HR: 0830h
AN: H11E-0895 INVITED     [PDF]
TI: Validation of Groundwater Models: Meaningful or Meaningless?
AU: * Konikow, L F
EM: lkonikow@usgs.gov
AF: U.S. Geological Survey, 431 National Center, Reston, VA 20192
AB: Although numerical simulation models are valuable tools for analyzing groundwater systems, their predictive accuracy is limited. People who apply groundwater flow or solute-transport models, as well as those who make decisions based on model results, naturally want assurance that a model is "valid." To many people, model validation implies some authentication of the truth or accuracy of the model. History matching is often presented as the basis for model validation. Although such model calibration is a necessary modeling step, it is simply insufficient for model validation. Because of parameter uncertainty and solution non-uniqueness, declarations of validation (or verification) of a model are not meaningful. Post-audits represent a useful means to assess the predictive accuracy of a site-specific model, but they require the existence of long-term monitoring data. Model testing may yield invalidation, but that is an opportunity to learn and to improve the conceptual and numerical models. Examples of post-audits and of the application of a solute-transport model to a radioactive waste disposal site illustrate deficiencies in model calibration, prediction, and validation.
DE: 1829 Groundwater hydrology
DE: 1832 Groundwater transport
DE: 3210 Modeling
SC: Hydrology [H]
MN: 2003 Fall Meeting