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Overview
The public water supply systems represented in this datalayer are based primarily on information in the DEP’s Water Quality Testing System (WQTS) database. The WQTS database is the Department’s central database for tracking water supply data. The PWS datalayer also contains the locations of proposed wells that have a defined DEP approved wellhead protection area (Zone IIs). Proposed sources are not currently tracked in WQTS. In ArcSDE the layer is named PWSDEP_PT.
Massachusetts Drinking Water Regulations (310 CMR 22.00)
As stated in 310 CMR 22.02, a Public Water System means a system for the provision to the public of piped water for human consumption if such system has at least 15 service connections or regularly serves an average of at least 25 individuals daily at least 60 days of the year. Such term includes (1) any collection, treatment, storage and distribution facilities under control of the operator of such a system and used primarily in connection with such system, and (2) any collection or pretreatment storage facilities not under such control which are used primarily in connection with such system. A public water system is either a “community water system” or a “non-community water system.”
- Community water system means a public water system which serves at least 15 service connections used by year-round residents or regularly serves at least 25 year-round residents.
- Non-community water system means a public water system that is not a community water system.
- Non-transient non-community water system or “NTNC” means a public water systems that is not a community water system and that regularly serves at least 25 of the same persons or more approximately four or more days per week, more than six months or 180 days per year, such as a workplace providing water to its employees.
- Transient non-community water system or “TNC” means a public water system that is not a community water system or a non-transient non-community water system but is a public water system which serves water to 25 different persons at least 60 days of the year. Some examples of these types of systems are: restaurants, motels, camp grounds, parks, golf courses, ski areas and community centers.
Production
The DEP PWS datalayer has been compiled from several sources. The original DEP PWS point dataset contained only community water supplies (CWS) which were located and digitized from stable mylar overlays based on USGS topographic quadrangles. In 1993 locations for community and non-community sources were generated from global positioning system (GPS) data collected by the U.S. Environmental Protection Agency (EPA). The EPA GPS locations were merged with the existing DEP CWS point data to create the DEP PWS datalayer. From June 1996 to February 1997 the DEP GIS Program and Drinking Water Program (DWP) conducted an intensive update of the PWS datalayer. This update involved several methodologies including map interpolation and GPS field verification.
Attributes
The layer's point attribute table has the following fields:
| General Identification Fields: | |
| SOURCE_ID | DWP assigned PWS source identifier (first 7 digits conform to PWSID). The SOURCE_ID is used to relate PWS source locations to WQTS and other DEP PWS datalayers (see Related Datalayers section below). |
| SITE_NAME | For community sources this is the source name (S_NAME) as listed in WQTS, for non-community sources this is the public water supply name (PWS_NAME) as listed in the WQTS table. For proposed sources, which are not tracked in WQTS, this is the source name as listed in DEP DWP’s Zone II database (see Related Database Files section below). |
| PWS_ID | DEP public water supplier or system identification number (First 4 digits are DEP Region ID, followed by MassGIS Town ID) |
| Geographic Information Fields: | |
| TOWN | Town in which the source is located |
| REGION | DEP Region code (1 = Western, 2 = Central, 3 = Northeast, 4 = Southeast, 6 = MWRA service territory) |
| LATITUDE | Latitude in decimal degrees, Clarke1866 Spheroid, NAD27 (actual) |
| LONGITUDE | Longitude in decimal degrees, Clarke1866 Spheroid, NAD27 (actual) |
| Other Fields: | |
| TYPE | The type of PWS according to WQTS or the DWP Zone II database: ESW = Emergency Surface Water GW = Community groundwater well SW = Community surface water source PW = proposed well NTNC = Non-Transient Non-community TNC = Transient Non-Community. |
| ZII_NUM | DEP DWP assigned ID number of Zone II associated with the source. Corresponds to the ZII-NUM item in the region subclass table (ZONEIIS_REG_ZONE2) of the ZONE II datalayer |
Related Datalayers
The PWSDEP_PT feature class should always be used in association with the following related DEP water supply protection datalayers:
DEP Approved Wellhead Protection Areas (Zone II)
PWS sources with assigned Zone IIs are related to the DEP Approved Wellhead Protection Area (Zone II) datalayer by ZII_NUM. Please note that multiple PWS sources may be associated with one Zone II.
Interim Wellhead Protection Areas (IWPA)
Although there is no database relate between the PWS sources and the IWPA datalayer, it is important to always display IWPAs with DEP PWS point data on any map or project.
Surface Water Supply Protection Areas (ZONE A, B, C)
Surface water supply protection areas are related to the PWS surface water source points by SOURCE_ID. Surface water protection areas are assigned to active and inactive surface water sources (TYPE = ‘SW’), but not to emergency surface water sources (TYPE = ‘ESW’). This layer replaces the now discontinued MassDEP ZONEA_POLY, ZONEB_POLY and ZONEC_POLY layers.
Surface Water Supply Watersheds
Contains the watershed extents for all surface water supplies including active, inactive, emergency, sources outside of Massachusetts, watersheds that extend into other states and watersheds of sources from other states that extend into Massachusetts. Surface water intakes on Class B Rivers are not included.
Related Database Tables
Several relatable database files are provided for the purpose of linking DEP PWS source locations with more detailed PWS attribute information and to provide standard DEP GIS metadata. Files are also provided for relating to the MassGIS drainage sub-basins datalayer, for the purpose of defining the contributing watersheds for DEP PWS surface water sources.
PWSDEP_PT_WQTS
The PWS_DEP.WQTS table contains information downloaded from the DWP Water Quality Testing System (WQTS) Oracle database. WQTS is DEP’s comprehensive repository for PWS information. The WQTS database contains many other data items that are not in the PWSDEP_PT_WQTS relate file. This table was designed for use by the DEP GIS Program to maintain the PWS datalayer in close relation to WQTS. Current fields include:
| SOURCE_ID | PWS source Identification number |
| PWS_NAME | Water supplier name – conforms to SITE-NAME for non-community sources |
| S_NAME | Source name, conforms to SITE-NAME for community sources |
| PWS_STATUS | Water supplier status: A = Active I = Inactive D = Declassified According to DEP Drinking Water Program a Declassified system is no longer considered a PWS by the DEP, but has not gone through the official process of abandoning all sources. |
| S_STATUS | Source status: A = Active I = Inactive D = Declassified According to DEP Drinking Water Program a Declassified system is no longer considered a PWS by the DEP, but has not gone through the official process of abandoning all sources. |
| PWS_CLASS | Source classification: COM = Community surface and groundwater sources NTNC = Non Transient Non Community NC = Transient Non Community |
| S_AVAILABI | Source availability (ACTIVE, INACT, EMERG, ABAND). Abandoned (ABAND) sources are NOT maintained in PWS_DEP. |
Only sources coded in WQTS as having Active (ACTIVE), Inactive (INACT) or Emergency (EMERG) availability (see: S_AVAILABI field) are maintained in PWS_DEP. As stated in 310 CMR 22.02:
- An Active Source means an approved source(s) used for primary or backup purposes to meet consumer demands as necessary.
- An Inactive source means an approved source(s) which is expected to be off-line for at least one year (12 months). A source may be deemed inactive only upon written approval of the Department.
- An Emergency source means any source of water used to supplement or temporarily replace a public water system’s active or inactive source(s) when water of sufficient quality or quantity is not available.
Sources listed as abandoned (ABAND) in WQTS are removed from the PWS datalayer. Sources in WQTS that are coded as abandoned include both abandoned and decommissioned wells. Abandoned sources are no longer in use or are otherwise unfit for the purposes of water supply. Abandoned sources have been physically disconnected from the distribution system but have not undergone DEP’s formal decommissioning process. Decommissioning requires physically rendering the source incapable of water supply delivery.
PWSDEP_PT_Z2DAT
The PWSDEP_PT_Z2DAT table contains information from the DEP DWP Zone II Database. Fields include:
| TOWN | City/town name |
| WELLNAME | Source name |
| PURVEYOR | Water supplier name |
| BASIN | Major drainage basin in which the PWS source is located |
| REGION | DEP Region identification number: 1 = Western 2 = Central 3 = Northeast 4 = Southeast 6 = MWRA Service Territory |
| METHOD | Method in which the Zone II was delineated |
| AQUIFER | Type of aquifer that comprises the Zone II |
| PRG | DEP DWP program under which the Zone II was approved |
| SUB_DATE | Date the Zone II was submitted to DEP DWP for approval |
| APP_DATE | Date that the Zone II was approved |
| GPM | Source pumping rate in gallons per minute (GPM) |
| STATUS | Current Zone II status: C = Current S = Superseded |
| SYSTEM | PWS Classification: COMM = Community NC = Non Community |
| SOURCE_ID | DEP PWS source ID (see SOURCE-ID description for PWS_DEP) |
| ZII_NUM | DEP DWP assigned ID of the Zone II protecting a source(s) |
| PWSID | DEP public water supplier or system identification number (First 4 digits are DEP Region ID, followed by MassGIS Town ID) |
PWSDEP_PT_SWPBASINS
Table is no longer supported. Use Surface Water Supply Protection Areas (ZONE A, B, C) (SWP_WATERSHEDS_POLY)
PWSDEP_PT_DRSBASINS
The PWSDEP_PT_DRSBASINS table links direct river sources to the MassGIS drainage sub-basins datalayer using the item SUB_ID. Direct River Sources (DRS) are PWS surface water supplies (TYPE = 'SW' and 'ESW') with intakes located on Class B rivers. Fields include:
| SOURCE_ID | DEP PWS source ID (see:SOURCE-ID description for PWS_DEP) |
| SUB_ID | Drainage sub-basin identification number that contributes to the surface water supply |
| REGION | DEP Region identification number in which the surface water supply intake is located: 1 = Western 2 = Central 3 = Northeast 4 = Southeast 6 = MWRA Service Territory |
| TOWN_ID | MassGIS town identification number in which the surface water supply intake is located |
| BAS_ID | MassGIS major drainage basin identifier (see: Major Drainage Basins data layer documentation) in which the surface water supply intake is located |
| PWSID | DEP public water supplier or system identification number (First 4 digits are DEP Region ID, followed by MassGIS Town ID) |
Maintenance
The DEP GIS Program, in cooperation with DEP Drinking Water Program (DWP) maintains this datalayer. Updates are made on a quarterly (Dec., Mar., June, and Sept.) basis, in accordance with the DWP’s PWS new PWS source approval schedule. The updated datalayer is then shared through MassGIS. As a standard component of this quarterly update, The DEP GIS Program removes abandoned sources in accordance with WQTS. The addition of new PWS sources is dependent on locational information made available by the DEP DWP at the time of quarterly update. Datalayer updates may also include refinements to existing PWS source locations.
General and technical questions regarding MassDEP well head protection areas should be referred to the MassDEP Drinking Water Program (email: program.director-dwp@mass.gov). GIS-related questions concerning these or other MassDEP water supply layers can be referred to the MassDEP GIS Program Director (email: Kashif.Rashid@mass.gov).
| Last updated: | April 22, 2024 |
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