Dams

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 largest rolled-earth fill dam in the world at the time of its completion, Denison Dam eventually served as a prototype for dam construction in future U.S. Army Corps of Engineers projects throughout the arid plains of the American Southwest. Procedures and equipment developed during its construction are now commonplace in the sampling and testing of soils.

The Cheesman Dam was the first major dam in the U.S. to incorporate the gravity arch, and upon completion it was the highest gravity arch stone masonry dam in the world. It is the key structure in Denver's water supply.

Three years into original construction, flooding swept away the partially completed rock-filled structure. A solid masonry replacement dam was completed in just five years - a major feat for such a remote and complex project. When it was finished, the dam rose higher than the tallest building in Denver. 

The Buffalo Bill Dam, known as the Shoshone Dam until 1946, was the first mass concrete dam in America. At nearly 325 feet high, it was also the tallest dam in the world at the time of completion.

Belle Fourche, meaning "Beautiful Forks" in French, refers to the confluence of the Redwater and Belle Fourche Rivers. The gold rush to the Black Hills in 1876 brought many people to the area, but agriculture and livestock soon became the principal industries. Farmers and civic leaders recognized the need for a reliable source of irrigation water in this semi-arid region and petitioned the Federal government for funds to build an irrigation and flood control system.

Ithamar A. Beard, an engineer of some prominence in New England, surveyed the mill brook and selected the best site for a storage dam. Contractor Simeon Cobb, knowledgeable of contemporary civil engineering practices, made major changes to the dam's original design, converting the linear dam into a gentle arch.

The Bonneville Dam, Columbia River Power and Navigation System consists of 55 major projects on Oregon's Columbia River and is said to be the largest hydroelectric system in the world.

The Columbia River forms part of the border between Washington and Oregon and flows inland through the only waterway that crosses the Cascade Mountains. To harness the energy of the ninth longest river in North America, engineers developed unique design and construction approaches to overcome problems caused by depth of water, current velocity, and an irregularly-shaped river bottom.