MassGIS logo

MassGIS maintains a comprehensive, statewide database of spatial information for mapping and analysis supporting emergency response, environmental planning and management, transportation planning, economic development, and transparency in state government operations.

Visit the MassGIS website

Browse all MassGIS data layers

Other Access

The information on this page (the dataset metadata) is also available in these formats.

JSON RDF

via the DKAN API

MassGIS Data: MassDEP Wetlands (2005)

December 2017
Wetland features from MassDEP including open water, marshes, swamps, tidal flats, etc.

Download statewide data
(shapefiles and ArcGIS LYRs; 314 MB)

Download smaller, regional sections in OLIVER
Wetlands viewer

The MassDEP Wetlands (2005) dataset comprises two feature classes:

  • The WETLANDSDEP_POLY layer contains polygon features delineating mapped wetland resource areas and attribute codes indicating wetland type.
  • The WETLANDSDEP_ARC layer was generated from the polygon features and contains arc attribute coding based on the adjacent polygons as well as arcs defined as hydrologic connections.
     

Together these statewide layers enhance and replace the original MassDEP wetlands layers, formerly known as DEP Wetlands (1:12,000). That original MassDEP wetlands layer is still available for reference.

The 2005 MassDEP Wetlands layers provide a medium-scale representation of the wetland areas of the state and are for planning purposes only. The wetlands boundaries shown on this map have been determined by photographic interpretation. They do not represent, and should not be used as, wetlands delineations under the Massachusetts Wetlands Protection Act (M.G.L. c. 131 §40) and its regulations. Wetlands boundary determination for other purposes, such as the Wetlands Protection Act MA Act M.G.L. c. 131 or local bylaws must use the relevant procedures and criteria.

Methodology

Wetlands map sample

The original MassDEP wetlands mapping project was based on the photo-interpretation of 1:12,000 stereo color-infrared (CIR) photography, captured between 1990 and 2000, and included field verification by the MassDEP Wetlands Conservancy Program (WCP). In 2007 the MassDEP WCP began a statewide effort to assess and, where necessary, update the original wetlands data. The MassDEP WCP used ESRI ArcGIS Desktop software, assisted by the PurVIEW Stereo Viewing extension, to evaluate and update the original wetlands features based on photo-interpretation of 0.5m (1:5,000) digital stereo CIR imagery statewide, captured in April 2005. No field verification was conducted on this updated 2005 wetlands data.

The 2005 WETLANDSDEP_POLY layer includes polygon features that distinguish it from its predecessor by overall changes in size and shape. In addition, new polygons have been created and original ones deleted. Many of the polygons, however, remain the same as in the original layer. All changes have been made according to the techniques described below. For the purpose of cartographic continuity, a small number of coastal polygons outside the state boundary were added based on data provided by the United States Geological Survey (USGS) and the National Oceanic and Atmospheric Administration (NOAA).

The 2005 WETLANDSDEP_ARC layer was generated to support map display and was designed to cartographically enhance the rendering of wetland features on a base map. Arc features in this layer were generated from the wetland polygons and coding (ARC_CODE) was assigned based on the adjacent polygon types. Hydrologic connection features (ARC_CODE = 7) were then added. Where delineated, these arc features indicate an observed hydrologic connection to or between wetland polygons. Although efforts were made to be comprehensive and thorough in mapping hydrologic connections, due to the limitations of aerial photo-interpretation some areas may have been missed.

The types of updates made to the original wetland features include alteration, movement/realignment and reclassification. In some cases original wetland areas have been deleted and new areas have been added. Updates to original wetland features resulted from the following factors: changes in the natural environment due to human activity or natural causes; advances in the field of remote sensing, allowing for more refined mapping.

Edits to the original wetland data include:

  • Addition of new wetland and hydrologic connection features
  • Appending (expansion or realignment) of existing (original) wetland and hydrologic connection features
  • Reclassification of wetlands features, due to change in wetlands environment from the original classification
  • Movement (or shifting) of original wetland features to better match the source imagery
  • Deletion of original wetland or hydrologic connection features due to changes in wetlands environment or inconsistency with mapping criteria. Features that are inconsistent with the mapping criteria include isolated wetlands that are are less than ¼ acre in size and hydrologic features that do not connect to wetland polygons.

Please note that although efforts were made to be comprehensive and thorough in the evaluation and mapping of statewide wetland resources some areas of the state may have been missed. Many of the wetland and hydrologic connection features remain the same as in the original data. The polygon attribute SOURCE_SCALE may be used to identify areas that have been altered from the original wetlands.

  • SOURCE_SCALE code 5000 indicates an updated wetland area.
  • SOURCE_SCALE code 12000 indicates an unaltered, original wetland polygon.

Attributes

Wetlands Polygons

The WETLANDSDEP_POLY attribute table contains these fields:

Field Name Type (Width) Description
WETCODE LONG INT WETLAND CONSERVANCY PROGRAM TYPE CODE
IT_VALC TEXT (16) WETLAND CONSERVANCY PROGRAM TYPE ABBREVIATION
IT_VALDESC TEXT (60) WETLAND CONSERVANCY PROGRAM TYPE DESCRIPTION
POLY_CODE LONG INT SIMPLIFIED POLY CODE ADAPTED FROM 1:25,000 HYDROGRAPHY
SOURCE TEXT (12) ORIGINATOR OF FEATURE
SOURCE_SCALE LONG INT RELATIVE SCALE OF THE BASE IMAGE USED TO DELINEATE THE FEATURE
AREAACRES DOUBLE AREA OF THE FEATURE IN ACRES
AREASQMI DOUBLE AREA OF THE FEATURE IN SQUARE MILES

The following types of wetland features are represented in the WETLANDSDEP_POLY layer:

WETCODE IT_VALC IT_VALDESC
1 BA COASTAL BANK BLUFF OR SEA CLIFF
2 BB BARRIER BEACH SYSTEM
3 BE COASTAL BEACH
4 BG BOG
5 CB CRANBERRY BOG
6 D COASTAL DUNE
7 DM DEEP MARSH
8 M SHALLOW MARSH, MEADOW, OR FEN
9 OW OPEN WATER
10 RS ROCKY INTERTIDAL SHORE
11 SM SALT MARSH
12 SS SHRUB SWAMP
13 TF TIDAL FLAT
14 WS1 WOODED SWAMP DECIDUOUS
15 WS2 WOODED SWAMP CONIFEROUS
16 WS3 WOODED SWAMP MIXED TREES
17 BB-BE BARRIER BEACH-COASTAL BEACH
18 BB-BG BARRIER BEACH-BOG
19 BB-D BARRIER BEACH-COASTAL DUNE
20 BB-DM BARRIER BEACH-DEEP MARSH
21 BB-M BARRIER BEACH-MARSH
22 B-OW BARRIER BEACH-OPEN WATER
23 BB-SS BARRIER BEACH-SHRUB SWAMP
24 BB-WS1 BARRIER BEACH-WOODED SWAMP DECIDUOUS
25 BB-WS2 BARRIER BEACH-WOODED SWAMP CONIFEROUS
26 BB-WS3 BARRIER BEACH-WOODED SWAMP MIXED TREES
27 BB-SM BARRIER BEACH-SALT MARSH
88 N/A NOT INTERPRETED

The codes for the POLY_CODE field in WETLANDSDEP_POLY are:

POLY_CODE WETCODE(s) Description
1 9.22 OPEN WATER PUBLIC WATER SUPPLY RESERVOIR
2 4,7,8,20,21 MARSH
3 12,14,15,16,23,24,25,26 WOODED SWAMP
4 5 CRANBERRY BOG
5 11,27 SALT MARSH
6 9,22 OPEN WATER FRESH
7 10,13 TIDAL FLAT/ROCKY SHORE
8 1,2,3,6,17,18,19 BEACH/DUNES
9 9 OPEN WATER TIDAL, BRACKISH, SALT POND
10 9 OPEN WATER OCEAN
88 88 NOT INTERPRETED

Linear Features

The WETLANDSDEP_ARC attribute table contains these fields:

Field Name Type (Width) Description
ARC_CODE SHORT INT SIMPLIFIED ARC CODE ADAPTED FROM 1:25,000 HYDROGRAPHY
ARC_CODE_DESC TEXT (50) ARC_CODE DESCRIPTION

The codes for the ARC_CODE field in WETLANDSDEP_ARC are:

ARC_CODE Description
1 SHORELINE
2 CLOSURE LINE
3 APPARENT WETLAND LIMIT
7 HYDROLOGIC CONNECTION
8 MEAN LOW WATER LINE
88 EDGE OF INTERPRETED AREA

NOTE: A closure line is defined as a boundary between similar, but different types of wetland resource areas. As an example, polygons with a POLY_CODE of 2 (marsh) or 3 (wooded swamp) are considered to be similar wetland resource types so the lines between these features are coded as closure lines and not as a wetland limit.

Maintenance

The MassDEP Wetlands data were developed by the MassDEP Wetland Conservancy Program. For questions call 617-556-1163.


Last Updated 12/13/2017

Contributor
Modified Date
2017-12-23
Release Date
2017-12-08
Identifier
dc897f7a-615e-4b2b-af82-0b148b26c83f
Spatial / Geographical Coverage Location
Massachusetts
License
Author
MassGIS (Bureau of Geographic Information)
Contact Name
MassGIS
Contact Email
Public Access Level
Public
Data Quality
False