The two pilots and the three passengers were enroute to a business meeting in the amphibious airplane when they encountered clouds and turbulence. The pilot, copilot, and passengers described that the pilot descended to a lower altitude and flew along a riverbed, at times at an altitude that was below the surrounding trees and terrain. The pilot stated that he next planned on doing a touch-and-go landing on the river to entertain the passengers. One of the passengers said that while flying along the river, the pilots were concerned about hitting powerlines and had to maneuver to prevent hitting them and a bridge. Shortly after, as the pilots were following a sharp bend in the river while looking for a place to conduct a touch-and-go landing, the airplane’s right wing stuck a power line. The airplane’s right wing and aileron were substantially damaged, though the damage did not prohibit the airplane from being able to fly, and the pilot characterized that the airplane felt out of trim and “a little heavier on one side.” The flight continued towards their destination and a subsequent conversation ensued between the pilot and the passengers, asking if the meeting could be missed, and if they should return to their departure airport, about 45 minutes away. The decision was made to return to the departure airport where the airplane landed without further incident. The pilot elected not to perform a precautionary landing at a nearby airport nor declare an emergency because the airplane appeared to be performing well. The operator stated there were no mechanical deficiencies with the airplane that contributed to the accident. Further, the operator did not have any guidance or policies relating to low-altitude maneuvering with passengers onboard.