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SolarBee samples to show effectiveness by summer's end

A SolarBee, a solar-powered device to help reduce algae blooms, is pictured across from the Lake Mitchell Campground on the south side of Lake Mitchell. (Luke Hagen/Republic)

The city of Mitchell is still determining whether a device purchased to reduce the algae problem in the lake is doing its job.

The SolarBee, placed in a bay near Lake Mitchell Campground on the south part of the lake, "is in there and operating," said Dusty Rodiek, parks, recreation and forestry director for the city.

However, he said its effectiveness is subjective.

"Right now, we're currently doing water clarity testing throughout the summer," Rodiek said.

Volunteers are taking water samples from different areas on the lake, including by the SolarBee. The city purchased the device in 2010 from a company by the same name in Dickinson, N.D. In total, it cost approximately $27,000 for the SolarBee and the installation into the lake. The device, anchored to the bottom of the lake, uses a rotor to blend cool and warm water together. The device, which is solar-powered, is meant to keep warm water from serving as a breeding ground for blue-green algae, which thrives in warm, stagnant water.

Algae blooms have long been a sore point in the manmade lake due to runoff from human activity around the lake and upstream in the Firesteel Creek watershed. The city has made several attempts over the years to reduce algae levels.

Rodiek said he will collect all samples taken from May through September to determine what affect the SolarBee has on the algae problem.

Rodiek said this is the first summer anyone has tested the water for algae reduction while the SolarBee is operating. In previous summers, the city saw some visual improvement in algae in the areas the SolarBee operated, but no quantitative data was taken on how well it worked.

He said more than one summer's worth of testing is needed to determine whether the city will purchase more devices to help clear the lake of algae.

Officials determined in 2011 the SolarBee's battery was dead, so it didn't work for half the summer and gathered little data. A couple summers were too wet and the algae problem wasn't as prevalent.

In June 2010, when the SolarBee was installed, officials said if it is successful in removing algae, as many as five more could be purchased. Rodiek said more data needs to be collected before a decision to purchase more SolarBees can be made.

The device was placed in Kippes Bay near the Sportsmen's Club last summer, but Rodiek said the bay by the campground is a better fit.

"Where it was before, it had a lot of wind effect," he said. "There was water circulating into that bay. ... We thought we'd have a better opportunity to test its effectiveness in the campground area."