This is all about some good-old-boy  Alaskans with toys who think they are special Americans.  In this case a big, loud noisy hovercraft that certainly degrades the area for anyone else.  Anyone else using that area would certainly be effected by such a large obnoxious machine. If you haven't been near a home-made Alaska hovercraft, think jet engine level noise over 150 decibels.  It's not so much about the harm to the riverbed, as it is about every other living creature in the area being negatively effected.  Get a canoe if you can't afford the 4-stroke. Some Alaskans thinks its their right to drive the biggest, noisiest piece of equipment over wilderness with little regard for others.