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Beach closings may be thing of the past

The Chicago Park District will try a new strategy next summer to ward off those pesky bacteria from the chronically infected 63rd Street Beach.

On trial will be a $385,000 "Gunderboom'' fabric filter system.

Picture a curtain hanging down from a floating rod--the boom--out in the lake. Water passes through it into the swimming area but it screens out unwelcome microbes.

"This is actually getting at the problem,'' said parks Supt. David Doig. "It is exciting because it attempts to address how we keep the bacteria out of the beach area.''

Richard Whitman of the U.S. Geological Survey welcomes the experiment.

"If it works, it'll be a ground-breaking model,'' he said.

The project still must be approved by the park board.

For years, 63rd Street Beach has been closed to swimmers a frustrating number of days each summer. It consistently shows the highest daily counts of E. coli among all the lakefront beaches during the swimming season, park officials say.

The source is a mystery. Possible culprits include seagulls and pets. A leaky sewage pipe was thought to be a big source and patched.

But other suspects are the very shallow water level and the curved shoreline that creates a cove.

The Gunderboom system was developed by engineers in Anchorage, Alaska, who were on hand in 1989 when oil from the Exxon Valdez threatened the shore. The system is named for engineer Bill Gunderson.

Next spring, 30 days before Memorial Day when beaches open, the Gunderboom patented filter will be dropped into Lake Michigan--hanging it from an 1,800-foot C-shaped rubberized boom filled with Styrofoam to keep it afloat.

It will protect a 1,000-foot stretch of beach.

"We guarantee a minimum of 50 percent reduction in bacteria and/or . . . safe swimming levels,'' said Jim Miner, executive vice president of Gunderson's company, PN&D Engineering. "It should be safe every day for swimming.''

The fabric is about Ã? inch thick, made of polypropylene and polyester and looks a bit like tough black felt.

The curtain will be sealed to the lake floor by a nonpermeable skirt.

Each end is fastened down on land, and several points are anchored under water.

Bathers on the beach will be able to see the boom in the water, 10 inches to a foot above the surface and 600 feet out at the farthest point.

A pump will be installed; ready to move water from inside the boom area to outside, if, say, a storm sends waves over the top and inside the swimming area and the bacteria count rises.

Ross Petersen, of the Jackson Park Advisory Council, who was briefed last week on the plan, said, so far, "we're sort of ambivalent about it.''

The idea should work well for pollution that originates out in the lake, but a contributing factor to the E. coli counts could be "a wet sand ecosystem'' that's not well understood, he said.

"We simply don't know how much of this bacteria rides in on the current from points offshore or how much of this material weeps out of the wet sand at the beach,'' Petersen said.

He said he would rather see the money used to make up for budget cuts for the south lakefront.

Miner, however, said sand pollution is very likely "minimal.''

If bacteria are in the sand, it's because water brought it there, he said.
- Mon, 12/16/2002

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