1. Dep. of Civil Engineering and Operations Research; Princeton Univ.; Princeton NJ 08544
2. Inst. of Terrestrial Ecology, Swiss Federal Inst. of Technology ETH; Grabenstr. 3/11a CH 8952 Schlieren Switzerland
3. U.S. Salinity Lab.; USDA-ARS; 450 W. Big Springs Road Riverside CA 92507-4617