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Mark D. Kozar , USGS Washington WSC, Tacoma WA Dick Yager , USGS New York WSC, Ithaca NY

Groundwater Resources in the Piedmont and Shenandoah Valley: A Comparison of Geologic Controls on Groundwater Quality and Sustainability PART I: Shenandoah Valley Enhanced Understanding for Aquifer Health. Mark D. Kozar , USGS Washington WSC, Tacoma WA

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Mark D. Kozar , USGS Washington WSC, Tacoma WA Dick Yager , USGS New York WSC, Ithaca NY

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  1. Groundwater Resources in the Piedmont and Shenandoah Valley: A Comparison of Geologic Controls on Groundwater Quality and SustainabilityPART I: Shenandoah ValleyEnhanced Understanding for Aquifer Health Mark D. Kozar, USGS Washington WSC, Tacoma WA Dick Yager, USGS New York WSC, Ithaca NY Kurt J. McCoy, George Harlow, and Dave Nelms USGS Virginia WSC, Richmond VA

  2. Karst Continuum Model Whitings Neck Cave http://www.swarpa.net/~danforth/photos/caves/wn_weddingcake.jpg • CAVES OF THE EASTERN PANHANDLE • •Not that many caves • –42 known caves in Jefferson County • –48 known caves in Berkeley County • •Most are short and not of hydrological interest

  3. Outline – Nested Modeling What is important for aquifer health depends on scale • Leetown • Science Center • (Kozar et al, 2007) • Shenandoah Valley • (Yager et al, 2009) • Opequon Creek • (Kozar and Weary, 2009) 3,300 mi2 300 mi2 10 mi2

  4. Structure Shenandoah Valley Model 3,300 mi2 Yager, RM, Voss, CI, Southworth, S, 2009, Comparison of alternative representations of hydraulic-conductivity anisotropy in folded fractured-sedimentary rock: modeling groundwater flow in the Shenandoah Valley (USA): Hydrogeology Journal, v. 17, p. 1111-1131.

  5. Shenandoah Valley Regional Conceptual Model (Yager et al., 2009)

  6. Numerical Representation Of Regional Scale Anisotropy Groundwater flows along preferential paths (Yager et al., 2009)

  7. Well Capture zones – Influence of Anisotropy

  8. Meso Scale - Opequon Creek Model

  9. Meso-Scale (300 mi2) Conceptual Model Photo courtesy of Craig Wagnell (portaec.net) Epikarst Fractured Karst Photo by WilOrndorff Fractured Rock

  10. Influence of Lithology – ALL ROCKS ARE NOT ALIKE

  11. Leetown Ground-Water Flow Model • Three layer model • Tectonic Deformation • KARST • Vertical permeability contrast • Fault Orientation

  12. Major fractures occur parallel to regional strike N. 20o E. and perpendicular to strike. Thrust faults parallel to strike and cross strike faults are especially important controls on ground-water flow. Fracture Orientations in the Leetown Area, WV Fractures mapped by a) Jones and Deike, 1981 and b) McCoy and others, 2005

  13. Faults Karst zones Fold Hinges or Lithologic Contacts Deformation Orthogonal Fracturing Fracture-Flow Bed-limited permeability

  14. Gradient

  15. Leetown Surface Geophysics – AMT Plan View X-Sect View

  16. Scale-Related Evolution of Conceptual Models Tectonic Deformation Primary Deposition Heterogeneity 3,300 mi2 300 mi2 10 mi2

  17. Conclusions Nested Models – Scale Dependent Controls on Flow Basin Geometry Orderly Preferential Flow Paths Carbonate Heterogeneity Not All Rocks are Alike Fault Zone Hydrology Important Routes to Drain The Aquifer

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