At 1305 Central time the airplane sustained substantial damage during a forced landing following a loss of engine power. The private pilot and passenger were not injured. Visual conditions prevailed. After the accident, the pilot told investigators the aircrafts engine began to experience a gradual reduction in rpm while in cruise flight. After unsuccessful attempts to restore power, the pilot determined the only suitable site for a forced landing was an area of reclaimed land. After the aircraft touched down, the nose wheel “got trapped in loose soil” and the aircraft nosed over and came to rest in an inverted position. Twelve minutes before the accident, a weather observation approximately seven nm northwest of the accident site included calm winds with a temperature of 96 degrees F and a dewpoint at 76 degrees F.