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Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash. Paper 7191 Presented at: Waste Management 07’ Symposium Tuesday, February 25 - March 1, 2007 Session 29: Performance Assessment of Geological Disposal Systems Tuesday, February 27, 2007: 8:30 AM

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Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

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  1. Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash Paper 7191 Presented at: Waste Management 07’ Symposium Tuesday, February 25 - March 1, 2007 Session 29: Performance Assessment of Geological Disposal Systems Tuesday, February 27, 2007: 8:30 AM Tucson Convention Center Room: Coconino By: Arturo Woocay and John C. Walton Environmental Science and Engineering The University of Texas at El Paso

  2. Acknowledgement This work was funded by the Nye County, Nevada, Nuclear Waste Repository Project Office through cooperative research grant DE-FC28-02RW12163 from the U.S. Department of Energy, Office of Civilian Radioactive Waste Management

  3. Overview • Introduction • Yucca Mountain Region • Amargosa Desert Region Water Levels • Geochemical Data from the Region • Previous Work • Introduction to Multivariate Statistical Methods (MSM) • Correspondence analysis (CA) • k-means Cluster Analysis (KMCA) Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  4. Overview (Cont’d) • MSM Results • Nine separate hydrochemical facies • At least two potential flowpaths • Very distinct flowpath under Fortymile Wash • Corroborating Isotopic Data • Oxygen-18 • Hydrogen-2 • Hydrogen-2 vs Oxygen-18 compared to GMWL • Conclusions Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  5. Amargosa Desert Yucca Mountain Fortymile Wash Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  6. Amargosa Desert Region Water Levels Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  7. Major Ion Chemistry from the Amargosa Desert Region • 211 wells/springs • Use MSM: CA & KMCA Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  8. Major Ion ChemistryPiper (Trilinear) Diagrams Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  9. Introduction to MSM • MSM are powerful tools for: • Investigating large complex data sets • Identifying parameters that describe a system and its behavior • Discovering patterns and relationships Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  10. Introduction to MSM (Cont’d) • Some types of MSM: • Principal Component Analysis • Canonical Correlation Analysis • Factor Analysis • Correspondence Analysis (CA) • Cluster Analysis • k-means Cluster Analysis (KMCA) Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  11. Correspondence Analysis • A weighted Principal Component Analysis (PCA) of a contingency table • Transforms correlated data into mutually orthogonal dimensions • Each successive dimension includes decreasing amounts of variation • Better that PCA for finding and interpreting nonlinearity in the system • Reduce number of dimensions of the system Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  12. k-means Cluster Analysis • Nonhierarchical supervised partitioning cluster analysis • Minimize variability within each cluster and maximize it between clusters • Uses Euclidean distances and centroids • One initial “seed” per k-cluster then centroids are recalculated after each observation is clustered • The number of desired groups must be predetermined Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  13. MSM Results • Using Major Ion data from 211 wells/springs in the Amargosa Desert Region • CA conducted in Statistica 7 • Reduce the number of variables • Detect relationships between variables • k-means Cluster Analysis (CA) • Nonhierarchical supervised partitioning CA • Empirically determined 9 groups • Analyze the first 3 CA dimensions Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  14. Interpretation of CA Dimensions • Dimension 1: • Separation of pH, Alkalinity & Na+ from Ca2+ & Mg2+ and Cl- & SO42- • Dimension 2: • Separation of Ca2+ & Mg2+ from Cl-, Na+ & SO42- • Dimension 3: • Explains less than 10% of variation Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  15. k-means CA Interpretation Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  16. Biplot of Dimension 1 - Dimension 2 Can Identify 9 Separate Groups with Cluster Analysis Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  17. Summary of Major Ions by Group Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  18. Hydrochemical Facies and Processes Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  19. Dimension 1 Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  20. Dimension 2 Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  21. MSM Conclusions • GW chemistry reflects prominent surface features more that contemporary water levels • GW chemistry below Oasis Valley and following the Amargosa River • GW below Yucca Mountain different from Fortymile Wash • Some connection between Amargosa Valley and Death Valley • Possible upwelling from carbonate aquifer • Very distinct signature around Fortymile Wash Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  22. Corroborating Isotopic Data • Oxygen-18 • Hydrogen-2 • Hydrogen-2 vs Oxygen-18 compared to GMWL Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  23. δ18O Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  24. δ2H Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  25. Deviation form the GMWL http://www.sahra.arizona.edu Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  26. δ2H vs. δ18O Cold (7oC) S = 6.1 More humid and colder climate than contemporary (Clark and Fritz 1997, p. 49 after Gat, 1980) Craig 8 10 1961, Int At Engy Agy (IAEA) global network 8.13 10.8 IAEA World Met Org (WMO) 8.17 11.27 true Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  27. δ 2H vs. δ18O Down Fortymile Wash Following the Amargosa River Mixing with Amargosa River Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  28. Conclusions • Distinct signature along Fortymile Wash • Closely follows topography • Lower TDS than adjacent water • Younger than adjacent groundwater • Implying: focused infiltration in the past of colder surface water in the wash that decreased as runoff events diminished • Runoff events diminished as climate became warmer and dryer • Contemporary groundwater flow may be slower than currently predicted Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  29. Questions? Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  30. Predicted Saturated Zone Particle Trajectories from Yucca Mountain From: Technical Basis Document No 11: Saturated Zone Flow and Transport Revision 2 Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  31. ISIP Background • The Nuclear Waste Policy Act(NWPA) in 1983 directed DOE to develop a geologic repository to dispose of the nation’s spent nuclear fuel and high-level waste. • In 1987, Congress amended the NWPA and designatedYucca Mountain as the only site to be considered. • The NWPAauthorizesNye County as the "site" jurisdiction and host county, to conduct on-site representation at Yucca Mountain. • In 1987 Nye County Board of Commissioners creates the Nye County Nuclear Waste Repository Project Office (NWRPO) to monitor and assess the federal effort to find a repository site. • In 1993, the County hired a full-time on-site representative and the Independent Scientific Investigations Program (ISIP) is established. • Though ISIP the County gathers data for independent analysis of geologic and hydrologic conditions and monitors and reviewsDOE's scientific characterization of Yucca Mountain • ISIP activities involve drilling and instrumenting boreholes, analyzing the geology and geochemistry of drill cuttings, instrumenting tunnels and drifts, monitoring, data analysis, and numerical modeling activities to address the concerns of Nye County. Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  32. ISIP Background • The Nuclear Waste Policy Act (NWPA) in 1983 directed DOE to develop a geologic repository to dispose of the nation’s spent nuclear fuel and high-level waste. • In 1987, Congress amended the NWPA and designated Yucca Mountain as the only site to be considered. • The NWPA authorizes Nye County as the "site" jurisdiction and host county, to conduct on-site representation at Yucca Mountain. • In 1987 Nye County Board of Commissioners creates the Nye County Nuclear Waste Repository Project Office (NWRPO) to monitor and assess the federal effort to find a repository site. • In 1993, the County hired a full-time on-site representative and the Independent Scientific Investigations Program (ISIP) is established. • Though ISIP the County gathers data for independent analysis of geologic and hydrologic conditions and monitors and reviews DOE's scientific characterization of Yucca Mountain • ISIP activities involve drilling and instrumenting boreholes, analyzing the geology and geochemistry of drill cuttings, instrumenting tunnels and drifts, monitoring, data analysis, and numerical modeling activities to address the concerns of Nye County. Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

  33. Nye County, Nevada Located in the south-central portion of Nevada • Third largest county in US (11,560,960 acres) • About 22 % designated for federal restricted access or for U.S. government classified activities. Includes: • Nevada Test Site • Nelis Air Force Range • Tonopah Test Range • Yucca Mountain Project Woocay-Walton: Multivariate Statistical Analyses of Groundwater Surrounding Fortymile Wash

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