1. Department of Civil and Environmental Engineering; University of Washington; Seattle WA 98195 USA
2. School of Earth and Space Exploration and School of Sustainable Engineering and the Built Environment; Arizona State University; Tempe AZ 85287 USA
3. Southwest Watershed Research Centre; Agricultural Research Service, USDA; Tucson AZ 85719 USA
4. School of Civil and Environmental Engineering and School of Earth and Planetary Sciences; Georgia Institute of Technology; Atlanta GA 30332 USA