When you’re reading the back-in-the-day stories of running the Colorado River through the Grand Canyon – of the riffles and rapids – remember that things have changed since the completion of the Glen Canyon Dam (built primarily to prevent silt buildup at the downstream Hoover Dam) in 1966.
The day’s CFS affects how many miles you can travel in a day – especially for oar trips.
Before construction of the Glen Canyon Dam, the section of the Colorado River running through the Grand Canyon would carry and deposit over 500,000 tons of silt throughout the Canyon. Fish and other wildlife rely on beaches and other silt buildup for habitat. Rafters rely on beaches for sweet campsites!
The US Geological Survey’s Controlled Flooding of the Colorado River in Grand Canyon: the Rationale and Data-Collection Planned is a nice read about controlled floods and the erosion of debris fans.
The Bureau of Reclamation has up-to-date information and study results from the five year controlled release of waters from the Glen Canyon Dam which proposed “a series of experimental releases of water from Glen Canyon Dam to help native fish, particularly the endangered humpback chub, and conserve fine sediment in the Colorado River corridor in Grand Canyon National Park.”