Wetland Restoration

Bank Stabilization  |  Enhancement of Predator Access and Habitat  |  Open Marsh Water Management  |  Fill Removal  |  Dam Removal  |  Artificial Dams  |  Beaver Dams  |  Reconnection of Floodplain

The District approaches each wetland project request from a holistic perspective. Whenever possible Wetland Management Projects incorporate a design strategy to address mosquito habitat, flooding as well as revitalization of degraded structures (ditch, etc.) and the environment it services.

Wetland habitat values are significant to people and creatures alike. A few of the obvious reasons include but are not limited to: water quality and quantity (storage, storm water and flood control) and aquatic flora and fauna productivity which also relate directly to eco-industry and tourism (hunting, fishing, boating, birding, etc.). The resilience or ability of our wetlands to sustain impact (artificial or natural) is essential now, more than any other time in our history. Building resilience strategies into wetland management projects can reduce the frequency of needed maintenance.


Bank Stabilization

Wetland Management Projects identify problem areas (i.e., erosion of soils) and attempt to incorporate features in the design process to improve conditions at Wetland Management Project sites.

Methuen bank stabilization - Before

                                                       Methuen ~ Before

Methuen bank stabilization - During

                                                     Methuen ~ During

Methuen bank stabilization - After

Methuen ~ After


Enhancement of Predator Access and Habitat

Fish are one of the District’s finest mosquito predators. Wetlands recommendations always consider opportunities for improvement to stream crossings, wildlife corridors and hydrologic connectivity.

Crooked Pond Brook Culvert Improvement, Boxford - Before, During and After

2 large black tubes in woods - Crooked Pond Brook Culvert Improvement, Boxford

truck carrying very large wide tubes - Crooked Pond Brook Culvert Improvement, Boxford

large wide tube being placed in woods by heavy equipment - Crooked Pond Brook Culvert Improvement, Boxford

footbridge built over very large wide tube - Crooked Pond Brook Culvert Improvement, Boxford

To sustain fish habitat, the District protects riffle and pool structures whenever possible during construction. Shade is instrumental in keeping predators cool, so vegetation is only cut to allow safe access of equipment and personnel and that which obstructs flow. This provides fish unobstructed access to mosquito habitat in and alongside waterways. Removing blockages from culvert gratings (both inlets and outlets) supports fish passage as well.

Salem Culvert Grate Clearing - Before and After

Overgrowth over grate - Salem Culvert Grate Clearing - Before

grate open and cleared of overgrowth - Salem Culvert Grate Clearing - After


Open Marsh Water Management

This salt marsh technique directly supports mosquito predation by creating fish refugia (reservoirs) and establishing access to mosquito larval sites (radial ditches) on the salt marsh. Though no longer permitted, the District evaluates its older sites for “maintenance” purposes.

aerial view wetlands OMWM Site - Newbury

OMWM Site - Newbury

Salt Marsh Mosquito Larvae on OMWM Site BEFORE Construction - Newbury

Salt Marsh Mosquito Larvae on OMWM Site BEFORE Construction ~ Newbury

Man Dipping for mosquitoes in OMWM Panne with deeper reservoir for fish

Dipping for mosquitoes in OMWM Panne with deeper reservoir for fish

 

OMWM MAP - Select "available data layers" (right side), open "Coastal and Marine Features", open "Northeast Salt Marsh Projects" and then add layer.


Fill Removal

The District includes fill removal in its wetland management projects as determined necessary and appropriate. Historically wetlands have been filled with items such as building rubble, trash, tires and landscaping debris. Fill removal of these items often reduces mosquito habitat, promotes better hydrology, increases wetland area and improves wetland values and functions for mosquito predator survival.

backhoevremoving soil - Fill Removal in Rumney Marsh - Saugus

Fill Removal in Rumney Marsh - Saugus    

lowland next to hill Fill Removal in Rumney Marsh - Revere

Fill Removal in Rumney Marsh ~ Revere


Dam Removal

According to the Association of State Dam Safety Officials there are over 3,000 dams exceeding 6 feet in height in Massachusetts today, and potentially over 1,200 dams under 6 feet in height (or that impound less than 15 acre feet of water). Many smaller dams remain uncounted. There have been costly impacts from dam building over the years. Disruption of natural flow regimes effects water quality, habitat, and the aquatic life that resides in and around them. Impounded waters are slow moving so that sediments drop out leading to shallower waters and poor flow upstream. Slower dropping sediments like clay and fine silts cloud the water column and contribute to rise in water temperature. Cold water streams evolve as they warm and oxygen-depletion is a major concern for fisheries. Eventually major shifts in plant, animal and insect species composition occurs. Warm oxygen depleted waters flowing over a dam can even raise temperatures below a dam. These degraded habitats are prime for mosquito larval development.

flooded area in woods

dead branches

dead fish floating


Artificial Dams

 

The District partnered with the Division of Ecological Restoration and others to complete the removal of the Ox Pasture Brook Dam in Rowley, MA.

 Rowley  Before -    2009

Ox Pasture Dam Brook Removal: Rowley  Before - 2009

 Rowley   During - 2009

Ox Pasture Dam Brook Removal: Rowley During - 2009

 Rowley  After - 2016

Ox Pasture Dam Brook Removal: Rowley After - 2016


Beaver Dams

beaver damThe District has and will continue to work in partnership with MA Fish and Wildlife – Division of Fish and Game, municipal officials (i.e., Board of Health, Conservation Commission and Department of Public Works) to find solutions to problem beaver populations.

Beaver dam impoundments are often characterized by shallow warm water areas where mosquitos can thrive, though largely dependent on site topography. Deeper water zones typically support mosquito predator species and therefore are less prone to support mosquito development. The District evaluates beaver sites on a case by case basis.

overgrown stream- Beaver Dam Removal Methuen ~ Before

Beaver Dam Removal Methuen - Before

Flowing stream - Beaver Dam Removal Methuen ~ After

Beaver Dam Removal Methuen - After

flooded area of woods - Beaver Dam Removal Methuen ~ Before

Beaver Dam Removal Methuen - Before

Grassy field with small pond -nBeaver Dam Removal Methuen ~ After

Beaver Dam Removal Methuen - After

 

tree stump - from tree beaver took downHelpful Links to Beaver Information – Massachusetts

 

 


Reconnection of Floodplain

Development, improperly sized or located infrastructure, previous ditching efforts and illegal fills are some of the many ways in which waterways become disconnected from their floodplains. Wetland functions diminish under these conditions and can contribute to increased mosquito habitat associated with decreased flood storage capacity (and increased flooding), isolated pockets of trapped floodwater and poor predator habitat.

 Spoils on Wetland ~ Peabody	 Dappled sunlight on floor of woods

Spoils on Wetland - Peabody

Before ~ Peabody  Stream in woods

Before - Peabody

After ~ Peabody - stream in woods

After - Peabody