Floating Aquatic Vegetation

Water hyacinth (Eichhornia crassipes), South American spongeplant (Limnobium laevigatum) and Uruguay water primrose (Ludwigia hexapetala) are floating, aquatic invasive plants that are not native to California. They grow in wetlands, marshes, shallow water bodies, slow moving waterways, lakes, reservoirs, and rivers.  Water hyacinth, South American spongeplant, and Uruguay water primrose can be a problem for boating, agriculture and public safety, and can negatively impact the environment, industry and local economies.

Technically, these plants can de-stabilize dissolved oxygen cycles, crowd out native plants, shade out crucial shallow-water fish habitat, obstruct waterways and navigational channels, and block agricultural and municipal water intakes.

CLICK HERE for more description and characteristics of Floating Aquatic Vegetation.

In 1983, lawmakers designated the California Department of Parks and Recreation Division of Boating and Waterways (DBW) as the lead agency for controlling water hyacinth in the Sacramento-San Joaquin Delta. More recently, other species of floating aquatic vegetation species have spread throughout the Delta requiring additional legislative treatment authority and a holistic approach to control.*

With the addition of Uruguay water primrose (Ludwigia hexapetala), the separate plant control programs have been combined and now are all under the Floating Aquatic Vegetation (FAV) Control Program. For more information about the FAV program, see our 2016 Annual Report.

Management and Control Methods

The FAV Control Program uses a strategic and adaptive Integrated Pest Management (IPM) system including herbicide treatment supported by hand-picking, herding, mechanical removal and biological efforts.

• Herbicide Control

  Approved herbicide application is our primary method of FAV control. The products we use have been approved for aquatic use by the U.S. Environmental Protection Agency and the California Department of Pesticide Regulation.

  For more information about this year treatment season CLICK HERE.

• Mechanical Control

  DBW uses mechanical harvesting vessels designed specifically for FAV removal at certain times during the year. FAV harvesting can be practical in heavily infested areas where herbicide control methods cannot be easily applied due to heavy plant matting.

  For more information about this year mechanical harvesting season CLICK HERE.

• Biological Control

  DBW’s partner in FAV control, the U.S. Department of Agriculture, Agricultural Research Service, evaluates and implements live, natural control agents where possible and effective. FAV control by water hyacinth weevils (Neochetina bruchi and Neochetina eichhorniae) have been used.

• Hand Picking

  DBW staff support other types of controls with hand picking.  This is typically done with smaller mats of FAV and/or when herbicide control methods cannot be applied due to permit restrictions.

• Environmental Monitoring

  DBW environmental scientists and field crews monitor all treatment areas to ensure that herbicide concentrations do not exceed allowable limits or have any significant adverse impacts on the environment, agriculture, or public health. In addition, we minimize and mitigate harm to state or federal endangered, threatened, or species of special concern when FAV control is underway.

  * Senate Bill No. 1344 (Garamendi and Nielsen), Chapter 2, Article 2, Section 64 amended the California Harbors and Navigation Code. Also, Assembly Bills 1540 and 763 included South American Spongeplant and holistic control plans.