Plugged Ditch, by Julie Slacum

In partnership with the Maryland Department of Natural Resources, Maryland Department of the Environment, and Maryland Department of Agriculture-Mosquito Control, the Chesapeake Bay Field Office received a North America Wetlands Conservation Act Small Grant Award to restore 450 acres of salt marsh by plugging mosquito grid ditches at E.A.Vaughn Wildlife Management Area (WMA), located in Worcester County in the Maryland Coastal Bays region.

The Maryland Coastal Bays watershed has lost an estimated 54,778 acres of wetlands to agriculture, development, grid ditches, and other human activities. Ditches were cut from high marsh water bodies and linked to their tidal sources, changing the natural hydrology of the salt marsh system. Undisturbed, healthy high marsh systems contain shallow pools, pannes, and permanent water bodies. The natural hydrology only allows for periodic recharge of these elements during spring and storm high tides.

After ditches were created, pools and pannes were drained and subject to daily high and low tides.  Permanent water bodies were drained, and in some cases, filled in over time.  The lack of stable water levels destroyed marsh habitat essential to various wetland dependent birds.

To restore the natural high marsh hydrology of 450 acres of coastal salt marsh, 35 ditch plugs were installed in ditches at elevations equal to the surrounding marsh. By stabilizing water levels, permanent and semi-permanent water bodies will emerge, resulting in an increase in aquatic invertebrates, fish and submerged aquatic vegetation (SAV) common to high marsh areas. These in turn will provide food and habitat needed by wetland dependent birds. 

A monitoring program will examine changes in marsh vegetation, SAV, fish species, and other wildlife in response to re-establishment of natural high marsh systems. Monitoring was conducted in September 2007, prior to installation of ditch plugs, and will continue one, three and five years later.

For more information about this project contact:

Julie Slacum

U.S. Fish and Wildlife Service

Chesapeake Bay Field Office

177 Admiral Cochrane Drive

Annapolis MD 21401

410.573.4517

julie_thompson@fws.gov