Operational aquatic weed management in the California Sacramento–San Joaquin River Delta

Aquatic weed management in the California Sacramento–San Joaquin Delta (Delta), and its tributaries has been conducted since 1982 by the California Department of Parks and the Recreation Division of Boating and Waterways (CDBW). The program uses chemical, physical, and biological control methods as a part of integrated pest management (IPM) in the Delta, which is approximately 28,000 ha (68,000 ac) of waterways. The CDBW targets nine invasive aquatic plant species, including water hyacinth [Eichhornia crassipes (Mart.) Solms] and Brazilian waterweed (Egeria densa Planch.). Weed management challenges, such as budget, regulatory requirements, and multiple stakeholder groups, require the program to be flexible and also aim at control of all target weeds in the Delta. An increased number of target invasive plants and trends in target plants and environmental conditions, such as high or low water flow years, have further emphasized the importance of IPM and a flexible toolset to control target invasive plants in the Delta.