The Green and Colorado Rivers flow smoothly through their canyons above the confluence of the two rivers. Almost any shallow-draft boat can navigate these waters: canoes, kayaks, rafts, and powerboats are commonly used.
Any travel requires advance planning because of the remoteness of the canyons and the scarcity of river access points. No campgrounds, supplies, or other facilities exist past Moab  on the Colorado River, or past the town of Green River on the Green.
All river-runners must follow park regulations, which include the carrying of life jackets, use of a fire pan for fires, and packing out all garbage and solid human waste.
The river flow on both the Colorado and the Green averages a gentle 2-4 miles per hour (7-10 mph at high water). Boaters typically do 20 miles a day in canoes and 15 miles a day in rafts.
The Colorado has one modest rapid called the Slide, 1.5 miles above the confluence, where rocks constrict the river to one-third of its normal width; the rapid is roughest during high water levels in May and June. This is the only difficulty on the 64 river miles from Moab. Inexperienced canoeists and rafters may wish to portage around it. The most popular launch points on the Colorado are the Moab Dock (just upstream from the U.S. 191 bridge near town) and the Potash Dock (17 miles downriver on the Potash Road, Hwy. 279).
On the Green, boaters at low water need to watch for rocky areas at the mouth of Millard Canyon (33.5 miles above the confluence, where a rock bar extends across the river) and at the mouth of Horse Canyon (14.5 miles above the confluence, where a rock and gravel bar on the right leaves only a narrow channel on the left side). The trip from the town of Green River through Labyrinth and Stillwater Canyons is 120 miles. Launch places include Green River State Park (in Green River) and Mineral Canyon (52 miles above the confluence, reached on a fair-weather road from Hwy. 313).
No roads go to the confluence. The easiest return to civilization for nonmotorized craft is a pick-up by jet-boat from Moab  by Tex's Riverways (435/259-5101, www.texsriverways.com ) or Tag-A-Long Tours (800/453-3292, www.tagalong.com ). A far more difficult way out is hiking either of two trails just above the Cataract Canyon Rapids to four-wheel-drive roads on the rim.
Park rangers require that boaters above the confluence obtain a $20 backcountry permit, either in person from the Moab office or by mail or fax (at least two weeks in advance; National Park Service Reservation Office, 2282 S. West Resource Blvd., Moab, UT 84532-3298, fax 435/259-4285). River notes on boating the Green and Colorado are available on request from the Moab office (435/259-3911). Bill and Buzz Belknap's Canyonlands River Guide has river logs and maps pointing out items of interest on the Green River below the town of Green River and all of the Colorado from the upper end of Westwater Canyon to Lake Powell.
The Colorado River enters Cataract Canyon at the confluence and picks up speed. The rapids begin four miles downstream and extend for the next 14 miles to Lake Powell . Especially in spring, the 26 or more rapids give a wild ride equal to the best in the Grand Canyon . The current zips along (up to 16 mph) and forms waves more than seven feet high.
When the excitement dies down, boaters have a 34-mile trip across Lake Powell to Hite Marina; most people either carry a motor or arrange for a powerboat to pick them up.
Because of the real hazards of running the rapids, the National Park Service requires boaters to have proper equipment and a permit ($30). Many people go on a commercial trip for which everything is taken care of by the operator. Private groups must contact the Canyonlands River Unit far in advance for permit details (435/259-3911, www.nps.gov/cany/planyourvisit/reservations.htm ).