From the Canyon Courier (Vicky Gits):
Aerating the lake during the summer months is expected to increase dissolved oxygen at the bottom of the lake, help lower the lake’s water temperature, produce cooler water going downstream over the dam and help reduce the amount of lakeweed or elodea in the water.
“The biggest concern we have is dissolved oxygen at the bottom of the lake,” said Gerry Schulte, executive director of the [Evergreen Metro District]. “If there isn’t enough (oxygen), the fish have a hard time, and it results in a process that releases iron and manganese into the water, and that creates a bigger treatment problem,” Schulte said.
The diffused aeration system is expected to increase dissolved oxygen concentrations. The new system is projected to run 10 hours at night only and recirculate the entire body of water every two days. The only visual effect will be bubbles on the lake.
Similar systems are currently at the wastewater plant in Kittredge and the Bear Creek reservoir east of Morrison. The Cherry Creek Water Authority is installing one in the Cherry Creek reservoir as well.
Aqua Sierra Inc. of Morrison will provide and install the equipment, which consists of eight underwater diffuser modules placed at an average depth of 20 feet or more. Modules will be placed 100 to 700 feet from the edge of the dam in the deepest part of the lake.
In addition to increasing the amount of dissolved oxygen, aeration is expected to counteract the heat-related water quality issues that occur in the summer months by creating a more constant temperature from top to bottom of the lake. So when the sun is out, it heats the top layer of water. The top layer goes over the dam and contributes to higher downstream temperatures.
More Bear Creek watershed coverage here.