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 Department 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 department at

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



    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 Department of Boating and Waterways is working with its federal agency representative, the US Department of Agriculture - Agricultural Research Service, to obtain the required approvals to treat Egeria densa in the Delta in 2013. The National Marine Fisheries Service and US Fish and Wildlife Service, the federal agencies charged with approving the permits, are in the process of reviewing the requests and working closely with the USDA and DBW. The review process is moving forward, and DBW will provide updated information as available.