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Tidal Wetlands

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The New York State Department Of Environmental Conservation
Digital 1974 Tidal Wetlands Inventory

These are digital renditions of the official 1974 tidal wetlands inventory maps of the New York State Department of Environmental Conservation (DEC). They represent tidal wetlands within the marine district of New York State (Tappan Zee bridge, south to and including Staten Island, east to and including Long Island and Fishers Island). Mylar maps were scanned with a large format 50-inch Contex scanner during December 2003 and January 2004. All maps were scanned in grayscale mode at a resolution of 100 or 150 dpi as *.jpg images. The images were then post-processed using Adobe Photoshop 7.0 to illuminate tidal wetland classifications and water bodies. The maps are provided for reference purposes only. They do not represent survey quality accuracy. Since tidal wetlands are a living entity, changes may and have occurred. Some changes have been recorded and map amendments are noted at the bottom left side of the affected map; others have not been documented. Developmental activities in and adjacent to tidal wetlands fall under the purview of the Tidal Wetlands Land Use Regulations Article 25, 6 NYCRR Part 661(www.dec.state.ny.us/website/regs/661a.htm) and are regulated. Therefore, any person planning to conduct such activities must contact their DEC Regional office for confirmation and a permit application. If a permit is required the tidal wetland boundary line will be determined at the time of a field inspection and may differ from the boundary line depicted on the respective map. Regional offices are as follows:

Region 1: Nassau and Suffolk Counties www.dec.state.ny.us/website/reg1/permits.html

Region 2: The City of New York: Boroughs of Manhattan, Brooklyn, Bronx, Queens and Staten Island www.dec.state.ny.us/website/reg2/index.html find Regional permit administrator’s phone number at bottom of webpage.

Region 3: Westchester County www.dec.state.ny.us/website/reg3/index.html find Regional permit administrator’s phone number at bottom of webpage.

Viewing the Digitized Tidal Wetlands Maps and Indexes

To view the tidal wetland indexes and the tidal wetland maps use the links below: First look at the index maps to locate your area of interest. If you use your web browser wait until the entire file is downloaded, then you can save the file or view it in the browser. Wait for the magnify icon to appear in the lower fight hand corner of the image, left click the mouse to magnify the image to full scale. The image at full scale is larger than the viewing area of the browser, use the scroll bar to navigate the image. Note the 6-digit number at the bottom of some of the grids. These numbered grids represent the extent (map number) of an individual tidal wetland map. Once an area has been identified go back and select the individual tidal wetland index map representing your area of interest (index * of *). This second index will contain the individual maps. Scroll down the list of photos (*.jpg) and looking for the number representing the area of interest, select the number and the tidal wetlands maps should download. Please note the Suffolk County tidal wetlands maps have been “rough registered” in NYTM NAD27. Therefore there are additional file extensions associated with each map (*.jgw and *.txt). If you are just reviewing a map for tidal wetland locations the *.jpg is all that is necessary. The other files are for GIS users and will not work with standard photo viewing software or the web browser. At the bottom of the tidal wetlands maps are descriptions of the symbols identifying the tidal wetlands. Additional information can be found at the DEC website:

1974TWI_Index 1 of 5.jpg   This index map covers Manhattan, Staten Island, the Hudson River to the Tappan Zee bridge and Brooklyn and Queens almost to the Nassau County border line

1974TWI_Index 2 of 5.jpg  This index map covers Westchester County, a small portion of Queens County, all of Nassau county and the western portion of Suffolk County east to Babylon (south shore) and Northport (north shore)

1974TWI_Index 3 of 5.jpg   This index map covers Suffolk county from Sunken Meadow State park (north shore) and West Bayshore (south shore) east to the Forge River (south shore) and Wildwood Park (north shore)

1974TWI_Index 4 of 5.jpg  This index map covers Suffolk county from Baiting Hollow (north shore) and Center Moriches (south shore) east to Bridgehampton (south shore) and Orient Harbor (north shore)

1974TWI_Index 5 of 5.jpg  This index map covers the east end of Suffolk County from Orient and Montauk points and Fishers Island

The links below contain the individual tidal wetland maps and index maps for further reference:

Index 1 tidal wetland maps

Index 2 tidal wetlands maps

Index 3 tidal wetlands maps

Index 4 tidal wetlands maps

index 5 tidal wetlands maps

Viewing The Geo-referenced Tidal Wetlands Indexes, Maps and Shapefiles and Metadata

To view the geo-referenced tidal wetland indexes and the geo-referenced tidal wetland maps you must have GIS software or a GIS viewer. It is recommended that you download the indexes and shapefiles, place them in your GIS software and create a project. Read the metadata in order to understand the nature of the maps and criteria used to develop them. Once the project is created you can then use the index to locate your area of interest on the index maps. Locate and record the 6-digit number found at the bottom of the index map matrix. Then locate that number in link below:

1974 geo-referenced TWI_Index 1 through 5

1974 shapefiles


The link below contains all of the individual geo-referenced tidal wetland maps:

Geo-referenced tidal wetlands maps


This page was last modified on March 3, 2012
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