Comment by martinpw
2 days ago
There are contracts around how much water needs to flow downstream, so they can't just hold it back like that. California and Arizona both have allocations that they pull from the river downstream of the dam. Mexico too in theory I think, although I don't know if they actually get their allocation any more.
Given how oversubscribed the river water already is, how the river flow rate is steadily diminishing due to increasing temperatures, and the politics involved, even a small or temporary additional reduction in downstream flow would encounter huge opposition.
With multiple dams you can release water early at one point in the system and have zero impact on users below the second dam.
The northeast and northwest has an abundance of water. Managing total water usage is a large problem for the southwest but there’s many opportunities to do things like evaporation reduction.