Hoover Dam the change, stating, "I didn't know Hoover was that small a man to take credit for something he had nothing to do with." Hoover Dam was recognized as a National Civil Engineering Landmark in 1984. It was listed on the National Register of Historic Places in 1981, and was designated a National Historic Landmark in 1985, cited for its engineering innovations. Other sources Hoover Dam Hoover Dam is a concrete arch-gravity dam in the Black Canyon of the Colorado River, on the border between the U.S. states of Nevada and Arizona. It was constructed between 1931 and 1936 during the
Steamboats of the Colorado River the river, except for the "Searchlight" that lingered on as property of the U. S. Reclamation Service until it was sunk in 1916. Steamboats were tried in Glen Canyon, the Green River in Utah and Wyoming and the Grand River, (after 1921 renamed as the upper part of the Colorado River), above its confluence with the Green River in Utah and in Colorado. Unlike the Lower Colorado, the railroads made possible most of this steam navigation on the Upper Colorado, bringing in the boats or their parts and their fuel to the points on the river where they were assembled