HR: 1340h
AN: H23B-1305    [Abstracts]
TI: A Proposed Objective-Oriented Groundwater Model for Conjunctive Use Planning of Surface and Groundwater
AU: * Chiu, Y
EM: ycchiu@ucla.edu
AF: Department of Civil and Environmental Engineering, University of California, Los Angeles, 6730C Boelter Hall, UCLA, Los Angeles, CA 90095-1593, Los Angeles, CA 90095, United States
AU: Sun, N
EM: nezheng@ucla.edu
AF: Department of Civil and Environmental Engineering, University of California, Los Angeles, 6730C Boelter Hall, UCLA, Los Angeles, CA 90095-1593, Los Angeles, CA 90095, United States
AU: Nishikawa, T
EM: tnish@usgs.gov
AF: California Water Science Center, San Diego Project Office, U.S. Geological Survey, 4165 Spruance Rd, Suite 200, San Diego, CA 92101, San Diego, CA 92101, United States
AU: Yeh, W W
EM: williamy@seas.ucla.edu
AF: Department of Civil and Environmental Engineering, University of California, Los Angeles, 6730C Boelter Hall, UCLA, Los Angeles, CA 90095-1593, Los Angeles, CA 90095, United States
AB: Groundwater models are used for planning and management of water resources systems. One of the most difficult problems in groundwater modeling is the assessment of model uncertainty. Up till today, this problem has not been completely resolved. The main reasons are that the real geological structure of an aquifer is complex and unknown, and the available data for model calibration are usually limited in both quantity and quality. It is well understood that a more complex model with more parameters may fit the existing data better, but it may cause over-parameterization. It is also well established that over-parameterization renders high uncertainty in model application. An objective-oriented model is constructed based on the reliability requirements in model applications as opposed to the traditional data-driven modeling approach. Specifically, an objective-oriented model seeks to identify a reliable model that is the simplest in model structure. A "reliable model" means that if the model is used for prediction and management it can produce reliable results for a specified model application, and "simple" means that the model has a structure as simple as possible. This study briefly reviews the theoretical basis of constructing an objective-oriented groundwater model. Afterwards, an objective-oriented model is constructed for a conjunctive-use project of imported surface water and groundwater in the desert area, Warren Basin in Southern California. Model fitting residual, model application objectives, and model structure error of replacing a complex model with a simpler model for the Warren Basin are formulated. The formulated problem is solved by a global-local optimization scheme. The sufficiency of the existing data is judged by solving a generalized inverse problem. When the existing data are insufficient for constructing a reliable model for the specified model application objectives, a robust and cost-effective field experiment is designed for collecting the necessary data to make the calibrated model reliable for the stipulated model application objectives.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1846 Model calibration (3333)
DE: 1847 Modeling
DE: 1873 Uncertainty assessment (3275)
SC: Hydrology [H]
MN: 2007 Fall Meeting