50
Note its not just climate thats causing the water shortage. The article even mentions that a bunch of that water is being used for livestock feed like alfalfa. It takes ~620 gallons of water to make a 150g hamburger and ~859 gallons for a gallon of milk (1). And 56 percent of the water of the colorado river is used for growing livestock feed (2).
Climate change is important to have in the conversation about our rivers drying up, but we can't forget about the elephant (or cow) in the room.
1: https://www.sciencedirect.com/science/article/abs/pii/S1470160X11004110?via%3Dihub
2: https://www.nytimes.com/interactive/2023/05/22/climate/colorado-river-water.html