Shadow Mountain Dam is a zoned earth-fill dam on the Colorado River in Grand County, Colorado. Constructed between 1944 and 1946, the Shadow Mountain Dam creates the Shadow Mountain Lake, with a structural height of 63 feet (19 m) and a drainage area of 187 square miles (480 km²). Shadow Mountain Lake is a holding reservoir for water pumped up from Lake Granby just to the south through the Granby Pumping Plant and Canal. Shadow Mountain Lake is connected by a short channel to the natural Grand Lake. The east portal of the Alva B. Adams Tunnel is located on Grand Lake.