The Washington Aqueduct is an
aqueduct that provides the public
water supply
Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Public water supply systems are crucial to properly functioning societies. Thes ...
system serving
Washington, D.C.
)
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, image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan, ...
, and parts of its suburbs, using water from 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 Augus ...
. One of the first major aqueduct projects in the
United States
The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
, the Aqueduct was commissioned by
Congress
A congress is a formal meeting of the representatives of different countries, constituent states, organizations, trade unions, political parties, or other groups. The term originated in Late Middle English to denote an encounter (meeting of a ...
in 1852, and construction began in 1853 under the supervision of
Montgomery C. Meigs
Montgomery Cunningham Meigs (; May 3, 1816 – January 2, 1892) was a career United States Army officer and civil engineer, who served as Quartermaster General of the U.S. Army during and after the American Civil War. Meigs strongly opposed sece ...
and the
US Army Corps of Engineers
, colors =
, anniversaries = 16 June (Organization Day)
, battles =
, battles_label = Wars
, website =
, commander1 = ...
. Portions of the Aqueduct went online on January 3, 1859, and the full pipeline began operating in 1864.
The system is owned and operated by the Corps of Engineers and has been in continuous use ever since. It is listed as a
National Historic Landmark
A National Historic Landmark (NHL) is a building, district, object, site, or structure that is officially recognized by the United States government for its outstanding historical significance. Only some 2,500 (~3%) of over 90,000 places listed ...
, and the
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. The bridge construction began in 1857 and was completed in 1864. The roadw ...
within the system is listed as a
Historic Civil Engineering Landmark
__NOTOC__
The following is a list of Historic Civil Engineering Landmarks as designated by the American Society of Civil Engineers since it began the program in 1964. The designation is granted to projects, structures, and sites in the United State ...
.
Design and facilities
The centerpiece of the Aqueduct is a 12-mile (19 km)
pipeline
Pipeline may refer to:
Electronics, computers and computing
* Pipeline (computing), a chain of data-processing stages or a CPU optimization found on
** Instruction pipelining, a technique for implementing instruction-level parallelism within a s ...
which connects the system's
dam
A dam is a barrier that stops or restricts the flow of surface water or underground streams. Reservoirs created by dams not only suppress floods but also provide water for activities such as irrigation, human consumption, industrial use ...
at
Great Falls
Great may refer to: Descriptions or measurements
* Great, a relative measurement in physical space, see Size
* Greatness, being divine, majestic, superior, majestic, or transcendent
People
* List of people known as "the Great"
*Artel Great (born ...
with the
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. The reservoir is loca ...
on the border with
Montgomery County, Maryland
Montgomery County is the most populous county in the state of Maryland. As of the 2020 census, the county's population was 1,062,061, increasing by 9.3% from 2010. The county seat and largest municipality is Rockville, although the census-design ...
. Portions of the Aqueduct went online on January 3, 1859, and the full pipeline began operating in 1864.
The pipeline runs along what is now
MacArthur Boulevard MacArthur Boulevard may refer to:
*MacArthur Boulevard (Washington, D.C.), a road that parallels the C&O Canal in Washington, D.C. and Montgomery County, Maryland
*MacArthur Boulevard in Oakland, California, a major boulevard in Oakland and a histo ...
, traversing some of the higher cliffs along the Potomac River.
![Washington Aqueduct dam - look SE - Great Falls of the Potomac River - 2007-10-31](https://upload.wikimedia.org/wikipedia/commons/1/18/Washington_Aqueduct_dam_-_look_SE_-_Great_Falls_of_the_Potomac_River_-_2007-10-31.jpg)
The
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. The bridge construction began in 1857 and was completed in 1864. The roadw ...
carries the pipeline and MacArthur Boulevard over
Cabin John Creek
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 U.S. Geological Surve ...
and the
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 Interstate 495 (I-495) in Bethesda in southwestern Montgomery County. Cabin John Parkway is a four-la ...
near the community of
Cabin John, Maryland
Cabin John is a census-designated place and an unincorporated area in Montgomery County, Maryland, United States. Its original southern boundary encompassed a section of the Chesapeake and Ohio Canal (C&O) including locks 8–12, and the northern ...
. This bridge was the longest
masonry
Masonry is the building of structures from individual units, which are often laid in and bound together by mortar; the term ''masonry'' can also refer to the units themselves. The common materials of masonry construction are bricks, building ...
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. A viaduct ...
in the world for 40 years after its completion.
The Dalecarlia Reservoir serves as a primary
sedimentation
Sedimentation is the deposition of sediments. It takes place when particles in suspension settle out of the fluid in which they are entrained and come to rest against a barrier. This is due to their motion through the fluid in response to the ...
basin. A portion of the water from the reservoir is treated at the nearby Dalecarlia Water Treatment Plant and distributed to municipal water mains. The remainder of the water from the reservoir flows to the
Georgetown Reservoir
The Georgetown Reservoir is a reservoir that provides water to the Washington, D.C., District of Columbia. Part of the city’s water supply and water purification, treatment infrastructure, it is located in the The Palisades, Washington, D.C., P ...
in the
Palisades neighborhood of Washington. This facility serves as an additional sedimentation basin, and then the water flows through the
Washington City Tunnel to the treatment facility at the
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. Ar ...
, after which it is pumped through city mains. The Dalecarlia Reservoir was modified in 1895 and 1935 to improve water quality and increase water supply.
System expansion
![Dalecarlia Water Treatment Plant](https://upload.wikimedia.org/wikipedia/commons/a/a9/Dalecarlia_Water_Treatment_Plant.jpg)
The system originally used a single pipe for water delivery, and did not have any
water purification
Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water that is fit for specific purposes. Most water is purified and disinfected for hu ...
plants, relying instead on the reservoirs to act as settling basins. By the turn of the 20th century, however, Washington's growth and the high amount of
sediment
Sediment is a naturally occurring material that is broken down by processes of weathering and erosion, and is subsequently transported by the action of wind, water, or ice or by the force of gravity acting on the particles. For example, sand an ...
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 filters are used in water purification for treating raw water to produce a potable product. They are typically deep, can be rectangular or cylindrical in cross section and are used primarily to treat surface water. The length and bre ...
bed system, was installed at McMillan Reservoir, and was completed in 1905.
[ Publication No. EP 870-1-67.] The regular use of
chlorine
Chlorine is a chemical element with the Symbol (chemistry), symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate betwee ...
as a
disinfectant
A disinfectant is a chemical substance or compound used to inactivate or destroy microorganisms on inert surfaces. Disinfection does not necessarily kill all microorganisms, especially resistant bacterial spores; it is less effective than st ...
began in 1923 at the McMillan plant. The McMillan plant was not replaced until 1985, when a
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.
Rapid sand filters were first developed in the ...
plant was opened adjacent to it.
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, 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, officially the Commonwealth of Virginia, is a state in the Mid-Atlantic and Southeastern regions of the United States, between the Atlantic Coast and the Appalachian Mountains. The geography and climate of the Commonwealth ar ...
communities that use the Aqueduct.
In 1926, Congress approved selling water from the aqueduct to
Arlington County, Virginia
Arlington County is a County (United States), county in the Virginia, Commonwealth of Virginia. The county is situated in Northern Virginia on the southwestern bank of the Potomac River directly across from the Washington, D.C., District of Co ...
.
A new water supply pipe was constructed at Chain Bridge and service to Arlington began in 1927. Additional pipes were built as Arlington's population grew, including a pipe built under the Potomac River. In 1947 Congress approved adding the city of
Falls Church, Virginia
Falls Church is an independent city (United States), independent city in the Commonwealth (U.S. state), Commonwealth of Virginia. As of the 2020 United States Census, 2020 census, the population was 14,658. Falls Church is included in the Wash ...
to the aqueduct system, and nearby portions of
Fairfax County, Virginia
Fairfax County, officially the County of Fairfax, is a county in the Commonwealth of Virginia. It is part of Northern Virginia and borders both the city of Alexandria and Arlington County and forms part of the suburban ring of Washington, D.C. ...
were added in the 1960s.
The Corps built an additional intake and pumping station at
Little Falls in 1959.
Operations and service area
The Aqueduct is a
wholesale
Wholesaling or distributing is the sale of goods or merchandise to retailers; to industrial, commercial, institutional or other professional business users; or to other wholesalers (wholesale businesses) and related subordinated services. In ...
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
DC Water
The District of Columbia Water and Sewer Authority (DC Water) provides drinking water, sewage collection and sewage treatment for the District of Columbia, in the United States. The utility also provides wholesale wastewater treatment services ...
)
* Arlington County
* The city of Falls Church and part of Fairfax County (particularly
McLean
MacLean, also spelt Maclean and McLean, is a Goidelic languages, Gaelic surname Mac Gille Eathain, or, Mac Giolla Eóin in Irish language, Irish Gaelic), Eóin being a Gaelic form of Johannes (John (given name), John). The clan surname is an A ...
).
References
*
Further reading
*
External links
U.S. Army Corps of Engineers: official Washington Aqueduct website
*
ttp://tps.cr.nps.gov/nhl/detail.cfm?ResourceID=1401&resourceType=Structure National Park Service.gov: National Historic Landmarks Program & the Washington Aqueduct
Maps of the Washington Aqueduct, Md. and Washington D.C. : to accompany supplemental report of Chief Engineer dated Feb. 22nd 1864* at Maryland Historical Trust website
{{Authority control
Aqueducts in the United States
Water in Washington, D.C.
Transportation buildings and structures in Montgomery County, Maryland
Bridges in Montgomery County, Maryland
Bridges in Washington, D.C.
Transportation buildings and structures in Washington, D.C.
Infrastructure completed in 1859
Water supply infrastructure on the National Register of Historic Places
National Historic Landmarks in Washington, D.C.
National Historic Landmarks in Maryland
Transportation buildings and structures on the National Register of Historic Places in Maryland
Transportation buildings and structures on the National Register of Historic Places in Washington, D.C.
Chesapeake Bay watershed
Potomac River watershed
National Register of Historic Places in Montgomery County, Maryland
Aqueducts on the National Register of Historic Places
The Palisades (Washington, D.C.)