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Invasive Species

Reclamation and its partners continued to conduct programs in 2011 that are designed to prevent the transport and spread of harmful aquatic invasive species to uninfested bodies of water, as well as evaluate and develop remedies to treat facilities already impacted by invasive species.


Common invasive species include Quagga and Zebra mussels, which are freshwater mollusks that can rapidly proliferate in dense clusters by adhering to hard surfaces. The mussels are of concern because their spread can damage water storage, water delivery and hydropower systems, as well as impact recreation and aquatic ecosystems.

The mussels spread from infested waters by attaching to the hard surfaces on watercraft and trailers or are transported as larvae in the water left in boat engines, bilges, live wells, buckets or crevices.

The mussels arrived in the United States from Europe and spread to many eastern waterways, rivers and lakes. The mussels were later discovered in Reclamation facilities in Colorado and in San Justo Reservoir in California.

interactive image:  photo - Quagga mussels attached to a boat in infested waters; click for larger photo
Quagga mussels attached to a boat in infested waters
















Knowledge and experience in the eastern United States indicates that once introduced, the mussels are nearly impossible to eradicate in bodies of water and in facilities. A key observation about the mussels is that no single eradication method can be applied at all facilities. The mussels react differently at different facilities because of water temperature, water chemistry and other factors.

Reclamation is concentrating on proactive measures, such as public education programs, to help reduce the spread and impacts of the mussels to other Reclamation facilities, thereby lessening the need for the more time-consuming and costly measures of eradication.

More information: http://www.usbr.gov/mussels/

Water Weeds

Water hyacinth and hydrilla are rapidly spreading invasive aquatic weeds that have serious impacts. Floating infestations of the weeds restrict water movement; reduce water storage capability; increase stress on levees; clog water intakes, control structures and hydroelectric generators; and damage fish and wildlife habitat.

Like other invasive species, the weeds spread from infested waters via watercraft and trailers, and through other means.

In the Sacramento-San Joaquin Delta at times, the weeds grow into colonies so widespread that they almost completely cover some of the waterways. The hyacinth crowds native species, prevents boating access and clogs water intakes.

interactive image:  photo - Water hyacinth spread across the intake channel for the C.W. “Bill” Jones Pumping Plant in the Sacramento-San Joaquin Delta; click for larger photo
Water hyacinth spread across the intake channel for the C.W. “Bill” Jones Pumping Plant in the Sacramento-San Joaquin Delta
















During fall 2011, hyacinth grew heavy at the Region’s Tracy Fish Collection Facility, which is located at the intake channel for the C.W. “Bill” Jones Pumping Plant at the southern end of the Delta. At one point, up to about 200 truckloads of hyacinth were being removed on a 24-hour basis each day. Ordinarily, the removal system is only used occasionally when Delta flows are high and large debris floats into the intake channel.

Workers at the facility remove hyacinth using a mechanical removal and transport process. A debris barrier, swing arm sweep and conveyor system collects the hyacinth and deposits it into dump trucks for transport to a spoils area.

The water hyacinth infestation in 2011 was unusual, according to the California Department of Boating and Waterways. The agency, which oversees hyacinth control, reported that high water, continued warm temperatures and a delay in receiving approval to start its annual spraying treatment program resulted in unprecedented levels of water hyacinth in some areas.

April 20, 2012