Peter B. McMahon, Ph.D., research hydrologist with the U.S. Geological Survey’s Colorado Water Science Center, has more than 30 years of experience conducting groundwater-quality studies across the United States and is currently studying the effects of energy development on groundwater quality in Arkansas, California, Colorado, Louisiana, and Texas. He earned his master’s degree in geology from the University of Texas at Austin and his Ph.D. in geology from the University of South Carolina.