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FGDC Metadata
DescriptionSpatialData StructureMetadata
+ Resource Description
Information used to reference the data.
Title: Impervious2012_by_basin_clipped
Data type: vector digital data
A characterization of the data, including its intended use and limitations.
Impervious Cover by Watershed Basins is based on the Connecticut Drainage Basins layer and is 1:24,000-scale, polygon feature data that define natural drainage areas in Connecticut and contain values for calculated impervious cover (2012) within each basin. Drainage basins have been clipped to the Connecticut state boundary as well as each municipal boundary. The features are small basin areas that make up, in order of increasing size, the larger local, subregional, regional, and major drainage basin areas. Impervious Cover by Watershed 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 by the Connecticut Department of Environmental Protection (CT DEP) at 1:24,000 scale (1 inch = 2,000 feet). Basin delineation information is not updated. 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 9580 basin areas (polygons), clipped to the boundaries of Connecticut’s 169 municipalities. Impervious cover for each basin area has been calculated from 1-foot impervious cover data (link to metadata). Basin area attributes for imperviousness included total impervious area (acres), percent impervious area, building impervious area (acres and percent), roads (acres and percent) and other impervious area (acres and percent). Road impervious area has also been summarized for state (DOT) road area and non-state owned road area. 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 9580 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 than unique basin numbers 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. Unique basin ID fields (BasinNoU and T_Basin_ID) have been added for the purposes of calculating impervious area. 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 Connecticut Local Drainage Basins.
The polygon features define the amount and type of impervious cover in contributing drainage areas for individual reservoirs, lakes, ponds and river and stream reaches in Connecticut. Please note that these drainage basins have been clipped to the municipal boundaries of Connecticut's 169 towns. Impervious area based on 2012 aerial imagery has been used to calculate area and percent of impervious cover (three major types: buildings, roads, and other impervious) for each drainage basin. The "roads" class has been broken down into town roads and DOT roads for the purposes of the State of Connecticut's General Permit for the Discharage of Stormwater from Small Municipal Separate Strom Sewer Systems (MS4) permit. All classes are calculated by total area (acres) and percent of the drainage basin. Drainage areas 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. 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 such as amount of imperviousness according to drainage basin by identifying the basin number for individual reservoir, lake, pond, stream reach, or location of interest. Such information is useful for compliance with the State of Connecticut's MS4 permit. 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.
Dataset credit:
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.

University of Connecticut, Center for Land use Education and Research (CLEAR) clipped the basin boundaries to the state of Connecticut and municipal boundaries and calculated all impervious area values.
Data Type
How the data are represented, formatted and maintained by the data producing organization.
Data type: vector digital data
Native dataset environment: Microsoft Windows 7 Version 6.1 (Build 7601) Service Pack 1; Esri ArcGIS
Key Words
Words or phrases that summarize certain aspects of the data.
Keywords: basin divide, subregional, impervious cover, MS4, municipal boundary, watershed, major, regional, drainage area, local, drainage basin, inland waters, elevation, basin, watershed, impervious cover, Connecticut, CT, United States
Keyword thesaurus: None
Data Access Constraints
Restrictions and legal prerequisites for accessing or using the data after access is granted.
Access constraints:
Use constraints:
+ Spatial Reference Information
Horizontal Coordinate System
Reference system from which linear or angular quantities are measured and assigned to the position that a point occupies.
Coordinate System Details
Map projection
Map projection name: NAD 1983 StatePlane Connecticut FIPS 0600 Feet
Standard parallel: 41.2
Standard parallel: 41.86666666666667
Longitude of central meridian: -72.75
Latitude of projection origin: 40.83333333333334
False easting: 999999.999996
False northing: 499999.999998
Planar Coordinate Information
Planar coordinate encoding method: coordinate pair
Coordinate representation:
Abscissa resolution: 0.000000026813284925708565
Ordinate resolution: 0.000000026813284925708565
Planar distance units: foot_us
Geodetic model
Horizontal datum name: D North American 1983
Ellipsoid name: GRS 1980
Semi-major axis: 6378137.0
Denominator of flattening ratio: 298.257222101
Spatial Domain
The geographic areal domain of the data that describes the western, eastern, northern, and southern geographic limits of data coverage.
Bounding Coordinates
In Unprojected coordinates (geographic)
West-73.732873 (longitude)
East-71.781365 (longitude)
North42.052612 (latitude)
South40.988874 (latitude)
+ Data Structure and Attribute Information
Summary of the information content of the data, including other references to complete descriptions of entity types, attributes, and attribute values for the data.
Direct spatial reference method: Vector
Attributes of Impervious2012_by_basin_clipped
Detailed descriptions of entity type, attributes, and attribute values for the data.
Internal feature number.
Attribute values: Sequential unique whole numbers that are automatically generated.
Attribute definition source:
Feature geometry.
Attribute values: Coordinates defining the features.
Attribute definition source:
SDTS Feature Description
Description of point and vector spatial objects in the data using the Spatial Data Transfer Standards (SDTS) terminology.
Spatial data transfer standard (SDTS) terms
Feature class
Type: GT-polygon composed of chains
Count: 9580
+ Metadata Reference
Metadata Date
Dates associated with creating, updating and reviewing the metadata.
Last updated: 20190830
Metadata Standards
Description of the metadata standard used to document the data and reference to any additional extended profiles to the standard used by the metadata producer.
Standard name: FGDC Content Standard for Digital Geospatial Metadata
Standard version: FGDC-STD-001-1998
Time convention: local time
FGDC Plus Metadata Stylesheet
Stylesheet: FGDC Plus Stylesheet
File name: FGDC Plus.xsl
Version: 2.3
Description: This metadata is displayed using the FGDC Plus Stylesheet, which is an XSL template that can be used with ArcGIS software to display metadata. It displays metadata elements defined in the Content Standard for Digital Geospatial Metadata (CSDGM) - aka FGDC Standard, the ESRI Profile of CSDGM, the Biological Data Profile of CSDGM, and the Shoreline Data Profile of CSDGM. CSDGM is the US Federal Metadata standard. The Federal Geographic Data Committee originally adopted the CSDGM in 1994 and revised it in 1998. According to Executive Order 12096 all Federal agencies are ordered to use this standard to document geospatial data created as of January, 1995. The standard is often referred to as the FGDC Metadata Standard and has been implemented beyond the federal level with State and local governments adopting the metadata standard as well. The Biological Data Profile broadens the application of the CSDGM so that it is more easily applied to biological data that are not explicitly geographic (laboratory results, field notes, specimen collections, research reports) but can be associated with a geographic location. Includes taxonomical vocabulary. The Shoreline Data Profile addresses variability in the definition and mapping of shorelines by providing a standardized set of terms and data elements required to support metadata for shoreline and coastal data sets. The FGDC Plus Stylesheet includes the Dublin Core Metadata Element Set. It supports W3C DOM compatible browsers such as IE7, IE6, Netscape 7, and Mozilla Firefox. It is in the public domain and may be freely used, modified, and redistributed. It is provided "AS-IS" without warranty or technical support.
Instructions: On the top of the page, click on the title of the dataset to toggle opening and closing of all metadata content sections or click section links listed horizontally below the title to open individual sections. Click on a section name (e.g. Description) to open and close section content. Within a section, click on a item name (Status, Key Words, etc.) to open and close individual content items. By default, the Citation information within the Description section is always open for display.
Download: FGDC Plus Stylesheet is available from the ArcScripts downloads at www.esri.com.