HR: 0830h
AN: H51B-03    [Abstracts]
TI: Using Dual-Region Calibration to Improve Recharge and Hydraulic Conductivity Estimates for Hydrologic Modeling
AU: * Kendall, A D
EM: kendal30@msu.edu
AF: Michigan State University, 206 Natural Sciences Building, East Lansing, MI 48824 United States
AU: Spansky, M C
EM: matt.spansky@erm.com
AF: ERM Southwest, 15810 Park Ten Place Suite 300, Houston, TX 77084-5140 United States
AU: Hyndman, D H
EM: hyndman@msu.edu
AF: Michigan State University, 206 Natural Sciences Building, East Lansing, MI 48824 United States
AB: High-resolution regional groundwater flow models commonly have large uncertainties as a result of poorly calibrated parameters. One source of these uncertainties is the inherently non-unique nature of recharge and hydraulic conductivity parameters estimated using either stream fluxes or hydraulic head as the primary data set. Elevated recharge can have the equivalent effect of a decrease in conductivity on the simulated hydraulic heads. Likewise, a predominately flux-calibrated model can have very low sensitivity to conductivity parameters. Thus simply calibrating a transient model to either head or stream flux measurements is inadequate. This study presents a novel solution to these problems by demonstrating that the linked calibration of two separate regional groundwater flow models can produce a parameter set superior to those obtained from either individual model calibration alone. The two regions are geological and climatologically similar, and each region was calibrated with predominantly one data type. The two modeled regions for this study are the Grand Traverse Bay watershed (GTBW) and the Muskegon River watershed (MRW) in northern lower-Michigan. Within the GTBW, a network of 16 pressure transducers was used to monitor hydraulic head continuously for almost two years. In the MRW, approximately 150 base flow stream discharges were collected over the same time period, yielding a dense set of flux calibration targets. A simultaneous, parallel, parameter optimization method is presented, and the results are compared to separate parameter optimizations of each individual model. The overall effectiveness of the technique is evaluated by comparing optimized parameters to available estimates of recharge and conductivity from other studies, demonstrating that the dual-model calibration method can improve our ability to jointly estimate recharge and hydraulic conductivity for regional aquifers.
DE: 1829 Groundwater hydrology
SC: Hydrology [H]
MN: 2005 Joint Assembly