Rock Creek (Potomac River)

From Wikipedia, the free encyclopedia

Rock Creek, Washington, D.C.

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 m) of the creek is affected by tides.^[1]

[edit] 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 Rock Creek Regional Park southward to the D.C. boundary. About 9 miles (14.5 km) of the creek flow though Rock Creek Park in Washington, 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. 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.

[edit] Water quality and restoration

Rock Creek in Chevy Chase, Maryland. Stream bank shows downcutting (vertical erosion) due to excessive stormwater runoff.

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.^[2] 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.^[3] The county is managing several stream restoration projects throughout the watershed.^[4]

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 (CSOs).^[5] 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.^[6] In 2009, the District of Columbia Water and Sewer Authority began a project to replace portions of the combined sewer with separate storm sewers. The project, which is expected to eliminate the CSO-related problems in the creek, is scheduled to be completed in 2011.^[7]

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. It is estimated that 2 million fish migrate up the creek each year.^{[citation needed]}

[edit] 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

[edit] See also

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

[edit] References

[edit] External links

Washington, D.C. portal

• Rock Creek Regional Park (Maryland)
• Friends of Rock Creek's Environment
• Countywide Stream Protection Strategy: Rock Creek Watershed Montgomery County Department of Environmental Protection