I've hauled many tons of riprap for dock landings, water crossings and general shoreline protection. I've used a tracked dumper with a heavy conveyor belt bed liner to protect the bed. The Yanmar C60R will haul 5-6 tons in a pass, run through swamps and exceed 35 degree slopes quite easily. I've even dumped 1/2 loads while on a 30 degree side slope. If you have access from the sides of the creek, a tracked dumper might be a fast option.
I was hired to do a shoreline riprap job for a fairly large dirt contractor at their lake house. I was questioned as to how I was able to move so many triaxle loads so quickly with minimal time, by myself. Load it, get it to the slope, back up to the top of the slope at a slightly pitched angle, start dumping at the top of the slope and keep working your loads until you hit the toe of the slope. Repeat process after tamping and filling any voids with a mini-ex, repeat until done. I think it was 13 or 15 tri-axle loads of rock in 2 days if memory serves me right. 4 loads per tri-axle so about 50-60 cycles to complete the job.