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About the Map

The shaded polygons in the map above represent Maryland’s 8-digit scale watersheds. The delineation breaks the state up into 138 watersheds whose boundaries generally represent drainage divides between 3rd order rivers or streams. These watersheds are identified via an 8-digit numeric code. The 8-digit scale is the most common management scale for watersheds across the state and therefore is the scale at which most of Maryland’s local TMDLs are developed. Watersheds in this map relate to TMDLs and WLAs in the applicable queries via an 8-digit watershed name identified in the location description.

Related Maps

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

How to Use the Map

Clicking on a shaded polygon will display information about that 8-digit watershed, including the watershed name and ID.

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 questions or comments concerning Maryland's TMDL Program to mde.tmdlcoordinator@maryland.gov at (410) 537-3818.​​