Connecticut Local Drainage Basins is 1:24,000-scale, polygon and line feature data that define local drainage basin areas in Connecticut. These relatively small basin areas mostly range from 0.5 to 8 square miles in size and make up, in order of increasing size the larger subregional, regional, and major drainage basin areas. Connecticut Local 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, and local basin boundary (line) feature. These data include 2,898 local basin area (polygon) features and 8,663 local basin boundary (line) features. Local Basin area (polygon) attributes include major, regional, subregional, and local basin number, and feature size in acres and square miles. The local basin number (LBAS_NO) uniquely identifies individual basins and is 7 characters in length. There are 2,895 unique local basin numbers. Examples include 6000-00, 4300-00, and 6002-00. 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 local basin polygon features (2,898) than unique local basin numbers (2,895) primarily due to a few stream confluences that split the same local basin into two polygon features. Local 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, and local 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 Local Drainage Basin polygon and line feature data are derived from the geometry and attributes of the Connecticut Drainage Basins data.
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 local 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 7-digit local basin number for individual geographic locations of interest will support tabulations by major, regional, subregional, and local basin as well as document the unique 7-digit local 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.
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).
publication date
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 Local Drainage Basins layer, compiled and published by CT DEP. Source map scale is 1:24,000.
79 Elm Street
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.
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 LBASIN_NO values except where expected (see definition of LBASIN_NO attribute). The LBASIN_NO is derived from the first 7-digits of BASIN_NO so the accuracy of the LBASIN_NO is dependent on that for the BASIN_NO. 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.
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).
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.
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.
Basins compiled on 1:24,000-scale 7.5 minute USGS quadrangle area mylar overlays.
Connecticut Drainage Basins is in ArcInfo Coverage format having both polygon and line features. The name of the ArcInfo Coverage is BASIN.
Connecticut Local Drainage Basins is in ArcInfo Coverage format having both polygon and line features. The name of the ArcInfo Coverage is LBASIN. These polygon and line feature data were subsequently converted to geodatabase feature format and named LOCAL_BASIN_POLY and LOCAL_BASIN_LINE, respectively.
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.
79 Elm Street
Create Local Drainage Basins - Using ArcInfo Workstation software, removed the BASIN_NO polygon feature attribute, calculated the ACREAGE and AREA_SQMI polygon attributes to zero, and dissolved polygon features on the remaining LBAS_NO, SBAS_NO, RBAS_NO, MBAS_NO, SUBREGIONAL, REGIONAL, and MAJOR attribute values to create local drainage basin polygon features. Using the ArcInfo Dissolve command, this step merged the smaller basin polygons into the larger local basin polygon features. Line features were preserved as part of the dissolve process and were merged using the ArcInfo Unsplit command afterwards. The ACREAGE and AREA_SQMI attributes were recalculated based on the new feature geometry, and ArcInfo coveage topology was re-established with the Build command.
79 Elm Street
Internal feature number.
ESRI
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.
State of Connecticut, Department of Environmental Protection
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.
State of Connecticut, Department of Environmental Protection
Pawcatuck River
Wyassup Brook
Green Fall River
Ashaway River
Shunock River
Wood River
Brushy Brook
Southeast Shoreline
Anguilla Brook
Copps Brook
Williams Brook
Whitford Brook
Haleys Brook
Mystic River
Great Brook
Jordan Brook
Latimer Brook
Oil Mill Brook
Niantic River
Pattagansett River
Bride Brook
Fourmile River
Thames River
Trading Cove Brook
Shewville Brook
Poquetanuck Brook
Oxoboxo Brook
Stony Brook
Hunts Brook
Willimantic River
Edson Brook
Middle River
Furnace Brook
Roaring Brook
Mill Brook
Skungamaug River
Burnap Brook
Hop River
Giffords Brook
Tenmile River
Natchaug River
Bungee Brook
Still River
Bigelow Brook
Stonehouse Brook
Squaw Hollow Brook
Mount Hope River
Fenton River
Sawmill Brook
French River
Mill Brook
Fivemile River
Rocky Brook
Mary Brown Brook
Cady Brook
Whetstone Brook
Moosup River
Quanduck Brook
Snake Meadow Brook
Ekonk Brook
Pachaug River
Great Meadow Brook
Mount Misery Brook
Denison Brook
Myron Kinney Brook
Billings Brook
Quinebaug River
Hamilton Reservoir Brook
Breakneck Brook
Hatchet Brook
Cohasse Brook
Lebanon Brook
English Neighborhood Brook
Mill Brook
Little River
Wappoquia Brook
Mashamoquet Brook
Blackwell Brook
Fry Brook
Mill Brook
Kitt Brook
Cory Brook
Broad Brook
Choate Brook
Shetucket River
Indian Hollow Brook
Beaver Brook
Merrick Brook
Beaver Brook
Little River
Yantic River
Exeter Brook
Bartlett Brook
Sherman Brook
Deep River
Pease Brook
Gardner Brook
Susquetonscut Brook
Connecticut River
Great Brook
Threemile Brook
Freshwater Brook
Podunk River
Folly Brook
Salmon Brook
Hubbard Brook
Cold Brook
Roaring Brook
Goff Brook
Reservoir Brook
Carr Brook
Sumner Brook
Higganum Creek
Mill Creek
Whalebone Creek
Chester Creek
Deep River
Falls River
Lieutenant River
Black Hall River
Stony Brook
Muddy Brook
Scantic River
Watchaug Brook
Gillettes Brook
Gulf Stream
Abbey Brook
Buckhorn Brook
Broad Brook
Ketch Brook
Farmington River
Slocum Brook
Mad River
Still River
Sandy Brook
Morgan Brook
Valley Brook
Hubbard Brook
East Branch Farmington River
Cherry Brook
Nepaug River
Burlington Brook
Roaring Brook
Poland River
Copper Mine Brook
Pequabuck River
Thompson Brook
Nod Brook
Hop Brook
West Branch Salmon Brook
Salmon Brook
Mill Brook
Park River
Bass Brook
Piper Brook
Trout Brook
North Branch Park River
Hockanum River
Charters Brook
Marsh Brook
Tankerhoosen River
South Fork Hockanum River
Mattabesset River
Belcher Brook
Willow Brook
Webster Brook
Sawmill Brook
Allyn Brook
Sawmill Brook
Coginchaug River
Salmon River
Raymond Brook
Judd Brook
Meadow Brook
Pine Brook
Jeremy River
Fawn Brook
Blackledge River
Dickinson Creek
Pine Brook
Moodus River
Eightmile River
Harris Brook
East Branch Eightmile River
Beaver Brook
South Central Shoreline
Oyster River
Patchogue River
Menunketesuck River
Indian River
Chatfield Hollow Brook
Hammonasset River
Neck River
East River
Sluice Creek
West River
Branford River
Farm River
Quinnipiac River
Eightmile River
Tenmile River
Misery Brook
Broad Brook
Sodom Brook
Harbor Brook
Wharton Brook
Muddy River
Willow Brook
Mill River
Sargent River
Wintergreen Brook
West River
Indian River
Wepawaug River
Housatonic River
Sages Ravine Brook
Schenob Brook
Andrus Brook
Konkapot River
Factory Brook
Spruce Swamp Creek
Salmon Creek
Mill Brook
Carse Brook
Furnace Brook
Guinea Brook
Kent Falls Brook
Cobble Brook
Bog Hollow Brook
Macedonia Brook
Womenshenuk Brook
Morrissey Brook
Pond Brook
Deep Brook
Pootatuck River
Kettletown Brook
Halfway River
Eightmile Brook
Means Brook
Farmill River
Pumpkin Ground Brook
Blackberry River
Whiting River
Hollenbeck River
Brown Brook
Wangum Lake Brook
Tenmile River
Indian Lake Creek
Mill Brook
Webatuck Creek
Deuel Hollow Brook
Mill River
Swamp River
Lake Candlewood
Sawmill Brook
Ball Pond Brook
West Aspetuck River
Merryall Brook
East Aspetuck River
Still River
Miry Brook
Boggs Pond Brook
Padanaram Brook
Sympaug Brook
East Swamp Brook
Limekiln Brook
Shepaug River
Marshepaug River
West Branch Shepaug River
West Branch Bantam River
Butternut Brook
Bantam River
Jacks Brook
Pomperaug River
East Spring Brook
Nonewaug River
Sprain Brook
Weekeepeemee River
Hesseky Brook
Transylvania Brook
Naugatuck River
Hall Meadow Brook
Hart Brook
Nickel Mine Brook
West Branch Naugatuck River
East Branch Naugatuck River
Spruce Brook
Rock Brook
Leadmine Brook
Northfield Brook
Branch Brook
Hancock Brook
Steele Brook
Beaver Pond Brook
Mad River
Fulling Mill Brook
Hop Brook
Long Meadow Pond Brook
Beacon Hill Brook
Bladens River
Little River
Southwest Shoreline
Lewis Gut
Bruce Brook
Yellow Mill Channel
Booth Hill Brook
Pequonnock River
Ash Creek
Cricker Brook
Mill River
Sasco Brook
Saugatuck River
Little River
Aspetuck River
West Branch Saugatuck River
Norwalk River
Comstock Brook
Silvermine River
Fivemile River
Darien River
Noroton River
Mill River
Rippowam River
East Branch Mianus River
Mianus River
Greenwich Creek
Horseneck Brook
East Branch Byram River
Byram River
Blind Brook
Hudson River
Croton River
Quaker Brook
Corner Pond Brook
East Branch Croton River
Titicus River
Waccabuc River
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.
State of Connecticut, Department of Environmental Protection
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.
State of Connecticut, Department of Environmental Protection
Pawcatuck Main Stem
Wood
Southeast Shoreline
Southeast Eastern Complex
Southeast Western Complex
Thames Main Stem
Willimantic
Natchaug
French
Fivemile
Moosup
Pachaug
Quinebaug
Shetucket
Yantic
Connecticut Main Stem
Stony Brook
Scantic
Farmington
Park
Hockanum
Mattabesset
Salmon
Eightmile
South Central Shoreline
South Central Eastern Complex
Quinnipiac
South Central Western Complex
Housatonic Main Stem
Blackberry
Hollenbeck
Tenmile
Candlewood
Aspetuck
Still
Shepaug
Pomperaug
Naugatuck
Southwest Shoreline
Southwest Eastern
Saugatuck
Norwalk
Southwest Western Complex
Hudson Main Stem
Croton
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.
State of Connecticut, Department of Environmental Protection
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.
State of Connecticut, Department of Environmental Protection
Pawcatuck
Southeast Coast
Thames
Connecticut
South Central Coast
Housatonic
Southwest Coast
Hudson
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.
State of Connecticut, Department of Environmental Protection
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.
State of Connecticut, Department of Environmental Protection
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.
State of Connecticut, Department of Environmental Protection
Feature geometry.
ESRI
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.
79 Elm Street
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.
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.
79 Elm Street