Egeria densa

  • About Facts Authority & Funding Program Restrictions Updates

    Egeria densa (Brazilian Elodea) is a shallow-water submerged aquatic plant from Brazil, popularly used as an aquarium accessory that was introduced into the Sacramento-San Joaquin Delta about 40 years ago (possibly from use in home aquariums). Egeria densa and other submerged vegetation now infest many thousands of surface acres of the Sacramento-San Joaquin Delta. The plant can spread very quickly depending on environmental conditions, often by fragmentation. The Division of Boating and Waterways (DBW) is the only entity authorized to treat Egeria densa in California with herbicides.


    Members of the public may contact DBW with questions or concerns relating to Egeria densa and treatment of this aquatic invasive species at (888) 326-2822 or e-mail the division at

    Include in your message the address or nearest landmark of the sighting. If possible, take photographs of the plant.


    Aquatic weeds currently treated by DBW in the Delta
    Aquatic weeds identified as potential problems by DBW in the Delta


    What is Egeria densa (Brazilian Elodea)?

    Can Egeria densa be eradicated?

    What effects does Egeria densa have on waterways?

    Are there any impacts to recreation and commercial activity?

    How does Egeria densa spread and how fast does it spread?

    How did Egeria densa enter the Delta?

    How much of the Delta is infested with Egeria densa?

    How can someone tell if the herbicide is working properly?


    • What is DBW's authority? Harbors and Navigation Code, Article 2, Section 64 provides that DBW is designated as the lead agency of the state for the purpose of cooperating with agencies of the United States and other public agencies in controlling water hyacinth and Egeria densa in the Sacramento-San Joaquin delta, its tributaries, and the Suisun marsh. State funding for controlling water hyacinth and Egeria densa is appropriated in California's annual Budget Act.
    • When did DBW begin treating Egeria densa? The Egeria densa program was authorized by law in 1997. Treatment for Egeria densa began in 2001.
    • Where does the funding for treatment of Egeria densa come from? Funding for the Egeria densa treatment comes from the Harbors and Watercraft Revolving Fund, which receives revenues from boaters' registration fees and gas taxes.


    For treatment, three permits are required to be obtained. These permits place restrictions on where and when DBW can treat the aquatic invasive weed (this varies throughout the Sacramento-San Joaquin Delta), establishes the chemical concentrations allowable in treated areas and requires extensive water quality monitoring.

    • Two permits are required by the federal Endangered Species Act from the United States Fish and Wildlife Service and the National Marine Fisheries Service (part of the National Oceanic and Atmospheric Administration).
    • A third permit, a National Pollutant Discharge Elimination System permit is required by the Central Valley Regional Water Quality Control Board.

    The California Department of Parks and Recreation, Division of Boating and Waterways will be conducting herbicide treatments to control Egeria densa in certain locations of the Sacramento-San Joaquin Delta Region.
    The following information is subject to change based on governmental requirements, weather conditions, plant growth, waterway traffic, and other conditions.

    This notice satisfies the public notification requirements of the State Water Resources Control Board Order No 2013-0002-DWQ, National Pollution Discharge Elimination System CAG990005

    Treatment Period
    June 2014 – September 2014

    Treatment Areas
    In and/or around the following areas:

    Bethel Island Area - Franks Tract
    King Island Area - Bishop Cut and Honker Cut
    Anchorages, Boat Ramps and Marinas
    Buckley Cove (River Point Marina and Ladd’s
    Marina), Cruiser Haven, Delta Yacht Club, Korth’s Pirate’s Lair, Oxbow Marina, Perry’s Yacht Harbor, BW Marina and Willow Berm Marina.
    Clifton Court Area of Old River - Italian Slough and Kings Island
    Sacramento Area - Sacramento Marina

    Herbicides Being Applied
    Fluridone (registered for aquatic use with US Environmental Protection Agency and the California Department of Pesticide Regulation)

    The public should not gather on or near boat docks during treatment applications. In addition, the manufacturer’s Material Data Safety Sheet, related to potential acute health effects, states there are no known significant effects or critical hazards.

    Treated areas will be monitored weekly to ensure herbicide levels do not exceed allowable limits, and herbicide treatments have no adverse impacts on the environment, agriculture or public health in or near the above mentioned treatment areas.

    Contact Information

    For more information regarding the control program, please see DBW’s website at or call 888-326-2822.