Never been on the river at Needles, seen it many times, but that HP is fine. I've run up to Hoover Dam on a 5HP outboard with the river running full-tilt (much more flow than Needles), and it worked.
I would be more concerned about reefs and sand bars on the river around there, lower unit and prop damage. Keep your head on a swivel running on the river around there, especially when they have Davis Dam down to a trickle, early and late.