Evacuees Due Back After Dam Seepage

With the water level receding and emergency repair work at Prado Dam finished, most residents near the dam in Riverside and Orange counties were expected to return to their homes today, authorities said.

“Fortunately, everything is quiet at this time,” Corona Police Sgt. Brian Servantes said Sunday.

More than 2,000 people living downstream of the dam, in the Corona area and Yorba Linda, were evacuated Friday morning when seepage was detected in the earthen structure.

The voluntary evacuation was called off Friday afternoon -- though some Corona leaders urged residents to stay away until today -- after officials with the Army Corps of Engineers began releasing some of the dam’s water and stabilized the area around the seepage.

The corps expects a decline in the water level to 45.1 feet behind the dam by today. The lower water level allows reconditioning work to begin on a secondary dam so more incoming water can be accommodated, Fred-Otto Egeler, a corps spokesman, said Sunday.

Emergency reinforcement of the seepage area was finished Saturday morning. Meanwhile, Army corps staff stayed on to monitor the dam through the weekend, Egeler said.

“There’s nothing wrong at the dam. We’ve been releasing water, and we’re ahead of the flow,” Egeler said.

As Prado’s water level is lowered, the pressure on the dam near the seepage is reduced, Egeler said.

According to the Corps of Engineers, the recent storm and floods have produced near record water levels behind Prado. The reservoir level peaked at 67.5 feet Tuesday. That’s just a few inches lower than the highest level recorded, in 1980.

After the seepage was discovered, the corps released more water into the Santa Ana River: 10,000 cubic feet per second, the maximum permitted. On an average day, the dam releases 200 to 500 cubic feet per second.

On Sunday, the flow into Prado’s basin was 600 cubic feet per second. The water level behind the dam was 51.1 feet, Egeler said.

By Friday afternoon and through the weekend, residents began trickling back to their homes near the dam and a Yorba Linda recreational vehicle park, which also was evacuated.

Because the reservoir rose almost to a record level, a portion of Corona Municipal Airport, which is in Prado’s flood control basin behind the dam, was underwater last week.