Proactive Catch Basins Treatments

Catch basins, also called storm sewers or storm water catch basins (CBs), are located throughout the County. Catch basins usually drain well and do not present a problem as far as mosquito breeding; however, some (particularly those in older communities in the County) may have structural problems or may be partially blocked, retain water, and produce excellent breeding sites for Culex mosquitoes. The exact number of CBs in the county is unknown, but it is estimated there are 75,000 to 100,000. The County treats CBs throughout the County with a larvicide in programmed treatment cycles.

First Treatment Cycle
The first treatment cycle begins in May and includes CBs in a large portion of the county, as seen here (Jpg image, 60K). This area contains over 65,000 CBs. Many of the CBs in this area are newer and are in good condition (not containing water). These areas of the County are not subsequently treated during the year.

Subsequent Treatment Cycle
After the initial large treatment cycle, a smaller portion of the County, as seen here (Jpg image, 59K), is treated with a larvicide on a regular basis (monthly). This portion of the County contains approximately 33,000 CBs that are older and often have structural problems leading to water retention.