A beach at Camanche Reservoir reopened this week after the East Bay Municipal Utility District shut it down because fecal matter from geese had polluted the water.
Also this week, utility officials said a project to reduce the goose population at the lake by oiling eggs has been completed and they are hopeful it will be successful.
District workers sprayed goose eggs with corn oil late this spring, which effectively keeps them from hatching.
This year, EBMUD oiled just under 300 eggs, though their state-issued permit allowed them up to 400. Spraying eggs with corn oil clogs the pores of the shell and suffocates the embryo within. Though geese numbers around the reservoir have not decreased since last year, Kent Lambert, a manager of Mokelumne Watershed and Recreation for the EBMUD, said he thought the new program was still successful.
"Coming out of a couple years of drought, where (water) resources are limited, to a pretty normal rain year is a factor there," Lambert said. "I imagine that the numbers would have been higher without any of our programs."
The district is also working closely with the California Department of Fish and Game to expand public hunting programs, which help keep the geese in check.
Lambert is quick to point out that EBMUD is not trying to exterminate the birds. The Canada geese, he said, are part of the charm of the reservoir.
"They're a beautiful part of the environment, and I would never want to see a Camanche without geese on it," Lambert said. "They add to the experience here, in their proper numbers."
However, right now the 2,500 Canada geese that make their home at Camanche are exceeding their 2,000-geese target number — and their welcome.
The program, which Lambert calls GIPM, or Goose Integrated Pest Management, began as a response to high concentrations of fecal coliforms, caused by goose feces, in the water near EBMUD's intake pumps, which draw water to the treatment plant.
Canada geese produce less than one pound of waste daily, approximately a third of a pound in the winter and up to six-tenths of a pound in the summer, said Dr. Bruce Manny, a fishery biologist with the U.S. Geological Survey. But, unfortunately, geese aren't regulated by the 9 a.m. to 5 p.m. grind — they work around the clock, generating an estimated 10,500 pounds of excrement a week around Camanche.
EBMUD water tests on the south side of the reservoir found fecal coliform levels, and officials deemed swimming unadvisable. Goose fecal matter is known to carry E. coli, a bacteria harmful to humans, said Tony Boitano, an EBMUD water supervisor for Pardee and Camanche.
Lodi Lake has had similar problems and was closed for about a week early this July, said Jeff Hood, Lodi city spokesman. Geese are suspected to be the cause of the poor water quality.
However, not all lakes are having issues with geese. Pete Lucero, a public affairs officer for the U.S. Bureau of Reclamation, said that while reservoirs like New Melones on the Stanislaus River have a considerable number of geese, levels of fecal matter have not caused them to close any beaches.
But California as a whole has had a lot of trouble with Canada geese, said Melanie Weaver, an associate wildlife biologist for the California Department of Fish and Game's waterfowl program.
The problem began in the 1960s, when overhunting caused Canada geese populations to decrease, said David Feld, the national program director for GeesePeace, a Virginia-based nonprofit. Breeding programs to reinstate their numbers created resident birds, which did not migrate and instead nested permanently in California.
"They're the same birds as the ones in Canada," he said, "and it's not that they're lazy, (and) they don't want to fly the 1,000 miles — it's biological, because they have to nest where they were born."
By oiling the goose eggs, adult geese no longer have offspring and are more likely to follow their instincts to migrate, leaving the area, Feld said.
But fans of the Camanche Reservoir shouldn't rejoice quite yet. Just because the south-side beach reopened doesn't mean Camanche is free from worry.
EBMUD only tests fecal coliform levels near the intake pipes, which means visitors to the reservoir could be swimming in water polluted by E. coli, Boitano said.
"It's highly advisable to not ingest water," said Jeff Carruesco, program coordinator for the San Joaquin County Environmental Health Department. "It's all about ingestion. If you accidentally swallow the water you're at higher risk."
Carruesco said swimmers should shower or at least wash their hands with soap after leaving the reservoir. Or, he said, they should stay out of the water altogether.
"If they're choosing to close the beach, I don't know if I would go in the rest of the water," he added.
Dean Kelaita, local health officer for Calaveras County, said the strain of E. coli in the reservoir is not life-threatening, and the health department has received no complaints of E. coli-related health issues due to contact with the geese.
Contact reporter Mollie Bloudoff-Indelicato at firstname.lastname@example.org.
Geese at a glance
- Geese lay five eggs in an average clutch.
- The eggs are incubated for almost a month.
- Geese are flightless from mid-June to early July.
- There were an estimated 3.6 million resident Canada geese in North America in 2008.
— Source: United States Department of Agriculture Wildlife Services.