1. Stroud Water Research Center; 970 Spencer Road Avondale PA 19311 USA
2. Department of Geological Sciences; University of Delaware; 255 Academy Street Newark DE 19716 USA
3. Department of Geography; University of Delaware; 125 Academy Street Newark DE 19716 USA
4. Department of Plant and Soil Sciences; University of Delaware; 531 South College Avenue Newark DE 19716 USA
5. College of Life and Environmental Sciences; University of Exeter; Amory Building, Rennes Drive Exeter Devon EX4 4RJ UK