Potomac Aqueduct Bridge

The Aqueduct Bridge (also called the Alexandria Aqueduct) was a bridge between Georgetown, Washington, D.C., and Rosslyn, Virginia, in Arlington County. It was built to transport cargo-carrying boats on the Chesapeake and Ohio Canal in Georgetown across the Potomac River to the Alexandria Canal. During their lives, the same eight piers supported three different bridges: a wooden canal bridge, a wooden double-deck canal and roadway bridge, and a roadway-only iron truss bridge.

History

In 1830, merchants from Alexandria, Virginia proposed linking their city to Georgetown to capitalize on the new Chesapeake and Ohio Canal. Congress granted a charter to the Alexandria Canal Company in 1830, and construction soon began on the Aqueduct Bridge that would carry canal boats across the Potomac River and downriver on the Virginia side without unloading in Georgetown. The bridge was designed by Major William Turnbull. Construction of the bridge and Alexandria Canal began in 1833; both were completed a decade later. To withstand Potomac ice floes, the piers were made of gneiss boated down from quarries upstream and were sloped upwards from the river on their upstream sides. The water-filled bridge was a weatherproofed timber queen-post truss construction. The Civil War interrupted plans to make an upper level for a railroad crossing above the lower canal level; instead, the canal was drained to make a roadway for military troops.

In 1866, the boat channel was restored to private ownership, and in 1868 arching Howe trusses were installed to support a toll highway and footpath on top of the lower canal level intersecting to M Street. The going rate for a foot passenger was two cents; a horse or cattle, five cents; a vehicle drawn by one animal cost fifteen cents, twenty-five cents if drawn by two; and a penny for any pig, sheep, or other live animal. Only military troops and munitions were exempt from the tolls.

In the 1880s, the old bridge was sold to the federal government and replaced in 1886 by a light iron truss bridge for wheeled traffic. In 1889, the northern arch in the Washington abutment was enlarged so that the Georgetown Branch of the Baltimore and Ohio Railroad could pass underneath. When that line was abandoned, Water Street (later K Street), NW, was extended west through the passageway to the Washington Canoe Club. The empty lot before the canoe club had previously been occupied by Dempsey's Canoe Livery. The rest of the Georgetown Branch right-of-way is now occupied by the Capital Crescent Trail.

In 1904, the Great Falls and Old Dominion Railroad constructed a superstructure that extended outward from the upstream side of the bridge's deck. The superstructure carried the electric trolleys of the railroad and its successor, the Washington and Old Dominion Railway, between Georgetown and Rosslyn, Great Falls, Leesburg, and Bluemont, Virginia until the bridge closed.

In 1923, the bridge was closed after the Key Bridge was built downstream about a hundred feet east. The Aqueduct Bridge's superstructure and most of the above-water portions of its piers were removed in 1933. The bases of the piers were retained to protect the Key Bridge's piers from ice floe damage. In 1962, seven of the eight remaining pilings from the Aqueduct Bridge were blasted out to a depth of twelve feet below the waterline after recreational boaters claimed that they were hazardous. [cite web
url=http://pubs.usgs.gov/gip/stones/stones2.html
title= Building Stones of Our Nation's Capital: Washington's Building Stones [2 of 4
publisher=United States Geological Survey
date=1999-01-13
accessdate=2008-02-09]

The Aqueduct Bridge Washington abutment still survives and is located west of the Key Bridge. The southern arch underneath the abutment is used to shelter rowing shells belonging to members of the Potomac Boat Club. [cite web
url=http://www.potomacboatclub.org/aboutus.php
title=About Us
publisher=Potomac Boat Club
accessdate=2008-02-09] The sole remaining pier is located in the river near the Virginia shore. The bridge's Virginia abutment remains in place beneath and upstream of the Key Bridge.

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Plans

First bridge

econd bridge

Third bridge

Remnants

Notes

References

*cite book
last = Turnbull
first = William
title = Reports on the construction of the piers of the aqueduct of the Alexandria canal across the Potomac River at Georgetown, District of Columbia
publisher = Scholarly Publishing Office, University of Michigan Library
year = 2005
id = ISBN 1-4181-9959-1

External links

* [http://www.victoriansecrets.net/acqueduct.html Photographs of Aqueduct Bridge and its remnants] . Last photo (colorized) shows electric trolley on bridge. Accessed on September 7, 2007.
* [http://mcmullans.org/canal/alexandria_canal_aqueduct.htm Aqueduct Bridge]
* Maps and aerial photos
** Aqueduct Bridge abutment, Georgetown: Hybrid satellite image/map from [http://wikimapia.org/#lat=38.90429&lon=-77.070411&z=17&l=0&m=h&v=2 WikiMapia]
** Aqueduct Bridge pier, Potomac River: Hybrid satellite image/street map from [http://wikimapia.org/#lat=38.901516&lon=-77.07061&z=18&l=0&m=h&v=2 WikiMapia]
** Aqueduct Bridge abutment, Rosslyn: Hybrid satellite image/street map from [http://wikimapia.org/#lat=38.901157&lon=-77.07068&z=19&l=0&m=h&v=2 WikiMapia]