Lake Balboa Leak Blamed on Forgotten Pipe : Environment: Millions of gallons of reclaimed water are lost. But officials say the spill has helped flush out chemicals illegally dumped in Bull Creek.

The U.S. Army Corps of Engineers took the blame Friday for the leakage of millions of gallons of reclaimed water that vanished down a long-abandoned sewer pipe when city workers began filling Lake Balboa in the Sepulveda Basin this week.

The corps simply lost track of the five-mile-long pipe it sealed off about 1940, a corps official said, adding: “I don’t know if you’d call it a goof or not.”

Regional water quality officials, however, said the leak had an unforeseen and unrelated--but welcome--side effect: the highly treated water poured into nearby Bull Creek, where it helped flush out contaminants blamed for killing more than 1,000 fish in the creek and the Los Angeles River earlier in the week.

“Although the two events are totally unrelated, one seems to be helping the other,” said Shirley Birosik, a specialist with the California Regional Water Quality Control Board.

The unidentified chemical that killed the fish may have come from an illicit dump site in the parking lot of a shopping mall miles upstream in Granada Hills, city officials said. The contamination left dead fish strewn over a quarter-mile of the creek south of Victory Boulevard, and more fish carcasses littering the Los Angeles River below the point where the creek flows into it.

On Friday, officials from various city and county agencies conducted tests at the creek south of Victory Boulevard to try to determine the cause of the fish kill. They also spent part of the day at the newly created lake to determine where to plug the leaky sewer pipe.

After pumping about 20 million gallons from the Donald C. Tillman Water Reclamation Plant into the lake bed Wednesday, city workers halted the effort when they noticed the leak.

They were draining it Friday so that the abandoned 21-inch sewer pipe can be filled with concrete to prevent further leakage, said Dick Ginevan, San Fernando Valley regional manager for the Los Angeles Department of Recreation and Parks.

Ginevan said city officials halted the project immediately because they were concerned the leak could suck in soil along with the water, undermining the lake bottom. There are no plans to remove the sewer pipe, and drainage should be completed by the end of the weekend, allowing repair work to start late next week.

Birosik said the leaky pipe “is not a pipe anyone knew about.” Ginevan said city officials found it by going to the city administration building in Van Nuys and pulling old records. He said city officials had no part in designing the lake, which was planned and built by the Army Corps.

Rick Grover, a top official in the corps’ local construction division, said the sewer line was clearly evident in the corps’ own drawings and diagrams dating back to 1939, when sewer lines in the Sepulveda Basin were relocated during construction of the Sepulveda Dam.

But Grover said corps workers who dug the lake never took the five-mile pipe into account because it was not shown on their diagrams, and no one told them about it. The pipe wasn’t noticed during construction, which started several years ago, Grover said, because it was about five feet under the excavated lake bed.

“The corps has known about it since 1939,” Grover said. “Research done during the design of the lake didn’t reveal that the pipe was there.”

The leak in the sewer pipe may have been created during the bulldozing of the lake bed, or it could have been cracked already, Grover said. Whatever the case, he said, the corps would have plugged the entire section of pipe under the lake to prevent leakage of any kind before filling the lake, had engineers known about it.

Asked who was responsible within the corps, Grover said: “I didn’t design it. The Corps of Engineers is a big organization.”

Grover said engineers in the corps planning division drew up the plans for the lake, which when finished will be the largest recreational lake in the Valley and the only recreational lake to use reclaimed water.

Ruth Villalobos, the top corps planning official in Los Angeles, and everyone associated with planning the lake were unavailable for comment, a corps planning employee said.

Bob Armogeda, a spokesman for the corps, said he had no information on possible oversight of the pipe by planners and would “look into” the matter.

Beginning in 1939 when the Sepulveda Dam was built, sewer lines in the Sepulveda Basin were rerouted outside the flood control area so floodwaters would not mix with sewage. Grover said the sewer pipe under the lake was plugged at both ends, leaving it empty for most of its length.

The pipe runs from Victory Boulevard and Balboa Boulevard south to Oxnard Street, east to Woodley Avenue, south to Burbank Boulevard and east to Sepulveda Boulevard, he said.

Times staff writer Myron Levin contributed to this story.