By CAROL BENFELL
THE PRESS DEMOCRAT
Article published - Jul 15, 2005
The first spraying of the Laguna de Santa Rosa to control a fast-growing water weed will begin within days when a herbicide is spread by boat over the affected area.
Members of the North Coast Regional Water Quality Control Board on Thursday agreed that the non-native Ludwigia is jeopardizing both human health and the Laguna's ecosystem. The board authorized ground spraying with glyphosate, a herbicide considered one of the least likely to contaminate ground water.
The health risk is created by the cover that Ludwigia's dense growth provides for mosquitoes, which can carry West Nile virus, making it difficult to kill or control the mosquito population. The weed's rampant growth also chokes out native plants, fouls the water and threatens to block the passage of spawning salmon.
Spraying will begin either Saturday or Monday in the Laguna between Occidental and Guerneville roads. Application of the herbicide is expected to begin Wednesday on the Rohnert Park flood control channels.
"We recognize this project is highly controversial, but also realize the need to address the issue of controlling Ludwigia infestation while ensuring the protection of water quality," said Catherine Kuhlman, the regional board's executive officer.
The Sebastopol City Council has opposed spraying, believing more environmentally friendly methods or removal could be found.
Thus far none has been identified.
"It's clear to me we have to address the situation," said Sam Pierce, Sebastopol councilman and a member of the Green Party. "I have a great deal of confidence in the Laguna Foundation, who are looking at the overall health of the ecosystem. The fact the Laguna Foundation has thrown its weight behind this gives me some confidence we are looking at the least toxic approach possible."
Ludwigia, the Uruquan water primrose, doubles in size every 15 to 90 days during the summer growing season. An estimated 10,000 tons of the plant are now carpeting 155 acres of the Laguna's surface. Crews will need seven to 10 days to complete the spraying.
The board's approval comes as Sonoma County enters its second West Nile summer season, typically the peak of the invasion. The virus leaves most people symptomless, but can cause a flu-like illness and, in rare cases, meningitis, encephalitis and death.
The Laguna Foundation, a nonprofit environmental group, is spearheading the spraying effort as part of its plan to restore the long-neglected Laguna.
"This is the first phase of the restoration of the Laguna," said Julian Meisler, the foundation's restoration project manager. "We can't really implement longer-term restoration without addressing this problem first."
The water board approved only the first year of the Laguna Foundation's proposed five-year program for controlling Ludwigia.
The five-year, $1.5 million project calls for spraying at least once a year for three years. During the final two years, the focus would be on making the habitat less inviting for Ludwigia by planting trees to shade the water and deepening the river bed so the plant can't put down roots.
But the water board wants the Laguna Foundation to come back again next year and report its results from the first year's spraying.
"It's not that we wouldn't support future years, it's that we wanted them to monitor the spraying, do surveys and provide a report on how effective it is," said John Short, a senior engineer with the regional water board. "They will spray, gather information, and then base next year's proposal on that new information."
Glyphosate breaks down quickly and is considered one of the least likely herbicides to contaminate ground water, according to the state Department of Pesticide Regulation.
The herbicide will be applied by Clean Lakes Inc. of Martinez, which will work with two or three crews using two airboats and a "swamp cat," a tractor-like device with a continuous tread designed to not disturb the earth.
Once the plant is dead, it will be removed by a mechanical harvester.
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