Three Gorges assisted Yu the Great in controling the waters and guiding boatmen. The Xiling Gorge comprises a series of famous gorges, including Military Book and Sword Gorge, Yellow Cow Gorge, and Lantern's Shadow Gorge. In 1919, after Sun Yat-sen had put forward the concept in the Plan for Industrial Development of his (), experts investigated damming the Three Gorges, but it was not until 1994 that the Three Gorges project officially started. In 1944, the Nationalist government recruited John L. Savage, the Chief Engineer of the United States Bureau of Reclamation, who came to China and made a 10-day investigation of
Risks to the Glen Canyon Dam of between 500–700 years. Glen Canyon Dam is a concrete arch dam on the Colorado River in northern Arizona in the United States, just north of Page. The dam was built to provide hydroelectricity and flow regulation from the upper Colorado River Basin to the lower. Its reservoir is called Lake Powell, and is the second largest artificial lake in the country, extending upriver well into Utah. The dam is named for Glen Canyon, a colorful series of gorges, most of which now lies under the reservoir. Construction of Glen Canyon Dam started in 1956 and was not finished until