Long's Peak, in Rocky Mountain National Park, Colorado , the river flows west until it is joined by the Green River and turns south to carve a series of deep sinuous canyons in the arid plateaus of southern Utah and northern Arizona. The river eventually finds the sea in the Gulf of California , forming a broad delta. The river drops over 3 km in elevation over its 2320 km length with an average gradient of a little over 1 meter per kilometer. The next section examines the stream profile , how stream characteristics change from the relatively steep and narrow channels near the stream source to the gentle gradients and broad channels near the river's mouth. One consequence of dam construction was the alteration of the physical environment downstream from the largest dams.
Regulated flows are much lower than the peak stream flow prior to dam construction.
Under pre-dam conditions, Spring floods eroded sand bars from the channel and formed beaches along the canyon walls. The rapid flows cleared the stream of obstructions created by boulders deposited at the mouths of tributary streams. These processes and the ecological environments they created disappeared following dam construction. In a spectacular experiment , scientists with the U.S. Geological Survey utilized controlled floods downstream from Glen Canyon dam to restore some of the pre-dam channel characteristics. The sections on stream profiles and channel migration investigate the role of stream velocity in controlling erosion and deposition of sediment within and adjacent to stream channels.