Coupled Hydro-Geophysical Inversion of River Water Intrusion and Biogeochemical Transport Modeling at the Hanford 300 Area
EMSL Project ID
47870
Abstract
As part of the 2013 research portfolio within the Climate and Environmental Sciences Division of the Office of Biological and Environmental Research (BER) at the Department of Energy Office of Science, the Pacific Northwest National Laboratory Subsurface Science Focus Area (PNNL SFA) is modeling system-scale groundwater-river water exchange at the Hanford 300 Area to study the impact of this mixing on groundwater geochemistry and microbial populations at the site. Groundwater flow and biogeochemical transport within the Hanford 300 Area is strongly coupled and very complex as the river stage fluctuates seasonally and daily due to seasonal and man-made influences (i.e. hydroelectric dams). As a result, the water table rapidly rises and falls as river water enters, mixes with groundwater, and recedes from the domain. The mixing process greatly impacts water chemistry and subsequently soil microbial life at the site as the river water chemistry can differ significantly from that of the groundwater. It also directly impacts the migration of contaminants at the site.The purpose of this research is to invert for hydrologic parameters employed within this system scale model through assimilating data from groundwater monitoring (water level and chemistry) and geophysical investigations (electrical resistivity tomography or ERT). A Bayesian data assimilation framework is being employed that requires the execution of ensembles of simulations (e.g. tens to hundreds) on a supercomputer using PFLOTRAN (Hammond et al., 2012) and FERM3D (Johnson et al., 2010), each simulation requiring on the order of thousands of processor cores. A single iteration of the data assimilation process can easily require several hundred thousands of hours on the supercomputer. Iteration continues as new data becomes available proceeding until uncertainty is adequately bounded. The optimized hydrologic model will then be used as the base flow model for the PNNL SFA's biogeochemical transport modeling effort where PFLOTRAN will further be employed to simulate the fate and transport of microbial populations at the site.
Accomplishments of this research will include the development of a parameterized system scale model that can be used to (1) predict variably saturated flow and biogeochemical transport within the Hanford 300 Area given future river water and groundwater elevation measurements and geochemistry, (2) study long-term microbial ecology within the site, and (3) assess indirect climatic impacts to biogeochemical cycles within the domain. The research will also demonstrate a novel inverse method for incorporating geophysical data in hydrologic parameter estimation.
Project Details
Project type
Large-Scale EMSL Research
Start Date
2013-10-01
End Date
2015-09-30
Status
Closed
Released Data Link
Team
Principal Investigator
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