Western Water Rights have significant unintended side-effects. The Colorado River is committed to give up more water than it has, never mind the needs of the fish. People with water rights are faced with use-it-or-lose-it rules so some irrigate lovely lawns in a desert or grow crops ill-suited to the land.
In Oregon, the Deschutes Water Trust was developed so that people with water rights could donate their rights for a year, writing off the value as a charitable donation, leaving the water in the river.
Efforts in Camp Verde, AZ have taken a different approach, operating more like carbon offsets. The Verde River Exchange needs two parties: someone who wants to sell their water rights and a buyer.
Acequias are an ancient, democratic process for sharing precious water in the desert. This process is more likely to keep water growing food instead of being diverted to the highest bidder like cities or dirty industries.
Whatever method we use, we need to address water conservation. We are already over-drawing (see the graph of Verde River low-flow points for three different points in the river over 5 decades) and droughts will become more fierce with climate change.