Maps

The Waterbody Inventory/Priority Waterbodies List (WI/PWL) is an inventory of the state's surface water quality. The dataset provides a summary of general water quality conditions, tracks the degree to which a water body supports its designated uses, and monitors progress toward the identification and resolution of water quality problems, pollutants, and sources. The category of No Known Impact represents 'segments where monitoring data and information indicate that there are no use restrictions or other water quality impacts/issues.'

Small, non-tidal watersheds with the largest population of rare, threatened and endangered aquatic animals.

Small, healthy non-tidal watersheds that are used for long term monitoring to detect changes from global climate change and from other natural phenomena.

Watersheds that support coldwater dependent species.

Large Watersheds that provide important spawning and nursery habitat for commercial and recreational anadromous fisheries.

Highest ranking (top 20th percentile) small watersheds important for protecting water quality based on biophysical characteristics.

Highest ranking small watersheds that support high quality coastal habitat, natural resources and critical fisheries spawning and nursery areas in tidal waters and near-shore areas.

Average yields for total sediment (TS) were estimated for the last five years at 65 sites and classified into thirds as high, medium, and low. While the distribution was spatially variable, there were some general patterns in location. Generally, spatial patterns not very discernible for sediment except for higher yields in the middle of the watershed, areas where total nitrogen and total phosphorus yields are also highest. The lowest yields are generally in the western areas of the Bay watershed, an area dominated by forests and on the Eastern Shore of Maryland and Delaware.

Average yields for total phosphorus (TP) were estimated for the last five years at 65 sites and classified into thirds as high, medium, and low. While the distribution was spatially variable, there were some general patterns in location. Generally, higher yields for TP are dominant in the middle of the watershed, areas that also coincide with large urban and agricultural land uses. The lowest yields are generally in the western areas of the Bay watershed, an area dominated by forests.

Average yields for total nitrogen (TN) were estimated for the last five years at 65 sites and classified into thirds as high, medium, and low. While the distribution was spatially variable, there were some general patterns in location. Generally, higher yields for TN are dominant in the middle of the watershed, areas that also coincide with large urban and agricultural land uses. The lowest yields are generally in the Virginia watersheds.