Planting artificial seaweed to halt US beach erosion

It has been a hard winter for the nation's beaches. Storms on both sides of Lake Michigan, for example, have chewed away at shorelines. And homeowners and municipalities are casting about for solutions.

This week, on an eroding waterfront near Holland, Mich., John Lauer, president of the young Erosion Technology Systems, will install his answer to the nation's vanishing shorelines.

It is called artificial seaweed, a device that resembles huge, upside-down combs.

Five-foot-long tubular, weighted bags are laid end-to-end in parallel rows on the lake bottom near the shore - with flexible ''teeth,'' or fronds, floating upward.

The fronds are supposed to slow the water just enough so that the sand usually carried along by the current will drop onto the base of the device.

The accumulated sand forms a sand bar, which absorbs the shock of incoming waves that normally would eat away at the shoreline.

The idea, which is controversial to begin with, is the latest in a long line of low-cost erosion prevention devices, says Charles N. Johnson, hydraulic engineer in the coastal engineering branch of the US Army Corps of Engineers' north central division. ''It's amazing how few of them have actually worked out.''

So far, results have been mixed.

For years, pounding waves and wind had eaten away the Langdon Park beach in Wilmette, Ill., leaving just a bare bluff.

But with the installation 18 months ago of an artificial seaweed called Seascape, there has been no waterfront erosion, says Ray Van de Walle, director of the Wilmette Park District.

But 50 miles south of Lauer's planned installation, Frank Lahr has watched Lake Michigan storms chew away at his waterfront property. Since 1981 he has lost all of his 50-foot-wide beach and another 30 feet of bluff.

So, a year ago, he and his neighbors installed 1,800 feet of Seascape.

The units ''never really got covered very well,'' Mr. Lahr recalls. ''And by fall they'd become all snarled up.''

But the seaweed idea simply needed refinement, according to Mr. Lauer. His innovation of the Seascape idea was to connect the five-foot-long units of seaweed in a grid-like pattern to keep them from shifting or floating away.

The seaweed concept being marketed by Lauer and others comes at a critical time.

Many communities just don't have the money to repair beaches that were severely eroded by last winter's storms, and federal help is getting scarce. The United States Army Corps of Engineers, for example, is having to shift its emphasis from construction projects to maintenance.

''This has been a bad year for the beaches - East and West,'' says Bill Forman, a civil engineer with the US Army Corps of Engineers. ''And many people are looking for a solution.''

What is attractive about artificial seaweed is its relatively low price. For the Wilmette beach, the Corps proposed solutions costing from $400,000 to $1 million, Mr. Van de Walle recalls.

The seaweed cost Wilmette just $3,000 (although that was a special price to test the product.)

Since the Wilmette installation, the concept has gained wide attention, observers say.

John Morrisroe, who marketed Seascape before forming his own company, Beach Builders of America, has been involved in more than 40 installations.

Surprisingly, erosion engineers and others say they're still not sure whether the concept will work. They say that shorelines are so dynamic and complicated that a full-scale study needs to be done.

The Corps of Engineers is analyzing a site in Cape Hatteras, N.C., where Seascape was originally installed, but their report won't be out until early next year.

''I'm putting it all on the line,'' admits Lauer. ''It's a shoestring operation.''

Van de Walle says that seaweed won't solve all the world's erosion problems, but ''in my opinion the artificial seaweed concept will work.''