Colorado River - This is a 17 mile run with some flatwater and class II for approximately the first half of the run. Then the canyon walls close in and the major rapids begin. There are several rapids before the water slows, the canyon walls recede and the last few miles are flatwater with little current . During spring runoff when flows reach the "terrible teens" - 13,000 - 20,000 cfs, the canyon is considered Class IV . At low levels, Skull rapid becomes more difficult for rafts due to exposed rocks.
A permit is required to run this section which come in 2 varieties, day trips and overnight trips (one night). Due to the length of this section and the spectacular canyon scenery, most boaters opt for an overnight trip. Certain gear is required for this trip (groover, firepan, etc.) which will be checked by the ranger on duty at the put-in.