Less sediment and salts are reaching the Colorado River because of major changes in its tributaries, a Colorado State University scientist says.

The Colorado River, and possibly other western U.S. rivers, are recovering naturally from a period in the late 1800s when climatic fluctuations and human activities such as the construction of roads and ditches caused deep erosions and gullies, said CSU professor Stanley Schumm.These deeply cut channels caused vast amounts of sediment to pour into the Colorado River in Utah, Arizona, New Mexico, Colorado and Wyoming.

"But during the past 100 years, these incised channels have widened," Schumm said. "During at least the last 40 years, new flood plains have formed as vegetation colonized the valley floors.

"The result is decreased erosion and increased sediment storage."

The natural evolution of the channels ultimately can save taxpayers millions of dollars in water treatment costs and greatly prolong the life of reservoirs such as Lake Mead and Lake Powell, Schumm said.