>>1709728In the case of the Colorado, the opposite is happening. The native fish species there adapted to muddy sediment flows, which keeps water temperature higher. Since Glen Canyon Dam was built many native species have been extirpated from immediately below the dam since the water is constantly between 32-68F now instead of up to 85F in its natural free flowing form. It is now a great cold water trout fishery now though. The lower Colorado has a problem with increasing salinity due to lack of flooding cycles and lower overall (sediment heavy) flows. Natural sediment runoff is good, agricultural runoff is bad and mostly only happens to the lower Colorado below Havasu. Arizona has the most species of endangered endemic fish in the US because of the number of dams within the state altering waterways, there's even proposals to build more.
