Frazier Announces Start of 2018 Efforts to Control Spread of Invasive Aquatic Weeds in Delta

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DISCOVERY BAY – Assemblymember Jim Frazier (D-Discovery Bay) today announced that the Division of Boating and Waterways (DBW) has begun the battle to control the spread of aquatic invasive plants that can clog Delta waterways.

DBW this week began mechanical harvesting of three types of aquatic invasive species and will soon start using herbicides to control the rest.

“As a Delta resident, I know how important it is to manage this issue and to get on top of the problem early,” Frazier said. “Maintaining navigable waterways is critical for the ecology and economy of the Delta. I’m glad the Legislature’s efforts to increase funding for aquatic invasive species treatment have allowed DBW to devote more staff and resources to this persistent problem.”

This week, DBW began mechanically harvesting water hyacinth, American spongeplant and Uruguay water primrose along waterways entering the Stockton Deep Water Channel.

On Monday, March 12, DBW may begin using herbicides to control water hyacinth, Egeria densa, South American spongeplant, Uruguay water primrose, curly-leaf pondweed, Eurasian watermilfoil, fanwort and coontail.  (Exact treatment dates will depend on weather conditions and plant growth and movement.)

These aquatic invasive plants have no known natural controls in the Delta, where warm temperatures help them proliferate quickly and displace native species, DBW says. They are known to form dense mats of vegetation, creating safety hazards for boaters and obstructing navigation channels, marinas and irrigation systems. It is likely these plants will never be eradicated from Delta waters, which is why DBW operates “control” programs rather than “eradication” programs.

Last year, DBW treated 3,023 acres (210 sites) of floating aquatic vegetation and 2,967 acres (46 sites) of submersed aquatic vegetation. Mechanical harvesting efforts totaled 8.08 acres. The division anticipates drier conditions in 2018, as compared to last year, and expects to treat up to 10,400 acres.

Funding for DBW’s aquatic invasive plant control programs comes from the Harbors and Watercraft Revolving Fund, which receives revenues from boaters’ registration fees and gasoline taxes.

To report water weed sightings, subscribe for program updates or for more information regarding the control program, visit, or contact DBW via email at [email protected] or by phone, (888) 326-2822.


Assemblymember Frazier represents the 11th Assembly District, which includes the communities of Antioch, Bethel Island, Birds Landing, Brentwood, Byron, Collinsville, Discovery Bay, Fairfield, Isleton, Knightsen, Locke, Oakley, Pittsburg (partial), Rio Vista, Suisun City, Travis AFB, Vacaville and Walnut Grove.