The drastic contrast between its desert landscape and the deep, blue waters of Lake Mead makes it difficult to envision the park's creation as merely incidental. After the completion of the Hoover Dam, the waters of the Colorado River began to flood the river valley and form one of the largest man-made lakes in the United States. The Bureau of Reclamation soon realized the vast recreational opportunities that Lake Mead would provide. Through a memorandum of agreement, the National Park Service was tasked with managing the first national recreation area, formerly known as the Boulder Dam National Recreation Area.