GlenCanyonDam.jpg
The Colorado River ran through the right-hand channel, until the dam stopped the flow and flooded both Glen Canyon and the lowlands out to Wahweap Marina (top left). Fragmenting a river causes profound ecological change. The downstream water temperature has dropped more than 20 degrees, warm water native fish migration is blocked, and one of the siltiest rivers in the world - blocked by the dam - can no longer create the sand bar backwaters vital to flora and fauna.