Parks and Recreation Commission

Will man-made floating islands clean up Atascadero Lake?

The city has long struggled to find ways to filter harmful chemicals

By Stephen Curran

TRIBUNE PHOTO BY JOE JOHNSTON

Small islands of native vegetation are being proposed for Atascadero Lake.

MEETING TONIGHT

The idea of adding floating vegetation islands to Atascadero Lake is scheduled to be discussed at the Atascadero Parks and Recreation Commission meeting at 7 tonight at Atascadero City Hall, 6907 El Camino Real. For more information, call 461-5000 or visit www.atascadero.org .

A natural and relatively inexpensive way to clean up the water in Atascadero Lake may be available, biologists expect to tell the Parks and Recreation Commission today.

Public works officials are considering whether to dot the lake with a half-dozen floating wetlands —basically small, circular islands about six feet across and made from native vegetation.

LynneDee Althouse, a water quality specialist for Paso Robles-based environmental consultant Althouse and Meade Inc., said these miniature plant habitats would absorb excess nitrates and phosphates. Those chemicals, she said, make the lake water unhealthy for humans and

even more dangerous for native fish.

Althouse said problems frequently arise in man-made lakes, which typically have limited shoreline vegetation to absorb bird waste and other toxins.

Floating islands are commonly used in other parts of the world as an affordable but natural filtration device, she said.

Constructing these substitute wetlands is relatively easy, she said. Her firm would provide the young tule, cattails and sedges to the public works department. City workers would then build the islands by affixing the vegetation to a material such as polymer mesh and foam, she said.

That process, she estimates, would cost Atascadero less than $200 per island.

“That was really our goal,” Althouse said, “to come up with some low-tech, low-cost ideas to improve water quality.”

Public works Director Geoff English said the city has long struggled to find ways to filter the chemicals from the artificial lake. When the City Council revised its master plan for the lake in 2001, it made improving the water quality its top priority.

The floating wetlands are one in a series of proposals being weighed for the lake, including well maintenance and other repairs. The City Council has approved $37,500 for water quality improvements as part of the 2007-09 budget.

Adding the floating wetlands, which would allow roots to grow through a hollow tube in the middle, would keep algae from blooming along the lake’s edge. And the islands would make it unlikely that the lake would experience a widespread fish die-off similar to one there that became national news in 2001.

In addition, Althouse said, her firm would recommend that local residents stop feeding the ducks in an effort to reduce the number of birds near the lake.

“That’s going to be a tough one,” she said, “but that bird population has a significant impact on water quality.”