Map of Approved TMDLs in Maryland: Total Nitrogen (State TMDLs)

Please note that it may take several seconds for the map to load and refresh.

View Larger Map      Download Shapefile

About the Map

The shaded polygons in the map above represent the direct watershed areas associated with applicable WLAs for EPA-approved TMDLs in Maryland.

Related Maps

Chesapeake Bay TMDL Map: The 58 nitrogen TMDLs that comprise the Chesapeake Bay TMDL

BOD TMDL Map: Map of BOD TMDLs in Maryland

Water Quality Map for Nutrients: Information about nitrogen impairments in Maryland's waters

How to Use the Map

Clicking on a shaded polygon will display information about the TMDL for that watershed, including the title of the TMDL report, a hyperlink to that report and the date the TMDL was approved by EPA. Each shape is identified through a GIS ID number which corresponds to a record in the online TMDL search tool.

To navigate the map, use your arrow to drag and pan. Click the plus and minus buttons to zoom in and out. Enter an address in the window (top right) to zoom to a location. Clicking on "Basemap" allows the user to change the background (e.g. aerial photography, topographic coverage, etc). Clicking on “View Larger Map” will take the user to a customizable map interface where additional layers may be added.

Please direct any questions or comments concerning this map to Jeff White at or 410-537-3884.​