been thinking of doing it soon here. are there any navigation hazards (shallow spots) between those two? been doing the lakes since i began boating 4 years ago, (have-a-screw, mo-choppy, and mead), but kinda sketched out on the river. been on the river only a few times putting in at needles and going down to havasu and back--late summer, mid-day--that was before i knew that the river level goes up and down. how do you know when it's safe on the river? seems like the experienced guys know that kind of stuff.