Washington Aqueduct
Encyclopedia
The Washington Aqueduct is an aqueduct
that provides the public water supply
system serving Washington, D.C.
, and parts of its suburbs. One of the first major aqueduct projects in the United States
, the Aqueduct was commissioned by Congress
in 1852, and construction began in 1853 under the supervision of Montgomery C. Meigs
and the US Army Corps of Engineers (which still owns and operates the system). Portions of the Aqueduct went online on January 3, 1859, and the full pipeline began operating in 1864. The system has been in continuous use ever since. It is listed as a National Historic Landmark
, and the Union Arch Bridge
within the system is listed as a Historic Civil Engineering Landmark.
which connects the system's dam
at Great Falls with the Dalecarlia Reservoir
on the border with Montgomery County, Maryland
. The pipeline runs along what is now MacArthur Boulevard
, traversing some of the higher cliffs along the Potomac River
.
The Union Arch Bridge carries the pipeline and MacArthur Boulevard over Cabin John Creek
and the Cabin John Parkway
near the community of Cabin John, Maryland
. This bridge was the longest masonry
arch bridge
in the world for 40 years after its completion.
Water from Dalecarlia also flows on to the Georgetown Reservoir
in Georgetown
. From there, some of the waters flow to the McMillan Reservoir
through the Washington City Tunnel.
The system originally used a single pipe for water delivery, and did not have any water treatment
plants, relying instead on the reservoir
s to act as settling basin
s. By the turn of the 20th century, however, Washington's growth and the high amount of sediment
in the Potomac's water kept the reservoirs from doing their jobs well, and so the first treatment plant, a massive slow sand filter
bed system, was installed at McMillan Reservoir, and was completed in 1905. The regular use of chlorine
as a disinfectant began in 1923 at the McMillan plant. The McMillan plant was not replaced until 1985, when a rapid sand filter
plant was opened adjacent to it. Efforts are under way to redevelop the land the slow sand plant used, while maintaining some of the plant's sand silos
for historical purposes.
In the 1920s, the Aqueduct was upgraded with the addition of a second pipe from Great Falls to Dalecarlia, along with several new reservoirs and a pumping station, and a rapid sand filter plant was built at Dalecarlia Reservoir, which went online in 1927. The Dalecarlia plant is the larger of the two plants in the system, having been upgraded in the 1950s, and is the plant that serves the Virginia
communities that use the Aqueduct. The Corps built an additional intake and pumping station at Little Falls in 1959.
water supplier. The communities it serves are responsible for billing customers and managing water mains. The service area is:
Aqueduct
An aqueduct is a water supply or navigable channel constructed to convey water. In modern engineering, the term is used for any system of pipes, ditches, canals, tunnels, and other structures used for this purpose....
that provides the public water supply
Water supply
Water supply is the provision of water by public utilities, commercial organisations, community endeavours or by individuals, usually via a system of pumps and pipes...
system serving Washington, D.C.
Washington, D.C.
Washington, D.C., formally the District of Columbia and commonly referred to as Washington, "the District", or simply D.C., is the capital of the United States. On July 16, 1790, the United States Congress approved the creation of a permanent national capital as permitted by the U.S. Constitution....
, and parts of its suburbs. One of the first major aqueduct projects in the United States
United States
The United States of America is a federal constitutional republic comprising fifty states and a federal district...
, the Aqueduct was commissioned by Congress
United States Congress
The United States Congress is the bicameral legislature of the federal government of the United States, consisting of the Senate and the House of Representatives. The Congress meets in the United States Capitol in Washington, D.C....
in 1852, and construction began in 1853 under the supervision of Montgomery C. Meigs
Montgomery C. Meigs
Montgomery Cunningham Meigs was a career United States Army officer, civil engineer, construction engineer for a number of facilities in Washington, D.C., and Quartermaster General of the U.S. Army during and after the American Civil War....
and the US Army Corps of Engineers (which still owns and operates the system). Portions of the Aqueduct went online on January 3, 1859, and the full pipeline began operating in 1864. The system has been in continuous use ever since. It is listed as a National Historic Landmark
National Historic Landmark
A National Historic Landmark is a building, site, structure, object, or district, that is officially recognized by the United States government for its historical significance...
, and the Union Arch Bridge
Union Arch Bridge
The Union Arch Bridge, also called the "Cabin John Bridge," is a historic masonry structure in Cabin John, Maryland. It was designed as part of the Washington Aqueduct and as a roadway bridge. The bridge construction began in 1857 and was completed in 1864. The roadway surface was added later...
within the system is listed as a Historic Civil Engineering Landmark.
Design and facilities
The centerpiece of the Aqueduct is a 12-mile (19 km) pipelinePipeline transport
Pipeline transport is the transportation of goods through a pipe. Most commonly, liquids and gases are sent, but pneumatic tubes that transport solid capsules using compressed air are also used....
which connects the system's dam
Dam
A dam is a barrier that impounds water or underground streams. Dams generally serve the primary purpose of retaining water, while other structures such as floodgates or levees are used to manage or prevent water flow into specific land regions. Hydropower and pumped-storage hydroelectricity are...
at Great Falls with the Dalecarlia Reservoir
Dalecarlia Reservoir
Dalecarlia Reservoir is the primary storage basin for drinking water in Washington, D.C., fed by an underground aqueduct in turn fed by low dams which divert portions of the Potomac River near Great Falls and Little Falls....
on the border with Montgomery County, Maryland
Montgomery County, Maryland
Montgomery County is a county in the U.S. state of Maryland, situated just to the north of Washington, D.C., and southwest of the city of Baltimore. It is one of the most affluent counties in the United States, and has the highest percentage of residents over 25 years of age who hold post-graduate...
. The pipeline runs along what is now MacArthur Boulevard
MacArthur Boulevard
MacArthur Boulevard may refer to:*MacArthur Boulevard , a road that parallels the C&O Canal in Washington, D.C. and Montgomery County, Maryland...
, traversing some of the higher cliffs along the Potomac River
Potomac River
The Potomac River flows into the Chesapeake Bay, located along the mid-Atlantic coast of the United States. The river is approximately long, with a drainage area of about 14,700 square miles...
.
The Union Arch Bridge carries the pipeline and MacArthur Boulevard over Cabin John Creek
Cabin John Creek (Potomac River)
Cabin John Creek is a tributary stream of the Potomac River in Montgomery County, Maryland. The watershed covers an area of . The headwaters of the creek originate in the city of Rockville, and the creek flows southward for to the Potomac River....
and the Cabin John Parkway
Cabin John Parkway
Cabin John Parkway is an automobile parkway in the U.S. state of Maryland. The parkway runs from Clara Barton Parkway in Cabin John north to the Capital Beltway in Bethesda...
near the community of Cabin John, Maryland
Cabin John, Maryland
Cabin John is a census-designated place and an unincorporated area in Montgomery County, Maryland, United States. The placename is a corruption of its original name of "Captain John's Mills."-Geography:...
. This bridge was the longest masonry
Masonry
Masonry is the building of structures from individual units laid in and bound together by mortar; the term masonry can also refer to the units themselves. The common materials of masonry construction are brick, stone, marble, granite, travertine, limestone; concrete block, glass block, stucco, and...
arch bridge
Arch bridge
An arch bridge is a bridge with abutments at each end shaped as a curved arch. Arch bridges work by transferring the weight of the bridge and its loads partially into a horizontal thrust restrained by the abutments at either side...
in the world for 40 years after its completion.
Water from Dalecarlia also flows on to the Georgetown Reservoir
Georgetown Reservoir
The Georgetown Reservoir is a reservoir that is part of the water supply and treatment infrastructure for the District of Columbia. It is located in the Palisades neighborhood of Washington, D.C., approximately two miles downstream from the Maryland–D.C. boundary.The reservoir was built by the...
in Georgetown
Georgetown, Washington, D.C.
Georgetown is a neighborhood located in northwest Washington, D.C., situated along the Potomac River. Founded in 1751, the port of Georgetown predated the establishment of the federal district and the City of Washington by 40 years...
. From there, some of the waters flow to the McMillan Reservoir
McMillan Reservoir
The McMillan Reservoir is a reservoir in Washington, D.C. that supplies the majority of the city's municipal water. It was originally called the Howard University Reservoir or the Washington City Reservoir, and was completed in 1902 by the U.S. Army Corps of Engineers. The reservoir was built on...
through the Washington City Tunnel.
System expansion
Water treatment
Water treatment describes those processes used to make water more acceptable for a desired end-use. These can include use as drinking water, industrial processes, medical and many other uses. The goal of all water treatment process is to remove existing contaminants in the water, or reduce the...
plants, relying instead on the reservoir
Reservoir
A reservoir , artificial lake or dam is used to store water.Reservoirs may be created in river valleys by the construction of a dam or may be built by excavation in the ground or by conventional construction techniques such as brickwork or cast concrete.The term reservoir may also be used to...
s to act as settling basin
Settling basin
A settling basin, settling pond or decant pond are devices used to treat turbidity in industrial wastewater. The basins are used to control water pollution in diverse industries such as agriculture, aquaculture, and mining....
s. By the turn of the 20th century, however, Washington's growth and the high amount of sediment
Sediment
Sediment is naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of fluids such as wind, water, or ice, and/or by the force of gravity acting on the particle itself....
in the Potomac's water kept the reservoirs from doing their jobs well, and so the first treatment plant, a massive slow sand filter
Slow sand filter
Slow sand filters are used in water purification for treating raw water to produce a potable product. They are typically 1 to 2 metres deep, can be rectangular or cylindrical in cross section and are used primarily to treat surface water...
bed system, was installed at McMillan Reservoir, and was completed in 1905. The regular use of chlorine
Chlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
as a disinfectant began in 1923 at the McMillan plant. The McMillan plant was not replaced until 1985, when a rapid sand filter
Rapid sand filter
The rapid sand filter or rapid gravity filter is a type of filter used in water purification and is commonly used in municipal drinking water facilities as part of a multiple-stage treatment system...
plant was opened adjacent to it. Efforts are under way to redevelop the land the slow sand plant used, while maintaining some of the plant's sand silos
Storage silo
A silo is a structure for storing bulk materials. Silos are used in agriculture to store grain or fermented feed known as silage. Silos are more commonly used for bulk storage of grain, coal, cement, carbon black, woodchips, food products and sawdust. Three types of silos are in widespread use...
for historical purposes.
In the 1920s, the Aqueduct was upgraded with the addition of a second pipe from Great Falls to Dalecarlia, along with several new reservoirs and a pumping station, and a rapid sand filter plant was built at Dalecarlia Reservoir, which went online in 1927. The Dalecarlia plant is the larger of the two plants in the system, having been upgraded in the 1950s, and is the plant that serves the Virginia
Virginia
The Commonwealth of Virginia , is a U.S. state on the Atlantic Coast of the Southern United States. Virginia is nicknamed the "Old Dominion" and sometimes the "Mother of Presidents" after the eight U.S. presidents born there...
communities that use the Aqueduct. The Corps built an additional intake and pumping station at Little Falls in 1959.
Operations and service area
The Aqueduct is a wholesaleWholesale
Wholesaling, jobbing, or distributing is defined as the sale of goods or merchandise to retailers, to industrial, commercial, institutional, or other professional business users, or to other wholesalers and related subordinated services...
water supplier. The communities it serves are responsible for billing customers and managing water mains. The service area is:
- Washington, D.C., and most of the federal installations in the city (via DCWASADistrict of Columbia Water and Sewer AuthorityThe District of Columbia Water and Sewer Authority provides drinking water, sewage collection and wastewater treatment in Washington, D.C., USA. DC Water also provides wholesale wastewater treatment services to several adjoining municipalities in Maryland and Virginia...
) - Arlington County, VirginiaArlington County, VirginiaArlington County is a county in the Commonwealth of Virginia. The land that became Arlington was originally donated by Virginia to the United States government to form part of the new federal capital district. On February 27, 1801, the United States Congress organized the area as a subdivision of...
- The city of Falls Church, VirginiaFalls Church, VirginiaThe City of Falls Church is an independent city in Virginia, United States, in the Washington Metropolitan Area. The city population was 12,332 in 2010, up from 10,377 in 2000. Taking its name from The Falls Church, an 18th-century Anglican parish, Falls Church gained township status within...
, and part of Fairfax CountyFairfax County, VirginiaFairfax County is a county in Virginia, in the United States. Per the 2010 Census, the population of the county is 1,081,726, making it the most populous jurisdiction in the Commonwealth of Virginia, with 13.5% of Virginia's population...
(particularly McLeanMcLean, VirginiaMcLean is an unincorporated community and census-designated place in Fairfax County in Northern Virginia. The community had a total population of 48,115 as of the 2010 census....
).
External links
- Washington Aqueduct - Official site US Army Corps of Engineers
- A longer history of the system, from the C&O Canal site National Park Service
- National Historic Landmarks Program: Washington Aqueduct National Park Service