Although a dry summer and algae death at Lake Atascadero have caused headaches and prompted plugged noses for locals, recent technological measures and the winding-down of summer have stabilized the environment at the city-owned body of water.
Though the lake’s volume is only at approximately one-third of its full capacity, Atascadero public works director Russ Thompson said his department has installed two floating aerating fountains in the lake, which churn the water, greatly increasing its dissolved oxygen levels.
“We wish there was a bunch more water in the lake, but the health of the water is now well above where we usually are at this point in the year,” Thompson explained.
High oxygen levels in the lake promote healthy flora and fauna, as well as reduce the putrid odor that’s permeated the east side of the lake for much of the summer.
The bad smell is caused by dead, sludgy biomass (largely algae), which is exposed to the air and decomposes when the water recedes, Thompson said. In a strange bit of biological inversion, healthy algae usually oxygenate a body of water, but dead or dying algae often deplete the same water of oxygen.
Thompson said his department received authorization from the City Council in June to buy and install four aerating fountains at a cost of roughly $9,500. The third fountain is scheduled for installation on Aug. 15.
Thompson said any plans to pipe in or transport water to the lake are too expensive or complicated to seriously consider.
Like almost all North County lakes, Lake Atascadero is completely dependent on rainfall. A hot and dry summer has the double-whammy effect of evaporating the existing water and also reducing the only water supply.
Thompson said the lake was losing roughly a half-inch of water every day at the summer’s zenith, but that evaporation rate is now lower—around a quarter-inch daily. The lake, when full, averages around 13 feet at its deepest point. That figure is currently hovering around six feet, according to Thompson.
“Our rainy season usually lasts from mid-October to mid-April,” Thompson said. “Needless to say, we’re hoping for some early rain.”