 Construction of the dam began in 1956 and several contracts were awarded two years later for the uphill relocation of the highway, which began shortly afterward.The new, section of the highway between the dam and Knapp's Hill was constructed in one year, opening in November 1959 at a cost of $8 million (equivalent to $ in dollars), and involved several large cuts in the nearby hills.During the 1964 state highway renumbering, PSH 10 was fully replaced by US 97, while the unfinished highway on the east side of the river between Wenatchee and Chelan Falls became US 2 and SR 151.