Coastal Mosquito Control in your Neighborhood

Do mosquitoes bother you in the summer? Are you concerned about your children getting bitten too much? Do you have concerns about the chemicals used in mosquito spraying? Are you concerned about the environment in your area?

Probably you can answer 'yes' to at least one of these questions. The Norfolk County Mosquito Control Project is utilizing a coastal mosquito control method called Open Marsh Water Management. Our first project was completed in the fall of 1999, at the Upper Black Creek Marsh in Quincy. Below is some information on Open Marsh Water Management. The only current Norfolk County Mosquito Control Project municipalities with salt marsh and therefore eligible for this type of work are Braintree, Milton, Quincy, and Weymouth and we have completed projects in each town.

What is Open Marsh Water Management?

In a nutshell, Open Marsh Water Management is a technique, which provides a greater access to the salt marsh for small fish, which eat mosquito larvae breeding on the marsh. This greatly reduces the need for mosquito spraying in the immediate neighborhood. The work also reverses some of the changes that were done to the marsh when it was originally ditched. OMWM also prevents the encroachment of invasive plants and provides better habitat for waterfowl and other birds. Open Marsh Water Management, was developed in New Jersey in the late 1960's and early 1970's and has been conducted in other parts of the eastern seaboard, but has never been implemented in Norfolk County.

How will OMWM affect the salt marsh?

In the 1930's, during the depression, the government put many people to work in programs designed to increase employment. One of the jobs created was ditch digging in salt marshes. Over 90% of all east coast salt marshes were ditched. This ditching was originally designed to eliminate mosquito-breeding habitat on the marsh by draining the water off the marsh quickly after high tides. In many cases there was effective mosquito control. One of the unforeseen side effects, though, was that since there was no longer any water on the marsh the marsh was no longer used by the wildlife that needed the water. Another problem was that the ditching was not always maintained and in some situations the ditches, that were designed to prevent mosquito breeding, became breeding habitat. Open Marsh Water Management is designed to utilize some of the old ditches, fill in certain other ditches and create small ponds that will provide habitat for the fish and birds. Immediately after the work is completed the marsh will look disturbed, but within a year or two the marsh vegetation returns and the marsh becomes more 'natural' looking than it was before. The accompanying photographs show the sequence of an Open Marsh Water Management project in Newbury, Massachusetts over the period of less than one year.

Photograph 1 - This section of marsh is devoid of ponds and provides little or no habitat for wading birds and waterfowl. The old ditch is visible in the center. It breeds mosquitoes but there is not enough water to support fish, which could eat the mosquito larvae.

Photograph 2 - A newly dug pond is shown here with the old ditch accessing it.

Photograph 3 - This is the pond during the first growing season, 10 months after the pond was dug. The marsh has recovered and this pond will now hold fish, which will eat any mosquito larvae in the water. The pond will also provide habitat for waterfowl and wading birds.

How is OMWM implemented?

The work on the marsh is primarily accomplished using track motion excavators, that have a very low ground pressure (less than 3.5 pounds per square inch - about the same or even less than a human foot). Material that is dug to create ponds is used to fill in old ditches, or is moved off the marsh. Photograph 4 shows a typical excavator used on the salt marsh.

Photograph 4 - A typical excavator working on the salt marsh.

Will this work increase the water on the marsh?

Some OMWM projects deliberately increase the water onto the marsh to help it restore to its original condition. This is usually done by increasing the size of culverts that may restrict tidal flow. Many OMWM projects are very successful without any increase in water/tide.

My property abuts the marsh. How will this affect my property?

Unless you are otherwise contacted, there will be no physical impact to your property. You will have to view a disturbed marsh for a season, but after a year the marsh will return to its natural state. With reduced mosquito populations, less invasive plant species, and more waterfowl, the long-term effect will be to make the surrounding properties more desirable.

How will this affect my mosquito problem?

Research shows that Open Marsh Water Management projects typically provide 90% + elimination of mosquito breeding, and we have seen similar results from OMWM projects we have already completed. This reduction will be noticeable to the surrounding residents. Although some mosquitoes will probably still find places to breed on the marsh, and some may come from other nearby marshes, you should see a marked decrease in the large mosquito outbreaks.

Is this an environmentally desirable project? http://partners.fws.gov/pdfs/pMA.pdf

Open Marsh Water Management has growing support from a wide range of environmental groups and agencies. The primary reason for this support is that OMWM provides mosquito control while, at the same time, reducing the need for chemical pesticides. OMWM also enhances the marsh ecosystem for wildlife use.