Wetlands Loss Maps Q&A

MassDEP has compiled aerial photographs of the state to track wetland alteration and loss. These photos help MassDEP enforce the Wetlands Protection Act.

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What is the purpose of the Wetlands Loss Project?

Wetlands have been misunderstood for many years, viewed as swampy areas to be drained and converted to other uses. We now understand the important role wetlands play in our ecosystem. In order to protect this valuable land, MassDEP began compiling aerial photographs of the state to track the alteration and loss of wetlands. By comparing the photos, MassDEP can more effectively enforce the Wetlands Protection Act to restore already damaged areas and devise better strategies to prevent the destruction of these valuable resource areas.

How was this information obtained?

The wetlands mapping is accomplished by the analysis of stereo 1:12,000 scale color infrared aerial photography taken during the period of 1990-99. The interpreted wetlands information was field verified when necessary to produce the most comprehensive wetlands dataset available. The wetlands data has been accurately transferred to the 1:5,000 scale digital orthophoto map series developed from 1995 photography and the digital wetlands data is distributed on the MASSGIS website. The wetlands data has a minimum mapping unit of 0.25 acres.

Additional Resources for How was this information obtained?

Has MassDEP mapped the entire state?

yes. You can see the entire map at the MassGIS website.

Can I get copies of the maps from MassDEP?

MassDEP cannot supply copies of the maps. Each mapped town has been sent a CD-ROM with the map images and the analysis of the mapped areas. We have contacted the regional planning agencies in the state and for a nominal fee they will print copies for the towns. However, these agencies are not required to provide these maps. Local print shops such as CopyCop and Kinko's will also print these maps for a reasonable fee.

How many towns have been mapped so far?

The entire state has been mapped.

What kinds of land development impact wetlands the most?

MassDEP has identified four major types of land development that can make the most impact on wetlands:

  • Cranberry bogs 
  • Residential development 
  • Commercial development 
  • Gravel operations

These identified uses account for most of the changes found in wetland resource areas to date.

What's the advantage of a color infrared (CIR) photo?

Using color infrared (CIR) photography better shows the impact of human activities on vegetation in a mapped area The color infrared film consistently displays surface water or wet soil conditions in a darker signature. When viewed in three dimensions under an 8-power stereoscope, an experienced photointepreter can accurately differentiate between upland and wetland areas.

What's the difference between a color infrared (CIR) photo and an orthophoto?

A CIR consistently displays surface and wet soil conditions in a recognizable dark signature. The CIR photos are captured in early spring prior to leaf-out, allowing a clear view of the ground conditions. The orthophoto map is another type of aerial photograph that has been corrected for displacement due to topography and other errors that make the image cartographically accurate to approximately three meters. There are two versions of orthophotographs taken at the same scale and specifications: the black and white photos of the spring 1995-1996 time frame and the color photos of 2001.

How many acres of wetlands are there in Massachusetts now? How many acres has the state lost?

Currently, there are over 48,000 acres of wetlands in Massachusetts. From 1991 to 2001, 800 acres of wetlands were lost or altered in the state. An additional 450 acres were either lost or altered in the state from 2001 to 2005.

What do wetlands do that makes their impact so important?

  • Wetlands are complex ecosystems that provide valuable services to humans and animals alike.
  • Wetlands protect our water supplies by recharging ground and surface waters and filtering contaminants.
  • Wetlands help control flooding by storing water during storm events and slowly releasing it into surface and ground waters.
  • Wetlands protect us from storm damage by serving as natural buffers.
  • Wetlands improve the quality of our rivers, streams and lakes by filtering and reducing pollutants before reaching these water bodies
  • Wetlands provide a place for fish and shellfish to spawn and grow, preserving our key fisheries and supporting ecosystems.
  • Wetlands are important wildlife habitat that provides food, shelter, breeding areas, and migration corridors for both wetlands and uplands wildlife.
  • Wetlands are beautiful areas of open space that provide enjoyment and increase property values.

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