Most of the location information was derived from historic data and has been ground-truthed against inspection and ownership reports that are maintained by the ODS. The locations of some dams have not been confirmed. These are pending verification and can be identified through the field 'LocStatus.' Dams regulated by the ODS in accordance with regulation CMR 302 10.00 are listed as 'Office of Dam Safety' in the field 'RegAuth'. Please report any data errors or inconsistencies to the Office of Dam Safety (email@example.com) or DCR-GIS (firstname.lastname@example.org)
The datalayer contained an identical number of records as the ODS database at the time it was created. New records subsequently may have been added to the ODS database that are not reflected in this GIS datalayer. There are many additional fields and information maintained by the ODS in its database that are not included in the GIS data. These data have been excluded for privacy, security, accuracy and administrative reasons.
MassGIS stores the GIS datalayer as DAMS_PT.
Original Source Manuscripts and Production
The Massachusetts Office of Dam Safety has historically maintained records of dams through maps, deeds, site visit documentation and correspondence. A unique identifier ('NATID') for each dam links all documents. The original GIS dataset was created from historical documents of varying accuracy in 2001. An organized digital data logging system in recent years has enabled better ground-truthing and location verifications through annual site inspections.
Current Source Manuscripts and Production Methodology
An interactive database is currently used by ODS staff to continually update information about dams.
The DAMS_PT attribute table has the following items:
|Field Name||Width||Type||Description /Codes|
|REGAUTH||254||String||The authority responsible for regulating the dam(see below for codes)
|NATID||254||String||Unique ID for the dam in the Office of Dam Safety database|
|DAMNAME||254||String||Currently recognized and official name of the dam|
|TOWN||254||String||Town in which the dam is located|
|DAMLAT||19||Double||Dam location – Latitude in decimal degrees|
|DAMLONG||19||Double||Dam location – Longitude in decimal degrees|
|HAZCODE||254||String||Codes that indicate severity of hazards presented to communities in case of dam failure
|OWNTYPE1||254||String||Basic information on owner type. See OwnType2 for further elaboration.
|OWNTYPE2||254||String||More details on owner type. See OwnType3 for further elaboration.
|OWNTYPE3||254||String||Details on owner type where available
|MGMTUNIT||254||String||Department or other management unit responsible for dams
|LOCSTATUS||30||String||Indicates whether geographic location of the dam has been verified
|TOWN_ID||3||Number||MassGIS town identifier (1-351)|
The shapefile will periodically be updated as better information becomes available in the ODS database. Future data enhancements include verifying all dam locations. Please report any data errors or inconsistencies to the Office of Dam Safety (email@example.com) or DCR-GIS (firstname.lastname@example.org)