Creek near Lake Tahoe has elevated E. coli levels (updated)
July 28, 2014
KINGS BEACH, Calif. — Placer County has issued a health advisory for residents to avoid water contact with Griff Creek on Lake Tahoe's North Shore due to elevated levels of E. coli bacteria.
The Placer County Environmental Health Department issued the advisory Wednesday afternoon; it includes the bridge where the creek widens and ponds. The location is fenced off, and warning signs are up.
"There is currently no health concern involving the waters of Lake Tahoe or any of the surrounding beaches," said Wesley Nicks, director of Environmental Health for Placer County. "There are no drinking water intakes anywhere close to that creek … and no swimming locations are in danger."
Lahontan Regional Water Quality Control Board officials have tested the creek, located roughly 75 yards from Lake Tahoe near the intersection of highways 28 and 267, at many locations the past several locations.
Levels spiked July 14 and 17. The first sampling showed E. coli levels at 270 colony forming units per 100 milliliters of water. The second recorded levels at 570 cfu/100 ml.
According to the California Department of Public Health, safe levels max out at 235 cfu/100 ml.
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Richard Booth, senior engineering geologist for Lahontan, described the creek's levels only as "slightly elevated."
Lahontan officials were scheduled to test the creek again on Thursday.
Nicks said the county health department will take weekly samples to monitor levels; a timeframe for when the public restriction will be lifted is unknown.
"As soon as they come below state levels, we'll … remove the signs and allow access again," Nicks said.
While the cause of elevated E. coli is undetermined, Nicks said it's likely naturally occurring from area wildlife, as well as worsening drought conditions.
"The amount of water in Griff Creek, it's just a trickle at this point … due to the drought," he said. "Flow rates are lower, the water is warmer … which we believe is why the bacteria levels are higher."
The samplings were taken as part of an upgraded study on bacteria in all waterbodies within Lahontan's jurisdiction, Booth said, which will take at least another year to complete.
What's new with this study is the focus on E. coli, Booth said. Before, only fecal coliform bacteria — of which E. coli is a subset — was monitored.
"Technology has improved enough that it's easier to test for E. coli, which is a better indicator of possible health risk," he said.
The Lahontan Regional Water Quality Control Board's jurisdiction extends from the Oregon border to the northern Mojave Desert and includes all of California east of the Sierra Nevada crest.
The water board reportedly found similar levels of elevated fecal coliform bacteria recently in portions of Bishop Creek off Highway 395.
While the city's drinking water is safe, more tests are being conducted on the lake to ensure safety, according to a July 14 statement.