On August 6, 2005, about 0930 eastern daylight time, an experimental homebuilt, Fox Alfred C. KitFox IV 1200, N86FX, registered to and operated by a private individual, as a Title 14 CFR Part 91 personal flight, flipped over during landing on a grass strip at the Immokalee Airport, Immokalee, Florida. Visual meteorological conditions prevailed and no flight plan was filed. The private-rated pilot received serious injuries, and the airplane incurred substantial damage. The flight originated from the La Belle Municipal Airport, La Belle, Florida, earlier that day, about 0915. The pilot stated it was clear weather with no wind but he knew there had been severe rain the night before. Knowing this, he decided to circle the field to check for water before landing. He had previously landed on the grass strip before and elected to land on the grass extension of runway 36. The touchdown was normal. At about 20 miles per hour and 100 feet into the landing roll, the airplane contacted standing water causing the airplane to nose over. The pilot further stated to a Collier County Sheriff's Office representative that the front of the airplane disappeared in a wall of water that went over the windscreen and the wing before it flipped upside down. The pilot stated there were no mechanical failures or malfunctions of the airplane or any of its systems prior to the accident. A witness stated that he saw the accident airplane land on the grass strip, hit water and flip over. He ran to his truck and drove out to the site. When he arrived, two other people were already helping the pilot out of the airplane and he was taken to the terminal. He stated that the pilot complained of neck pains but did not want any help there. A friend of the pilot's flew him to La Belle for medical attention. The representative from the Collier County Sheriff's office who responded to the accident via helicopter stated that on departure from Immokalee he noted a large amount of standing water on the approach end of runway 36.