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Hydraulic Tomography for Aquifer Properties in Heterogeneous Aquifers

This presentation discusses the use of hydraulic tomography surveys, specifically cross-hole pumping tests, to estimate hydrogeological properties in heterogeneous aquifers. Topics covered include the concept of hydraulic tomography, an example test, the effect of aquifer heterogeneity on the inverse model, preliminary results, and future work.

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Hydraulic Tomography for Aquifer Properties in Heterogeneous Aquifers

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  1. Field –scale Cross-hole Pumping Tests to Estimate Hydrogeological Properties in Heterogeneous Aquifers Presenter: Huang, yi-ru Advisor: Ni, chuen-fa Date: 2008/10/09

  2. Outline • Introduction • Concept of hydraulic tomography surveys • Test example(VSAFT2 model) • Effect of aquifer heterogeneity on inverse model • Experiment site • Preliminary results • Future work

  3. Introduction (1) • Ground water investigations have relied on the determination of aquifer parameters. • Traditional analysis only measure the depth-averaged K values around wells. • Hydraulic tomography is a viable technology to estimate the parameters in heterogeneous aquifer.

  4. Introduction (2) • Hydraulic tomography: development of a new aquifer test method [Yeh and Liu, 2000] • Characterization of aquifer heterogeneity using transient hydraulic tomography [Yeh and Zhu, 2005] • Sequential aquifer tests at a well field, Montalto Uffugo Scalo, Italy [Strface et al., 2007] • Application of tomography surveys to estimate heterogeneous hydrogeological properties [Yeh and Ni, 2008]

  5. Introduction (3) • To estimate the spatial distribution of hydraulic properties in the inverse model (VSAFT2) at field scale and evaluate the accuracy and the applicability of the numerical inverse model for practical problems.

  6. Concept of Hydraulic Tomography – horizontal cross-hole pumping test observation observation observation pumping observation observation pumping observation observation observation observation observation observation observation pumping pumping

  7. Concept of Hydraulic Tomography -vertical cross-hole pumping test

  8. Hydraulic Tomography Survey • Data collection: Cross-hole pumping test To obtain many independent pumping data. • Data integration: Numerical model inversion To integrate information of aquifer and estimate the spatial distributions of hydraulic conductivity.

  9. Test Example – VSAFT2 Model K (m/day) Correlation length x=40 m Correlation length z= 5 m Variance= 1.0 Mean=1.0 m/day Pumping rate= 25 m3/day

  10. Effect of Aquifer Heterogeneity on Inverse Model Basic setting: area: 60x20m , Pumping rate= 25 m3/day correlation length (x)= 40m, correlation length (z)= 5m variance= 1.0 , mean = 1.0, observation no.= 9 L1: mean absolute error , L2: mean square error Case: • Variance: 0.1, 0.5, 1.0, 2.0 • Correlation length (x): 20m, 40m, 60m, 80m

  11. Case: variance

  12. Case: correlation length (x)

  13. Introduction of Experiment Site 資料來源: 高雄輔英科技大學

  14. Water table before pumping at 2008/01/24

  15. Conceptual Position (horizontal plane)

  16. PreliminaryResult - steady state 03 02 01 01 04 05

  17. Future Work • Horizontal plane: transient state • Vertical plane: steady & transient state • To combine with the data of horizontal and vertical pumping test and to estimate the spatial distribution of hydraulic parameters in quasi-3D model.

  18. Thank you!

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