Rock Creek (Potomac River)

Rock Creek is a free-flowing tributary of the Potomac River, which empties into the Atlantic Ocean via the Chesapeake Bay. The creek is about 33 miles (53.1 km) long, with a drainage area of about 76.5 mi² (198 km²). The last quarter-mile (402 meters) of the creek is affected by tides. [U.S. Geological Survey, Baltimore, MD, 2002. [http://pubs.usgs.gov/wri/wri024067/#pdf "Water Quality, Sediment Quality, and Stream-Channel Classification of Rock Creek, Washington, D.C., 1999-2000."] Anita L. Anderson et al. Water-Resources Investigations Report 02-4067.]

Geography

The creek rises from a spring near Laytonsville in Montgomery County, Maryland and joins the Potomac near Georgetown and the Watergate in Washington, D.C. Beginning in the Derwood–Rockville area in Maryland, the creek flows through [http://www.mc-mncppc.org/Parks/facilities/regional_parks/rockcreek/index.shtm Rock Creek Regional Park] southward to the Washington, D.C. boundary. About 9 miles (14.5 km) of the creek flow though Rock Creek Park in Washington, D.C., where it is fed by several small creeks — Piney Branch, Pinehurst Branch, Broad Branch, Soapstone Branch, and Luzon Branch — and numerous storm sewers.

The Maryland portion of the watershed comprises the second-largest watershed in Montgomery County, about 60 mi². About 21 percent of the creek's watershed is in Washington, D.C. Total land usage in the watershed is 896 acres (3.6 km²) of wetlands or water, 22,272 acres (90 km²) of residential and commercial areas, 15,488 acres (63 km²) of forest or grasslands, and 10,304 acres (42 km²) of agricultural areas. The creek has a fairly steep gradient, with rapid changes in elevation. The man-made Lake Needwood is located on the creek, north of Rockville.

Water quality and restoration

In Maryland, most of the northern Rock Creek watershed has good to excellent water quality, according to studies conducted by the county government. In 2004, to preserve water quality in partially developed areas, the county imposed restrictions on development (i.e., designation of a "Special Protection Area") in parts of this sub-watershed. [Montgomery County Department of Environmental Protection, Rockville, MD. [http://www.montgomerycountymd.gov/content/dep/SPA/2005reportspa.pdf "Special Protection Area Program Annual Report 2005."] January 2007.] The southern portion of the Maryland watershed is highly urbanized. The majority of this portion of the creek and its tributaries has poor water quality. [Montgomery County Department of Environmental Protection, Rockville, MD. [http://www.montgomerycountymd.gov/content/dep/restoration/Action.pdf "Rock Creek Watershed Restoration Action Plan, July 2001."] ] The county is managing several stream restoration projects throughout the watershed. [Montgomery County Department of Environmental Protection, Rockville, MD. [http://www.montgomerycountymd.gov/deptmpl.asp?url=/content/dep/restoration/home.asp#factsheets "Watershed Restoration Factsheets."] ]

The D.C. segment of Rock Creek also has poor water quality. In addition to typical urban stormwater pollution problems such as runoff from streets and other impervious surfaces, the creek has high bacteria levels due to combined sewer overflows. [U.S. Environmental Protection Agency. Philadelphia, PA. February 27, 2004. [http://ddoe.dc.gov/ddoe/frames.asp?doc=/ddoe/lib/ddoe/tmdl/yrc_bact_tmdl_dr.pdf "Decision Rationale: Total Maximum Daily Loads for Fecal Coliform Bacteria in Rock Creek."] ] The D.C. government, which has a stormwater discharge permit issued by the United States Environmental Protection Agency, is improving its stormwater management to improve water quality in Rock Creek. [District of Columbia. Department of the Environment. August 17, 2007. [http://ddoe.dc.gov/ddoe/frames.asp?doc=/ddoe/lib/ddoe/stormwaterdiv/Imp.Plan07.pdf "2007 Implementation Plan: District of Columbia NPDES Permit No. DC0000221 Municipal Separate Storm Sewer System."] ]

In December 2003, the National Park Service announced plans to remove or bypass eight fish barriers in the creek; activities include adding a fish ladder to bypass the 1905 Peirce Mill Dam, modifying historic fords, and removing abandoned sewage lines and fords. The effort is designed to restore American shad, river herring, and other migratory fish to the creek and their historic upriver spawning grounds.

Tributaries

Tributaries of Rock Creek are listed in order from the mouth upstream.

In D.C.:
*Dumbarton Oaks
*Normanstone Creek
*Klingle Valley Creek
*Piney Branch
*Melvin Hazen Valley Branch
*Broad Branch
**Soapstone Branch
*Luzon Branch
*Pinehurst Branch
*Fenwick Branch
**Portal Branch

In Maryland:
*Donnybrook Tributary
*Coquelin Run
*Capitol View Tributary
*Kensington Heights Branch
*Stoney Creek
*Alta Vista Tributary (formerly Bethesda Run)
*Luxmanor Branch
*Stoneybrook Tributary
*Josephs Branch
*Turkey Branch
*Sycamore Creek
*Croydon Park Tributary
*Southlawn Branch
*North Branch (Lake Bernard Frank)
*Lake Needwood (in-line on Rock Creek)
*Crabbs Branch
*Mill Creek
*Pope Farm Branch
*Airpark Road Branch

ee also

*List of District of Columbia rivers
*List of Maryland rivers
*Rock Creek and Potomac Parkway
*Tidewater Lock

References

External links

* [http://www.mc-mncppc.org/Parks/facilities/regional_parks/rockcreek/index.shtm Rock Creek Regional Park (Maryland)]
* [http://www.friendsofrockcreek.org Friends of Rock Creek's Environment]
* [http://www.montgomerycountymd.gov/deptmpl.asp?url=/content/dep/csps/watersheds/csps/html/rock.asp Countywide Stream Protection Strategy: Rock Creek Watershed] Montgomery County Department of Environmental Protection