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Connecticut Drainage Basins Polygon

Frequently-asked questions:


What does this data set describe?

Title:
Connecticut Drainage Basins Polygon

Abstract:
Connecticut Drainage Basins is 1:24,000-scale, polygon and line feature data that define natural drainage areas in Connecticut. These are small basin areas that average approximately 1 square mile in size and make up, in order of increasing size, the larger local, subregional, regional, and major drainage basin areas. Connecticut Drainage Basins includes drainage areas for all Connecticut rivers, streams, brooks, lakes, reservoirs and ponds published on 1:24,000-scale 7.5 minute topographic quadrangle maps prepared by the USGS between 1969 and 1984. Data is compiled at 1:24,000 scale (1 inch = 2,000 feet). This information is not updated.

Polygon and line features represent drainage basin areas and boundaries, respectively. Each basin area (polygon) feature is outlined by one or more major, regional, subregional, local, impoundment, or river reach boundary (line) feature. These data include 7,076 basin area  (polygon) features and 20,945 basin boundary (line) features.

Basin area (polygon) attributes include major, regional, subregional, local, (full) basin number, and feature size in acres and square miles. The full basin number (BASIN_NO) uniquely identifies individual basins and is up to 13 characters in length. There are 7,031 unique basin numbers. Examples include 6000-00-1+*, 4300-00-1+L1, and 6002-00-2-R1. The first digit (column 1) designates the major basin, the first two digits (columns 1-2) designate the regional basin, the first 4 digits (columns 1-4) designate the subregional basin, and the first seven digits (columns 1-7) designate the local basin. Note, there are slightly more basin polygon features (7,076) than unique basin numbers (7,031) primarily because a few water supply watershed boundaries split a basin into two polygon features at the location of a small dam or point of diversion along a stream.

Basin boundary (line) attributes include a drainage divide type attribute (DIVIDE) used to cartographically represent the hierarchical drainage basin system. This divide type attribute is used to assign different line symbology to major, regional, subregional, local, stream reach, and lake impoundment drainage basin divides. For example, major basin drainage divides are more pronounced and shown with a wider line symbol than regional basin drainage divides.

Connecticut Drainage Basins is the data source for other digital spatial data including the Connecticut Major Drainage Basins, Connecticut Regional Drainage Basins, Connecticut Subregional Drainage Basins, and Connectcut Local Drainage Basins.

Supplemental information:
A standardized mapping of natural drainage basins in Connecticut was completed in 1981 by the Connecticut Department of Environmental Protection. This drainage basin system divided Connecticut into 8 major basins, 45 regional basins, 337 subregional basins, 2,898 local basins, and 7,067 small drainage basin areas. Major basins are subdivided into regional basins. Regional basins are subdivided into subregional basins. Subregional basins are subdivided into local basins. Local basins are subdivided into smaller drainage basin areas for impoundments and river reaches. 

A pair of 1:24,000-scale polygon and line feature classes is available for all basin levels. These data are named Connecticut Major Basins, Connecticut Regional Basins, Connecticut Subregional Basins, Connecticut Local Basins, and Connecticut Drainage Basins. Connecticut Drainage Basins includes the most detailed information upon which the other basin datasets are based.

A hierarchical drainage basin number was assigned to uniquely identify drainage basin areas. Drainage basin areas are numbered sequentially beginning upstream and proceeding downstream. The first digit (column 1) identifies the major basin, the first two digits (columns 1-2) identify the regional basin, the first 4 digits (columns 1-4) identify the subregional basin, and the first seven digits (columns 1-7) identify the local basin. Below are examples of the hierarchical drainage basin numbers.

Basin Numbers:

4 = Major drainage basin number, MBAS_NO (column 1)
43 = Regional drainage basin number, RBAS_NO (columns 1-2)
4302 = Subregional drainage basin number, SBAS_NO (columns 1-4)
4302-04 = Local drainage basin number, LBAS_NO (columns 1-7)
4302-04-1-R12 = Basin drainage identification number, BASIN_NO (columns 1-13)

Stream Order (column 9):

4304-00-1 = Stream order value of 1 represents a headwater basin.
4304-00-2 = Stream order value > 1 denotes the complexity of the drainage basin morphology.

Mapping Status Element (column 10):

4302-00-2- = Ending with minus sign (-) denotes detail mapping at 1:24,000 scale for entire basin.

4302-00-2+ = Ending with plus sign (+) denotes detailed mapping not performed at 1:24,000 scale for the entire drainage basin. The Stream Order value will not reflect the complexity of the drainage basin morphology.

4302-00-1* = Ending with asterisk sign (*) denotes a headwater basin containing a delineated impoundment into which a delineated drainage basin outlets.

Reach-Impoundment Identifier (column11) and Number (column 12-13):

4302-00-1-L1 = The value for the Reach-Impoundment Identifier for an impounment basin is L (for lake). It is followed by the Reach-Impoundment Number (1).

4302-04-1-R12 = The value for the Reach-Impoundment Identifier for a stream reach basin is R (for reach). It is followed the Reach-Impoundment Number (12).

  1. How should this data set be cited?

    State of Connecticut, Department of Environmental Protection (data compiler, editor and publisher), 1988, Connecticut Drainage Basins Polygon: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Online links:
    Other citation details:
    The State of Connecticut, Department of 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 and digitized from the 1:24,000-scale compilation sheets for the 1:125,000-scale Natural Drainage Basins in Connecticut Map, McElroy, 1981. The 2006 Edition includes the same basin features originally published in 1988 with some minor corrections and improvements made to feature attribute information. Previously undetected errors have been corrected and are included in this 2006 edition. This data is not updated. Source map scale is 1:24,000.

    This is part of the following larger work:

    Marianne McElroy, State of Connecticut, Department of Environmental Protection, Natural Resources Center, 1981, Natural Drainage Basins in Connecticut: Connecticut Natural Resources Atlas SeriesDrainage Basins Map, State of Connecticut, Department of Environmental Protection, Hartford, Connecticut, USA.

    Online links:
    Other citation details:
    The Natural Drainage Basins in Connecticut map is published by the State of Connecticut, Department of Environmental Protection, Natural Resources Center in cooperation with the U.S. Geological Survey. The map was funded in part by the Water Resources Council. Map scale 1:125,000.

  2. What geographic area does the data set cover?

    Bounding coordinates:
    West: -73.760405
    East: -71.465712
    North: 42.603944
    South: 40.936173

  3. What does it look like?

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/basinfullview.gif (GIF)
    Full view of Connecticut Drainage Basins - Drainage Basin line features are symbolized by the Drainage Basins Divide (DIVIDE) attribute to illustrate the basin hierarchy.

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/basindetailview.gif (GIF)
    Detail view of Connecticut Drainage Basins - Drainage Basins polygon features are labeled with the 13-digit basin number. Drainage Basin line features are symbolized by the Drainage Basins Divide (DIVIDE) attribute to illustrate the basin hierarchy.

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/basinstreamreachbasins.gif (GIF)
    Detail view of Stream Reach and Stream Order 1 Basins - The value for the Reach-Impoundment Identifier for a stream reach basin is R (for reach) and is followed the Reach-Impoundment Number (columns 12-13). Stream order (column 10) values of 1 denote a headwater basin with values greater than 1 denoting the complexity of the drainage basin morphology.

    http://www.cteco.uconn.edu/metadata/dep/browsegraphic/basinimpoundmentbasins.gif (GIF)
    Detail view of Impoundment Basins - The value for the Reach-Impoundment Identifier (column 11) for an impoundment basin is L (for lake) and is followed by the Reach-Impoundment Number (columns 12-13).

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

    Calendar date: 1988
    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:
      Connecticut DEP Major Basin Number, Regional Basin Number, Subregional Basin Number, Local Basin Number, Basin Number

      This is a Vector data set. It contains the following vector data types (SDTS terminology):
      • G-polygon (7067)

    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?

    depgis.DEP.BASIN_POLY
    Drainage basin polygon features cover the geographic area of the State of Connecticut, plus the entire headwater upstream areas of all rivers and streams that drain into Connecticut from New York, Massachusetts, and Rhode Island, with the exception of the Connecticut River. The drainage basin area for the Connecticut River starts at the mouth of the Connecticut River and extends upstream into Massachusetts to just over the Connecticut-Massachusetts state boundary. (Source: State of Connecticut, Department of Environmental Protection)

    OBJECTID
    Internal feature number. (Source: ESRI)
                      

    Sequential unique whole numbers that are automatically generated.

    BASIN_NO
    Drainage Basin Identification Number - A 13-digit character code that uniquely identifies each drainage basin. The first digit is the Major basin number. The first two digits represent the Regional basin number. The first 4 digits represent the Subregional basin number. And the first 7 digits represent the Local drainage basin number. All basin polygon features in the same Major, Regional, Subregional, and Local basin have the same first, first 2, first 4, and first 7 digits, respectively. The BASIN_NO is a unique number assigned to each polygon feature. However, in a few instances, two adjacent basin polygon features are assigned the same BASIN_NO when separated by a drainage basin line feature encoded as a Water diversion point divide (DBARC_COD = 10). (Source: State of Connecticut, Department of Environmental Protection)
                      

    LBAS_NO
    Local Drainage Basin Number - This number defines the Local drainage basin and is the first 7 digits of the 13-digit drainage basin identification number (BASIN_NO). The first digit corresponds to the Major basin number (MBAS_NO). The first 2 digits represent the Regional basin number (RBAS_NO). The first 4 digits represent the Subregional basin number (SBAS_NO). All Local basins in the same Major, Regional, Subregional, and Local basin have the same first, first 2, and first 4 digits, respectively. A Local drainage basin number ending in "00" defines the main-stem basin for the corresponding Subregional drainage basin. For example, Local basin 4300-00 is the main-stem basin for Subregional basin 4300, Local basin 4301-00 is the main-stem basin for Subregional basin 4301, and so on. Unlike Major, Regional, and Subregional basins, Local drainage basins are not named after the river or stream drainage area they represent. (Source: State of Connecticut, Department of Environmental Protection)
                      

    SBAS_NO
    Subregional Drainage Basin Number - This number defines the Subregional drainage basin and is the first 4 digits of the 13-digit drainage basin identification number (BASIN_NO). The first digit corresponds to the Major basin number (MBAS_NO) and the first 2 digits represent the Regional basin number (RBAS_NO). All Subregional basins in the same Major and Regional basin have the same first and first 2 digits, respectively. A Subregional drainage basin number ending in "00" defines the main-stem basin for the corresponding Regional drainage basin. For example, Subregional basin 4300 is the main-stem basin for Regional basin 43. These main-stem Subregional basins are usually named after the corresponding Regional basin. (Source: State of Connecticut, Department of Environmental Protection)
                      

    ValueDefinition
    1000
    Pawcatuck River
    1001
    Wyassup Brook
    1002
    Green Fall River
    1003
    Ashaway River
    1004
    Shunock River
    1100
    Wood River
    1101
    Brushy Brook
    2000
    Southeast Shoreline
    2101
    Anguilla Brook
    2102
    Copps Brook
    2103
    Williams Brook
    2104
    Whitford Brook
    2105
    Haleys Brook
    2106
    Mystic River
    2107
    Great Brook
    2201
    Jordan Brook
    2202
    Latimer Brook
    2203
    Oil Mill Brook
    2204
    Niantic River
    2205
    Pattagansett River
    2206
    Bride Brook
    2207
    Fourmile River
    3000
    Thames River
    3001
    Trading Cove Brook
    3002
    Shewville Brook
    3003
    Poquetanuck Brook
    3004
    Oxoboxo Brook
    3005
    Stony Brook
    3006
    Hunts Brook
    3100
    Willimantic River
    3101
    Edson Brook
    3102
    Middle River
    3103
    Furnace Brook
    3104
    Roaring Brook
    3105
    Mill Brook
    3106
    Skungamaug River
    3107
    Burnap Brook
    3108
    Hop River
    3109
    Giffords Brook
    3110
    Tenmile River
    3200
    Natchaug River
    3201
    Bungee Brook
    3202
    Still River
    3203
    Bigelow Brook
    3204
    Stonehouse Brook
    3205
    Squaw Hollow Brook
    3206
    Mount Hope River
    3207
    Fenton River
    3208
    Sawmill Brook
    3300
    French River
    3301
    Mill Brook
    3400
    Fivemile River
    3401
    Rocky Brook
    3402
    Mary Brown Brook
    3403
    Cady Brook
    3404
    Whetstone Brook
    3500
    Moosup River
    3501
    Quanduck Brook
    3502
    Snake Meadow Brook
    3503
    Ekonk Brook
    3600
    Pachaug River
    3601
    Great Meadow Brook
    3602
    Mount Misery Brook
    3603
    Denison Brook
    3604
    Myron Kinney Brook
    3605
    Billings Brook
    3700
    Quinebaug River
    3701
    Hamilton Reservoir Brook
    3702
    Breakneck Brook
    3703
    Hatchet Brook
    3704
    Cohasse Brook
    3705
    Lebanon Brook
    3706
    English Neighborhood Brook
    3707
    Mill Brook
    3708
    Little River
    3709
    Wappoquia Brook
    3710
    Mashamoquet Brook
    3711
    Blackwell Brook
    3712
    Fry Brook
    3713
    Mill Brook
    3714
    Kitt Brook
    3715
    Cory Brook
    3716
    Broad Brook
    3717
    Choate Brook
    3800
    Shetucket River
    3801
    Indian Hollow Brook
    3802
    Beaver Brook
    3803
    Merrick Brook
    3804
    Beaver Brook
    3805
    Little River
    3900
    Yantic River
    3901
    Exeter Brook
    3902
    Bartlett Brook
    3903
    Sherman Brook
    3904
    Deep River
    3905
    Pease Brook
    3906
    Gardner Brook
    3907
    Susquetonscut Brook
    4000
    Connecticut River
    4001
    Great Brook
    4002
    Threemile Brook
    4003
    Freshwater Brook
    4004
    Podunk River
    4005
    Folly Brook
    4006
    Salmon Brook
    4007
    Hubbard Brook
    4008
    Cold Brook
    4009
    Roaring Brook
    4010
    Goff Brook
    4011
    Reservoir Brook
    4012
    Carr Brook
    4013
    Sumner Brook
    4014
    Higganum Creek
    4015
    Mill Creek
    4016
    Whalebone Creek
    4017
    Chester Creek
    4018
    Deep River
    4019
    Falls River
    4020
    Lieutenant River
    4021
    Black Hall River
    4100
    Stony Brook
    4101
    Muddy Brook
    4200
    Scantic River
    4201
    Watchaug Brook
    4202
    Gillettes Brook
    4203
    Gulf Stream
    4204
    Abbey Brook
    4205
    Buckhorn Brook
    4206
    Broad Brook
    4207
    Ketch Brook
    4300
    Farmington River
    4301
    Slocum Brook
    4302
    Mad River
    4303
    Still River
    4304
    Sandy Brook
    4305
    Morgan Brook
    4306
    Valley Brook
    4307
    Hubbard Brook
    4308
    East Branch Farmington River
    4309
    Cherry Brook
    4310
    Nepaug River
    4311
    Burlington Brook
    4312
    Roaring Brook
    4313
    Poland River
    4314
    Copper Mine Brook
    4315
    Pequabuck River
    4316
    Thompson Brook
    4317
    Nod Brook
    4318
    Hop Brook
    4319
    West Branch Salmon Brook
    4320
    Salmon Brook
    4321
    Mill Brook
    4400
    Park River
    4401
    Bass Brook
    4402
    Piper Brook
    4403
    Trout Brook
    4404
    North Branch Park River
    4500
    Hockanum River
    4501
    Charters Brook
    4502
    Marsh Brook
    4503
    Tankerhoosen River
    4504
    South Fork Hockanum River
    4600
    Mattabesset River
    4601
    Belcher Brook
    4602
    Willow Brook
    4603
    Webster Brook
    4604
    Sawmill Brook
    4605
    Allyn Brook
    4606
    Sawmill Brook
    4607
    Coginchaug River
    4700
    Salmon River
    4701
    Raymond Brook
    4702
    Judd Brook
    4703
    Meadow Brook
    4704
    Pine Brook
    4705
    Jeremy River
    4706
    Fawn Brook
    4707
    Blackledge River
    4708
    Dickinson Creek
    4709
    Pine Brook
    4710
    Moodus River
    4800
    Eightmile River
    4801
    Harris Brook
    4802
    East Branch Eightmile River
    4803
    Beaver Brook
    5000
    South Central Shoreline
    5101
    Oyster River
    5102
    Patchogue River
    5103
    Menunketesuck River
    5104
    Indian River
    5105
    Chatfield Hollow Brook
    5106
    Hammonasset River
    5107
    Neck River
    5108
    East River
    5109
    Sluice Creek
    5110
    West River
    5111
    Branford River
    5112
    Farm River
    5200
    Quinnipiac River
    5201
    Eightmile River
    5202
    Tenmile River
    5203
    Misery Brook
    5204
    Broad Brook
    5205
    Sodom Brook
    5206
    Harbor Brook
    5207
    Wharton Brook
    5208
    Muddy River
    5301
    Willow Brook
    5302
    Mill River
    5303
    Sargent River
    5304
    Wintergreen Brook
    5305
    West River
    5306
    Indian River
    5307
    Wepawaug River
    6000
    Housatonic River
    6001
    Sages Ravine Brook
    6002
    Schenob Brook
    6003
    Andrus Brook
    6004
    Konkapot River
    6005
    Factory Brook
    6006
    Spruce Swamp Creek
    6007
    Salmon Creek
    6008
    Mill Brook
    6009
    Carse Brook
    6010
    Furnace Brook
    6011
    Guinea Brook
    6012
    Kent Falls Brook
    6013
    Cobble Brook
    6014
    Bog Hollow Brook
    6015
    Macedonia Brook
    6016
    Womenshenuk Brook
    6017
    Morrissey Brook
    6018
    Pond Brook
    6019
    Deep Brook
    6020
    Pootatuck River
    6021
    Kettletown Brook
    6022
    Halfway River
    6023
    Eightmile Brook
    6024
    Means Brook
    6025
    Farmill River
    6026
    Pumpkin Ground Brook
    6100
    Blackberry River
    6101
    Whiting River
    6200
    Hollenbeck River
    6201
    Brown Brook
    6202
    Wangum Lake Brook
    6300
    Tenmile River
    6301
    Indian Lake Creek
    6302
    Mill Brook
    6303
    Webatuck Creek
    6304
    Deuel Hollow Brook
    6305
    Mill River
    6306
    Swamp River
    6400
    Lake Candlewood
    6401
    Sawmill Brook
    6402
    Ball Pond Brook
    6500
    West Aspetuck River
    6501
    Merryall Brook
    6502
    East Aspetuck River
    6600
    Still River
    6601
    Miry Brook
    6602
    Boggs Pond Brook
    6603
    Padanaram Brook
    6604
    Sympaug Brook
    6605
    East Swamp Brook
    6606
    Limekiln Brook
    6700
    Shepaug River
    6701
    Marshepaug River
    6702
    West Branch Shepaug River
    6703
    West Branch Bantam River
    6704
    Butternut Brook
    6705
    Bantam River
    6706
    Jacks Brook
    6800
    Pomperaug River
    6801
    East Spring Brook
    6802
    Nonewaug River
    6803
    Sprain Brook
    6804
    Weekeepeemee River
    6805
    Hesseky Brook
    6806
    Transylvania Brook
    6900
    Naugatuck River
    6901
    Hall Meadow Brook
    6902
    Hart Brook
    6903
    Nickel Mine Brook
    6904
    West Branch Naugatuck River
    6905
    East Branch Naugatuck River
    6906
    Spruce Brook
    6907
    Rock Brook
    6908
    Leadmine Brook
    6909
    Northfield Brook
    6910
    Branch Brook
    6911
    Hancock Brook
    6912
    Steele Brook
    6913
    Beaver Pond Brook
    6914
    Mad River
    6915
    Fulling Mill Brook
    6916
    Hop Brook
    6917
    Long Meadow Pond Brook
    6918
    Beacon Hill Brook
    6919
    Bladens River
    6920
    Little River
    7000
    Southwest Shoreline
    7101
    Lewis Gut
    7102
    Bruce Brook
    7103
    Yellow Mill Channel
    7104
    Booth Hill Brook
    7105
    Pequonnock River
    7106
    Ash Creek
    7107
    Cricker Brook
    7108
    Mill River
    7109
    Sasco Brook
    7200
    Saugatuck River
    7201
    Little River
    7202
    Aspetuck River
    7203
    West Branch Saugatuck River
    7300
    Norwalk River
    7301
    Comstock Brook
    7302
    Silvermine River
    7401
    Fivemile River
    7402
    Darien River
    7403
    Noroton River
    7404
    Mill River
    7405
    Rippowam River
    7406
    East Branch Mianus River
    7407
    Mianus River
    7408
    Greenwich Creek
    7409
    Horseneck Brook
    7410
    East Branch Byram River
    7411
    Byram River
    7412
    Blind Brook
    8000
    Hudson River
    8100
    Croton River
    8101
    Quaker Brook
    8102
    Corner Pond Brook
    8103
    East Branch Croton River
    8104
    Titicus River
    8105
    Waccabuc River

    SUBREGION
    Subregional Drainage Basin Name - Text values that correspond to numeric SBAS_NO attribute values. SUBREGION is the English language equivalent of (decodes) the SBAS_NO field. (Source: State of Connecticut, Department of Environmental Protection)
                      

    See Enumerated Domain Value Definitions for SBAS_NO attribute.

    RBAS_NO
    Regional Drainage Basin Number - This number defines the Regional drainage basin and is the first 2 digits of the 13-digit drainage basin identification number (BASIN_NO). The first digit corresponds to the Major basin number (MBAS_NO). All Regional basins in the same Major basin have the same first digit. A Regional drainage basin number ending in "0" defines the greater main-stem basin for the corresponding Major drainage basin. For example, Regional basin 40 is the main-stem basin for Major basin 4. These main-stem Regional basins are usually named after the corresponding Major basin. (Source: State of Connecticut, Department of Environmental Protection)
                      

    ValueDefinition
    10
    Pawcatuck Main Stem
    11
    Wood
    20
    Southeast Shoreline
    21
    Southeast Eastern Complex
    22
    Southeast Western Complex
    30
    Thames Main Stem
    31
    Willimantic
    32
    Natchaug
    33
    French
    34
    Fivemile
    35
    Moosup
    36
    Pachaug
    37
    Quinebaug
    38
    Shetucket
    39
    Yantic
    40
    Connecticut Main Stem
    41
    Stony Brook
    42
    Scantic
    43
    Farmington
    44
    Park
    45
    Hockanum
    46
    Mattabesset
    47
    Salmon
    48
    Eightmile
    50
    South Central Shoreline
    51
    South Central Eastern Complex
    52
    Quinnipiac
    53
    South Central Western Complex
    60
    Housatonic Main Stem
    61
    Blackberry
    62
    Hollenbeck
    63
    Tenmile
    64
    Candlewood
    65
    Aspetuck
    66
    Still
    67
    Shepaug
    68
    Pomperaug
    69
    Naugatuck
    70
    Southwest Shoreline
    71
    Southwest Eastern
    72
    Saugatuck
    73
    Norwalk
    74
    Southwest Western Complex
    80
    Hudson Main Stem
    81
    Croton

    REGIONAL
    Regional Drainage Basin Name - Text values that correspond to numeric RBAS_NO attribute values. REGIONAL is the English language equivalent of (decodes) the RBAS_NO field. (Source: State of Connecticut, Department of Environmental Protection)
                      

    See Enumerated Domain Value Definitions for RBAS_NO attribute.

    MBAS_NO
    Major Drainage Basin Number - This number defines the major drainage basin and is the first digit of the 13-digit drainage basin identification number (BASIN_NO). There are 8 Major basins. (Source: State of Connecticut, Department of Environmental Protection)
                      

    ValueDefinition
    1
    Pawcatuck
    2
    Southeast Coast
    3
    Thames
    4
    Connecticut
    5
    South Central Coast
    6
    Housatonic
    7
    Southwest Coast
    8
    Hudson

    MAJOR
    Major Drainage Basin Name - Text values that correspond to numeric MBAS_NO attribute values. MAJOR is the English language equivalent of (decodes) the MBAS_NO field. (Source: State of Connecticut, Department of Environmental Protection)
                      

    See Enumerated Domain Value Definitions for MBAS_NO attribute.

    ACREAGE
    Calculated area of polygon feature in acres. Note, ACREAGE values are not automatically updated after modifying feature geometry (shape). Values must be recalculated after features are edited, simplified, generalized, clipped, dissolved, etc. (Source: State of Connecticut, Department of Environmental Protection)
                      

    Numeric value

    AREA_SQMI
    Calculated area of polygon feature in square miles. Note, AREA_SQMI values are not automatically updated after modifying feature geometry (shape). Values must be recalculated after features are edited, simplified, generalized, clipped, dissolved, etc. (Source: State of Connecticut, Department of Environmental Protection)
                      

    Numeric value

    GAZRECNO
    Gazetteer Record Number - An identifier used to relate Basin polygon features to records in a separate Drainage Basin Gazatteer data table. This related data table includes additional information such the description of each basin outlet location, basin area and cumulative basin area. This information is also available in the Gazatteer of Drainage Areas of Connecticut published by the State of Connecticut, Department of Environmental Protection, Water Resources Bulletin Number 45, 1997. (Source: State of Connecticut, Department of Environmental Protection)
                      

    SHAPE
    Feature geometry. (Source: ESRI)
                      

    Coordinates defining the features.

    SHAPE.area
    SHAPE.len
    Entity and attribute overview:
    Drainage basin information is comprised of a set of polygon and line features that together describe different types of drainage basins and drainage basin divides.  
    
    Part 1 - Drainage Basin Polygon Features
    
    Information encoded for drainage basin polygon features generally includes drainage basin number and name. Below is a brief explanation of the drainage basin identification number. Use the BASIN_NO attribute to uniquely identify drainage basins. The BASIN_NO is a unique number assigned to each polygon feature. However, in a few instances, two adjacent basin polygon features are assigned the same BASIN_NO when separated by a drainage basin line feature encoded as a Water diversion point divide (DBARC_COD = 10).
    
    Basin Numbers:
    
    4 = Major drainage basin number, MBAS_NO (column 1)
    43 = Regional drainage basin number, RBAS_NO (columns 1-2)
    4302 = Subregional drainage basin number, SBAS_NO (columns 1-4)
    4302-04 = Local drainage basin number, LBAS_NO (columns 1-7)
    4302-04-1-R12 = Basin drainage identification number, BASIN_NO (columns 1-13)
    
    Stream Order (column 9):
    
    4304-00-1 = Stream order value of 1 represents a headwater basin.
    4304-00-2 = Stream order value > 1 denotes the complexity of the drainage basin morphology.
    
    Mapping Status Element (column 10):
    
    4302-00-2- = Ending with minus sign (-) denotes detail mapping at 1:24,000 scale for entire basin.
    
    4302-00-2+ = Ending with plus sign (+) denotes detailed mapping not performed at 1:24,000 scale for the entire drainage basin. The Stream Order value will not reflect the complexity of the drainage basin morphology.
    
    4302-00-1* = Ending with asterisk sign (*) denotes a headwater basin containing a delineated impoundment into which a delineated drainage basin outlets.
    
    Reach-Impoundment Identifier (column11) and Number (column 12-13):
    
    4302-00-1-L1 = The value for the Reach-Impoundment Identifier for an impounment basin is L (for lake). It is followed by the Reach-Impoundment Number (1).
    
    4302-04-1-R12 = The value for the Reach-Impoundment Identifier for a stream reach basin is R (for reach). It is followed the Reach-Impoundment Number (12).
    
    Part 2 - Drainage Basin Divide Line Features
    
    Information encoded for line features categorizes drainage basin divides (boundaries) for cartographic purposes. Use the AV_LEGEND or IMS_LEGEND attribute to classify and symbolize boundary lines on a map. The AV_LEGEND attribute classifies basin boundary features into the same categories as DBARC_COD and DIVIDE. It is included for convenience. Unlike the IMS_LEGEND attribute, it does not condense features into broader categories. When symbolizing drainage basins arc features on AV_LEGEND values, be sure to exclude features not intended to be shown on the map by using the following layer definition query: AV_LEGEND <> "No Show". The IMS_LEGEND attribute condenses the 9 drainage basin line feature types (DBARC_COD values) into 6 broader categories (Major, Regional, Subregional, Local, Shoreline, and No Show). When symbolizing drainage basins arc features on IMS_LEGEND values, be sure to exclude features not intended to be shown on the map by using the following layer definition query: IMS_LEGEND <> "No Show". Use the AREA_SQMI and ACREAGE attributes to determine drainage basin polygon feature size. These values reflect the area of the respective polygon feature. They do not reflect the cumulative (upstream) drainage area for each basin. Note, ACREAGE and AREA_SQMI values are not automatically updated after modifying feature geometry (shape). These values must be recalculated after features are edited, simplified, generalized, clipped, dissolved, etc.
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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?

    Tom Nosal, State of Connecticut, Department of Environmental Protection, for the final compilation and delineation of 1:24,000-scale drainage basin boundaries, assignment of drainage basin numbers, and conversion to digitial format. Basin boundaries were manually delineated at 1:24,000-scale by visually interpreting the 10 feet contour elevation lines and waterbody features appearing on 1:24,000-scale 7.5 minute USGS topographic quadrangle maps for Connecticut published between 1969 and 1984. The metadata abstract includes a brief description of a drainage basin obtained from material written by Jim Murphy in an article entitled Reading the Landscape published in the Citizen's Bulletin, a CT DEP monthy magazine.

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

    Tom Nosal
    State of Connecticut, Department of 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
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Why was the data set created?

The polygon features define the contributing drainage area for individual reservoirs, lakes, ponds and river and stream reaches in Connecticut. These are hydrologic land units where precipitation is collected. Rain falling in a basin may take two courses. It may both run over the land and quickly enter surface watercourses, or it may soak into the ground moving through the earth until it surfaces at a wetland or stream. In an undisturbed natural drainage basin, the surface and ground water arrive as precipitation and leave either by evaporation or as surface runoff at the basin's outlet. A basin is a self-contained hydrologic system, with a clearly defined water budget and cycle. The amount of water that flows into the basins equals the amount that leaves. A drainage divide is the topographic barrier along a ridge or line of hilltops separating adjacent drainage basins. For example, rain or snow melt draining down one side of a hill generally will flow into a different basin and stream than water draining down the other side of the hill. These hillsides are separated by a drainage divided that follows nearby hilltops and ridge lines.

Use these basin data to identify where rainfall flows over land and downstream to a particular watercourse. Use these data to categorize and tabulate information according to drainage basin by identifying the basin number for individual reservoir, lake, pond, stream reach, or location of interest. Due to the hierarchical nature of the basin numbering system, a database that records the 13-digit basin number for individual geographic locations of interest will support tabulations by major, regional, subregional or local basin as well as document the unique 13-digit basin number. To identify either all upstream basins draining to a particular location or all downstream basins flowing from a particular location, refer to the Gazetteer of Drainage Basin Areas of Connecticut, Nosal, 1977, CT DEP Water Resources Bulletin 45, for the hydrologic sequence, headwater to outfall, of drainage basins available at http://cteco.uconn.edu/docs/wrb/wrb45_gazetteer_of_drainage_areas_of_connecticut.pdf

Not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.). Not intended for analysis with other digital data compiled at scales greater than or more detailed than 1:24,000 scale. Use these data with 1:24,000-scale hydrography data also available from the State of Connecticut, Department of Environmental Protection.

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How was the data set created?

  1. Where did the data come from?

    Source 1 - Source Materials (source 1 of 2)

    State of Connecticut, Department of Environmental Protection, Unpublished Material, drainage basin compilation sheets.

    Type of source media: stable-base material
    Source scale denominator: 24000
    Source contribution:
    Basins compiled on 1:24,000-scale 7.5 minute USGS quadrangle area mylar overlays.

    Source 2 - Drainage Basins (source 2 of 2)

    State of Connecticut, Department of Environmental Protection, 1988, Connecticut Drainage Basins: State of Connecticut, Department of Environmental Protection, Hartford, Connecticut USA.

    Online links:
    Other citation details:
    The State of Connecticut, Department of 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 and digitized from the 1:24,000-scale compilation sheets for the 1:125,000-scale Natural Drainage Basins in Connecticut Map, McElroy, 1981. The 2006 Edition includes the same basin features originally published in 1988 with some minor corrections and improvements made to feature attribute information. Previously undetected errors have been corrected and are included in this 2006 edition. This data is not updated. Source map scale is 1:24,000.

    Type of source media: disc
    Source scale denominator: 24000
    Source contribution:
    Connecticut Drainage Basins is in ArcInfo Coverage format having both polygon and line features. The name of the ArcInfo Coverage is BASIN. These polygon and line feature data were subsequently converted to geodatabase feature format and named BASIN_POLY and BASIN_LINE, respectively.

  2. What changes have been made?

    Date: 1988 (change 1 of 1)
    Feature digitizing and attribution (digitizing tablet method) - Using ESRI ArcInfo software, basin boundary line features were digitized by registering the individual compilation sheets 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 corners of the USGS 7.5 minute topographic quadrangle maps are used as registration points and are depicted on the source map. The source map was registered to the digitizing tablet by digitizing (entering) the locations of four quadrangle corner registration points shown on the map. 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. With a correct registration, basins boundaries features were manually digitized off the source map. Where necessary, additional minor corrections (edits) to feature geometry were manually digitized on the screen (heads-up digitizing) at display scales greater than 1:24,000.  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 source maps in order to visually inspect digitizing quality and the assignment of attribute values. 
    
    Individual quadrangle level basin boundary coverages were appended and edgematched along quadrangle boundaries to create a statewide layer in ArcInfo Coverage format having both polygon and line features. Polygon label points were created and assigned BASIN_NO values that uniquely identified each polygon feature. Most other related polygon and line feature attributes were assigned through automated procedures based on the format and hierarchical nature of the BASIN_NO value. Four additional fields (MBAS_NO, RBAS_NO, SBAS_NO, LBAS_NO) were added and populated based on the first, first 2, first 4, and first 7 columns of the BASIN_NO attribute. The MAJOR, REGIONAL, and SUBREGION attributes store drainage basin names based on MBAS_NO, RBAS_NO, SBAS_NO values, respectively. Basin names were attributed by joining basin name lookup tables to the polygon features base on MBAS_NO, RBAS_NO, SBAS_NO key values and populating the corresponding fields. These basin names are from the Natural Drainage Basins in Connecticut map, McElroy, 1981. The AREA_SQMI (area in square miles) and ACREAGE (area in acres) field were automatically calculated for each polygon feature based on computer generated feature area in square feet. The GAZRECNO attribute was manually assigned to each basin polygon feature.
    
    For line features, the DBARC_COD attribute was populated through a combination of automated and manual processes that compared the BASIN_NO attribute value of the polygon on each side of the line. For example, if the two polygons are in different major basins (MBAS_NO on the left <> MBAS_NO on the right), then the line feature represents a Major basin drainage divide and is assigned a DBARC_COD value of 1. If the left and right polygons are in the same Major basins but in different regional basins (RBAS_NO on the left <> RBAS_NO on the right), the line feature is a Regional basin drainage divide and is assigned a DBARC_COD value of 2, and so on. DIVIDE is the English language equivalent of (decodes) the DBARC_COD attribute value and was populated by joining a lookup table to the line features instead of manually attributing these values for each line feature. AV_LEGEND and IMS_LEGEND values were also attributed through table joins.

    Person responsible for change:
    Tom Nosal
    State of Connecticut, Department of Environmental Protection
    79 Elm Street
    Hartford, Connecticut 06106
    USA

    806-424-3540 (voice)
    860-424-4058 (FAX)
    Hours of Service: Mondy to Friday, 8:30 to 16:30 Eastern Standard Time

    Data sources used in this process:
    • Source 1 - Source Materials

    Data sources produced in this process:
    • Source 2 - Drainage Basins

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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 Drainage Basins layer retains the feature types and information identified on the 1:24,000-scale compilation sheets for the Natural Drainage Basins in Connecticut map, McElroy, 1981. All attributes have valid values. Values are within defined domains. There are no duplicate BASIN_NO values except where expected (see definition of BASIN_NO attribute).
    
    For polygon features, the accuracy test for the BASIN_NO attribute values was conducted by visually comparing the basin number information depicted on the source Mylar overlays with 1:24,000-scale check plots or interactive displays of the digital data on a computer graphic system. These check plot maps and computer displays labeled polygon features with BASIN_NO values and differentiated line features based on DBARC_COD values for comparison with the original source Mylars. Subsequently, four additional fields (MBAS_NO, RBAS_NO, SBAS_NO, LBAS_NO) were added and populated based on the first, first 2, first 4, and first 7 columns of the BASIN_NO attribute. The MAJOR, REGIONAL, and SUBREGION attributes store drainage basin names based on MBAS_NO, RBAS_NO, SBAS_NO values, respectively. Basin names were attributed by joining basin name lookup tables to the polygon features base on MBAS_NO, RBAS_NO, SBAS_NO key values and populating the corresponding fields. These basin names are from the Natural Drainage Basins in Connecticut map, McElroy, 1981. The AREA_SQMI (area in square miles) and ACREAGE (area in acres) field were automatically calculated for each polygon feature based on computer generated feature area in square feet.
    
    For line features, the DBARC_COD attribute was populated through a combination of automated and manual processes that compared the BASIN_NO attribute value of the polygon on each side of the line. For example, if the two polygons are in different major basins (MBAS_NO on the left <> MBAS_NO on the right), then the line feature represents a Major basin drainage divide and is assigned a DBARC_COD value of 1. If the left and right polygons are in the same Major basins but in different regional basins (RBAS_NO on the left <> RBAS_NO on the right), the line feature is a Regional basin drainage divide and is assigned a DBARC_COD value of 2, and so on. DIVIDE is the English language equivalent of (decodes) the DBARC_COD attribute value and was populated by joining a lookup table to the line features instead of manually attributing these values for each line feature. AV_LEGEND and IMS_LEGEND values were also attributed through table joins. 

  2. How accurate are the geographic locations?

    The horizontal positional accuracy of this data complies with 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.
    
    Drainage basin boundaries were interpolated from 10 FT elevation contours and surface water body (hydrography) information published on a set of USGS 1:24,000-scale, 7.5-minute topographic quadrangle maps that cover the State of Connecticut. Natural drainage basin boundaries were manually delineated by interpolating elevation and water body information found on topographic quadrangle maps published by the USGS between 1962 and 1984.

  3. How accurate are the heights or depths?

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

    The data reflects the content of the data source, which is a set of 1:24,000 scale mylar sheets used to compile and publish the 1:125,000-scale Drainage Basins in Connecticut Map, McElroy, 1982. All major, regional, subregional, local and smaller basin divides were digitized from these 1:24,000-scale mylar compilation sheets. This data is not 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. Lines are single part. Line features conform to the following topological rules. There are no duplicate lines. Lines do not self overlap. Lines do not overlap other lines. Lines intersect only at nodes, and nodes anchor the ends of all lines. Lines do not overshoot or undershoot other lines they are supposed to meet and intersect. In general, there are no duplicate features, unresolved intersections, overshooting lines, open polygons, sliver polygons, or unlabeled (unattributed) 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 0 feet (dangle length).

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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 Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of 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 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 Environmental Protection as the source for this information. For example, include the following data source description when printing this layer on a map: Basins - From the Drainage Basins layer, compiled and published by CT DEP. Source map scale is 1:24,000.

Distributor 1 of 1

  1. Who distributes the data set?

    State of Connecticut, Department of Enviromental 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?

    Connecticut Drainage Basins Polygon

  3. What legal disclaimers am I supposed to read?

    Although this data set  has been used by the State of Connecticut, Department of Environmental Protection, no warranty, expressed or implied, is made by the State of Connecticut, Department of 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 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.

  4. How can I download or order the data?

    • Availability in digital form:


    • Data format:
      in format Shapefile, Feature Class, ArcInfo Coverage (version ArcGIS) Size: 11.417
      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: 20120125

Metadata author:
Tom Nosal, Howie Sternberg
State of Connecticut, Department of 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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