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Ground Water Quality Classifications Polygon

Frequently-asked questions:


What does this data set describe?

Title:
Ground Water Quality Classifications Polygon

Abstract:
Ground Water Quality Classifications is a polygon feature-based layer compiled at 1:24,000 scale that includes water quality classification information for groundwaters for all areas of  the State of Connecticut. Ground Waters means waters flowing through earth materials beneath the ground surface and the Ground Water Quality Classifications is a designation of the use of the ground waters. The Ground Water Quality Classifications is based primarily on the Adopted Water Quality Classifications Map sheets with information collected and compiled from 1986 to 1997 by major drainage basin. The maps were hand-drawn at 1:50,000-scale in ink on Mylar which had been underprinted with a USGS topographic map base. The digital layer includes ground water water quality classifications. It does not include water quality classifications for ground waters below surface waterbodies. Surface Water Quality Classifications are defined separately in a set of data layers comprised of line and polygon features. The Ground Water Quality Classifications and the Surface Water Quality Classifications are usually presented together as a depiction of water quality classifications in Connecticut. The Ground Water Quality Classes are GA, GAA, GAAs, GB and GC. Classes GAA and GA designate areas of existing or potential drinking water. All ground waters not otherwise classified are considered as Class GA. Class GAAs is for ground water that is tributary to a public water supply reservoir. Class GB is used where ground water is not suitable for drinking water. Class GC is used for assimilation of permitted discharges. Modified classes GA-Impaired, GAA-Impaired, GAA-Well-Impaired, GAA-Well  and GA-NY are found in the data layer to categorize special cases of GA or GAA that may not be meeting the goal (impaired), surround public water supply wells (Well)  or contribute to a public water supply watershed for another state (NY).

There are three elements that make up the Water Quality Standards which is an important element in Connecticut's clean water program. The first of these is the Standards themselves. The Standards set an overall policy for management of water quality in accordance with the directive of Section 22a-426 of the Connecticut General Statutes. In simple terms the policies can be summarized by saying that the Department of Energy and Environmental Protection shall:  Protect surface and ground waters from degradation, Segregate waters used for drinking from those that play a role in waste assimilation, Restore surface waters that have been used for waste assimilation to conditions suitable for fishing and swimming, Restore degraded ground water to protect existing and designated uses, Provide a framework for establishing priorities for pollution abatement and State funding for clean up, Adopt standards that promote the State's economy in harmony with the environment. The second element is the Criteria, the descriptive and numerical standards that describe the allowable parameters and goals for the various water quality classifications. The final element is the Classification Maps that show the Class assigned to each surface and groundwater resource throughout the State. These maps also show the goals for the water resources, and in that manner provide a blueprint and set of priorities for Connecticut's efforts to restore water quality. Although federal law requires adoption of Water Quality Standards for surface waters, Water Quality Standards for ground waters are not subject to federal review and approval. Connecticut's Standards recognize that surface and ground waters are interrelated and address the issue of competing use of ground waters for drinking and for waste water assimilation. These Standards specifically identify ground water quality goals, designated uses and those measures necessary for protection of public and private drinking water supplies; the principal use of Connecticut ground waters. These three elements comprise the Water Quality Standards and are adopted using the public participation procedures contained in Section 22a-426 of the Connecticut General Statutes. The Standards, Criteria and Maps are reviewed and revised roughly every three years. Any change is considered a revision requiring public participation. The public participation process consists of public meetings held at various locations around the State, notification of all chief elected officials, notice in the Connecticut Law Journal and a public hearing. The Classification Maps are the subject of separate public hearings which are held for the adoption of the map covering each major drainage basin in the State. The Water Quality Standards and Criteria documents are available on the DEEP website, www.ct.gov/deep.

The Ground and Surface Water Quality Classifications do not represent conditions at any one particular point in time. During the conversion from a manually maintained to a digitally maintained statewide data layer the Housatonic River and Southwest Coastal Basins information was updated. The publication date of the digital data reflects the official adoption date of the most recent Water Quality Classifications. Within the data layer the adoption dates are: Housatonic and Southwest Basins - March 1999, Connecticut and South Central Basins - February 1993, Thames and Southeast Basins - December 1986. This data is updated.

Supplemental information:
Additional information on Water Quality Standards and Classification is available on the DEP website at www.ct.gov/dep/wqsc.

  1. How should this data set be cited?

    State of Connecticut, Department of Energy and Environmental Protection (data compiler, editor and publisher), 19990101, Ground Water Quality Classifications Polygon: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Online links:
    Other citation details:
    The State of Connecticut, Department of Energy and Environmental Protection is the collector of the data (compiler), the creator and maintainer of the data layer (editor), and producer (publisher) of this information for use. Data compiled at 1:24,000 scale. Ground Water Quality Classifications was most recently published per edition date and originally published in approximately 1995. Groundwater Quality Classification is periodically updated whereby features are added or modified to reflect more recently collected water quality classifications. This data layer includes information that is dynamic and changes over time.

  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -73.742172
    East: -71.781365
    North: 42.052612
    South: 40.979708

  3. What does it look like?

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/groundwaterqualityclassfullview.gif (GIF)
    Full view of Ground Water Quality Classification

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/groundwaterqualityclassdetailview.gif (GIF)
    Detail view of Ground Water Quality Classification.

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/groundwaterqualityclassdetailviewortho.gif (GIF)
    Detail view of Ground Water Quality Classification with orthophotography displayed in background.

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/surfaceandgroundwaterqualityclassdetailview.gif (GIF)
    Detail view of Surface Water Qualitity Classification and Ground Water Quality Classification shown together.

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/surfaceandgroundwaterqualityclassdetailviewortho.gif (GIF)
    Detail view of Surface Water Qualitity Classification and Ground Water Quality Classification shown together with orthophotography displayed in the background.

  4. Does the data set describe conditions during a particular time period?

    Beginning date: 1986
    Ending date: edition date
    Currentness reference:
    publication date

  5. What is the general form of this data set?

    Geospatial data presentation form: vector digital data

  6. How does the data set represent geographic features?

    1. How are geographic features stored in the data set?

      Indirect spatial reference:
      State of Connecticut, United States of America

      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • G-polygon (1690)

    2. What coordinate system is used to represent geographic features?

      The map projection used is Lambert Conformal Conic.

      Projection parameters:
      Lambert Conformal Conic
      Standard parallel: 41.200000
      Standard parallel: 41.866667
      Longitude of central meridian: -72.750000
      Latitude of projection origin: 40.833333
      False easting: 999999.999996
      False northing: 499999.999998

      Planar coordinates are encoded using coordinate pair.
      Abscissae (x-coordinates) are specified to the nearest 0.000250.
      Ordinates (y-coordinates) are specified to the nearest 0.000250.
      Planar coordinates are specified in survey feet.

      The horizontal datum used is North American Datum of 1983.
      The ellipsoid used is Geodetic Reference System 80.
      The semi-major axis of the ellipsoid used is 6378137.000000.
      The flattening of the ellipsoid used is 1/298.257222.

      Vertical coordinate system definition:
      Altitude system definition:
      Altitude resolution: 1.000000
      Altitude encoding method: Explicit elevation coordinate included with horizontal coordinates

  7. How does the data set describe geographic features?

    Ground Water Quality Classifications Polygon
    Ground Water Quality Classifications represented as polygon features. Water polygon features such as lakes, ponds and streams were removed from the classifications areas and have no attributes. The polygon attribute field WQCLASSP contains the ground water quality classes GA, GAA, GAAs, GB and GC and the modified classes GA-Impaired, GAA-Impaired, GAA-Well-Impaired, GAA-Well  and GA-NY. All the classes are aggregated and symbolized by using the attribute field AV_LEGEND. Class GA is classified in the data layer but is not symbolized on maps by shading or labeling. In the digital data Class GA and GAA polygons that may not be currently meeting the GA or GAA standards are indicated by GA-Impaired, GAA-Impaired, GAA-Well-Impaired. These areas are customarily shaded on maps but not labeled, however, earlier versions of the Water Quality Classifications Maps label them with a current class and a goal (e.g. GB/GA). A Class GAA-Well-Impaired is an impaired area that surrounds a public water supply well. Polygon features classed as GAA-Well and GAA-Well-Impaired are the area of contribution to a public water supply well represented by a 500 ft radius around a well. Well areas are symbolized by creating an overlay after using WEL_LEGEND = 'Well' to select the polygons that represent the area of contribution to wells.  A notation of GAA with a state abbreviation (e.g. GAA-NY) indicates a GAA area that contributes to a public water supply watershed for another state. It is symbolized the same as other GAA areas. Generation of annotation for classified polygons is controlled through the use of the polygon attribute field LABEL_FLG. LABEL_FLG contains N (no label) if the word "impaired" is present in the polygon attribute WQCLASSP field, if WQCLASSP is GA, or if the polygon is a part of a larger area that already has a label. To label features use LABEL_FLG = Y to select features for labeling and use the WQCLASSP attributes for the label. (Source: State of Connecticut, Department of Energy and Environmental Protection)

    OBJECTID
    Internal feature number. (Source: ESRI)
                      

    Sequential unique whole numbers that are automatically generated.

    SHAPE
    Feature geometry. (Source: ESRI)
                      

    Coordinates defining the features.

    AV_LEGEND
    ArcView Legend. Text field for symbolizing polygon feature types on a map. For a legend, the following substitutions can be used: value GA - label GA; value GAA,GAAs - label GAA, GAAs; value GB - label GB; value GC - label GC; value To GA,GAA - label GA, GAA May be impaired. (Source: State of Connecticut, Department of Energy and Environmental Protection)
                      

    Value Definition
    GA
    This category includes WQCLASSP value GA 
    GAA, GAAs
    This category includes WQCLASSP values GAA, GAAs, GAA-Well, GAA-NY
    GB
    This category includes WQCLASSP value GB
    GC
    This category includes WQCCLASSP value GC
    To GA, GAA
    This category includes WQCLASSP value GA-Impaired, GAA-Impaired, GAA-Well-Impaired

    WQCLASSP
    Ground Water Quality Polygon Code. Text values that identify water quality feature types. Certain attributes (GAA-Well, GAA-NY, GA-Impaired, GAA-Impaired and GAA-Well-Impaired) are used only in the digital data for retrieval of features and not as labels (unless LABEL_FLG = "Y"). The Enumerated_ Domain_Value_Definitions come from the Summary of the Water Quality Standards and Classifications found at the http://www.dep.state.ct.us/wtr/wq/wqsinfo.htm website. (Source: State of Connecticut, Department of Energy and Environmental Protection)
                      

    Value Definition
    GA
    Designated uses: existing private and potential public or private supplies of water suitable for drinking without treatment; baseflow for hydraulically connected surface water bodies.
    GAA
    Designated uses: existing or potential public supply of water suitable for drinking without treatment; baseflow for hydraulically connected surface water bodies.
    GAAs
    Designated uses: existing or potential public supply of water suitable for drinking without treatment; baseflow for hydraulically connected surface water bodies. Ground water that is tributary to a  public water supply reservoir.
    GAA-Well
    Designated uses: Class GAA, an existing or potential public supply of water suitable for drinking without treatment; baseflow for hydraulically connected surface water bodies. The 500 ft radius area that represents an area of contribution to a public water supply well. Modified class designation unique to digital data.
    GAA-NY
    Designated uses: Class GAA, an existing or potential public supply of water suitable for drinking without treatment; baseflow for hydraulically connected surface water bodies. Area is part of a New York State watershed. Modified class designation unique to digital data.
    GB
    Designated uses: industrial process water and cooling waters; baseflow for hydraulically connected surface water bodies; presumed not suitable for human consumption without treatment.
    GC
    Designated uses: assimilation of discharge authorized by the Commissioner pursuant to Section 22a-430 of the General Statutes. As an example a lined landfill for disposal of ash residue from a resource recovery facility. The GC hydrogeology and setting provides the safest back up in case of technological failure.
    GA-Impaired
    Actual quality of groundwater does not meet the assigned classifications criteria for GA. Modified class designation unique to digital data.
    GAA-Impaired
    Actual quality of groundwater does not meet the assigned classifications criteria for GAA. Modified class designation unique to digital data.
    GAA-Well-Impaired
    Actual quality of groundwater does not meet the assigned classifications criteria for GAA for the 500 ft radius area that represents an area of contribution to a public water supply well. Modified class designation unique to digital data.

    WEL_LEGEND
    The field identifies polygon features that are 500 ft buffer areas around public water supply wells. (Source: State of Connecticut, Department of Energy and Environmental Protection)
                      

    Value Definition
    Well
    This area represents a water quality classification area around a well.

    ACREAGE
    Area of a polygon feature in acres. (Source: State of Connecticut, Department of Energy and Environmental Protection)
                      

    Sequential unique whole numbers that are automatically generated.

    LABEL_FLG
    The field is used to select those polygon features that should be labele. (Source: State of Connecticut, Department of Energy and Environmental Protection)
                      

    Value Definition
    N
    Water Quality Class of this polygon should not be labeled.
    Y
    Water Quality Class of this polygon may be labeled.

    SHAPE.area
    SHAPE.len
    Entity and attribute overview:
    Includes Ground Water Quality Classifications for ground water areas of Connecticut. Information encoded about these features includes the classification information, standard cartographic symbology classification schemes for features and labels, and guidance for labeling. Use the WQCLASSP to uniquely identify features. WQCLASSP contains actual water quality classifications and modified classifications used for retrieval of features. Use the AV_LEGEND and WEL_LEGEND attributes to symbolize features by classification and type on a map. To label features use the LABEL_FLG attributes to decide whether (LABEL_FLG = "Y") or not to label a feature and use the WQCLASSP attributes for the label.
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Who produced the data set?

  1. Who are the originators of the data set? (may include formal authors, digital compilers, and editors)


  2. Who also contributed to the data set?

    The 1:50,000-scale Adopted Water Quality Classifications Map Sheets were drafted and maintained by Carol Smith, a cartographer with the State of Connecticut, Department of Energy and  Environmental Protection.

  3. To whom should users address questions about the data?

    Robert Hust
    State of Connecticut, Department of Energy and Environmental Protection
    79 Elm Street
    Hartford, Connecticut 06106-5127
    USA

    860-424-3020 (voice)
    860-424-4067 (FAX)
    dep.gisdata@ct.gov
    Hours of Service: Monday to Friday, 08:30 to 16:30 Eastern Standard Time
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Why was the data set created?

Ground Water Quality Classification is 1:24,000-scale data. It depicts the location of water quality classifications for ground waters in Connecticut. Use this data layer to show the ground water quality classifications or to spatially query information from other data layers that occurs within the ground water quality classifications areas. Use this data layer with other 1:24,000-scale map data such as Surface Water Quality Classifications, Aquifer Protection Areas, Leachate and Wastewater Discharge Sources, Public Water Supply information, Hydrography and other base map data layers. Not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.)

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How was the data set created?

  1. Where did the data come from?

    Source 1 - Adopted Water Quality Classifications Mylar Map Sheets (source 1 of 29)

    State of Connecticut, Department of Environmental Protection, 1995, Adopted Water Quality Classifications Mylar Map Sheets: State of Connecticut, .

    Type of source media: stable-base material
    Source scale denominator: 50000
    Source contribution:
    This data source provided a visual record of the ground water classification features and the classification applied to each feature.

    Source 2 - Water Quality Classifications Mylar Quadrangles (source 2 of 29)

    State of Connecticut, Department of Environmental Protection, Unpublished Material, Water Quality Classifications Mylar Quadrangles for Connecticut, South Central Coast, Thames, and Southeast Coast: State of Connecticut, .

    Type of source media: stable-base material
    Source scale denominator: 24000
    Source contribution:
    This data source provided the ground water classification features and the classification applied to each feature for digitizing.

    Source 3 - USGS Topographic Quadrangles (source 3 of 29)

    U.S. Geological Survey, National Mapping Program, 1969-1984, USGS 7.5 Minute Topographic Quadrangles: State of Connecticut, .

    Type of source media: paper
    Source scale denominator: 24000
    Source contribution:
    This data source provided the base map and the registration points for digitizing the ground water classification features.

    Source 4 - Draft Water Quality Classifications Quadrangles (source 4 of 29)

    State of Connecticut, Department of Environmental Protection, Unpublished Material, Water Quality Classifications Manuscripts for Housatonic, Southwest Coastal and Hudson Basins: State of Connecticut, .

    Type of source media: paper
    Source scale denominator: 24000
    Source contribution:
    This data source provided the ground water classification features and the classification applied to each feature for the Housatonic, Southwest Coastal and Hudson basins for digitizing.

    Source 5 - Public Water Supply Wells (source 5 of 29)

    State of Connecticut, Department of Public Health, 1995, Public Water Supply Wells: State of Connecticut, .

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    This data layer provided the point locations of Public Water Supply Wells which were buffered to a radius of 500 feet to create areas representing the areas of contribution.

    Source 6 - Public Water Supply Well Buffers (source 6 of 29)

    State of Connecticut, Department of Environmental Protection, Unpublished Material, Public Water Supply Well Buffers: State of Connecticut, .

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    This data layer provided polygon areas representing the areas of contribution to the public water supply by buffering the point locations of Public Water Supply Wells to a radius of 500 feet.

    Source 7 - Base Map data layers (source 7 of 29)

    1995, Base Map Data Layers: State of Connecticut, .

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    These data layers provided line features to build the polygons where the Ground Water Quality Classifications features were coincident with the 1:24,000-scale base map. Included are 1:24,000-scale Hydrography, Roads and Trails, Town Boundaries and Railroads.

    Source 8 - Drainage Basins (source 8 of 29)

    State of Connecticut, Department of Environmental Protection, 1995, Drainage Basins: State of Connecticut, .

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    This data layer provided line features to build the polygons where the Ground Water Quality Classifications features were coincident with the 1:24,000-scale natural drainage basins published by the State of Connecticut, Department of Environmental Protection.

    Source 9 - Leachate and Wastewater Discharge Sources (source 9 of 29)

    State of Connecticut, Department of Environmental Protection, 1995, Leachate and Wastewater Discharge Sources: State of Connecticut, .

    Type of source media: disc
    Source scale denominator: 50000
    Source contribution:
    This data source is a point data layer of surface and groundwater discharges that have received a wastewater discharge permit from the state, are active or historic (no longer active) waste disposal sites, salt storage, or are locations of spills, leaks, deposits or discharges of a variety of liquid or solid wastes. This data provided a guide for the delineation and attribution of Water Quality Classifications areas that were updated.

    Source 10 - Tables for Leachate and Wastewater Discharge Sources (source 10 of 29)

    State of Connecticut, Department of Environmental Protection, 1995, Data tables for Leachate and Wastewater Discharge Sources: State of Connecticut, .

    Type of source media: disc
    Source contribution:
    This data source provided additional tabular information about the Leachate and Wastewater Discharge Sources. It is published as booklet to accompany Leachate and Wastewater Discharge Sources maps.

    Source 11 - Shellfish Area Classifications Maps (source 11 of 29)

    State of Connecticut, Department of Agriculture, Bureau of Aquaculture, 1993 - 2005, Shellfish Area Classifications: State of Connecticut, .

    Type of source media: paper
    Source scale denominator: Varies
    Source contribution:
    This source provided guidance for the delineation and attribution of Water Quality Classifications areas along the coast. This source is the classifications of shellfishing growing waters for  Connecticut shoreline towns. The shellfishing areas are delineated and classified by the Connecticut Department of Agriculture, Bureau of Aquaculture.

    Source 12 - Water Quality Classifications Maps for DEP Staff Review (source 12 of 29)

    State of Connecticut, Department of Environmental Protection, Unpublished Material, Water Quality Classifications Maps for DEP Staff Review.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    This data source provided maps of  Water Quality Classifications data, Leachate and Wastewater Discharge Sources data, Base map data and Drainage Basin data covering the Housatonic River and Southwest Coastal Basins for the purpose of in-house reviewing and updating of the Water Quality Classifications by DEP staff.

    Source 13 - Water Quality Classifications Maps for Town Review (source 13 of 29)

    State of Connecticut, Department of Environmental Protection, 1995, Water Quality Classifications for Town Review : State of Connecticut, .

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    This source provided town-based maps of the Water Quality Classifications data, Base Map data layers, Drainage Basin data and Leachate and Wastewater Discharge Sources data  for the Housatonic River and Southwest Coastal Basins for the purpose of reviewing Water Quality Classifications by town officials.

    Source 14 - Water Quality Classifications Maps for Public Hearing (source 14 of 29)

    State of Connecticut, Department of Environmental Protection, 1995, Draft Water Quality Classifications Town Maps.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    This source provided the updated Water Quality Classifications data on town-based maps for the Housatonic River and Southwest Coastal Basins for use during the Public Hearing phase of the Water Quality Classifications Maps adoption process.

    Source 15 - Water Quality Classifications (source 15 of 29)

    State of Connecticut, Department of Environmental Protection, 1995, Water Quality Classifications : State of Connecticut, .

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    This data source refers to all surface and ground water classification features combined in one statewide data layer. Since initial publication in 1995, subsequent publications or editions of the data layer were generated by the State of Connecticut in order to change data format, convert from NAD 27 to NAD 83, or add and modify features. Consequently, over the period of many years, different copies of this data layer were produced, representing various steps in the data layer development and maintenance process (metadata lineage). Changes made to the entire data layer are reflected in metadata process steps where this particular data source is cited as both the Source Used and the Source Produced. The Water Quality Classifications is in ArcInfo Coverage format.

    Source 16 - Ground Water Quality Classifications (source 16 of 29)

    State of Connecticut, Department of Environmental Protection, 2005, Ground Water Quality Classifications.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    This data source refers to all ground water quality classifications features separated from the statewide water quality classifications data layer and with the hydrography polygon features removed (erased). Since initial publication in 2000, subsequent publications or editions of the data layer were generated by the State of Connecticut in order to add and modify features. Consequently, over a period of years, different copies of this data layer were produced. Changes made to the entire data layer are reflected in metadata process steps where this particular data source is cited as both the Source Used and the Source Produced. The Ground Water Quality Classifications is in ArcInfo Coverage format.

    Source 17 - Surface Water Quality Classifications (source 17 of 29)

    State of Connecticut, Department of Environmental Protection, 2000, Surface Water Quality Classifications: State of Connecticut, .

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    This data source refers to all surface water quality classifications features separated from the statewide water quality classifications data layer and with additional hydrography line and polygon features added. The Surface Water Quality Classifications is in ArcInfo Coverage format.

    Source 18 - Ground_Water_Quality_Classifications_Polygon.shp (source 18 of 29)

    State of Connecticut, Department of Environmental Protection , Ground Water Quality Classifications Polygon: State of Connecticut , .

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Includes all polygon features from the Ground Water Quality Classifications where the AV_LEGEND attribute was not blank (AV_LEGEND  <> " "). This criterion only includes true ground water classifications features and excludes secondary polygon features from the ArcInfo coverage that represent areas where surface water features exist and the ground water is not classified. Ground_Water_Quality_Classifications_Polygon.shp is in Shapefile format.

    Source 19 - WaterQualityClass_Ground_Master (source 19 of 29)

    State of Connecticut, Department of Environmental Protection, Unpublished Material, WaterQualityClass_Ground_Master.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Statewide geodatabase format ground water classification datalayer. Includes all ground water classifications polygon features except public water supply well buffered areas or final aquifer protection areas. Includes temporary (and potentially inaccurate) ground water classifications under surface waters. This layer forms the base for the derived WaterQualityClass_Ground datalayer.

    Source 20 - WaterQualityClass_Surface_Poly (source 20 of 29)

    State of Connecticut, Department of Environmental Protection, Unpublished Material, WaterQualityClass_Surface_Poly.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Statewide geodatabase format surface water quality classifications for all waterbody area features such as lakes, ponds, bays, harbors, sounds and rivers and streams large enough to be represented as polygons at 1:24,000 scale.

    Source 21 - WaterQualityClass_Surface_Line (source 21 of 29)

    State of Connecticut, Department of Environmental Protection, Unpublished Material, WaterQualityClass_Surface_Line.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Statewide geodatabase format surface water quality classifications for all waterbody line features such as rivers and streams represented as lines at 1:24,000 scale.

    Source 22 - Public Water Supply Well Buffer 500 Ft (source 22 of 29)

    State of Connecticut, Department of Environmental Protection, Unpublished Material, Public Water Supply Well Buffer 500 Ft.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Statewide geodatabase format datalayer of 500 foot buffer areas around Public Water Supply Wells. These buffers are ground water classification areas and are added to the WaterQualityClass_Ground_Master datalayer during creation of the final WaterQualityClass_Ground datalayer. These buffered areas are kept separate for easier maintenance of the ground water classifications data.

    Source 23 - WaterQualityClass_Ground (source 23 of 29)

    State of Connecticut, Department of Environmental Protection, Unpublished Material, WaterQualityClass_Ground.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Statewide geodatabase format of ground water quality classification as polygon features. It includes the 500 ft buffered areas around public water supply wells and final aquifer protection areas (as this data is adopted). It excludes ground water classifications under surface waterbodies.

    Source 24 - WaterQualityClass_Ground.shp (source 24 of 29)

    State of Connecticut, Department of Environmental Protection, 2006, WaterQualityClass_Ground.shp.

    Online links:
    Type of source media: disc
    Source scale denominator: 24,000
    Source contribution:
    Statewide shapefile format of ground water quality classification as polygon features. It includes the 500 ft buffered areas around public water supply wells and final aquifer protection areas (as this data is adopted). It excludes ground water classifications under surface waterbodies.

    Source 25 - WaterQualityClass_Surface_Poly.shp (source 25 of 29)

    State of Connecticut, Department of Environmental Protection, 2006, WaterQualityClass_Surface_Poly.shp.

    Online links:
    Type of source media: disc
    Source scale denominator: 24,000
    Source contribution:
    Statewide shapefile format of surface water quality classification as polygon features.

    Source 26 - WaterQualityClass_Surface_Line.shp (source 26 of 29)

    State of Connecticut, Department of Environmental Protection, 2006, WaterQualityClass_Surface_Line.shp.

    Online links:
    Type of source media: disc
    Source scale denominator: 24,000
    Source contribution:
    Statewide shapefile format of surface water quality classification as line features.

    Source 27 - Connecticut State Polygon (source 27 of 29)

    State of Connecticut, Department of Environmental Protection, 1994, Connecticut State Polygon.

    Online links:
    Type of source media: disc
    Source scale denominator: 24,000
    Source contribution:
    Provides the State of Connecticut and State waters as a single polygon

    Source 28 - WaterQualityClass_Ground_Master_GA (source 28 of 29)

    State of Connecticut, Department of Environmental Protection, Unpublished Material, WaterQualityClass_Ground_Master_GA.

    Type of source media: disc
    Source scale denominator: 24,000
    Source contribution:
    The ground water quality class GA assigned to the State of Connecticut and state waters as a single polygon. Provides this class during the creation of the Source 23 - WaterQualityClass_Ground.

    Source 29 - USGS Quadrangle Index (source 29 of 29)

    State of Connecticut, Department of Environmental Protection, 1985, USGS Quadrangle Index.

    Online links:
    Type of source media: disc
    Source scale denominator: 24,000
    Source contribution:
    Provides a recognizable regularly-sized, systematically-organized set of polygons.

  2. What changes have been made?

    Process Overview - The original Water Quality Classifications mapping (e.g. Source 1 Adopted Water Quality Classifications Map Sheets) contain both Surface Water and Ground Water Classifications. Both surface water and ground water features were processed as this information was recreated in a digital form as the Source 15 Water Quality Classifications data layer. The Water Quality Classifications data layer was maintain with both surface and ground  water features until 2000 when the data model was changed to separate Surface Water Quality Classifications and Ground Water Quality Classifications. Process steps up to this time refer to both the surface and ground water features.

    Date: 1995 (change 2 of 15)
    Feature digitizing and attribution (using tablet digitizing and feature selection methods) - Source 2 Water Quality Classifications Mylar Quadrangles and Source 4 Draft Water Quality Classifications Quadrangles depict both surface water and ground water quality classifications. From these two sources line features (polygons began as outlines) for all classifications were captured and attributed as work progressed quadrangle by quadrangle in the creation of  Source 15 Water Quality Classifications. Using ESRI ArcInfo software, features were tablet digitized by registering the source map to the digitizing tablet and using the crosshairs of the digitizer's mouse to manually capture the geometry (location) of features drafted on the map. The source map was registered to the digitizing tablet by first digitizing (entering) the locations of four corner registration points shown on the USGS 7.5 minute topographic quadrangle maps. ArcInfo software compared the values of the digitized coordinates with the actual (true) values for the quadrangle corner (tic) features. The Root Mean Square (RMS) error generated by the ArcInfo software indicated the amount of error involved in transforming coordinates from the registered map to the digital layer.  RMS errors higher than 0.004 were not acceptable and required re-registering the source map by digitizing the tic locations again. The source maps were positioned on top of the USGS Topographic Quadrangles for a best fit. After correct registration, individual features that were not coincident with existing 1:24,000-scale Base Map data layers (hydrography, roads and trails, railroads, town boundaries) or 1:24,000-scale Drainage Basins were manually digitized off Source 2 or Source 4 and assigned WQCLASSA values for line features, including outlines of ground water quality classifications. Lines were not digitized for ground water quality Class GA. Where necessary, additional minor edits to feature geometry were manually digitized on the screen (heads-up digitizing) at display scales greater than 1:24,000. Using ESRI ArcInfo software, features appearing in and coincident with the existing 1:24,000-scale Base Map Data Layers (hydrography, roads and trails, railroads, town boundaries) or 1:24,000-scale Drainage Basins were manually selected, copied and used as the basis for features in the Water Quality Classifications. Hydrography features were used for surface water quality classifications features. Only features classified other than A or SA were taken from Hydrography, except for Class A waters emanating from GAA (public water supply watershed) areas. Feature geometry (location) required partial editing and adjustment to match information on Source 1 Adopted Water Quality Classifications Mylar Maps, Source 2 and Source 4. Using ESRI ArcInfo software, the Water Quality Classifications was built as both line features and  polygon features. The polygons were checked and edited to follow the topology rules. Label points were automatically added. Polygon features were assigned WQCLASSP attribute values based on information in Source 1, Source 2 and Source 4. Ground water quality Class GA was not designated since no polygon features for it were digitized directly in the Water Quality Classifications. Any ground water areas not otherwise classified are assumed to be Class GA. Most surface water quality Class A and SA were not designated since only certain instances of these features were created directly in the Water Quality Classifications. Most surface water quality Class A and  SA features were represented by those features in the 1:24,000-scale Hydrography that were not incorporated in the Water Quality Classifications. Feature location and attribute accuracy was visually checked and inspected by symbolizing and labeling features according to attribute value on the computer screen and on hard copy paper maps, and comparing this information to the orginal source data. These check plot maps were printed at the same scale as the Water Quality Classifications Mylar Quadrangles in order to visually inspect digitizing quality and the assignment of attribute values.

    Person responsible for change:
    Diana Danenberg, Carol Smith
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 1 - Adopted Water Quality Classifications Mylar Map Sheets
    • Source 2 - Water Quality Classifications Mylar Quadrangles
    • Source 7 - Base Map data layers
    • Source 8 - Drainage Basins
    • Source 4 - Draft Water Quality Classifications Quadrangles

    Data sources produced in this process:
    • Source 15 - Water Quality Classifications

    Date: 1995 (change 3 of 15)
    Feature creation and attribution  - Using ESRI ArcInfo software,  the Public Water Supply Wells were buffered to a radius of 500 feet to create areas that represent areas of contribution. Features were assigned WQCLASSP attribute values based on information in the Adopted Water Quality Classifications Mylar Map Sheets. 

    Person responsible for change:
    Diana Danenberg
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 5 - Public Water Supply Wells
    • Source 1 - Adopted Water Quality Classifications Mylar Map Sheets

    Data sources produced in this process:
    • Source 6 - Public Water Supply Well Buffers

    Date: 1995 (change 4 of 15)
    Combining of data layers - Using ESRI ArcInfo software, the Public Water Supply Well Buffers features were added to the Water Quality Classifications using the Update method. Feature location and attribute accuracy was visually checked and inspected by symbolizing and labeling features according to attribute value both on the computer screen and on hard copy paper maps, and comparing this information to the orginal source data.

    Person responsible for change:
    Diana Danenberg
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 6 - Public Water Supply Well Buffers
    • Source 1 - Adopted Water Quality Classifications Mylar Map Sheets
    • Source 15 - Water Quality Classifications

    Data sources produced in this process:
    • Source 15 - Water Quality Classifications

    Date: 1995 (change 5 of 15)
    Update of  water quality in two major basins - In 1995, the DEP revised Water Quality Classifications in the Housatonic River and Southwest Coastal Basins. The source information for Water Quality Classifications for these two basins was in draft form and was compiled prior to 1986. A set of quadrangle-based maps showing the Water Quality Classifications, Leachate and Wastewater Discharge Sources, Base map data layers and Drainage Basins was prepared for review by DEP staff. The results of the staff review were compiled into a list of changes. A set of town-based maps with the Water Quality Classifications, Leachate and Wastewater Discharge Sources, Base map data layers and Drainage Basins was prepared and mailed to each town for review by town officials. The results of the town review were compiled into a list of changes. State of Connecticut, Department of Environmental Protection staff Randy May and Fred Banach conducted a review of the Water Quality Classifications based on the staff review, the town review, the Shellfish Area Classifications and their own extensive knowledge and experience of the area and the conditions. During the review notes for updates were placed on copies of  the same maps that DEP staff reviewed. Features and attributes of the Water Quality Classifications data were revised to reflect the decisions of  May and Banach. 1:24,000-scale Base Map data layers and 1:24,000-scale Drainage Basin data provided the source for coincident features and other feature changes were digitized on screen. Surface water and ground water were revised. The Surface Water Quality  Classifications are required by statute to be adopted through a public process. The Water Quality Classifications were printed on town-based maps and made available at the DEP and at a location in each town for a period of public review and comment. The maps were available at the Public Hearings held at several locations in these two major basins. Comments from the public review process were incorporated into the Water Quality Classifications data where acceptable by the DEP. After the revisions were finalized the adopted date for the Water Quality Classifications features within Housatonic River and Southwest Coastal Basins became 1997

    Person responsible for change:
    Diana Danenberg, Carol Smith
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 9 - Leachate and Wastewater Discharge Sources
    • Source 10 - Tables for Leachate and Wastewater Discharge Sources
    • Source 11 - Shellfish Areas Classification Maps
    • Source 12 - Staff Review Water Quality Classifications Maps
    • Source 13 - Town Review Water Quality Classifications Maps
    • Source 14 - Draft Water Quality Classification Town Maps
    • Source 15 - Water Quality Classifications

    Data sources produced in this process:
    • Source 15 - Water Quality Classifications

    Date: 1997 (change 6 of 15)
    Federal review - The Environmental Protection Agency (EPA) conducted a review of the updated Water Quality Classifications maps for the Housatonic River and Southwest Coastal Basins in 1997. The surface water quality classifications are subject to federal review and adoption. Edits were made to the digital data for changes to the water quality maps agreed to by the EPA and the DEP. The most significant changes were made to the marine water quality classifications along the coastline of the Southwest Coastal Basin.

    Person responsible for change:
    Diana Danenberg
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 15 - Water Quality Classifications

    Data sources produced in this process:
    • Source 15 - Water Quality Classifications

    Date: 1999 (change 7 of 15)
    Datum conversion - Using ESRI ArcInfo software, the Water Quality Classifications was converted from the Connecticut State Plane Coordinate System of 1927 (NAD27) to the Connecticut State Plane Coordinate System of 1983 (NAD83). The NADCON (North American Datum CONversion) data transformation was used.

    Person responsible for change:
    Howie Sternberg
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 15 - Water Quality Classifications

    Data sources produced in this process:
    • Source 15 - Water Quality Classifications

    Date: 2000 (change 8 of 15)
    Data model change, data layer separation - The Water Quality Classifications was separated into two data layers, one for Ground Water Quality Classifications and one for Surface Water Quality Classifications. The reasons for this change are several: the user will have the choice of displaying one or both of the classifications data layers without manipulating the data, Surface Water Quality Classifications and Ground Water Quality Classifications potentially have different user communities, Surface Water Quality Classifications has oversight by the Environmental Protection Agency, Ground Water Quality Classifications are subject to changes in classification through an application process and may change twice yearly. The separation was accomplished using ESRI ArcInfo software by eliminating the Ground Water features from a copy of the Water Quality Classifications and by eliminating the Surface Water features from a copy of the Water Quality Classifications. The Public Water Supply Wells Buffers were added to the Ground Water Quality Classifications again using the ArcInfo Update command. Each new data layer was inspected on-screen and errors in topology, pseudonodes and label errors were corrected. Printed maps at 1:24,000 scale were inspected and the data was corrected for coding errors.

    Person responsible for change:
    Diana Danenberg
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 15 - Water Quality Classifications
    • Source 6 - Public Water Supply Wells Buffers

    Data sources produced in this process:
    • Source 16 - Ground Water Quality Classifications
    • Source 17 - Surface Water Quality Classifications

    Date: 2000 (change 9 of 15)
    Data model change, integration with hydrography - After the Water Quality Classifications data layer was separated into Ground Water Quality Classifications and Surface Water Quality Classifications, the Surface Water Quality Classifications needed to be fully integrated with the Hydrography. The reasons for this change are that the user can get a complete picture of water quality classifications without displaying the Hydrography and the data can be queried in a web or other GIS application. Previously, the user had to assume that water features not found in the Water Quality Classifications  were Class A and that areas not found in Ground Water Quality Classifications were Class GA. Using ESRI ArcInfo software and several processing iterations, the attributes of the Surface Water Quality Classifications were transferred to a copy of the Hydrography data. The line feature attributes and the polygon feature attributes were processed separately. Line features were split to allow the correct placement of line attributes. Polygon features were split where necessary by on-screen digitizing of closure lines to allow the correct placement of polygon attributes. The Ground Water Quality Classifications contained areas that were beneath surface waters where DEP does not classify ground water. Using ESRI ArcInfo software, the water features were isolated from the Hydrography and used with the ArcInfo Erase command to eliminate (knock out) polygon areas where water features exist in Hydrography. Both new data layers were inspected on-screen for errors in topology. Printed maps at 1:24,000 scale were inspected and the data was corrected for coding errors.

    Person responsible for change:
    Diana Danenberg
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 7 - Base Map data layers (Hydrography)
    • Source 16 - Ground Water Quality Classifications
    • Source 17 - Surface Water Quality Classifications

    Data sources produced in this process:
    • Source 16 - Ground Water Quality Classifications
    • Source 17 - Surface Water Quality Classifications

    Date: 2001 (change 10 of 15)
    Attribute enhancements - WQCLASSP and WEL_LEGEND attributes were changed from storing abbreviated values in upper case to full length values in both upper and lower case. 

    Person responsible for change:
    Diana Danenberg, Elizabeth Doran
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 16 - Ground Water Quality Classifications
    • Source 17 - Surface Water Quality Classifications

    Data sources produced in this process:
    • Source 16 - Ground Water Quality Classifications
    • Source 17 - Surface Water Quality Classifications

    Date: 20050428 (change 11 of 15)
    Export to Shapefile Format - Converted data from ArcInfo Coverage to Shapefile format and named the shapefile Ground_Water_Quality_Classifications_Polygon.shp. Excluded the AREA, PERIMETER, WQGCLASS#, WQGCLASS-ID attributes from the Shapefile because their values are only maintained by ArcInfo software with data that is in ArcInfo Coverage format. Includes all polygon features from the Ground Water Quality Classifications where the AV_LEGEND attribute was not blank (AV_LEGEND <> " "). This criterion only includes ground water classifictations areas and excludes  polygon features from the ArcInfo coverage that represent areas where surface water features exist and ground water is not classified.

    Person responsible for change:
    Diana Danenberg
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 16 - Ground Water Quality Classifications

    Data sources produced in this process:
    • Source 18 - Ground_Water_Quality_Classifications_Polygon.shp

    Date: 2006 (change 12 of 15)
    Convert to GeoDatabase Feature Class format - Water Quality Classifications datalayers were converted to geodatabase format feature classes according to the following steps: defined new Feature Class, imported the spatial reference, defined or imported the attribute definitions, loaded features from coverage, imported metadata from shapefile, edited metadata. The unpublished parent to Source 16 - Ground Water Quality Classification was converted to polygon feature class Source 19 - WaterQualityClass_Ground_Master.
    Source 16 - Ground Water Quality Classification was not converted from coverage format. The equivalent datalayer, Source 20 - WaterQualityClass_Ground, is generated through overlay techniques from Source 19 - WaterQualityClass_Ground_Master, Source 23 - Public Water Supply Well Buffers 500 Ft and Source 21 -  WaterQualityClass_Surface_Poly polygon feature classes. Source 17 - Surface Water Quality Classification was converted to polygon feature class Source 21 - WaterQualityClass_Surface_Poly and to line feature class Source 22 - WaterQualityClass_Surface_Line. Source 6 - Public Water Supply Well Buffers was converted to polygon feature class Source 23 - Public Water Supply Well Buffers 500 Ft. 
    
    Spatial Reference Properties used for Feature Classes:
    Coordinate System: NAD_1983_StatePlane_Connecticut_FIPS_0600_Feet
    XY Domain MinX: 100000; MaxX: 2247483.645 XY Domain MinY: 200000; MaxY: 2347483.645
    Precision: 1000
    
    WaterQualityClass_Ground_Master feature class was reworked to eliminate the empty areas originally introduced by erasing the ground water quality layer with the surface water quality layer. The original purpose of the erasure was to eliminate ground water classifications occuring under surface waterbodies. This erasure step now occurs live during creation of the WaterQualityClass_Ground feature class derived from the WaterQualityClass_Ground_Master. To create the new WaterQualityClass_Ground_Master feature class the tools and processes available in ESRI ArcGIS 9.1 were employed. Automated and manual methods were used iteratively to eliminate "doughnut holes" and replace empty areas with appropriately attributed polygons. Where ground water polygons changed classification across waterbodies, centerlines following the waterbodies were manually digitized to form the boundary between classifications. Source 19 - WaterQualityClass_Ground_Master contains continuous Ground Water Quality polygon features, including temporary features that are fully or partially replaced during the generation of the final ground water datalayer, Source 20 - WaterQualityClass_Ground. The steps used to create Source 20 - WaterQualityClass_Ground are 1) used the ESRI ArcMap 9.1 Update tool to replace ares of Source 19 - WaterQUalityClass_Ground_Master with Source 23 - Public Water Supply Well Buffers 500 Ft 2) used the ESRI ArcMap 9.1 Erase tool to eliminate areas contained in Source 21 - WaterQualityClass_Surface_Poly from the output datalayer resulting from step 1. This method of maintaining the Ground Water Quality CLassifications datalayer simplifies the process and reduces errors. Changes can be made to any of the participating datalayers or another datalayer can be introduced and a new Source 20 - WaterQualityClass_Ground can be generated.The attribute field HY_LEGEND was retained for WaterQualityClass_Surface_Line, for maintenance purposes, but dropped from WaterQualityClass_Surface_Poly. During the conversion from coverage to geodatabase format certain attribute fields were dropped from the surface water quality. The attribute fields HYARC_COD, HYPOLY_COD, STREAM_NO, STREAM, STREAM_NO2, LAKE_NO, LAKE, LAKE_NO2, BAY_NO, BAY_NO2, HARBOR_NO, HARBOR_NO2, SOUND_NO and SOUND_NO2 were dropped from WaterQualityClass_Surface_Line and WaterQualityClass_Surface_Poly.

    Person responsible for change:
    Diana Danenberg
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 16 - Ground Water Quality Classifications
    • Source 17 - Surface Water Quality Classifications
    • Source 6 - Public Water Supply Well Buffers

    Data sources produced in this process:
    • Source 19 - WaterQualityClass_Ground_Master
    • Source 20 - WaterQualityClass_Surface_Poly
    • Source 21 - WaterQualityClass_Surface_Line
    • Source 22 - Public Water Supply Well Buffer 500 Ft
    • Source 23 - WaterQualityClass_Ground

    Date: 2006 (change 13 of 15)
    Export to Shapefile Format - Converted data from Geodatabase to Shapefile format and named the shapefiles after the geodatabase version. Excluded the SHAPE_Area and SHAPE_Length fields because their values are not maintained by the shapefile format. Excluded HY_LEGEND attribute field from WaterQualityClass_Surface_Line.shp.WaterQualityClass_Ground.shp includes all polygon features from WaterQualityClass_Ground. WaterQualityClass_Surface_Poly.shp includes all polygon features from WaterQualityClass_Surface_Poly.  WaterQualityClass_Surface_Line.shp includes all line features from WaterQualityClass_Surface_Line except for those line features classified in AV_LEGEND as "No Show". Earlier designations of "SHARED" or of "Change of Class" are subsets of "No Show" and are eliminated also.

    Person responsible for change:
    Diana Danenberg
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 23 - WaterQualityClass_Ground
    • Source 25 - WaterQualityClass_Surface_Poly.shp
    • Source 21 - WaterQualityClass_Surface_Line

    Data sources produced in this process:
    • Source 24 - WaterQualityClass_Ground.shp
    • Source 25 - WaterQualityClass_Surface_Poly.shp
    • Source 26 - WaterQualityClass_Surface_Line.shp

    Date: 2009 (change 14 of 15)
    Create an independent ground water quality Class GA datalayer - Using ESRI ArcMap software, selected and deleted Class GA polygons from  Source 19 - WaterQualityClass_Ground_Master. This makes it easier to update the areas that are subject to Class GB  reclassification. The Source 27 - Connecticut State Polygon was copied, given the same attribute fields as Source 19 - WaterQualityClass_Ground_Master and assigned Class GA to form Source 28 - WaterQualityClass_Ground_Master_GA. This single polygon layer is used to reintroduce Class GA whenever Source 23 - WaterQualityClass_Ground is recreated.

    Person responsible for change:
    Diana Danenberg
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 19 - WaterQualityClass_Ground_Master
    • Source 27 - Connecticut State Polygon

    Data sources produced in this process:
    • Source 19 - WaterQualityClass_Ground_Master
    • Source 28 - WaterQualityClass_Ground_Master_GA

    Date: 2009 (change 15 of 15)
    Split WaterQualityClass_Ground_Master_GA polygon into smaller sections - Using ESRI ArcMap  software, intersected Source 29 - USGS Quadrangle Index and Source 27 - Connecticut State Polygon to form Source 28 - WaterQualityClass_Ground_Master_GA. This creates a statewide polygon datalayer that is subdivided into multiple polygons equivalent to the size and shape of the USGS Quadrangle Index polygons that cover the State of Connecticut. When added back to the Source 19 - WaterQualityClass_Ground_Master to form the Source 23 - WaterQualityClass_Ground it is obvious that the Class GA areas have been deliberately split into smaller polygons. Smaller Class GA polygons improve performance when drawing or identifying the ground water quality datalayer.

    Person responsible for change:
    Diana Danenberg
    State of Connecticut, Department of Environmental Protection

    Data sources used in this process:
    • Source 28 - WaterQualityClass_Ground_Master_GA
    • Source 29 - USGS Quadrangle Index

    Data sources produced in this process:
    • Source 28 - WaterQualityClass_Ground_Master_GA

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How reliable are the data; what problems remain in the data set?

  1. How well have the observations been checked?

    The Ground Water Quality Classifications retains the feature types and information identified by the State of Connecticut, Department of Energy and Environmental Protection and obtained from the 1:50,000 scale Adopted Water Quality Classification Mylar Map Sheets. All attributes have valid values. Values are within defined domains. The accuracy test for the WQCLASSP attribute values was conducted by comparing the Ground Water Quality Classifications information presented in the source data with 1:24,000-scale check plots or interactive displays of the data on a computer graphic system. These check plot maps and computer displays depicted and labeled the Ground Water Quality Classifications features in different colors based on WQCLASSP values for comparison with the original data source. AV_LEGEND is a broad classification of Ground Water Quality Classifications features. AV_LEGEND was not manually entered. This additional field was populated by joining to a lookup data table with WQGCLASSP as the relate key field. Lookup data tables contain records that account for the unique occurrences of WQGCLASSP and AV_LEGEND values in the Ground Water Quality Classifications. Ground Water Quality Classifications features were manually selected and populated with WQGCLASSP, WEL_LEGEND, and LABEL_FLG attributes values to identify and describe individual features. See Process Step 12 - Convert to GeoDatabase Feature Class format for changes to attribute fields.

  2. How accurate are the geographic locations?

    The horizontal positional accuracy of this data is no better than the United States National Map Accuracy Standards for 1:24,000 scale maps. According to this standard, not more than 10 percent of the locations tested are to be in error by more than 1/50 inch (40 feet) measured on the publication scale of a USGS 7.5 minute topographic quadrangle map. Feature locations were created by using features from hydrography, roads and trails, railroads and town boundaries data layers based on USGS 7.5 minute topographic quadrangle DLG data and from drainage basin boundaries and from screen-digitized lines interpreted from features depicted on USGS 7.5 minute topographic quadrangle maps.

  3. How accurate are the heights or depths?

  4. Where are the gaps in the data? What is missing?

    The completeness of the data reflects the feature content of the data sources which include the Adopted Water Quality Classifications Mylar Map sheets. The Ground Water Quality Classifications is complete in the sense that it accurately reflects the contents of the Water Quality Classifications information available at the time the State of Connecticut, Department of Energy and Environmental Protection created the data layer. This data is updated.

  5. How consistent are the relationships among the observations, including topology?

    Polygon features conform to the following topological rules. Polygons are single part. There are no duplicate polygons. Polygons do not self overlap. Polygons do not overlap other polygons. The tests of logical consistency were performed by the State of Connecticut using ESRI ArcInfo software to maintain feature topology in ArcInfo coverage format. The data is topologically clean. The ArcInfo Clean function was repeatedly used following edits to verify topology and enforce a minimum distance between vertices of 4 feet (fuzzy tolerance) and a minimum allowed overshoot length of 10 feet (dangle length). Polygon features in the Geodatabase format conform to a 2 foot cluster tolerance.

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How can someone get a copy of the data set?

Are there legal restrictions on access or use of the data?

Access constraints: None. The data is in the public domain and may be redistributed.
Use constraints:
No restrictions or legal prerequisites for using the data. The data is suitable for use at appropriate scale, and is not intended for maps printed at scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet). Although this data set  has been used by the State of Connecticut, Department of Energy and Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of Energy and Environmental Protection as to the accuracy of the data and or related materials.  The act of distribution shall not constitute any such warranty, and no responsibility is assumed by the State of Connecticut, Department of Energy and Environmental Protection in the use of these data or related materials. The user assumes the entire risk related to the use of these data. Once the data is distributed to the user, modifications made to the data by the user should be noted in the metadata. When printing this data on a map or using it in a software application, analysis, or report, please acknowledge the State of Connecticut, Department of Energy and Environmental Protection as the source for this information.

Distributor 1 of 1

  1. Who distributes the data set?

    State of Connecticut, Department of Energy and Environmental Protection
    79 Elm Street
    Hartford, Connecticut 06106-5127
    USA

    860-424-3540 (voice)
    860-424-4058 (FAX)
    dep.gisdata@ct.gov
    Hours of Service: Monday to Friday, 08:30 to 16:30 Eastern Standard Time

  2. What's the catalog number I need to order this data set?

    Ground Water Quality Classifications Polygon

  3. What legal disclaimers am I supposed to read?

  4. How can I download or order the data?

    • Availability in digital form:


    • Data format:
      in format Shapefile, Feature Class (version ArcGIS)
      Network links: http://www.ct.gov/deep

    • Cost to order the data: An online copy of the data may be accessed without charge.


  5. Is there some other way to get the data?

    The data distributor does not provide custom GIS analysis or mapping services. Data is available in a standard format and may be converted to other formats, projections, coordinate systems, or selected for specific geographic regions by the party receiving the data.

  6. What hardware or software do I need in order to use the data set?

    Geographic information sytem (GIS), computer-aided drawing or other mapping software is necessary to display, view and access the information.

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Who wrote the metadata?

Dates:
Last modified: 20151118

Metadata author:
Diana Danenberg
State of Connecticut, Department of Energy and Environmental Protection
79 Elm Street
Hartford, Connecticut 06106-5127
USA

860-424-3540 (voice)
860-424-4058 (FAX)
dep.gisdata@ct.gov
Hours of Service: Monday to Friday, 08:30 to 16:30 Eastern Standard Time

Metadata standard:
FGDC Content Standards for Digital Geospatial Metadata(FGDC-STD-001-1998)

Metadata extensions used:
  • http://www.esri.com/metadata/esriprof80.html

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