The Colorado River provides water for millions of people, including Coloradans from the Western Slope to the Eastern Plains. But much of the river system is overallocated, its waters are overused and its flows are shrinking. “It’s not a rosy picture. We’ve been in a drought for a very long time,” said Kevin Reidy, senior state water efficiency specialist with the Colorado Water Conservation Board, the state’s top water agency. “Really, what we’re looking at is aridification across the state, across the Southwest.”