Responding to concerns over last weekend’s massive fish die-off at Atascadero Lake, city officials say it wouldn’t be cost-effective to add water to the drought-plagued local attraction, as some residents have suggested.
Such a move would cost a minimum of $500,000 over 48 days, according to the city.
“Right now, pumping water in a drought — where it would be very costly and most of it would evaporate — wouldn’t be the most cost-effective thing we could do,” Mayor Tom O’Malley said Wednesday.
Hundreds of dead fish floated to the lake’s surface this past weekend, prompting a widespread cleanup. In hot weather, algae blooms grow and decrease the water’s oxygen levels. That process, paired with shallow water warmed by summer temperatures in the 90s and 100s, caused the fish to die.
The scene wasn’t new. Hundreds of fish died in 2001, and about 30 more died in 2008.
The city doesn’t know exactly how many fish died Friday through Sunday. Members of the cleanup crew didn’t count as they plucked the dead carp and perch from the murky water’s banks and hauled them away in trucks, officials said.
“Atascadero Lake was a mess (last) weekend, and I don’t think you can just brush it off. It’s an embarrassment to the city,” lakeside resident Nancy Hair said at Tuesday’s City Council meeting. She wants water added to the man-made lake off Highway 41, on the city’s west side.
Before Hair spoke, City Manager Rachelle Rickard presented the statistics and costs associated with such a move.
The lake, which can hold up to 68 million gallons of water over 30 acres at capacity, is currently about 30 percent full, Rickard said. The maximum depth at capacity is 13 feet, but the lakebed is currently just 4 1/2 feet below the surface at its deepest point. The southern half of the lake, meanwhile, is no more than 1 1/2 to 2 feet deep today, she said.
The conditions are the worst the city has seen in decades.
It would cost the city $8,600 — at 1.4 million gallons per day — to buy water from the area’s private utility, the Atascadero Mutual Water Co. (plus additional money to dechlorinate it), to pump it into the lake bed.
The effort would add about 3 inches of water per day, Rickard said, slowing as the water level rises and evaporates at a rate of 135,000 gallons per day.
Hair also suggested that the water company pump in water without charging the city. John Neil, general manager of the utility who attended the council meeting on another topic, said his board of directors would have to approve such a measure but that it’s not something the board is considering because of pumping and treatment costs.
Meanwhile, while the five-member City Council didn’t discuss whether to support adding water since the topic wasn’t officially on the agenda, O’Malley said it’s not something the city is considering, either.
“It really wouldn’t be that effective at this point. This would be a good time to dredge what we can and clean up the lake,” he said.
Officials already have applied for a state permit to dredge the dead plant material and silt that builds up over the years from the lake’s bottom, hoping to improve its health when rain returns.
“Dredging would also deepen (the lake). That would be the best we could do, and then let Mother Nature fill it up,” O’Malley said.
The city has also been monitoring the water’s oxygen levels and, earlier this summer, installed three floating fountains designed to produce more oxygen in the water. Last weekend, three additional pumps were brought in to aerate the water.