HR: 1340h
AN: H23B-1300    [Abstracts]
TI: Sensitivity Analysis of Hydraulic Parameters on Radionuclide Transport Uncertainty in the Unsaturated Zone of Yucca Mountain
AU: * Pan, F
EM: feng.pan@dri.edu
AF: Division of Hydrologic Sciences Desert Research Institute, 755 E Flamingo Rd, Las Vegas, NV 89119, United States
AU: * Pan, F
EM: feng.pan@dri.edu
AF: Department of Geosciences University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, United States
AU: Zhu, J
EM: Jianting.zhu@dri.edu
AF: Division of Hydrologic Sciences Desert Research Institute, 755 E Flamingo Rd, Las Vegas, NV 89119, United States
AU: Ye, M
EM: mingye@scs.fsu.edu
AF: School of Computational Science Florida State University, 441 Dirac Science Library, Tallahassee, FL 32306, United States
AU: Ye, M
EM: mingye@scs.fsu.edu
AF: Department of Geologic Sciences Florida State University, 108 Carraway Building, Tallahassee, FL 32306, United States
AU: Wu, Y
EM: YSWu@lbl.gov
AF: Earth Sciences Division Lawrence Berkeley National Laboratory, 1 Cyclotron Rd., Berkeley, CA 94720, United States
AU: Yu, Z
EM: zhongbo.yu@unlv.edu
AF: Department of Geosciences University of Nevada Las Vegas, 4505 Maryland Parkway, Las Vegas, NV 89154, United States
AU: Hu, B
EM: hu@gly.fsu.edu
AF: Department of Geologic Sciences Florida State University, 108 Carraway Building, Tallahassee, FL 32306, United States
AB: The parametric uncertainty and heterogeneity in matrix permeability, porosity and matrix van Genuchten alpha and n can cause significant uncertainty of unsaturated flow and radionuclide transport predictions in the unsaturated zone (UZ) of Yucca Mountain (YM). Sensitivity analysis is necessary to determine the contribution of individual hydraulic parameters to the uncertainty of flow and radionuclide transport processes. In this study, we conduct the sensitivity analysis of the hydraulic parameters (i.e., matrix permeability, porosity, van Genuchten alpha and n) on the flow and transport uncertainty using a sampling-based (i.e. Monte Carlo) approach in the three-dimensional heterogeneous UZ of YM. The random fields of the hydraulic parameters were generated using Latin Hypercube Sampling (LHS) and the Monte Carlo simulations of flow and transport were conducted. The stepwise regression analysis is applied to find the relationships between the input variables (i.e., hydraulic parameters) and the output variables (e.g., saturation, percolation flux, and radionuclide travel time) and then to rank the importance of uncertainty in individual parameters to the flow and transport uncertainty using the standardized rank regression coefficient (SRRC) for each gridblock. The top down coefficient of concordance (TDCC) is then used to measure the agreement of input parameter rankings obtained by stepwise regression analysis for different gridblocks in the same hydrogeologic layer. Therefore, the important input variables for each hydrogeologic layer can be identified and their rankings can be obtained. The analysis results indicate that the matrix permeability and van Genuchten alpha are most influential parameters on the uncertainty of flow and transport for most hydrogeologic layers. The outcome of this study can not only reduce the computational cost but also provide the important information about which parameters should be the focus for future monitoring efforts.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 1847 Modeling
DE: 1869 Stochastic hydrology
DE: 1873 Uncertainty assessment (3275)
SC: Hydrology [H]
MN: 2007 Fall Meeting