Arizona would be the first state to feel the effects of Colorado River cutbacks if the water level continues to fall at drought-stricken Lake Mead, an environmental advocacy group says in a new report. The Western Resource Advocates reached its conclusion as the vast reservoir behind Hoover Dam sits at 39 percent of capacity. The group concluded that farmers would be first to feel the pinch; that suburban growth in Phoenix and Tucson could be slowed by cutbacks; and the cities themselves could face water reductions by 2020.