On July 7, 2002, about 1700 Alaska daylight time, a float-equipped Piper PA-18 airplane, N91855, sustained substantial damage during a collision with a hidden obstruction while water taxiing after landing on the King Salmon River, about 70 nautical miles northwest of Dillingham, Alaska. The airplane was being operated as a visual flight rules (VFR) personal flight under Title 14, CFR Part 91, when the accident occurred. The solo private pilot was not injured. Visual meteorological conditions prevailed, and no flight plan was filed. The flight originated on the Nushagak River, about 20 nautical miles north of the accident location. During a telephone conversation with the National Transportation Safety Board (NTSB) investigator-in-charge (IIC) on July 9, the pilot said he departed a camp on the Nushagak River en route to a camp on the King Salmon River. He said he landed on the King Salmon River without incident, but during the water taxi he ran the left float in water that was too shallow. When the left float hit the bottom of the river, he said it caused the right float to swing into the riverbank, and the right wing to swing into trees and brush. He said the right float was punctured, and about five feet of the right wing was bent upward. The right wing leading edge, ribs, and spar were damaged. The pilot did not respond to written requests from the NTSB IIC asking him to complete a Pilot/Operator Aircraft Accident Report (NTSB Form 6120.1).