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Aquatic Pest Control Program

Program Description

• State legislation in 1982, designated the Department of Boating and Waterways (DBW) as the lead state agency to cooperate with other state, local and federal agencies in controlling Water Hyacinth in the Sacramento-San Joaquin Delta (Delta), its tributaries, and the Suisun Marsh.
• The Egeria Densa program was authorized by law in 1997. Treatment began in 2001.
• DBW currently spends approximately $6.5 million per year on this program, subject to annual appropriation of funds by the California Legislature.
• Water hyacinth and Egeria densa have a negative impact on the Delta ecosystem. They displace native plants, block light needed for photosynthesis, reduce the amount of dissolved oxygen in the water, and deposit silt and organic matter several times the normal rate.
• These aquatic invasive plants also have a significant impact on recreation and commercial activity in the Delta. They form dense mats of vegetation creating safety hazards for boaters, obstructing navigation channels, marinas and irrigation systems.
• Both plant species have no known natural controls in the Delta environment.
• DBW’s Aquatic Weed Control Program obtains permits from the National Oceanic and Atmospheric Administration Fisheries, the U.S. Fish and Wildlife Service, and the Regional Water Resources Control Board.
• DBW operates a “control” program as opposed to an “eradication” program. It is not likely that Water Hyacinth and Egeria Densa will ever be eradicated from Delta waterways.
• DBW operates an extensive water quality monitoring program that shows that the control program meets water quality standards for herbicide use.
• Permits restrict treatment in the Delta from April 1 through October 15.
• Annual hydro acoustic monitoring is done in the treatment regions to monitor changes in infestations over time.

Water Hyacinth (Eichhornia crassipes)

• Water Hyacinth is an attractive floating aquatic plant with shiny green leaves and delicate lavender flowers.
• It was introduced into the Delta from South America more than 100 years ago.
• This extremely prolific aquatic invasive plant can double in size every ten days in hot weather and can quickly become a dense floating mat of vegetation up to six feet thick.
• The mats can travel with river currents and with tidal movement.
• Mats can also attach to structures in the water, limiting access to boats and reducing swimming areas.

Egeria Densa (Brazilian Elodea)

• Egeria densa is a shallow-water submerged aquatic plant from Brazil, popularly used as an aquarium accessory that was introduced into the 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 Delta.
• The plant can spread very quickly depending on environmental conditions.
• Egeria densa spreads by fragmentation. Therefore, the two most practical options for removal are harvesters to cut the Egeria densa, or using other means, such as aquatic vegetation management firms, to pull the Egeria densa by its roots.
• DBW is the only entity authorized to treat Egeria densa with herbicides.