State wages war
on waterweed

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By Diana Leone
dleone@starbulletin.com

The war against the invasive waterweed in Lake Wilson moved forward on several fronts yesterday as the state:

>> Closed the Lake Wilson State Recreation Area until further notice to set up heavy machinery to remove Salvinia molesta from the water.

>> Ordered enough of an environmentally friendly herbicide to treat the lake twice.

>> Investigated buying, renting or borrowing an air boat, which would allow workers to ply the plant-choked lake.

>> Planned to begin spraying the herbicide Rodeo on Friday on upper reaches of the 300-acre reservoir, where salvinia is not as well established.

>> Continued making arrangements for more staging areas to remove the weed from the lake.

Since November the South American water fern, which is used as an aquarium plant but is also on the federal Noxious Weeds list, has bloomed on the lake until it covers 95 percent of its surface.

The herbicide Rodeo has been safely used in water for decades and is the quickest, most efficient way to reduce its hold, said Linda Nelson, one of five consultants from mainland offices of the U.S. Army Corps of Engineers.

"Rodeo is completely safe for aquatic life," agreed Bill Devick, administrator of the state Division of Aquatic Resources.

At a meeting among state, city and Corps of Engineers officials yesterday, Honolulu-based Corps engineer Derek Chow reiterated that killing the plants chemically and removing them with machinery are only a short-term solution.

Chow urged the state to consider seeking federal matching funds for long-term control of the pest. For instance, he said, an ecosystem restoration plan for the Wahiawa basin could ultimately fund keeping salvinia in check, he said.

In other developments:

>> State Sen. Bob Hogue has announced a meeting to discuss removal of salvinia from Kawainui Marsh. Community members will gather at 7 p.m. Tuesday at Kailua District Park.

>> Ahahui Malama i ka Lokahi and Kawai Nui Heritage Foundation are considering attacking salvinia at a March 22 Community Stewardship Day at the Kailua marsh.