Envisioning No Trash and No Mosquitoes - Working Together for a Better Tomorrow
CASQA and the Mosquito and Vector Control Association of California have enjoyed a long working relationship to ensure that mosquito control in stormwater infrastructure is able to be achieved effectively and efficiently. Work was conducted by the California Department of Transportation and the California Department of Public Health in the 1990s examining a variety of methods to eliminate mosquitoes from developing and breeding within catch basins and drywells, thereby converging stormwater and pollution control goals with public health pest control. The results indicated that outfall height requirements and the mosquitoes’ drive to find water to lay eggs makes their elimination from structures a challenge.
In 2012, the San Francisco Bay Regional Water Quality Control Board (Region 2) approved limits on the amount of trash permitted to discharge from stormwater systems. This, in conjunction with continued trash TMDLs to areas in the Los Angeles Regional Water Quality Control Board (Region 4), led to many cities within the regions looking to install trash capture devices to separate the trash from the water. Unfortunately, a number of these were created without considering the impacts to mosquito inspection, prevention, and treatment.
The Mosquito and Vector Control Association of California works with the State Water Resources Control Board to ensure that approved devices allow structures to be inspected and treated for mosquitoes. Ideally, mosquito control districts would like to ensure that standing water does not reside in the stormwater system for more than 96 hours. Trash capture devices need to not cause undue burden on mosquito control districts to inspect for mosquito larvae in standing water underneath or behind the trash. These devices also need to be maintained with enough frequency to ensure that trash is not collecting water, becoming a second mosquito breeding source within the device.
Here we focus on the variety of trash capture devices with a particular focus on the changes that manufacturers and regulators have requested to better meet the dual needs of reduction of trash in waterways and the reduction of mosquitoes within the stormwater conveyance systems. MVCAC has continued its collaborative work with the State Water Resources Control Board as devices are being reviewed by SWRCB for functionality. To assist manufacturers seeking verification that the device will allow mosquito control professionals to complete their work, the MVCAC has completed a video demonstrating how field personnel interact with devices while making inspections and treatments.
We focus on a collaborative approach using our knowledge of mosquitoes and chronically breeding systems, with the information others know about water flow and pollution control requirements.
Although the State Water Board has an approved list of devices, not all devices are appropriate for every region. Municipalities are encouraged to work with their local mosquito control districts to discuss how to minimize the impacts of stormwater structures, their ability to collect irrigation run-off, and trash capture from bringing mosquitoes into local neighborhoods. By engaging in a collaborative approach, municipalities and mosquito control agencies can work together to best protect Californians from mosquito-borne diseases while improving the water quality through trash capture.