Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area
Abstract
This report to the Nuclear Regulatory Commission (NRC) describes the development and application of a methodology to systematically and quantitatively assess predictive uncertainty in groundwater flow and transport modeling that considers the combined impact of hydrogeologic uncertainties associated with the conceptualmathematical basis of a model, model parameters, and the scenario to which the model is applied. The methodology is based on a n extension of a Maximum Likelihood implementation of Bayesian Model Averaging. Model uncertainty is represented by postulating a discrete set of alternative conceptual models for a site with associated prior model probabilities that reflect a belief about the relative plausibility of each model based on its apparent consistency with available knowledge and data. Posterior model probabilities are computed and parameter uncertainty is estimated by calibrating each model to observed system behavior; prior parameter estimates are optionally included. Scenario uncertainty is represented as a discrete set of alternative future conditions affecting boundary conditions, source/sink terms, or other aspects of the models, with associated prior scenario probabilities. A joint assessment of uncertainty results from combining model predictions computed under each scenario using as weight the posterior model and prior scenario probabilities. The uncertainty methodology was applied to modeling of groundwatermore »
 Authors:
 Publication Date:
 Research Org.:
 Pacific Northwest National Lab. (PNNL), Richland, WA (United States)
 Sponsoring Org.:
 USDOE
 OSTI Identifier:
 921264
 Report Number(s):
 NUREG/CR6940; PNNL16396
401001060; TRN: US0800942
 DOE Contract Number:
 AC0576RL01830
 Resource Type:
 Technical Report
 Country of Publication:
 United States
 Language:
 English
 Subject:
 11 NUCLEAR FUEL CYCLE AND FUEL MATERIALS; 58 GEOSCIENCES; HANFORD RESERVATION; GROUND WATER; URANIUM; RADIONUCLIDE MIGRATION; COLUMBIA RIVER; FLOW MODELS; HYDROLOGY; GEOLOGIC MODELS; DATA COVARIANCES; GEOCHEMISTRY; hydrogeologic; US Nuclear Regulatory Commission; conceptual model; groundwater flow; Columbia River; Hanford Site; 300 Area
Citation Formats
Meyer, Philip D., Ye, Ming, Rockhold, Mark L., Neuman, Shlomo P., and Cantrell, Kirk J. Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area. United States: N. p., 2007.
Web. doi:10.2172/921264.
Meyer, Philip D., Ye, Ming, Rockhold, Mark L., Neuman, Shlomo P., & Cantrell, Kirk J. Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area. United States. doi:10.2172/921264.
Meyer, Philip D., Ye, Ming, Rockhold, Mark L., Neuman, Shlomo P., and Cantrell, Kirk J. 2007.
"Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area". United States.
doi:10.2172/921264. https://www.osti.gov/servlets/purl/921264.
@article{osti_921264,
title = {Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty with Application to Uranium Transport at the Hanford Site 300 Area},
author = {Meyer, Philip D. and Ye, Ming and Rockhold, Mark L. and Neuman, Shlomo P. and Cantrell, Kirk J.},
abstractNote = {This report to the Nuclear Regulatory Commission (NRC) describes the development and application of a methodology to systematically and quantitatively assess predictive uncertainty in groundwater flow and transport modeling that considers the combined impact of hydrogeologic uncertainties associated with the conceptualmathematical basis of a model, model parameters, and the scenario to which the model is applied. The methodology is based on a n extension of a Maximum Likelihood implementation of Bayesian Model Averaging. Model uncertainty is represented by postulating a discrete set of alternative conceptual models for a site with associated prior model probabilities that reflect a belief about the relative plausibility of each model based on its apparent consistency with available knowledge and data. Posterior model probabilities are computed and parameter uncertainty is estimated by calibrating each model to observed system behavior; prior parameter estimates are optionally included. Scenario uncertainty is represented as a discrete set of alternative future conditions affecting boundary conditions, source/sink terms, or other aspects of the models, with associated prior scenario probabilities. A joint assessment of uncertainty results from combining model predictions computed under each scenario using as weight the posterior model and prior scenario probabilities. The uncertainty methodology was applied to modeling of groundwater flow and uranium transport at the Hanford Site 300 Area. Eight alternative models representing uncertainty in the hydrogeologic and geochemical properties as well as the temporal variability were considered. Two scenarios represent alternative future behavior of the Columbia River adjacent to the site were considered. The scenario alternatives were implemented in the models through the boundary conditions. Results demonstrate the feasibility of applying a comprehensive uncertainty assessment to largescale, detailed groundwater flow and transport modeling and illustrate the benefits of the methodology I providing better estimates of predictive uncertiay8, quantitative results for use in assessing risk, and an improved understanding of the system behavior and the limitations of the models.},
doi = {10.2172/921264},
journal = {},
number = ,
volume = ,
place = {United States},
year = 2007,
month = 7
}

The objective of the research described in this report is the development and application of a methodology for comprehensively assessing the hydrogeologic uncertainties involved in dose assessment, including uncertainties associated with conceptual models, parameters, and scenarios. This report describes and applies a statistical method to quantitatively estimate the combined uncertainty in model predictions arising from conceptual model and parameter uncertainties. The method relies on model averaging to combine the predictions of a set of alternative models. Implementation is driven by the available data. When there is minimal sitespecific data the method can be carried out with prior parameter estimates basedmore »

Combined Estimation of Hydrogeologic Conceptual Model, Parameter, and Scenario Uncertainty
We describe the development and application of a methodology to systematically and quantitatively assess predictive uncertainty in groundwater flow and transport modeling that considers the combined impact of hydrogeologic uncertainties associated with the conceptualmathematical basis of a model, model parameters, and the scenario to which the model is applied. The methodology is based on an extension of a Maximum Likelihood implementation of Bayesian Model Averaging. Model uncertainty is represented by postulating a discrete set of alternative conceptual models for a site with associated prior model probabilities that reflect a belief about the relative plausibility of each model based on itsmore » 
Borehole Completion and Conceptual Hydrogeologic Model for the IFRC Well Field, 300 Area, Hanford Site
A tight cluster of 35 new wells was installed over a former waste site, the South Process Pond (3161 waste site), in the Hanford Site 300 Area in summer 2008. This report documents the details of the drilling, sampling, and well construction for the new array and presents a summary of the site hydrogeology based on the results of drilling and preliminary geophysical logging. 
DEVELOPMENT OF A GEOCHEMICAL MODEL FOR URANIUM TRANSPORT IN THE UNSATURATED AND SATURATED SEDIMENTS AT THE 200 WEST AREA OF THE US DEPARTMENT OF ENERGY HANFORD SITE WASHINGTON (SEPTEMBER 2004)
Final Deliverable under GWPHQLMT02 contract for Hanford Sci. & Tech. Gp. to BHI. The scope of work covered laboratory analyses and gephysical logging for 299W1943 near the 200 West U Plant. Other isotopic analyses were conducted for holes around 216U1&2, including U236. 
Hydrogeologic Model for the Gable Gap Area, Hanford Site
Gable Gap is a structural and topographic depression between Gable Mountain and Gable Butte within the central Hanford Site. It has a long and complex geologic history, which includes tectonic uplift synchronous with erosional downcutting associated with the ancestral Columbia River during both Ringold and Cold Creek periods, and by the later Ice Age (mostly glacial Lake Missoula) floods. The gap was subsequently buried and partially backfilled by mostly coarsegrained, Ice Age flood deposits (Hanford formation). Erosional remnants of both the Ringold Formation and Cold Creek unit locally underlie the highenergy flood deposits. A large window exists in the gapmore »