Pumphouse to State Bridge on upper Colorado River Rapid Classification: III (beginner whitewater) Length: 15 miles Time on the river: 6 hours Shuttle time from Grand Junction (getting to and from the river): 2.5 hours on each end of the trip When: May through August Price: $125 per person (what's included?) Trip Dates and Reservations

The Pumphouse access marks the start of the Pumphouse Run, Colorado's second most popular stretch of river. Here, below Gore Canyon, the Colorado reverts to a moderate and pastoral character, winding for the most part through a shallow, semi-arid valley sparsely mantled in sagebrush, juniper, and pinyon pine. Two short mini-canyons -- carved from the same dark bedrock as Gore -- and a wealth of big waves at high water provide some scenery and excitement.

Colorado's most popular raft trip offers a great mixture of moderate rapids as well as relaxing, intermediate water. The fast water begins about one mile downriver at the entrance to the upper gorge. Precambrian gneiss, schist, and granite rock make up Gore Canyon and Lower Gore Canyon. This geologic layer is nearly 1,800 million years old, made of metamorphosed shale, sandstone, and limestone deposits. Uplifting of the formations and downcutting by the river created the canyons.