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For Immediate Release: 2/17/2015

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Herbicide Control of Water Hyacinth to Begin in the Delta in early March


Vicky Waters


SACRAMENTO, Calif. —California State Parks Division of Boating and Waterways (DBW) issued a public notice today to begin herbicide treatment of the aquatic invasive weeds Water Hyacinth and Spongeplant in the Sacramento-San Joaquin Delta region beginning on Wednesday, Mar. 4, 2015 and continue through the end of November.

The herbicide treatment will initially focus on the following areas: Middle River, Whiskey Slough, Old River, Coney Island, Indian Slough, Rock Slough, San Joaquin River and the Tuolumne River, with an expansion of treatment to other areas of the Delta beginning on June 1. Spongeplant will be concurrently treated with Water Hyacinth, since both aquatic weeds share common biology and distributions. DBW is permitted to treat 3,500 acres of Water Hyacinth in the Delta.

In addition to the herbicide treatment, DBW is continuing to conduct mechanical harvesting of Water Hyacinth in the South Delta (Old River) and around the Stockton area on an as-needed-basis.

The Division will also begin treatment of Egeria densa and curly leaf pondweed in early March. Treatment areas will be made public next week.

In the 2014 season, 2,617 acres of Water Hyacinth were treated with glyphosate and 2,4-D. There is no known eradication method for Water Hyacinth once it has been established. Therefore, DBW conducts a control program in the Delta as opposed to an eradication program. The program seeks to minimize negative impacts of the invasive plant on navigation, public safety, recreation, agricultural activities and ecosystem services in Delta waterways.

In 1982, California state legislation designated DBW as the lead state agency to cooperate with other state, local and federal agencies in controlling Water Hyacinth in the Delta, its tributaries and the Suisun Marsh. DBW works with the U.S. Department of Agriculture to obtain approval for conducting the Water Hyacinth Control Program from the U.S. Fish and Wildlife Service and the National Marine Fisheries Service (part of the National Oceanic and Atmospheric Administration). A third approval is also obtained from the Central Valley Regional Water Quality Control Board.   The approval process is in place to determine if the use of these herbicides may affect any threatened, endangered or sensitive species, and critical habitats.

Funding for Water Hyacinth treatment comes from the Harbors and Watercraft Revolving Fund, which receives revenues from boaters’ registration fees and gasoline taxes.

In addition to mechanical harvesting, DBW crews will provide assistance with other removal methods, such as herding and hand-picking, in an effort to continue providing an essential public service.

To report sightings or for more information regarding the controlprogram,please see DBW’s website at, call 888-326-2822, or email at

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