TMDL Maps

This page provides links to online maps and GIS downloads to assist in implementing TMDLs. The resources below include maps of every approved TMDL (categorized by pollutant) as well as shapefiles relating to the implementation process. Two separate TMDL maps are provided for nitrogen, phosphorus and sediment; one map for those TMDLs that were developed by the state, and one map for those TMDLs which are part of the 2010 Chesapeake Bay TMDLs. The geodatabase with all of the pollutant map files is available here.

TMDL Maps by Pollutant

Bacteria		Low pH
Metals		Nutrients
Polychlorinated Biphenyls (PCBs)		Pesticides
Sediment		Trash

Additional Geographic Resources for TMDL Implementation

Watershed Delineations

Chesapeake Bay Segments (view | download)
Chesapeake Bay Land-River Segments (view)
Maryland 8-Digit Watersheds (view | download)
Maryland 12-Digit Watersheds (view | download)

County Boundaries

Maryland County Boundaries (view | download)

Stormwater Delineations

Phase 6 - NPDES-Regulated Stormwater Systems (download)

Chesapeake Bay Program Phase 5 Model Files (deprecated)

2006 USGS-CBP Land-Cover (info | download)
Phase 5 - NPDES-Regulated Stormwater Systems (info | download)

Other Mapping Resources