Lake Wilson cleanup nearly done
By Catherine E. Toth
Advertiser Central O'ahu Writer
By the end of the week, Lake Wilson will be 95 percent free of the noxious Salvinia molesta weed, according to state officials, and the waterway could reopen for recreational use in June.
Gregory Yamamoto • The Honolulu Advertiser
The Lake Wilson Recreation Area may open as early as next month.
The cleanup project at Lake Wilson is mostly finished, with major work expected to be completed this week in two spots. The next phase will be removal of Salvinia molesta from the shorelines.
In the cleanup that began Feb. 18, boats and booms were used to extract the noxious weed. Later, an herbicide was used to wilt the weed and keep it from multiplying.
Declaring victory in the battle against the invasive species at Lake Wilson, officials yesterday said the eradication effort that began Feb. 18 and cost hundreds of thousands of dollars is winding down. Two remaining extraction sites are expected to shut down by Friday.
That will be followed by the final phase of cleanup — removing salvinia by hand along the edges of the waterway — and monitoring to ensure that the weed doesn't overrun the 300-acre lake again.
Officials termed the progress an "amazing" turnaround from the start of the eradication effort, which went slower than anticipated because all but 5 percent of the lake was covered by the fast-growing weed that sucked oxygen from the water, raising fears of a massive fish kill.
Eric Hirano, head of engineering for the state Department of Land and Natural Resources, which has led the cleanup, credited what he called an aggressive interagency effort.
"It's just amazing," said Hirano. "The different agencies — the state, the city and the military — have done an outstanding job. I'm just astonished at the job they did."
When work began, officials said they expected to clear the lake in 28 working days. It took nearly twice as long: Friday will be 53 working days.
Early efforts were limited to extracting the salvinia with boats and booms. The state Department of Agriculture began spraying herbicide on the weeds on Feb. 25.
The herbicide stopped the weed from multiplying. The treated salvinia shrank and turned brown, making removal easier. Some dead plants sank to the bottom.
"That was a very, very crucial part of the overall project," Hirano said.
Some people criticized the state for waiting too long to attack the problem. Hirano said the Lake Wilson cleanup taught officials important lessons in how to handle invasive species.
"We definitely have to prevent invasive species from coming to Hawai'i," Hirano said. "Prevention is always much less costly than when you have to deal with it once it's here.
"And once it's here, we need to take a very aggressive posture against it. We have to hit it early."
This weekend, volunteers from the Hawai'i Freshwater Fishing Association will provide 15 small boats and enough hands to remove weeds along the shoreline.
Volunteers will begin clearing the area between 8:30 a.m. and 12:30 p.m. on Saturday and Sunday, with fuel, equipment and lunch provided by the state.
"It's great to see (the lake cleared)," said Jason "Brock" Brockington, 70, first vice president of the fishing club. "Pretty soon we can get back to fishing."
Because he hasn't been able to fish in Lake Wilson since January, Brockington has been helping with the bass hatchery at Wahiawa Middle School, where more than 3,000 largemouth bass are ready to be tagged and released into the lake.
"We fish there every month, so we saw the beginning of it," he said. "It just got out of hand too fast and we just didn't have the personnel and equipment to do it."
Although Hirano didn't know how much the eradication has cost the state so far, he said he doesn't think the department has spent the $1 million pledged to the fight.
While clearing the edges may take a few weeks, the noxious weed will probably never be completely eradicated, officials said. The Division of Aquatic Resources will be responsible for monitoring Lake Wilson to keep the weed from overrunning the waters again.
The state plans to put up a sign near the boat ramp at the Lake Wilson Recreation Area asking fishermen to remove whatever plant material is floating in the lake. The weed that is picked up can be dumped into garbage cans at the park.
Reach Catherine E. Toth at 535-8103 or ctoth@honoluluadvertiser.com.
