ASCE

In an era when roads and canals were the most common means of overland transportation, the Allegheny Portage Railroad provided a novel alternative. The railway carried fully-loaded canal boats over the steep grades of the Allegheny Mountain. The 36-mile system rose almost 2,300 feet above sea level at its summit - the highest level to which canal boats had ever been carried. The project included ten double-tracked inclined planes, powered by steam engines. Its 900-foot Staple Bend Tunnel, cut from solid rock, was the first railroad tunnel constructed in America.

The Alaska Highway, initially called the Alaskan-Canadian (Alcan) Military Highway, provided an essential transportation link to the Yukon and Alaska during World War II. It begins at the junction with several Canadian highways in Dawson Creek, British Columbia and runs to Delta Junction, Alaska, via Whitehorse, Yukon. After the shock of Pearl Harbor, the Alaska Highway was a first step in America's defense strategy -- a vital military supply line during the war. Over ten thousand Army Engineers were rushed to the far Northwest.

For 2,000 years, Aqueducto de Segovia has been conveying drinking water from the Frio River to Segovia, approximately 18 kilometers away. Built under the reign of Roman emperor Trajan, the aqueduct is one of the most intact and best-preserved Roman engineering masterpieces. Roman engineers built the channel of the aqueduct with an average one percent gradient over its whole length.

Queretaro's aqueduct, in Central Mexico, is one of the most eloquent symbols of colonial Mexico. As one of the early major hydraulic engineering projects in North America, it defines the city both nationally and internationally. The aqueduct, designed in 1723 by Juan Antonio de Urrutia y Arana, Marquis of Villa del Villar del Aquila, was inspired by the aqueducts of Segovia, Merida and Tarragona in Spain. It began supplying clean water to the city in this arid region of Mexico on October 17, 1738.

The roman emperor Trajan ordered a new aqueduct be built to bring fresh water to Italy's Trastevere region and parts of Rome. The water is collected from five springs that feed the lake at Bracciano, and traverses over 25 miles into Rome. To maintain an even gradient, the aqueduct follows a meandering alignment through the countryside to avoid hills and major valleys. The water runs through an open-channel canal that is either arch-supported, at-grade, or underground.

This is one of the earliest uses of engineered water supply and irrigation systems in the United States. The first of eight original acequias was under construction in 1718 and two are still in operation. The remains of one are visible on the grounds of the Alamo. The Acequias of San Antonio are among the earliest engineered water supply and irrigation systems recorded in the United States. The Acequias served an integral role in the growth and stability of the San Antonio community for nearly 200 years.

Maine's heavy snows led turnpike maintenance personnel to bring "left-handed" snow plows into prominence. By using left-handed and traditional right-handed plows in tandem, they were able to distribute snow more evenly - an important advance that has been emulated by many highway maintenance crews across the country.

The Miami Conservancy District flood control project was the direct result of the disastrous flood of 1913, when waters from the Miami, Stillwater, and Mad rivers flooded Dayton and surrounding communities in the Miami Valley. More than 400 lives were lost and property damage exceeded $100 million. When Dayton flooded, great fires raged, adding to the devastation. Many believed that the area would never recover. 

The 1.6-mile Holland Tunnel was the first underwater vehicular crossing of the Hudson River and the first tunnel specifically designed for automobiles and trucks. It dramatically reduced the time required to traverse the Hudson River, a trip previously possible only by ferry. 

A major difficulty when tunneling beneath a river is to keep water and mud from inundating the workers and equipment in the tunnel. Builders of the Holland Tunnel used a shield that enveloped the work site as the excavation progressed; this also avoided obstruction of shipping traffic during construction.

Spearheaded by Hugh Cooper, the Keokuk Dam & Power Plant served as a prototype for many future power plants. The project harnessed the hydropower of the Mississippi River, between Keokuk, Iowa and Hamilton, Illinois.

The crest of the dam is nearly a mile long. The dam structure features 119 arch spans between six-foot-thick piers and a 110-foot-wide pneumatic lock. Combined with the lock, the dam reduced travel time for steamboats by nearly two hours.