Mosquitoes and Stormwater Facilities
Mosquitoes can be a serious nuisance. Large populations of mosquitoes can make it unpleasant to be outside and they keep families indoors when they should be out enjoying warm weather.
Mosquito populations can be controlled by limiting the number of places they can breed. Any small, stagnant pool of water can promote mosquito breeding, even as little as a teaspoon of water. In most cases, the source of mosquito breeding can be found in public areas or backyards.
Stormwater management facilities are often blamed for large numbers of mosquitoes, because the facilities contain rainfall runoff. But if a stormwater management facility is designed and maintained properly, it should not promote mosquito breeding.
If you know the facts about mosquitoes and how to prevent them, your family can be back outside, enjoying the warm weather, in no time.
► Know Your Mosquitoes: There are about 200 species of mosquito in the U.S. and they differ in their preferred habitat or the types of animals they bite.
► Breeding: Mosquitoes breed in stagnant, standing water. They lay their eggs in standing water, and depending on the species, the eggs take about a week to reach maturity. As little as a teaspoon or bottle cap of water left standing for more than a week is enough for eggs to develop into adult mosquitoes
► Natural Prevention: Mosquitoes cannot complete their life cycle to become adult mosquitoes if:
Do Mosquitoes Breed in Stormwater Management Facilities?
If designed and maintained properly, stormwater management facilities should not promote mosquito breeding.
Stormwater management facilities hold and treat rainfall runoff. Without stormwater management, the runoff would go directly into our streams, causing flooding, polluting our waterways and eroding streams. There are thousands of stormwater management facilities in the County.
Types of stormwater management facilities include:
Some of these facilities hold water permanently, while others hold stormwater runoff temporarily.
Stormwater Management Facilities that Hold Water Permanently
Stormwater management facilities that continuously have water, such as wet ponds, typically do not promote mosquito breeding because they contain predators that feed on mosquitoes. Mosquitoes are a favorite food for aquatic predators. Their larva is eaten by fish and other aquatic wildlife. Wet ponds and stormwater wetlands serve as aquatic habitats with plenty of natural predators to control the mosquito population.
Stormwater Management Facilities that Hold Water Temporarily
Dry detention basins, bioretention and rain gardens are designed to detain and infiltrate stormwater. Facilities fill up during storm events and then release the water within two to three days. Because these systems are designed to hold water for only short periods of time, less than the week needed for mosquito growth, they do not provide mosquitoes with enough time to reach maturity.
I Think the Nearby Stormwater Management Facility is the Source of Mosquitoes in My Area. What Should I Do?
If you see large numbers of mosquitoes around a stormwater management facility, please contact the Montgomery County Customer Service Center at 3-1-1 or send an email to firstname.lastname@example.org.
Preventing Mosquitoes in Your Neighborhood
It is important that we all do our part to eliminate mosquito breeding habitat. One of the best ways is to check for standing water in backyards and on porches and balconies.
Checklist for Preventing Standing Water:
Most importantly, share this information with your neighbors. Download a PDF flyer of the material presented on this page. (PDF, 847KB)
Larvicides only kill mosquito larvae and not the pupae or adults. They are preferred over the use of adulticides because larvicides are effective at killing mosquitoes, and at the same time, they minimize the impacts to the environment and non-target organisms. They are also not harmful to animals such as squirrels, raccoons and dogs if they are accidentally ingested.
Because VectoLex ® only targets mosquito larvae, it is safe to use in natural water bodies or in water that flows to natural water bodies, such as stormwater facilities and storm drains.
Do not use VectoLex ® in drinking water reservoirs. It can only be purchased and applied by a licensed applicator with aquatic certification.
Mosquito Dunks can be used in small containers of water around residential properties, private rain gardens, rain barrels and other places that do not flow into streams, lakes or rivers.
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