain water and mud in local catch basins ahead of another major storm that is due in the area Thursday.
But the county's move is causing stir with local activists. Environmentalists on Wednesday announced plans to sue the county over what it calls the "Big Dig" at Devil's Gate Dam in Pasadena.
What is hard to fathom is how fast the hillsides erode after a fire, officials say. The Colby Fire incinerated 1,900 acres in January. The debris from the last month of rainfall made a pile 2 1/2 stories tall.
It's the worse-case scenario that county flood control officials say they must plan for, even if clearance projects cause a clash.
After decades, the collected sediment has sprouted a small forest. The county says it must be cleared. But the activists disagree.
"This is the most precious environmental treasure in our area and we're not going to let it be destroyed by the trucks and bulldozers of Los Angeles County," said Tim Brick with the Arroy Seco Foundation.
The environmentalists say the potential flood hazards could still be minimized if the county removed half of what is planned, and executed it over 10 years instead of five years. They assert the county only expanded the project because it got more funds.
Yet, the county says, it has examined the risks, including the chances for a repeat of the Station Fire here, or the potential for catastrophic flooding in an extreme storm season.
"You would be in the situation where the dam would fill up with sediment and would no longer be able to protect the downstream communities at a much more frequent rate," said Gary Hildebrand, department director of L.A. County Public Works.
Downstream is the Rose Bowl, South Pasadena and downtown L.A. Activists say they will push for a compromise in court.
LA rain catch basin clearing causes stir with activists