Connecticut Dams is a 1:24,000-scale, point feature-based layer that displays the locations of dams in Connecticut that are owned and operated by individuals, businesses, corporations, water and electric utilities, local, state, and federal governments. Each dam is assigned a unique dam number. This information was compiled in 1996 and is based on dam safety information from the Inland Water Resources Division, Connecticut Department of Environmental Protection. The dams were mapped on 7½ Minute U.S. Geological Survey topographic quadrangle maps and digitized at 1:24,000 scale. Attributes include dam number and name, dam hazard classification, ownership type, town name and number, and major, regional and subregional basin numbers. This layer does not include all dams in Connecticut and has not been updated since its creation in 1996.
Connecticut Dams is a 1:24,000 scale spatial data developed for use by the Dam Safety Section of the Inland Water Resources Division, Bureau of Water Protection and Land Reuse, Department of Environmental Protection, State of Connecticut. The Dam Safety Section of the Inland Water Resources Division is charged with the responsibility for administration and enforcement of Connecticut's dam safety laws. The existing statutes require that permits be obtained to construct, repair or alter dams, dikes or similar structures and that existing dams, dikes and similar structures be registered and periodically inspected to assure that their continued operation and use does not constitute a hazard to life, health or property. The dam safety statutes are codified in Section 22a-401 through 22a-411 inclusive of the Connecticut General Statutes. Sections 22a-409-1 and 22a-409-2 of the Regulations of Connecticut State Agencies, have been enacted which govern the registration, classification, and inspection of dams. The Connecticut Dams data depict the locations of dams throughout the state of Connecticut. The information may be dated in some instances and is best used in conjunction with other 1:24,000 scale data such as hydrography, drainage basins, and political boundaries. Attribute information includes a unique dam number and dam hazard classification that rates the potential hazard to life and property as defined by Connecticut State Statute (Section 22a-409-1d), in the event of a dam breach. This information is not intended to be used or printed at map scales greater or more detailed than 1:24,000 scale (1 in. = 2,000 ft.).
For additional information, refer to the Dam Safety Program at the Connecticut Department of Environmental Protection found on website http://www.ct.gov/dep/dams.
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: Dams - From the Connecticut Dams layer, compiled and published by CT DEP. Source map scale is 1:24,000.
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James Bogar from the Natural Resources Center, DEP originally mapped dam locations at 1:24,000 scale by compiling information primarily available from the Dam Safety program, Inland Water Resources Division, Bureau of Water Protection and Land Reuse, DEP. Tom Nosal and Ann Kuzyk, also from DEP, digitized the maps compiled by James Bogar to create the first statewide digital spatial dataset of Connecticut dams.
The Connecticut Dams layer retains the feature types and information identified by the State of Connecticut, Department of Environmental Protection and obtained from the Dam Safety Program database. Values are within defined domains, but attributes may not have correct or valid values. Information may be incorrect or out of date. Accuracy check of attribute data is unknown.
Point features conform to the following topological rules. Points are single part. There are no duplicate points. Points do not overlap. Establishment of logical consistency was performed by the State of Connecticut, Department of Environmental Protection using ESRI ArcGIS software to manually create and control feature topology in originally in ArcInfo coverage format. No automated procedures or tests were performed to guarantee desired topology other than visual inspection.
The completeness of the data reflects the feature content of the data sources, which include the dam safety program records and maps on file at the Connecticut Department of Environmental Protection in 1996. This layer is complete in the sense that it accurately reflects the information available at the time the State of Connecticut, Department of Environmental Protection initially created the Dam layer (1996). However, it is not a complete compilation relative of dams in existence today.
The horizontal positional accuracy of this data is no better than the United States National Map Accuracy Standards for 1:24,000 scale maps. According to this standard, not more than 10 percent of the locations tested are to be in error by more than 1/50 inch (40 feet) measured on the publication scale of a USGS 7.5 minute topographic quadrangle map. Point features may not be accurately positioned because the locations were interpolated relative to features on USGS 7.5 minute topographic quadrangle maps such as dams, waterbodies, roads, trails, buildings, and elevation contours.
This data source refers to the original dam safety records, files, and maps maintained by the Dam Safety program, Inland Water Resources Division, CT Department of Environmental Protection.
This data source refers to a set of 1:24,000-scale 7.5 Minute USGS Topographic Quadrangle maps used as mapping base for locating dams on a set of corresponding Mylar overlays. Includes 116 USGS topographic quadrangle maps.
Point locations shown on these mylars were digitized. Includes 116 Mylay overlays, one for each 1:24,000-scale 7.5 Minute USGS topographic quadrangle map.
This is a statewide dataset of Connecticut dams in ESRI ArcInfo coverage format initially created in 1996.
This is a statewide dataset of Connecticut dams converted to ESRI Shapefile format in 2000.
This is a statewide dataset of Connecticut dams converted to ESRI Geodatabase feature class format in 2005
A separate Mylar overlay was prepared and registered to each USGS topographic quadrangle map. At 1:24,000 scale, a point location for each dam located on the quadrangle map was plotted on the Mylar overlay and labeled with the corresponding dam number, the unique identifier, and dam name. Includes 116 Mylar overlays, one for each 7.5 minute USGS topographic quadrangle area in Connecticut
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Feature digitizing and attribution (digitizing tablet method) - Using ESRI ArcInfo Workstation software, point features were digitized by registering the source map (Mylars) 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, individual features were manually digitized off the source map and assigned their unique DAM_NO values. Feature location and attribute accuracy was visually checked and inspected by symbolizing and labeling features according to attribute value on the computer screen, comparing it to the original source data. Dam name and dam hazard information was also manually entered. Town, major, regional, and subregional basin numbers were assigned using the ArcInfo Identity command in conjunction with town and basin layers.
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Convert to Shapfile format - Converted all point features from ArcInfo coverage to shapefile format and omitted the following standard ArcInfo coverage items: AREA, PERIMETER, {cover}-ID, and {cover}#.79 Elm Street
Convert to Geodatabase Feature Class format - Connecticut Dams Shapefile was converted to geodatabase format feature classe according to the following steps: defined new geodatabase feature class, imported the spatial reference, defined attribute definitions, loaded features from shapefile, and created metadata.
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Internal feature number.
ESRI
Symbolset Code - A field used by ArcInfo Workstion software to symbolize the dams.This field is obsolete and should be eventually be removed from the attribute table in the event the Dam database model is revised in the future.
State of Connecticut, Department of Environmental Protection
Numbers
Unique identification number of feature.
State of Connecticut, Department of Environmental Protection
Number
Hazard Classification of dam.
State of Connecticut, Department of Environmental Protection
Negligible hazard potential
State of Connecticut, Department of Environmental Protection
Low hazard potential
State of Connecticut, Department of Environmental Protection
Moderate hazard potential
State of Connecticut, Department of Environmental Protection
Significant hazard potential
State of Connecticut, Department of Environmental Protection
High hazard potential
State of Connecticut, Department of Environmental Protection
Name of dam.
State of Connecticut, Department of Environmental Protection
Quadrangle Number - An ID number designated by the State of Connecticut, Department of Environmental Protection, Natural Resources Center in the 1980's to uniquely identify individual quadrangle maps. This value indicates the USGS topographic quadrangle the dam is located on.
State of Connecticut, Department of Environmental Protection
Town Number - ID number for the Connecticut Town (municipality), based on the Town Codes issued by the State of Connecticut, Office of the State Controller, which range from 1 to 169. This value indicates the town the dam point feature is located in.
State of Connecticut, Office of the State Controller
Town Name - Text values that correspond to numeric TOWN_NO attribute values. TOWN is the English language equivalent of (decodes) the TOWN_NO field.
State of Connecticut, Office of the State Controller
Type of Ownership of Dam.
State of Connecticut, Department of Environmental Protection
Owned by CT DEP
Federal government owned
Local (municipal) government owned
Privately owned
State goverment other than CT DEP owned
Utility owned
meaning of blank field value is uknown
Paradox database flag - A field used to flag whether information for a dam is also originated from and is available in an associated database developed with Paradox software. This is an obsolete attribute and should be removed from the attribute table in the event the Dam database model is revised in the future.
State of Connecticut, Department of Environmental Protection
Yes, entered into database
meaning of blank field value is uknown
Subregional Drainage Basin Number - Identifies the Subregional drainage basin the dam is located in. 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
Regional Drainage Basin Number - Identifies the regional drainage basin the dam is located in. 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
Major Drainage Basin Number - Identifies the major drainage basin the dam is located in. There are 8 Major basins in Connecticut.
State of Connecticut, Department of Environmental Protection
X Coordinate of dam in CT state plane feet, NAD 83 - This data field is no longer necessary and should be removed from the attribute table in the event the Dam database model is revised in the future.
State of Connecticut, Department of Environmental Protection
Y Coordinate of dam in CT state plane feet, NAD 83 - This data field is no longer necessary and should be removed from the attribute table in the event the Dam database model is revised in the future.
State of Connecticut, Department of Environmental Protection
Feature geometry.
ESRI
Includes Dam features such as dam number and name, hazard classification, type of ownership, town name, town number, USGS topo quadrangle number, and major, regional and subregional basin numbers. Use the DAM_NO to uniquely identify features. Use the dam hazard (DAM_HAZ) attribute to symbolize features by potential hazard on a map. Use the OWNER attribute to symbolize features by type of ownership (private, public, state, etc.)
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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.
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