Water Quality Analyses (WQA) with EPA Concurrence of MDE's Findings: Cabin John Creek

The Cabin John Creek watershed is located in southern Montgomery County, Maryland, just northwest of Washington, DC.  The Cabin John Creek watershed encompasses 16,500 acres. The headwaters of Cabin John Creek originate in the City of Rockville. The creek flows south about 10 miles, passing under Interstate 270, through Cabin John Regional Park under the Capital Beltway (I-495), and the historic Cabin John Bridge to its confluence with the Potomac River near the towns of Cabin John and Glen Echo.  The watershed is bounded by Rockville Pike (Rte. 355) and Old Georgetown Pike (Rte. 187) to the east and Falls Road (Rte. 189) to the west.  The major tributaries of the Creek are Bogley Branch, Booze Creek, Buck Branch, Congressional Branch, Ken Branch, Old Farm Branch, Snakeden Branch and Thomas Branch (also called Beltway Branch).  

The waters of Cabin John Creek (MD basin code 02140207), located in Montgomery County, have been identified on the Integrated Report under Category 5 as impaired by nutrients (1996), sediments (1996), and impacts to biological communities (2002).  All impairments are listed for non-tidal streams.  The 1996 suspended sediment listing was refined in the 2008 Integrated Report to a listing for total suspended solids.  Similarly, the 1996 nutrients listing were refined in the 2008 Integrated Report and phosphorus was identified as the specific impairing substance.  Consequently, for the purpose of the report available below, the terms “nutrients” and “phosphorus” will be used interchangeably.  The listings for sediments and impacts to biological communities will be addressed separately at a future date.


Water Quality Analysis of Eutrophication for the Cabin John Creek Basin in Montgomery County, Maryland

(Concurrence September 24, 2009)

EPA's Decision Letter EPA's Decision Letter

Main Report 

WQA_Cabin_John_Creek_eutro.pdf (481KB)

Comment Response Document

CRD_Cabin_John_Creek_eutro.pdf (7KB)
Additional Supporting Information
Biological Stressor Identification Cabin John Creek Watershed Report BSID CabinJohnCreek.pdf (588KB)

Biological Stressor Identification Methodology Report

BSID Methodology.pdf (459KB)

Contact Information

Please direct questions or comments concerning this project to Maryland's TMDL Program at (410) 537-3818.