Wastewater managers battling an avian cholera epidemic that has felled 200 birds at a popular Silicon Valley bird-watching spot have hit on a stinky solution -- draining a pond and carting away poop from the bottom.
With warm winter weather temperatures expected to be "record setting" this week in the low 70s, officials from the South Bayside System Authority, which operates the 7-acre pond in Redwood City, say that the odors could be "greatly enhanced."
"To mitigate what we can, we have heavy equipment ordered and coming in to try and keep the area as fresh as possible, but it is going to smell," Authority Manager Dan Child said. Mostly, it will stink for the 50 to 100 daily bird watchers and early-morning walkers in the area, he said, as well as the nearby homeowners and office park employees.
"It's going to be a long-term process," Child said. "We're expecting several months before it's actually dried out to the point the bacteria dies out, that it's not in the soil anymore."
Foul odors have been emanating from the pond since crews began suctioning out the water on Friday because of the "several inches of bird excrement" that have been collecting on the bottom of the pond over the last 15 years.
Since that process began, Child said the number of visitors to the pond has "drastically dropped." Extracting the water may take about a week, but fully draining, drying and refilling the pond may take all the way through summer and into the fall at the earliest, Child said.
This is the first avian cholera outbreak at this spot. But Child suspects that the birds flew over from an East Bay Regional Park District's pond at the Hayward Regional Shoreline, which has grappled with the disease both this year and last.
State Dept. Fish and Game Lt. Patrick Foy said that avian cholera is "very common" in California and the location of where it breaks out "fluxes from year to year." He added it's not a "huge biological issue, but something we have to manage." Aside from Hayward and Redwood City, the Woodbridge Ecological Reserve and the San Joaquin River National Wildlife Refuge, both in San Joaquin County, had avian cholera deaths this season in California.
Biologists said the season's unusually dry weather may be behind the current avian cholera outbreaks across the Bay Area.
"In heavy rain years if there's a bacterial outbreak of avian cholera in the freshwater areas of the marsh, heavy rains can help flush it out," said Doug Bell, an East Bay Regional Parks District biologist.
Bell also said another way the drought may be spreading disease is by bringing more birds together.
A bird watcher noticed a plethora of dead ducks at the Redwood City pond at 1400 Radio Road over the winter holidays, Child said, and it wasn't until Monday that a U.S. Fish & Wildlife Service lab in Wisconsin came back with the results of avian cholera.
Avian cholera typically erupts in wild fowl living in wetlands, which often have a lot of bacteria in the soil and water during the outbreak. Once the bacteria gets introduced, infected birds will die within six to 12 hours, according to "Avian Cholera in Waterfowl," which ran in the Journal of Wildlife Diseases. Ponds are natural homes for this disease because birds live in close quarters, according to Fish and Game.
On Tuesday, wastewater management crews resumed the week long work of draining the man-made pond. Child said he had the choice not to drain the pond and let the ducks die, but that "wasn't an option for me."
Child could not begin to estimate how much this would cost his water authority. But he did say that draining the pond would have no real human impact - no one drinks the wastewater - other than affecting the bird watchers who will have no birds to watch for several months.
The pond was created in 1998 on the west side of the treatment plant to eliminate dust from the dry barren dirt in the area. The pond is kept fresh by a flow of recycled water from the treatment facility to replace water lost by evaporation and by allowing a certain amount to overflow back to the treatment plant.