You do not even need to force water rights owners to list their rights on the open market. They already want to, it is just illegal for them to sell their water rights (separate from their land) to entitys with more productive uses of the water.
That's not a solution, either. See William Mulholland buying up the water rights in the Owens Valley to feed Los Angles, thus turning Owens Lake into toxic dust that is costing $1 billion and counting to manage. Mulholland is long dead, and we're just getting started paying for that.
Water rights in the West are hard, and we've known that since John Wesley Powell was in charge, as a nearby commenter explained. The Colorado was divided up during an unusually wet year a long time ago, and rising demand and falling supply have only made things worse ever since.
