Maps

The 92-segment scheme for the Chesapeake Bay and its tidal tributaries used for dissolved oxygen and water clarity assessments in the most recent 303d/305b listing efforts of the four Bay tidal jurisdictions is documented here. The 92-segment scheme was derived from 1) the 2003 published 78-segment scheme with the addition of jurisdictional boundary lines imposed to create 89-segments, then 2) additionally includes only split segments agreed upon for the tidal James and Potomac rivers.

The 2003 Chesapeake Bay Program Segmentation Scheme is a revision of the 2000 version that incorporates four changes: the addition of a new segment (ANATF) that separates the Anacostia River from the rest of the Potomac Tidal Fresh (POTTF) segment, the merger of two Elizabeth River segments (ELIMH and ELIPH into ELIPH) and the small segment boundary location changes between Mattaponi River segments MPNTF and MPNOH and between Choptank River segments CHOTF and CHOOH. Further information about the 2003 Chesapeake Bay Program Segmentation Scheme can be found at http://www.chesapeakebay.net/segmentscheme.htm

n order to divide the model domain into county based land segments, a finer segmented river reach network and associated watersheds.This data set is an ArcGIS shapefile depicting land segments in the Chesapeake Bay Watershed and adjacent states of New York, Pennsylvania, Maryland, West Virginia, Delaware, Virginia as well as North Carolina and Tennessee (not shown). Land segmentation was based on county boundaries represented by a 1:100,000-scale digital dataset. Fifty of the 254 counties and incorporated cities in the model region were divided on the basis of physiography and topography, producing a total of 310 land segments. The data are projected to the UTM grid coordinate system - Zone 18 NAD83. Land and watersheds segments were intersected to create land-watershed segments for the model. The land segments are to be used with the Chesapeake Bay Regional Watershed Model to represent the county political boundaries and areas of differing physiography and topography in the study area.

Final 2003 Phase 4.3 Chesapeake Bay Watershed Model Segments. The intersection of counties found in the study are roughly 8-digit HUC sized watersheds used in conjunction with the HSPF based Phase 4.3 Chesapeake Bay Watershed Model for simulation of nutrient and sediment delivery to the tidal waters of the Chesapeake Bay.