page_title: Columbia Island (District of Columbia)
section_title: Arlington Memorial Bridge and the expansion of Columbia Island
hierarchical_section_title: Columbia Island (District of Columbia) / Expanding and developing Columbia Island / Arlington Memorial Bridge and the expansion of Columbia Island
caption_attribution_description: English: Dredging operations in the Potomac River in Washington, D.C., in the United States in 1930. The double-bridge in the center is the Highway Bridge (later replaced, and today known as the 14th Street Bridges). Boot-shaped Columbia Island, Arlington Memorial Bridge, Theodore Roosevelt Island, and Francis Scott Key Bridge are visible upstream (to the left and top of the image). Note the pontoons between Columbia Island the north span of Highway Bridge, middle left. They indicate the area to be filled with dredged material from the Potomac River to create what will eventually be called the Pentagon Lagoon, and to narrow the outlet from Boundary Channel to the Potomac River. This will also allow the Mount Vernon Memorial Parkway (later named the George Washington Memorial Parkway) to be built along the axis of Columbia Island, cross the outlet channel, and proceed south below the soon-to-be-replaced Highway Bridge. Note the parallel pontoons in the lagoon south of Highway Bridge. They indicate where dredged material from the Potomac River will be placed to allow the parkway to continue south. The lagoon is the wide mouth of Roaches Run, a creek in Virginia. A large dredge can be seen tied up at the pier near the spit of land extending into the Potomac River. Several barges (to hold the material dredged up) are also nearby.
context_page_description: Columbia Island is an island located in the Potomac River in Washington, D.C., in the United States. It formed naturally as an extension of Analostan Island in the latter part of the 1800s, and over time erosion and flooding severed it from Analostan. The U.S. federal government deposited material dredged from the Potomac River on the island between 1911 and 1922, and again from 1925 to 1927. The island was also reshaped by the government at this time. It received the name "Columbia Island" about 1918. In 1968, the island was renamed Lady Bird Johnson Park. Located within the park are the Lyndon Baines Johnson Memorial Grove, Navy – Merchant Marine Memorial, and the Columbia Island Marina. The island, park, memorials, and marina are part of the George Washington Memorial Parkway and administered by the National Park Service.
context_section_description: In 1922, Congress authorized the Arlington Memorial Bridge Commission (AMBC) to hold a design competition for the proposed Arlington Memorial Bridge. It awarded the design commission to the firm if McKim, Mead and White, which appointed architect William Mitchell Kendall to be the lead designer.  Congress subsequently authorized construction of Kendall's bridge on February 24, 1925. The legislation authorizing construction of the bridge also provided for the construction of approaches (on-ramps, off-ramps, and pedestrian areas) on both the D.C. and Virginia ends of the bridge; for the improvement of B Street NW as a new ceremonial avenue to link to the bridge; and for the construction of a roadway (eventually called Memorial Drive) between the bridge and the main gate of Arlington National Cemetery as well as a new ceremonial entrance at this gate (subsequently known as the Hemicycle).
  Preliminary designs for the bridge showed it terminating on Columbia Island, which necessitated expansion of Columbia Island. The United States Army Corps of Engineers already planned to dredge the Potomac River and enlarge Columbia Island, so on April 1, Secretary of War John W. Weeks ordered the expenditure of $114,500 to dredge the river between the Highway Bridge and the Lincoln memorial. The dredged material was to be dumped on Columbia Island. To ensure the island could support the bridge, the Corps also planned to construct a 20-foot (6.1 m) levee around the island.
  The Corps reached an agreement with the AMBC in April 1925 to jointly share the cost of dredging, which involved the removal of 2.5 million cubic feet (71,000 m³) of river bottom, and the construction of 2,000 feet (610 m) of seawall and 15,000 feet (4,600 m) of levee. About 40 acres (160,000 m²) of Columbia Island was to be removed in order to widen the main Potomac River channel, and the height of the island raised from 6 feet (1.8 m) above average water level to 22 feet (6.7 m) over two years.
caption: Dredging operations in the Potomac River in 1930. Note the floating pontoons which outline the soon-to-be-completed land which will define the Pentagon Lagoon, and the unfinished central bascule span in Arlington Memorial Bridge.
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