First, I want to pretend to be shocked that your take on this is 'why not do it since we have wasted money on worse things!'...but it doesnt surprise me at all.
Obvious obliviousness is always impressive to see.
As for why not do this...well here are some reasons-
- Water would need to be pumped more than 1500mi UP AND OVER THE CONTINENTAL DIVIDE.
- The distance water would need to be pumped(Memphis to Lake Powell AZ) is longer than the Colorado River itself.
- The Mississippi River already experiences drought conditions impacting commerce...so pumping water away isnt exactly great.
- Less water reaching the Gulf means less sediment reaching the Gulf, which will impact land barrier quality.
- Lower water level in the Gulf means more saltwater creep in Louisiana.
- Moving fish and invasive species from the Mississippi to the Colorado and Arizona seems less than ideal.
I trust there are more reasons for 'why not'.