According to the pilot, while conducting a low-level flight over a river, and upon attempting a low-level pass over a riverbed sand bar in his tail wheel-equipped airplane, he did not see a high-water fence cable guy-line above the riverbed. The airplane’s main landing gear impacted the cable guy-line, and the airplane subsequently impacted the sand bar. The airplane came to rest upright, and the pilot and the passenger were able to egress from the airplane without further incident. The airplane was destroyed due to a post impact fire that started forward of the firewall. The pilot reported that there were no preaccident mechanical failures or malfunctions with the airplane that would have precluded normal operation. The pilot further reported that the accident could have been prevented by maintaining a higher altitude to avoid objects.