12 
UNRESOLVED BOUNDARY FOR DISTRICT 
OF COLUMBIA UPPER POTOMAC RIVER 
This 92-segment scheme is the agreed upon 2008 assessment segmentation. Final 
programming adjustments for boundary conditions of the jurisdictions were made in 
autumn 2007. During early winter 2007/8, an unresolved upper boundary location 
for the District of Columbia segment of the Tidal Fresh Potomac River came to light 
due to unresolved station classifications (tidal vs. nontidal) to revise the boundary. 
With assessment calculations underway, it was a nontrivial task to revise the map at 
this segment boundary which could have affected assessments already completed for 
the jurisdictions. The result, coupled with data limitations affected Washington 
District of Columbia in 2008 for a “no attainment assessment” result in their 
303d/305b listing. This boundary condition will be resolved for the next triennial 
review. 
LITERATURE CITED 
U.S. Environmental Protection Agency. 2003a. Ambient Water Quality Criteria for Dissolved 
Oxygen, Water Clarity and Chlorophyll a for the Chesapeake Bay and Its Tidal Tributaries 
(Regional Criteria Guidance) April 2003. EPA 903-R-03-002. Region III Chesapeake Bay 
Program Office, Annapolis, MD. 
U.S. Environmental Protection Agency. 2003b. Technical Support Document for Identifica¬ 
tion of Chesapeake Bay Designated Uses and Attainability. October 2003. October 2004. 
Region III Chesapeake Bay Program Office. EPA 903-R-03-004. Annapolis, MD. 
U.S. Environmental Protection Agency. 2004a. Technical Support Document for Identifica¬ 
tion of Chesapeake Bay Designated Uses and Attainability - 2004 Addendum. October 2004. 
Region III Chesapeake Bay Program Office. EPA 903-R-04-006. Annapolis. MD. 
U.S. Environmental Protection Agency. 2004b. Chesapeake Bay Program Analytical 
Segmentation Scheme: Revisions, Decisions and Rationales 1983-2003. October 2004. 
Region III Chesapeake Bay Program Office, Annapolis, MD. EPA 903-R-04-008. 
U.S. Environmental Protection Agency. 2005. Chesapeake Bay Program Analytical Segmen¬ 
tation Scheme: Revisions, Decisions and Rationales 1983-2003. 2005 Addendum. December 
2005. Region III Chesapeake Bay Program Office, Annapolis. MD. EPA 903-R-05-004. 
chapter ii 
2008 92-Segment Scheme for the Chesapeake Bay Water Quality Criteria 
