*Weinberg is Assistant Professor, Department of Environmental Science and Policy, University of California, Davis.
Knapp is Professor, Department of Environmental Sciences, University of California, Riverside.
Howitt is Professor, Department of Agricultural and Resource Economics, University of California, Davis.
Posnikoff is Research Associate, Collins Associates, Newport Beach, CA.
A more complete version of this paper is included in Ground Water and Future Supply: Proceedings of the 21st Biennial Conference on Groundwater, Johannes DeVries and Jeff Woled, editors, Water Resources Center Report #95, Centers for Water and Wildland Resources, University of California, Davis, (in-press)