From www.lovelandfyi.com on Friday June 13, 2003:

Solar circulation

By Doug Crowl

Reporter-Herald Staff Writer

Residents on Silver Lake in central Loveland have invested $25,000 in what they believe is a solar solution for problems with algae and low-oxygen water.

A new Solar Bee pond circulator was installed in the lake Thursday.

There are three solar panels on top of the floating machine to collect and convert the sun's rays into electricity and a blade in the middle to pump the water.

On a sunny day, the contraption, which looks like a spacecraft, pumps 10,000 gallons of water. [SolarBee note - should have said 10,000 gallons per minute.]

The Solar Bee circulates the less-oxygenated water from the bottom half of the lake to the top, where beneficial algae will be able to grow in it and produce oxygen.

Sunlight doesn't shine through to the bottom half of the 25-foot-deep lake, so oxygen-producing green algae, dependent on that sunlight for life, doesn't grow there, explained Christopher Knud-Hansen, a limnologist (an expert on freshwater chemistry and biology) and consultant for Aquatic Solutions of Boulder.

Circulating the water allows for the whole lake to become oxygenated, he said.

Meanwhile, the circulating water reduces blue-green algae, a type of plant life that settles on the top of water and blocks sunlight.

The 44 households in the Silver Lake Home Owners Association pitched in to buy the Solar Bee. The hope was that it would clear up the lake, reduce the rotten-egg smell from the algae and prevent a second fish kill, explained Sliver Lake homeowner Paul Tungesvick.

Silver Lake is just south of Conrad Ball Middle School. It covers 44 acres on the surface and holds 460 acre-feet of water. For years, the lake has had an algae and oxygen problem.

An estimated 2,000 bass, crappie, catfish, perch and carp died in a natural phenomenon called fall turnover in September of 1997. The surface water cooled during the evening and circulated to the bottom of the lake, dispersing the low-oxygen water from the bottom throughout the lake and killing the fish.

Knud-Hansen said that an algae and nutrient buildup also played a role in the fish kill.

"If there is another fish kill in this lake, it won't be from fall turnover," Knud-Hansen said.

The homeowners group hired Knud-Hansen as a consultant to help solve the oxygen problems in the lake and advise the members on what to spend their money on. They also worked with the nonprofit group Big Thompson Watershed Forum, which aids the community with water quality issues.

Knud-Hansen and Barb Maynard from the Big Thompson Watershed said the Solar Bee is a good solution.

The water-circulating device is a fairly new idea, patented in 1998 out of South Dakota. [SolarBee note - should have said North Dakota.] There are several Solar Bees in Colorado, including at the Platte River Power Authority.

"Everything went really smoothly," Tungesvick said of the installation.

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