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
The list below shows the types of pollutants for which the State has developed TMDLs. To view TMDL coverage on the
TMDL webmap, select the pollutant from the Table of Contents and turn on the corresponding TMDL layer. Pollutant layers are grouped by type.
- Bacteria (fecal coliform, E.coli)
- Low pH
- Metals (aluminum, iron, mercury)
- Nutrients [nitrogen, phosphorus, biochemical oxygen demand (BOD)]
- Polychlorinated Biphenyls (PCBs)
- Pesticides (chlordane)
- Sediment
- Trash
Additional Geographic Resources for TMDL Implementation
Watershed Delineations
County Boundaries
Stormwater Delineations
- Phase 6 - NPDES-Regulated Stormwater Systems (download)
Chesapeake Bay Program Phase 5 Model Files (deprecated)
Other Mapping Resources
