The MassDEP Human Altered Areas layer contains polygon features delineating anthropogenic activity that occurred within mapped wetland resource areas and attribute codes indicating the previous wetlands type. These activities were identified during the 2005 update to the MassDEP Wetlands Data Layer. This data is similar to the MassDEP Wetlands Change Data; however, because it was derived using a different methodology and contains different attributes, it is presented as a separate layer.
This layer, named WETLANDSDEP_ADHC_POLY, provides a medium-scale representation of the wetland areas of the state and is for planning purposes only. While aerial photography can be a useful and reliable tool for ascertaining potential anthropogenic activities to wetlands, it is not a substitute for appropriate ground survey information (vegetation, history of hydrology, soil profiles, etc.).
The wetlands boundaries shown in this layer 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.
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 aerial photo-interpretation of 0.5m (1:5,000) digital stereo CIR imagery, captured in April 2005. All data was developed using heads up digitizing (i.e. manual digitizing by a human photo-interpreter). No field verification was conducted on this updated wetlands data. That data layer is named WETLANDSDEP_POLY. See MassDEP Wetlands (2005).
During the course of the update, potential changes to wetlands polygons which were not captured in the MassDEP Wetlands Change Analysis were encountered. These changes involved anthropogenic activity within mapped wetlands. The human activity was such that it altered the area to an extent that it could no longer be considered wetland. Examples include new homes, roads and lawn expansion. The photo-interpreter identified and tracked the change to the mapped wetland as a human change; however, no effort was made to determine when the human activity originally occurred nor to track and differentiate the cause of the change (i.e. residential versus commercial versus new road). MassDEP routinely reviews changes identified through the MassDEP Wetlands Change Project to determine if such human caused changes are permitted, unpermitted or exempt from permitting requirements. Cases are selected for enforcement based on this review.
The WETLANDSDEP_ADHC_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|
|AREAACRES||DOUBLE||Area of the feature in acres|
|AREASQMI||DOUBLE||Area of the feature in square miles|
|LABEL||TEXT (50)||Description of human-altered wetland type|
The following types of wetland features, which represent the former type of the wetland, are included in the WETLANDSDEP_ADHC_POLY layer:
|1||BA||COASTAL BANK BLUFF OR SEA CLIFF|
|2||BB||BARRIER BEACH SYSTEM|
|8||M||SHALLOW MARSH, MEADOW, OR FEN|
|10||RS||ROCKY INTERTIDAL SHORE|
|14||WS1||WOODED SWAMP DECIDUOUS|
|15||WS2||WOODED SWAMP CONIFEROUS|
|16||WS3||WOODED SWAMP MIXED TREES|
|17||BB-BE||BARRIER BEACH-COASTAL BEACH|
|19||BB-D||BARRIER BEACH-COASTAL DUNE|
|20||BB-DM||BARRIER BEACH-DEEP 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|
The codes for the POLY_CODE field in WETLANDSDEP_ADHC_POLY are:
|1||9.22||OPEN WATER PUBLIC WATER SUPPLY RESERVOIR|
|6||9,22||OPEN WATER FRESH|
|7||10,13||TIDAL FLAT/ROCKY SHORE|
|9||9||OPEN WATER TIDAL, BRACKISH, SALT POND|
|10||9||OPEN WATER OCEAN|
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.
The WETLANDSDEP_ADHC_POLY data were developed by the MassDEP Wetland Conservancy Program. For questions call 617-556-1163.
|Date published:||December 13, 2017|
|Last updated:||December 13, 2017|