Quick Resource on drought: http://wrrc.arizona.edu/sites/wrrc.arizona.edu/files/Quick%20Resouce-%20Drought%20%28final%29.pdf
Quick Resource on climate change: http://wrrc.arizona.edu/sites/wrrc.arizona.edu/files/Quick%20Resouce-%20Climate%20Change%20%28final%29.pdf
Other resources:
Climate change impacts on the US Southwest. Information from the U.S. EPA. http://www.epa.gov/climatechange/impacts-adaptation/southwest.html#impactswater and http://www.epa.gov/climatechange/impacts-adaptation/water.html
Southwest Climate Assessment