City officials are keeping their fingers crossed in hopes that an infestation of tiny green wormlike larvae in the city's primary drinking water supply has peaked.
City utilities director Robert J. Dixon said Monday that it has been a week since officials have received a complaint about a "sighting" of the threadlike insect in a sink, bathtub or shower. During warm summer months, Dixon said, it is not uncommon for the half-inch-long pests--which pose no apparent health hazard, even if accidentally ingested--to get into a glass of water or a bathtub.
In recent weeks, complaints were received almost daily from city residents about the harmless midge fly larvae, prompting city officials to triple the dosage of chemicals added to the Big Canyon Reservoir, the suspected source.
But Dixon said it apparently took a spate of cooler weather and light showers last week to slow the reproductive habits of the adult midges and reduce the number of larvae embedded in the algae on the slopes and at the bottom of the reservoir.
About two-thirds of the city's 70,000 residents get their drinking water from the open-air reservoir that covers 23 acres near San Joaquin Hills Road and Marguerite Avenue.
"It seems that little cold spell may have done in their mating cycle," Dixon said. "The wind and rain probably discouraged them some."
What puzzled city officials most was the lengthy stay of the midges and their larvae at the reservoir, and their large numbers. By early fall, the insect--which is often encountered in large swarms near open bodies of fresh water--has normally dissipated.
One bayside restaurateur welcomed the news of the diminishing larvae by saying:
"Let's hope it's over. All of our drinking and cooking water here is bottled. But some customers don't believe it unless they get a tour of the kitchen. This is hardly the kind of thing to boost business."