HR: 0800h
AN: H11C-0318    [Abstracts]
TI: Calibration of the Geometry of Hydraulic Conductivity Zones in Groundwater Flow Models
AU: * Matott, L S
EM: lsmatott@buffalo.edu
AF: University at Buffalo, Department of Civil, Structural, and Environmental Engineering 207 Jarvis Hall, Buffalo, NY 14260 United States
AU: Fredrick, K C
EM: kncfred@yahoo.com
AF: University at Buffalo, Department of Geology 876 Natural Science Complex, Buffalo, NY 14260 United States
AU: Rabideau, A J
EM: rabideau@eng.buffalo.edu
AF: University at Buffalo, Department of Civil, Structural, and Environmental Engineering 207 Jarvis Hall, Buffalo, NY 14260 United States
AU: Becker, M W
EM: mwbecker@geology.buffalo.edu
AF: University at Buffalo, Department of Geology 876 Natural Science Complex, Buffalo, NY 14260 United States
AB: Subsurface properties in groundwater models are commonly defined using zones of uniform hydraulic conductivity, based upon geologic maps and data from different types of aquifer tests. Because of the sparsity and varying resolution of geologic data, true conductivity values and the precise location of zonal or transitional boundaries are unknown. Automated calibration software typically adjusts uncertain conductivity values to minimize the sum of the squared differences between simulated and measured observation data. However, the geometry of the conductivity zones is usually not adjusted during this process. This approach limits the flexibility of the model and introduces a subjective bias with regard to the assignment of conductivity boundaries. In this study, both the geometry and conductivity of model subregions are treated as uncertain parameters to be calibrated by automated inverse modeling software. Two different types of zonal geometry are examined: circular and polygonal. During the calibration process, the radii and centroid coordinates of circular heterogeneities and the vertices of polygonal heterogeneities are treated as adjustable parameters. A test case is studied where the geometry and hydraulic conductivity of a region of suspected heterogeneity are simultaneously calibrated. To allow for direct representation of continuously varying coordinate parameters, a two-dimensional analytic-element groundwater model is used.
DE: 1800 HYDROLOGY
DE: 1829 Groundwater hydrology
SC: Hydrology [H]
MN: 2004 AGU Fall Meeting