On September 25, 1994, at 1405 central daylight time, a Cessna 172D, N2830U, collided with the ground during a forced landing attempt at Shelby County Airport, Alabaster, Alabama. The personal flight operated under the provisions of 14 CFR Part 91, with no flight plan filed. Visual weather conditions prevailed at the time of the accident. The airplane sustained substantial damage; the pilot and passenger were not injured. The accident occurred during the initial takeoff attempt from Alabaster. According to the pilot, as the airplane climbed through 100 feet above ground level (agl), takeoff rpm dropped to 1700 rpm. Attempts to regain full engine power failed; the pilot selected a forced landing area in the clear cut section off the departure end of the runway. During the emergency landing, the airplane bounced once and nosed over when the nose wheel dug into the soft ground. During the post-accident examination of the airplane, water was discovered in the fuel system and in the carburetor; the engine operated normally during the functional check. According to the pilot, the airplane was parked on a slope during the preflight inspection.