1. Undergrad. Student, Dept. of Geological Sci., Univ. of California, Santa Barbara, CA 93106.
2. Asst. Prof., Dept. of Geological Sci., Univ. of California, Santa Barbara, CA (corresponding author).
3. Orange County Water Dist., 10500 Ellis Ave., Fountain Valley, CA 92708.
4. Orange County Water Dist., 10500 Ellis Ave., Fountain Valley, CA.