Rock Creek is a free-flowing

tributary A tributary, or affluent, is a stream or river that flows into a larger stream or main stem (or parent) river or a lake. A tributary does not flow directly into a sea or ocean. Tributaries and the main stem river drain the surrounding drai ...

of the

Potomac River The Potomac River () drains the Mid-Atlantic United States, flowing from the Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Dataset high-resolution flowline dataThe National Map. Retrieved Augu ...

that empties into the

Atlantic Ocean The Atlantic Ocean is the second-largest of the world's five oceans, with an area of about . It covers approximately 20% of Earth's surface and about 29% of its water surface area. It is known to separate the " Old World" of Africa, Europe ...

via the

Chesapeake Bay The Chesapeake Bay ( ) is the largest estuary in the United States. The Bay is located in the Mid-Atlantic region and is primarily separated from the Atlantic Ocean by the Delmarva Peninsula (including the parts: the Eastern Shore of Maryland / ...

. The creekU.S. Geological Survey. National Hydrography Dataset high-resolution flowline data
The National Map
accessed August 15, 2011 drains about . Its final quarter-mile (400 m) is affected by

tide Tides are the rise and fall of sea levels caused by the combined effects of the gravitational forces exerted by the Moon (and to a much lesser extent, the Sun) and are also caused by the Earth and Moon orbiting one another. Tide tables ...

Geography

Course

Lake Needwood Rock Creek Regional Park 13

The creek rises from a culvert under Dorsey Road at the north edge of Laytonsville Golf Course in Montgomery County,

Maryland Maryland ( ) is a state in the Mid-Atlantic region of the United States. It shares borders with Virginia, West Virginia, and the District of Columbia to its south and west; Pennsylvania to its north; and Delaware and the Atlantic Ocean t ...

. A dam forms a small lake near its source. After exiting the golf course, Rock Creek flows between residential developments until it meets Agricultural History Farm Park, where the Upper Rock Creek Trail starts. It flows underneath the

Intercounty Connector Maryland Route 200 (MD 200), also known as the Intercounty Connector or ICC, is an , six-lane toll road in the U.S. state of Maryland. A controlled-access highway, it connects Gaithersburg in Montgomery County and Laurel in Prince George's Cou ...

, which crosses it on a large arch bridge visible from the trail. It then flows into

Lake Needwood Lake Needwood is a reservoir in Derwood, Maryland, United States. Located east of Rockville, in the eastern part of Montgomery County, it is situated on Rock Creek. The lake was created by damming Rock Creek in 1965 with the goal of providing ...

at Rock Creek Regional Park in Maryland's Derwood– Rockville area. South of the Lake Needwood Dam, Rock Creek flows in a deep gorge and is paralleled by the main Rock Creek Trail, and is joined by the North Branch Rock Creek. It exits the gorge near the Twinbrook neighborhood of Rockville and the

Parklawn Memorial Cemetery The Wilkins Estate is a historic estate in Rockville, Maryland, built in 1916 by Robert Crew Wilkins, later an executive of the Wilkins Coffee Co. (later a part of Maxwell House coffee), founded in 1923 in Washington, D.C., by a relation, John ...

. At North Kensington,

Beach Drive A beach is a landform alongside a body of water which consists of loose particles. The particles composing a beach are typically made from rock, such as sand, gravel, shingle, pebbles, etc., or biological sources, such as mollusc shell ...

begins to parallel the creek. The creek eventually crosses the Capital Beltway and later reaches the Washington, D.C., border. The creek flows for about through Rock Creek Park in Washington, where it is fed by several small creeks (

Piney Branch Piney Branch is a tributary of Rock Creek in Washington, D.C. It is the largest tributary located entirely within the Washington city limits. Course Located in the Northwest quadrant of Washington, D.C., the stream flows next to Piney Branch Pa ...

, Pinehurst Branch, Broad Branch, Soapstone Branch, and Luzon Branch) and numerous

storm sewers A storm drain, storm sewer (United Kingdom, U.S. and Canada), surface water drain/sewer (United Kingdom), or stormwater drain ( Australia and New Zealand) is infrastructure designed to drain excess rain and ground water from impervious surface ...

. The Chesapeake and Ohio Canal joins Rock Creek in Georgetown; the creek's mouth is the canal's eastern terminus. Just below this confluence, the Canal Company in 1831 completed a mole, causeway, and waste weir. This area, which the company dubbed "Rock Creek Basin", silted up and was dredged several times for the Canal's use. The creek (and the canal) empty into the Potomac River at the Tidewater Lock near the Watergate complex.

Watershed

The Maryland portion of the

watershed Watershed is a hydrological term, which has been adopted in other fields in a more or less figurative sense. It may refer to: Hydrology * Drainage divide, the line that separates neighbouring drainage basins * Drainage basin, called a "watershe ...

comprises the second-largest watershed in Montgomery County, about . About 21 percent of the creek's watershed is in Washington. Total land usage in the watershed is of wetlands or water, of residential and commercial areas, of forest or grasslands, and of agricultural areas. The creek has a fairly steep gradient, with rapid changes in elevation. The man-made

is located on the creek, north of Rockville. The conditions at the Rock Creek are monitored by the

USGS The United States Geological Survey (USGS), formerly simply known as the Geological Survey, is a scientific agency of the United States government. The scientists of the USGS study the landscape of the United States, its natural resources, ...

Water quality and restoration

In Maryland, most of the northern Rock Creek watershed has good to excellent

water quality Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...

, 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 "Special Protection Areas") in parts of this sub-watershed. The southern portion of the Maryland watershed is highly urbanized. Most of this portion of the creek and its tributaries have poor water quality. As of 2018 the county has completed several

stream restoration Stream restoration or river restoration, also sometimes referred to as river reclamation, is work conducted to improve the environmental health of a river or stream, in support of biodiversity, recreation, flood management and/or landscape developm ...

projects throughout the watershed, and has additional projects planned or under construction. The D.C. segment of Rock Creek also has poor water quality. In addition to typical urban

stormwater Stormwater, also spelled storm water, is water that originates from precipitation ( storm), including heavy rain and meltwater from hail and snow. Stormwater can soak into the soil ( infiltrate) and become groundwater, be stored on depressed l ...

pollution Pollution is the introduction of contaminants into the natural environment that cause adverse change. Pollution can take the form of any substance (solid, liquid, or gas) or energy (such as radioactivity, heat, sound, or light). Pollutants, th ...

problems such as

runoff Runoff, run-off or RUNOFF may refer to: * RUNOFF, the first computer text-formatting program * Runoff or run-off, another name for bleed, printing that lies beyond the edges to which a printed sheet is trimmed * Runoff or run-off, a stock marke ...

from streets and other impervious surfaces, the creek has high

bacteria Bacteria (; singular: bacterium) are ubiquitous, mostly free-living organisms often consisting of one biological cell. They constitute a large domain of prokaryotic microorganisms. Typically a few micrometres in length, bacteria were am ...

levels due to leaking sewer pipes and combined sewer overflows (CSOs). The D.C. government, which has a stormwater discharge permit from the

United States Environmental Protection Agency The Environmental Protection Agency (EPA) is an independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon proposed the establishment of EPA on July 9, 1970; it ...

, is improving its stormwater management to raise water quality in Rock Creek. In 2009, the District of Columbia Water and Sewer Authority began a planned two-year effort to replace portions of the combined sewer with separate storm sewers, and so eliminate CSO-related problems in the creek. As of 2021, the bacteria levels in the creek remained dangerously high due to the leaking sewer pipes, even during dry weather, and the public has been warned not to wade into the creek. Fish species observed in Rock Creek and its tributaries include eastern blacknose dace, bluntnose minnow, yellow bullhead, satinfin shiner, swallowtail shiner, longnose dace, and

American eel The American eel (''Anguilla rostrata'') is a facultative catadromous fish found on the eastern coast of North America. Freshwater eels are fish belonging to the elopomorph superorder, a group of phylogenetically ancient teleosts. The Amer ...

Restoration projects

In 2006, the

National Park Service The National Park Service (NPS) is an agency of the United States federal government within the U.S. Department of the Interior that manages all national parks, most national monuments, and other natural, historical, and recreational properti ...

finished a project to remove or bypass eight fish barriers in the creek by 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 The American shad (''Alosa sapidissima'') is a species of anadromous clupeid fish naturally distributed on the North American coast of the North Atlantic, from Newfoundland to Florida, and as an introduced species on the North Pacific coast. Th ...

river herring ''Alosa'' is a genus of fish, the river herrings, in the family Clupeidae. Along with other genera in the subfamily Alosinae, they are generally known as shads. tp://ftp.fao.org/docrep/fao/009/ac482e/ac482e27.pdf Subfamily AlosinaeFAO Fisheri ...

, and other migratory fish to the creek and their historic upriver spawning grounds. An estimated two million fish migrate up the creek each year. The D.C. government completed a restoration project on the Milkhouse Run and Bingham Run tributaries in 2013. As of 2014, ongoing restoration projects in the watershed include the Broad Branch and Klingle Run tributaries.District of Columbia, Dept. of Transportation (2014-01-16)
"Klingle Valley Trail Public Meeting."
/ref>

Tributaries

(Listed in order from the mouth upstream) ;In D.C. *Dumbarton Oaks *Normanstone Creek *Klingle Valley Creek (also called Klingle Creek, Klingle Run) *

*Melvin Hazen Valley Branch *Broad Branch **Soapstone Branch *Luzon Branch *Milkhouse Run *Bingham Run * 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 *Williamsburg Run *North Branch (

Lake Bernard Frank Lake Bernard Frank (also Lake Frank), is a reservoir on the North Branch of Rock Creek in Derwood, Maryland, U.S., just east of Rockville. In the late 1960s it was renamed after Bernard Frank, a wilderness activist and a co-founder of The ...

) *

(in-line on Rock Creek) *Crabbs Branch *Mill Creek *Pope Farm Branch *Airpark Road Branch

References

External links

* Montgomery County: *
Overview of Rock Creek Watershed
*
Rock Creek Watershed Implementation Plan (2012)
- Stormwater management * Rock Creek Park: *
Environmental Inventory & Monitoring
* Volunteer stewardship organization: *
Rock Creek Conservancy
{{authority control Rivers of Washington, D.C. Rivers of Maryland Tributaries of the Potomac River Rivers of Montgomery County, Maryland Rock Creek and Potomac Parkway Rock Creek Park