Sewage leak, high bacteria levels plague Nevada County’s Lake Wildwood
August 8, 2017
An estimated 1,680 gallons of sewage spilled into Lake Wildwood Sunday, Aug. 13, when a power outage caused a wastewater pump station to fail.
The sewage leak was stopped quickly, but Amy Irani, director of Nevada County's Environmental Health Department, said there is no way to immediately clean up what has already contaminated the lake.
Sunday's power outage affected the power supply to all 14 wastewater pump stations in Lake Wildwood, according to a news release issued by the county. The stations each have backup generators, which kick in when a power failure occurs. But this weekend, one station had trouble when it rebooted.
According to Irani, the pump stations have electrical meters that sense the level of wastewater they contain. When a meter detects that a pump station is full, it pushes out the sewage to the wastewater treatment plant. But one meter did not reset when the generator kicked in, resulting in a sewage overflow that eventually spilled into the lake.
The Nevada County Public Works Department was on scene quickly after the power outage occurred Sunday. Department employees reset the sewage level-sensing electrical equipment, cleaned up the spill, notified the Environmental Health Department and posted public notices at the location of the spill.
"Based upon the location of the overflow, and the amount (1,680 gallons), it is highly unlikely that the amount of sewage released would affect the overall quality and condition of the lake with a total capacity of 4,000-acre feet (well over 1.3 billion gallons). However, the spill information will be reported to the CDC and the CDPH as well. Meanwhile, the level sensing equipment issue is being addressed," Monday's release stated.
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Sunday's incident occurred in the wake of an E. coli outbreak that began last month, and has been attributed to elevated levels of bacteria in shallow water at Lake Wildwood.
E. COLI OUTBREAK
Eleven children and three adults have reported E. coli-related illness in connection with Lake Wildwood, the Nevada County Public Health Department said Aug. 8. Nine of the affected individuals have been hospitalized, and some have already been discharged.
The department closed Lake Wildwood's Community Center Pool Beach July 28 when an investigation found that numerous individuals who reported experiencing symptoms of E. coli-related illness had all recently gone swimming in shallow water near the beach.
The Environmental Health Department received results from an initial water test July 29 which showed elevated levels of E. coli bacteria near the Pool Beach, and issued a health advisory to all Lake Wildwood residents that day recommending no recreational swimming in the lake until initial beach areas were tested.
Additional tests found high levels of E. coli in shallow water near two other Lake Wildwood beaches on Aug. 1. Hideaway Park and Meadow Park beaches were closed that evening in addition to the continued closure of the Pool Beach, and a health advisory has remained in effect.
Irani said the county will continue to test the water twice-weekly, but E. coli levels are expected to remain high for some time to come.
It's "anybody's guess" when the E. coli levels will drop, she said.
"The inflow isn't great because we're in the non-rainy season, so only a little water comes in off Deer Creek," Irani said.
The Nevada Irrigation District tested water samples from Deer Creek in an area close to where the creek enters Lake Wildwood and an area close to where it leaves the lake, according to Irani. She said both samples showed normal levels of bacteria and no safety concerns were identified in those areas.
The department is still looking for the source of the elevated E. coli levels that occurred prior to Sunday's spill, Irani said.