Connecticut Erosion Susceptibility a 1:24,000-scale, polygon feature-based layer that was developed as a predictive tool to show areas most susceptible to terrace escarpment type erosion. The layer compiled from the soils and quaternary geology data layers and was field tested during October-December, 2005. The Erosion Susceptilibity layer was developed as part of Project #03-02 Statewide GIS Analysis and Mapping of the Geologic Conditions Contributing to Eroding Terrace Escarpments. The layer does not represent eroding conditions at any one particular point in time, but rather base or general conditions which can be accounted for during planning or management strategies. The layer includes 4 types of areas susceptible to erosion, ranked 1 (most susceptible) through 4, and their descriptive attribute. Areas outside of the mapped polygons can be considered less susceptible to erosion.  Data is compiled at 1:24,000 scale. This data is not updated.

Connecticut Erosion Susceptibility is 1:24,000-scale, polygon feature-based layer that was developed as a predictive tool to show areas most susceptible to terrace escarpment type erosion. This map can be used in conjunction with the 1:24,000 scale Erosion_Sites layer and other documents developed for the Project #03-02: Statewide GIS Analysis and Mapping of the Geologic Conditions Contributing to Eroding Terrace Escarpments.  The objective of this project is to identify the geologic conditions that lead to eroding terrace escarpments throughout the state. This layer is part of an information package that can be used as a planning and management tool by state and municipal officials. Not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.)

For additional information, refer to Statewide GIS Analysis and Mapping of the Geologic Conditions Contributing to Eroding Terrace Escarpments, Project #03-02 Final Report, prepared by Mary L. DiGiacomo-Cohen, Long Island Sound Resource Center, University of Connecticut, Avery Point, Groton, CT 06340 in conjunction with North Central Conservation District, 24 Hyde Ave., Vernon, CT, 06066. Report prepared for Nonpoint Source Management Grant Program, Funded under Section 319 (h) of the Federal Clean Water Act, administered by the Connecticut Department of Environmental Protection.

publication date

None. The data is in the public domain and may be redistributed.

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: Erosion susceptibility from the Erosion susceptibility layer, compiled and published by CT DEP.  Source map scale is 1:24,000.

Includes erosion_category which ranks area features on their susceptibility to erode due to geologic and soils  conditions. Information encoded about these features includes standard cartographic symbology classification schemes. Use the erosion_category to uniquely identify features. Use the AV_LEGEND attribute to symbolize features by type on a map. Use the IMS_LEGEND attribute to more generally symbolize the features by type. 

erosion susceptibility represented as polygon features.

State of Connecticut, Department of Environmental Protection

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.

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 SHAPEFILE format. No automated procedures or tests were performed to guarantee desired topology other than visual inspection.

The completeness of the data reflects the chosen feature content of the data sources, which include the soils and quaternary geology data layers. The erosion_susceptibility layer is complete in the sense that it accurately reflects the contents of units chosen by the compiler to represent erodible given the source layers available at the time the State of Connecticut, Department of Environmental Protection created the layer. However, compared to current conditions, the erosion_susceptibility layer is incomplete in that there are minor data gap 'slivers' resulting from merges between the soils data layers for the northwestern portion of the state and the remainder of the state. This data is not updated.

The erosion_susceptibility layer retains the feature types and information identified by the State of Connecticut, Department of Environmental Protection and obtained from the compiler. All attributes have valid values. Values are within defined domains. The accuracy test for the attribute values was conducted by comparing the erosion category information presented in the source data with  interactive displays of the data on a computer graphic system.  AV_LEGEND and IMS_LEGEND are broad classifications of erosion_category feature.  AV_LEGEND, and IMS_LEGEND were not manually entered. These additional fields were populated by calculating values equal to existing fields.  The description field was manually selected and populated.

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. Features are derived from the union of other 1:24,000 scale (Quaternary geology) and 1:12,000 scale (soils) data layers.

Connecticut Erosion Susceptibility

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.

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

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.