The Coastal Boundary layer is a 1:24,000-scale, polygon feature-based layer of the legal mylar-based maps adopted by the Commissioner of the Department of Environmental Protection (DEP) (i.e., maps were adopted on a town by town basis) showing the extent of lands and coastal waters as defined by Connecticut General Statute (C.G.S.) 22a-93(5)) within Connecticut's coastal area (defined by C.G.S. 22a-94(c)). The coastal boundary is a hybrid of the original 1:24,000 version maps prepared by DEP consistent with C.G.S. 22a-94(d) (Coastal Area) and the revised boundary mapping undertaken by twenty-two coastal towns prepared pursuant to C.G.S. 22a-94(f). This layer therefore does not replace the legal maps and may not be used for legal determinations.  

The Coastal Boundary layer includes a single polygon feature that represents the coastal boundary.  No other features are included in this layer.  Data is compiled at 1:24,000 scale.  Attribute information is comprised of an Av_Legend attribute and a CoastB_Flg attribute to denote the coastal boundary.  Other attributes include automatically calculated Shape_Length and Shape_Area fields.  This data is not updated.

Any regulated activity conducted within the coastal boundary by a municipal agency (i.e., plans of development, zoning regulations, municipal coastal programs and coastal site plan review (i.e., site plans submitted to zoning commission, subdivision or resubdivision plans submitted to planning commission, application for special permit or exception to the zoning or planning commissions or zoning board of appeals, variance submitted to zoning board of appeals and a referral of a municipal project)) must be conducted in a manner consistent with the requirements of the Connecticut Coastal Management Act (CMA; C.G.S. 22a-90 to 22a-113).  As the Coastal Boundary is a hybrid of the Coastal Area, all state and federal agency activities must be consistent with the requirements of the CMA.

As defined in C.G.S. 22a-94(b) the coastal boundary is a "continuous line delineated on the landward side by the interior contour elevation of the one hundred year frequency coastal flood zone, as defined and determined by the National Flood Insurance Act, as amended (USC 42 Section 4101, P.L. 93-234), or a one thousand foot linear setback measured from the mean high water mark in coastal waters, or a one thousand foot linear setback measured from the inland boundary of tidal wetlands mapped under section 22a-20, whichever is farthest inland; and shall be delineated on the seaward side by the seaward extent of the jurisdiction of the state."

The original boundary maps were created in 1979 on stable mylar overlay using the 1:24,000-scale US Geological Survey topographic quadrangle maps (mylar film format). The source for tidal wetland maps were the legal 1:24,000 maps (mylar format) adopted by the Commissioner of DEP and transformed to 1:24,000 mylar-scale maps by the Office of Policy and Management (OPM) using an accurate pantograph. OPM similarly converted FEMA's flood insurance maps (various scales) to a 1:24,000 mylar overlay. The inland extent of coastal waters was plotted on 1:24,000 USGS topographic maps following the procedures and sources described in The Boundary Between Saltwater and Freshwater in Connecticut, December 1978 prepared by the State of Connecticut, Department of Environmental Protection, Coastal Area Management Program.

The following twenty-two towns have adopted municipal coastal boundaries: Chester, Clinton, Darien, Deep River, East Haven, Essex, Fairfield, Greenwich, Groton, Guilford, Hamden, Ledyard, Madison, Milford, New Haven, New London, North Haven, Norwalk, Old Lyme, Old Saybrook, Stamford and Waterford. The coastal boundary maps for these towns may be at different scales than the original DEP draft maps and may contain minor adjustments to the boundary as permitted in C.G.S. 22a-94(f).

The Coastal Boundary layer is 1:24,000-scale data. It shows the extent of lands and coastal waters as defined by C.G.S. 22a-93(5) within Connecticut's coastal area (defined by C.G.S. 22a-94(c)).  Use this layer to show the Coastal Boundary on maps with other 1:24,000-scale data such as Coastal Area, Town Boundaries, Roads and Trails, Airports, Railroads and other base map data derived from the USGS 7.5 Minute Quadrangle Maps and compiled at a 1:24,000 scale.  Not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.)

publication date

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

None. No restrictions or legal prerequisites for using the data.  Note:  the data is not intended for maps printed at map scales greater or more detailed than 1:24,000 scale (1 inch = 2,000 feet.)  Once acquired, any modification made to the data must be noted in the metadata. When printing this information 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.

Information encoded about the Coastal Boundary is limited.  Use the Av_Legend attribute to denote the coastal boundary.  The COASTB_FLG attribute also designates the coastal boundary and is represented by a "T" (True) value.  The remaining attributes are software generated and include unique identification number (ObjectID), area (Shape_Area), and length (Shape_Length) attributes.

Coastal Boundary represented as a single polygon

This layer consists of a single polygon.  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. Logical consistency testing methods are unknown.

The Coastal Boundary layer is complete in the sense that it accurately reflects the coastal boundary as defined in Connecticut General Statutes 22a-93(5).  This data is not updated.

There is only one polygon feature in the Coastal Boundary layer.  The Av_Legend attribute value is "In coastal boundary", CoastB_Flg holds the value of "T" (True for coastal boundary), and the Shape_Area and Shape_Length attribute values are automatically calculated.  The attributes have valid values.

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. 

Coastal Boundary

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.