COURTESY OF JOHN D. MANLEY / MARCH 2003 Essex Mottley, standing, and Dominic Valderrama, both of waterfront operations at Marine Corps Base Hawaii, aided Army personnel in March on the Lake Wilson cleanup.

Lake Wilson almost
free of waterweed

An aggressive effort has
cleared 95 percent of the
Salvinia molesta

---

By Diana Leone
dleone@starbulletin.com

Thanks to a two-month-long multi-agency effort to clear it of Salvinia molesta, Lake Wilson is no longer green, a state official said.

"Frankly, I'm somewhat amazed at the rate of removal. I thought it would take longer than it did," Bill Devick, state Division of Aquatic Resources administrator, said yesterday.

The lake is 95 percent clear of Salvinia, according to Devick and Eric Hirano, the Department of Land and Natural Resources chief engineer who coordinated cleanup efforts.

"The conditions on the lake look excellent. We got through this without having a large fish kill, which was the basic purpose of this effort," Devick said.

In early February, when the surface of the 300-acre Wahiawa lake was solid green with the invasive plant, officials had hoped to have 90 percent of its surface cleared by July.

But they weren't at all sure they could do it and were worried about the potential death of the 500 tons of game fish that live there. Mainland consultants questioned whether the stuff could be beaten back.

At the height of activity there were as many as 50 people with the DLNR, the state departments of Agriculture and Transportation, the City and County of Honolulu, the Army and the National Guard working on the project, said Hirano.

On Saturday, the city finished work at its removal site near the lake's dam. State work with excavators is slated to end Friday. And this weekend, volunteers with the Hawaii Freshwater Fishing Association will go out in their boats to nab stray bits of the plant with nets.

"I am just astonished at the progress we have made," said Hirano. Herbicide spraying by the Agriculture Department was crucial to the progress, he said.

Hirano also thanked Wahiawa residents for their patience with having heavy machinery in their backyards for weeks at a time.

The success didn't come cheap or easy and the victory is by no means permanent. Salvinia overgrowths have been a pernicious problem on the mainland and in other countries.

Devick's division will continue to patrol the lake, watching for any outbreaks and attacking it with herbicide and physical removal.

Testing will be done over the coming year to determine if a Salvinia-eating weevil that's used to fight the plant in other locales could safely be used here.

DLNR Director Peter Young said yesterday that he hopes the public attention given to Lake Wilson's Salvinia problem will help people understand that invasive species are a serious problem in Hawaii.

Action needs to be taken now on battling miconia, coqui frogs and other threats to Hawaii's unique plants and animals -- and to its economic well-being, Young said.

Hirano said yesterday that he hopes costs will come in at less than the $1 million that was predicted for the Salvinia war.