The detailed knowledge of field operations managers with the Division of Boating and Waterways-California Department of Parks and Recreation, a DRAAWP project partner, who can identify sites at which persistent water hyacinth populations are difficult to control using other methods.These ‘backwater nursery’ sites are well-suited for biocontrol, as the stable water hyacinth populations will permit development of large populations of biocontrol agents. These sites act as ‘nurseries’ for new populations to develop each year. Analysis of images over the past several years has revealed backwaters, such as flooded islands, where water hyacinth populations persist in spite of nearby control. DRAAWP project partners from NASA-Ames have developed an automated processing tool to determine acreage of water hyacinth from Landsat images. Remote sensing of water hyacinth populations using Landsat satellite and airplane-borne systems.Selection of sites for water hyacinth biological control is being informed by several sources of information, including: To implement adaptive, integrated management under the DRAAWP, selection of sites at which specific types of weed control strategies will be emphasized is critical. Water hyacinth blocks water flow for pumping intakes, impedes recreational and commercial navigation and creates danger for boats, alters water quality for fish, blocks light for submersed plants and displaces native aquatic plant and animal species. Water hyacinth ( Eichhornia crassipes), a floating aquatic invasive weed, covers up to 10,000 acres in the Sacramento-San Joaquin Delta, including areas that are inaccessible or impractical for herbicide treatment and mechanical removal.