Map of Maryland's Chesapeake Bay Land-River Segments - Phase 5


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About the Map

The shaded polygons in the map above represent the Chesapeake Bay Program watershed model land-river segments in Maryland. The delineation breaks the state up into 686 individual watersheds, which have an average size of 9,000 acres. The segments are at a scale smaller than Maryland’s 8-Digit watersheds; however, the segments were delineated so that they aggregated to Maryland’s 8-Digit watersheds, thus remaining consistent with the State’s watershed planning level scale. The segments are identified via a unique code (FIPSCATWAT), which is a combination of the county FIPS code (the land segment) and a watershed/river segment code. The land-river segment represents the finest scale at which Chesapeake Bay Phase 5 watershed model nutrient and sediment loads are available. The Chesapeake Bay TMDL and its associated allocations were developed at the Chesapeake Bay Segment scale, which divides Maryland into 58 watersheds. The land-river segments also aggregate to these Chesapeake Bay Segments.

Related Maps

Chesapeake Bay Phase 6 Segmentation​: Phase 6 version of the Chesapeake Bay Model segmentation.

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