On July 12, 1995, about 1100 Alaska daylight time, N725, a Cessna 185C on floats, operated by the U.S. Department of the Interior, landed hard on Walker Lake, Alaska, located about 50 miles west of Bettles, Alaska, and was substantially damaged. The commercial pilot and the two passengers aboard were not injured. Visual meteorological conditions prevailed and a company flight plan had been filed. The airplane was operated as a passenger-carrying, government use flight, and it was conducted under 14 CFR 91. According to the pilot, he had made two previous uneventful glassy water landings on the lake. He stated that on the third landing, he misjudged the height above the water and reduced power too soon; the aircraft descended abruptly to a hard landing. An examination of the airplane revealed that the fuselage structure adjacent to the left rear float attach fitting was deformed.