Pond Will Be Lowered in Fight on Mosquitoes : Insects: Officials say draining part of the Chatsworth Reservoir will reduce the pest problem without endangering other wildlife.

Part of a 10-acre pond and marsh in the Chatsworth Reservoir that serves as a wildlife refuge will be drained to combat a mosquito infestation that has plagued nearby residents, officials said Tuesday.

An agreement on how to control the mosquitoes without harming wildlife was worked out at a meeting Tuesday between representatives of several agencies, including the Southeast Mosquito Abatement District, the Los Angeles Department of Water and Power, which owns the reservoir, and the city Department of Animal Regulation.

According to the plan, the DWP will lower the pond, which is about five feet deep in places, by 16 inches and will remove about 40% of the tule plants, or bulrushes, along the shore.

Mosquitoes thrive in the water and thick vegetation, which also prevents mosquito fish that live in the pond from getting to the insects, officials said.

“This is a long-term solution to a bad problem,” said Sabrina Brummond, public information officer for the South Gate-based mosquito control district, which operates in most of Los Angeles County.

The wildlife pond, a remnant of what was once a big lake in the 1,320-acre reservoir, is used by waterfowl and other birds, raccoons, deer and coyotes. Wildlife officials were concerned that a more complete draining of the pond would hurt the animals and send them into residential areas to slake their thirst.

But Gary Olsen, district supervisor for the animal regulation department, said he believed the agencies “came up with a reasonable solution that would abate the mosquito problem and also not endanger any of the wildlife.”

DWP crews are expected to start pumping water from the pond Wednesday, although officials said the project could take several weeks to complete.

Reservoir neighbors have complained about hordes of mosquitoes, and Brummond of the abatement district said trapping by district entomologists confirmed an unprecedented number of the insects.

Mosquito traps placed in the reservoir in late June netted 27,000 mosquitoes in a 12-hour period, compared to a norm of several hundred captured in a 24-hour day.

Brummond said tests have not been conducted to determine if the mosquitoes were infected with the dangerous St. Louis encephalitis virus. She said the insects would be sent to the lab today.