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Divisions of Boating and Waterways, Historic Preservation and Off-Highway Vehicles

News Release

For Immediate Release: 3/2/2018

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Boating and Waterways Begins Control Activities in the Delta for Aquatic Invasive Plants


Gloria Sandoval I 916.956.6814
Deputy Director of Public Affairs

Sacramento, Calif. – The Division of Boating and Waterways (DBW) announced today its plans for this year’s control efforts for aquatic invasive plants in the Sacramento-San Joaquin Delta (Delta). Starting March 5, DBW will be controlling water hyacinth, American spongeplant and Uruguay water primrose along waterways entering the Stockton Deep Water Channel via mechanical harvesting. The use of herbicides will start on Monday, March 12 for the following aquatic invasive plants: water hyacinth, Egeria densa, South American spongeplant, Uruguay water primrose, curly-leaf pondweed, Eurasian watermilfoil, fanwort and coontail. Treatment start dates may change depending on weather conditions and plant growth/movement.

These aquatic invasive plants have no known natural controls in the west coast’s largest estuary, the Delta. They negatively affect the Delta’s ecosystem as they displace native plants. Continued warm temperatures help the plants proliferate at high rates. Plants are also known to form dense mats of vegetation creating safety hazards for boaters, obstructing navigation channels, marinas and irrigation systems. Due to their ability to rapidly spread to new areas, it is likely that the plants will never be eradicated from Delta waters. Therefore, DBW operates “control” programs as opposed to “eradication” programs. The division works with local, state, and federal entities to better understand the plants and implement new integrated strategic methods and increase efficacy.

“DBW recognizes the impact of these aquatic invasive plants on people’s daily lives and businesses,” said DBW’s Acting Deputy Director Ramona Fernandez. “In an effort to minimize the impact, we continue to leverage technology and resources through collaboration and cooperation with the public and our local, state and federal partners who are helping us manage this challenge.”

All herbicides are registered for aquatic use with the U.S. Environmental Protection Agency and California Department of Pesticide Regulation. Treated areas will be monitored to ensure herbicide levels do not exceed allowable limits and that herbicide treatments have no expected adverse impacts on the environment, agriculture or public health in or near the planned treatment areas. The public may view the public notices and sign up to receive weekly updates on this year’s treatment season on DBW's website.

Below is a list of proposed control actions for the 2018 treatment season:

Floating Aquatic Vegetation Control Program (Public Notice)

Water Hyacinth, South American spongeplant and Uruguay water primrose.

Herbicide Control

  • Proposed Treatment Period

           o   Select Area 1 Sites and Areas 2-4: Mar. 12, 2018 – Nov. 30, 2018
           o   All Area 1 Sites: June 1, 2018 – Nov. 30, 2018 (north of Hwy 12)

  • Type of Herbicides: Glyphosate, 2,4-D or Imazamox.
  • Potential Treatment Areas: Initially in and/or around, but not limited to the following areas: San Joaquin River, Empire Tract Slough, Middle River, Fourteen Mile Slough, and Latham Slough. See map for treatment areas.


Mechanical Harvesting

  • Harvesting Sites:March 2018 – April 2018 and July 2018 – December 2018
  • Mechanical Harvesting Sites:Select areas of the Delta with high infestations or coverage of South American spongeplant, Uruguay water primrose and/or water hyacinth. See map for potential mechanical harvesting control areas.

Submersed Aquatic Vegetation Control Program (Public Notice)

Egeria densa, curly-leaf pondweed, Eurasian watermilfoil, fanwort and coontail.

Herbicide Control (Map)

  • Treatment Period: Starting March 12, 2018 through October 31, 2018, treatment period based upon DBW field survey data, water temperatures and fishery surveys.
  • Type of Herbicide: Fluridone.
  • Potential Treatment Areas: In and/or around the following areas (individual areas will be noticed prior to treatment application):

           o   Anchorages, Boat Ramps and Marinas:

               B & W Resort
               Big Break Marina
               Das Cliff House
               Delta Marina Rio Vista
               Delta Yacht Club
               Driftwood Marina
               Gridstone Joe’s
               Hidden Harbor Resort
               Korth’s Pirates Lair
               Lloyd’s Holiday Harbor
               Long Island Slough
               New Bridge Marina
               Owl Harbor
               Oxbow Marina
               Perry’s Boat Harbor
               Rivers End
               Snug Harbor
               St. Francis Yacht Club
               Tower Park
               Willow Berm

           o   Near Old River: Cruiser Heaven, Diablo Ski Club, Discovery Bay, Franks Tract, Piper Slough, Sandmound Slough and Taylor Slough.
           o   Sacramento Area: Barker Slough, French Island, Lindsey Slough and The Meadows.
           o   Stockton Area: Atherton Cove, Bishop Cut, Buckley Cove, Disappointment Slough, Duraflame, Fourteenmile Slough, Honker Cut, Mosher Slough, Pixley Slough, White Slough and Windmill Cove.

Mechanical Harvesting

This type of control method is not used for submersed aquatic vegetation. These plants spread by fragmentation. Cutting the plants back exacerbates the problem, as shreds of the plants float away and re-propagate.

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 2018 to have drier conditions compared to 2017 and treatment of aquatic invasive plants up to 10,400 acres. A combination of herbicide, biological and mechanical control methods will be used to help control invasive plants at high priority sites in the Delta.

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.

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. The Egeria Densa Control Programwas authorized by law in 1997 and treatment began in 2001. In 2012, Spongeplant was authorized for control upon completion of the biological assessment. In 2013, DBW was able to expand its jurisdiction to include other invasive aquatic plants, and since then other aquatic invasive plants such as Uruguay water primrose, Eurasian watermilfoil, Carolina fanwort and coontail have been added to the AIPCP program.

To report sightings, subscribe for program updates or for more information regarding the control program, connect with us online at, via email at or by phone (888) 326-2822.


Division of Boating and Waterways
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To provide for the health, inspiration and education of the people of California by helping to preserve the state’s extraordinary biological diversity, protecting its most valued natural and cultural resources, and creating opportunities for high quality outdoor recreation.