mountain rough river merges into abyss between huge boulders

abyss boat boating boiling bottleneck boulders canoe canoeing canyon cascade cataract cleft defile difficult fall ferocious gorge huge jaw jaws kayak kayaking ledge merges mountain narrow narrows niagara notch pass racing raft rafting rapid ravine riffle rise river rock rockbar rough rowing swirling tourism water waterfall whitewater wild wildness wingless