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GIS Data Guide
Tidal Wetlands - 1970's and 1990's 

Publisher Connecticut DEP, Office of Long Island Sound Programs
Publication Date 2002
Data Collection Scale 1:24,000
Data Collection Date See below
Update Frequency Not updated                  DEP GIS Data Downloads

1970's Tidal Wetlands

This coverage represents the historic regulatory tidal wetland boundaries, produced during the early 1970's by the State of Connecticut Department of Agriculture and Natural Resources, which defined the areas of tidal wetlands that were subject to the 1969 Tidal Wetlands Act. The regulatory tidal wetland boundaries were surveyed in the field and these boundaries were transferred to 1" = 200' (1: 24000 scale) mylars derived from black and white low altitude aerial photography. It is known that the mapping criteria did change or evolve as the surveyors became more experienced with tidal wetland delineation. It also was not unusual for controversial parcels to be omitted as a result of adverse comments received at public hearings prior to the adoption of the maps. Thus, even at the time of their adoption, the 1970's tidal wetland maps did not include all known tidal wetlands.

Tidal Wetlands of 1970's

1990's Tidal Wetlands

This coverage shows all mapped tidal wetlands across the state of Connecticut. The mapping has been compiled from two sources; the 1994 Ramsar Tidal Wetlands Mapping and the 1995 OLISP Tidal Wetlands Mapping, both produced by the State of Connecticut, Department of Long Island Sound Programs. The tidal wetland boundaries are not regulatory boundaries but should be interpreted as a guide to the location of tidal wetlands throughout the state.

The Ramsar tidal wetlands mapping extends south from Cromwell Connecticut to the mouth of the Connecticut River. 1990, 1:12,000 scale, color infrared aerial photographs were used to identify the tidal wetland boundaries. These boundaries were mapped and transposed onto a topographic map base and digitized.

The 1995 OLISP Tidal Wetlands Mapping covers all the tidal wetlands in Connecticut that were not mapped as part of the Ramsar project. The mapping was done using 1995, 1:12,000 scale, color infrared aerial photographs and 1990/91 black and white Digital Orthophotographs. Tidal wetlands were identified on the 1995 aerial photographs and then digitized in ArcEdit using the digital orthophoto as the map base. This mapping process has resulted in a very geometrically accurate map but one that does not align perfectly with the older topographic base data such as the RAMSAR mapping and much of the DEP library information such as roads and hydrography. Boundary lines are as precise as the source information permit.

NOTES: With the exception of the Connecticut River data both Ramsar and other mapping, coverage polygons have not been thoroughly verified and are still considered DRAFT quality. The tidal wetland polygons north of the Ramsar Data, on the Connecticut River, were checked by Ken Metzler of the Environmental and Geographic Information Center.

Tidal Wetlands 1990's

Theme Properties

Theme Name Tidal Wetlands 1970's or 1990's
Data Source tidalwetlands1970s [1990s] .shp
Recommended Minimum Display Scale None
Recommended Maximum Display Scale None
Recommended Label Field Av_Legend
Legend Classification Field None (single symbol)

Theme Attribute Table

Field Name Description Type Units Domain
Av_Legend Arcview Legend Generates a Legend in Arcview string "T_Wetlands", null
Class Classification Numeric Code to designate existence of wetlands integer 111, 0
Acreage Acreage Acreage of All Polygons number acres >0
Source Source Tags the Source Coverage of Each Polygon string "OLISP1995AIRPHOTOS", "RAMSAR"

Horizontal Coordinate System

Coordinate System State Plane Coordinate System of 1983
State Plane Zone Connecticut, Zone 3526
Horizontal Datum North American Datum of 1983 (NAD 83)
Map Projection Lambert Conformal Conic
Spheriod GRS 80
Map Scale 1:24,000
Map Units Feet

Point of Contact

Contact Person Howie Sternberg
Organization State of Connecticut
Department of Environmental Protection
Mailing Address 79 Elm Street
Hartford, CT 06106-5127
Phone (860) 424-3540
Fax (860) 424-4058