Civil

In the decade following the Civil War, the Mississippi River began to lose its standing as the primary transport artery in the Midwest. Railroads were taking over, and Chicago was rapidly becoming the center of Midwestern commerce. The Eads Bridge was the first major railroad link over the Mississippi, constructed by the city of St. Louis in an attempt to maintain its dominance as a regional commercial hub.

The Durango-Silverton Narrow Gauge Branch of the Denver & Rio Grande Western Railroad extends from the town of Durango to the mining camp of Silverton. Built in 1882 through one of the most rugged mountain areas of the nation, its complexity remains a testament to the role civil engineering played in the development of the western United States. 

The tracks rise up the sheer, steep Animas Canyon, running along a rock ledge just wide enough to carry the train. The line is used today as a tourist attraction, carrying visitors through the picturesque San Juan Mountains.

Not only was Dunlap's Creek Bridge the first cast-iron bridge in America, it was the first metal bridge anywhere to use what its builder, Capt. Richard Delafield, U.S. Army Corps of Engineers, described as "standardized, interchangeable, manufactured parts." The bridge was built as part of the federal government's effort to make repairs on the National Road  before handing authority over to the states. Dunlap's Creek at Brownsville was an especially troublesome crossing, having destroyed three previous bridges since 1801.

The significance of the 15-mile Whitewater Canal was not in its ability to create a profit, but rather its effect on the economic growth of the Whitewater River Valley, considered the gateway to the interior of Indiana. Before the canal, travel was challenging. Most waterways in Indiana were only navigable by canoe, and the alternative - horse and wagon - was difficult, slow and expensive.  

Like other American cities in the late 19th century, Baltimore had grown so quickly its supply system was unable to provide city residents with a dependable supply of water. Two reservoirs built outside the city helped increase capacity, but heavy rainfalls in the largely agricultural area tended to foul this additional water supply. City officials elected to construct a holding reservoir within the city - contained by an earthen dam - where silty water would be allowed to settle. No such project had ever been undertaken in the United States.

The Dorton Arena was the first use of a cable-supported roof system in the world. Commissioned in 1949 by North Carolina State Fair manager J.S. Dorton, the new building was intended to be a livestock judging pavilion. Architect Matthew Nowicki (1910 - 1950) proposed a structure that included a pair of intersecting parabolic arches supported by slender columns around its perimeter with a network of wire cables that supported the saddle-shaped roof.

The Dismal Swamp Canal was created as a 22-mile waterway, extending from Deep Creek, Virginia to South Mills, North Carolina. The canal enabled North Carolina producers of building and agricultural products to deliver goods to the Port of Norfolk where they were transferred to ocean-going vessels.   

The Detroit-Windsor Tunnel is a 5,160-foot structure that carries traffic under the Detroit River between Detroit, Michigan and Ontario, Canada. Privately financed, built, and owned, it was completed in 26 months, 10 months ahead of schedule. 

The Delaware Aqueduct provided an important transportation link between the Pennsylvania's coalmines and New York's booming industrial marketplace. It is the earliest surviving work of John A. Roebling, who designed the Brooklyn Bridge  30 years later. The cable anchorage system first used on this project was also used on the Brooklyn Bridge. The aqueduct is patterned after Roebling's design of the Pennsylvania Canal over the Allegheny River, and is the oldest metal strand cable suspension bridge still standing in the U.S.

Before the Davis Island Lock & Dam were built, the flow of the Ohio River slowed to little more than a trickle during dry periods. For several months each year, the unreliable flow stranded Pittsburgh's steamboats, towboats, and barges.    

The Davis Island Lock & Chanoine Dam experimental project was the first lock and dam ever constructed on the Ohio River. Its achievements also included the first rolling lock gates, the largest movable dam built in the 19th century, and the widest chamber in world history.