I don't know what is right or wrong in this debate, BUT don't dredgers look for exposed bedrock and not free stone cobble (locations of redds)?
Seems like they would be in a different part of the river. How does small operation dredging affect the down stream turbidity? It probably would be less impactful than a decent size slide correct? Just asking questions here...you know...for science.
_________________________
“If the military were fighting for our freedom, they would be storming Capitol Hill”. – FleaFlickr02