On October 28, 1995, at 0927 hours Pacific daylight time, a Cessna 172H, N2552L, collided with ground obstructions during a forced landing near Borrego Springs, California. The forced landing was precipitated by a loss of power while the aircraft was descending toward the Borrego Valley airport for landing. The aircraft was operated by the pilot on a personal cross-country flight from San Diego to Borrego Springs. Visual meteorological conditions prevailed and no flight plan was filed. The aircraft incurred substantial damage. The private pilot, the sole occupant, was not injured. The flight originated from Brown Field in San Diego, California, on the morning of the accident at 0900. The pilot stated that while descending for landing at Borrego Valley Airport, he applied carburetor heat. The engine rpm decreased to about 1000 rpm and subsequently could not be adjusted by the pilot. The pilot then elected to land on a dirt area in a land fill southeast of the airport. The nose gear collapsed rearward during the subsequent landing on the uneven terrain. An FAA airworthiness inspector from the San Diego Flight Standards District Office examined the aircraft at the accident site. The inspector stated that the aircraft right fuel tank appeared to be about 3/4 full and that the fuel selector was positioned on the right tank. Flight and engine control continuity was established. The carburetor was also examined. When the throttle lever was actuated, fuel was observed squirting. Fuel was also observed in the carburetor bowl assembly. Straw debris was found surrounding the heat muff leading to the carburetor air box. Similar debris was also found in a large quantity inside the air box behind the air cleaner bracket. Thermal Airport is located about 25 miles to the northeast of the accident site. The 0851 local surface observation included a temperature of 67 degrees and a dew point of 53 degrees Fahrenheit. This temperature/dew point range is in an area on the carburetor icing probability chart annotated "moderate carburetor icing at cruise power and serious carburetor icing at glide power." This aircraft is equipped with a Continental O-300 engine.