HOW TO DETERMINE HYDRAULIC CONDUCTIVITY WITHOUT ANY WELL?

1. HOW TO DETERMINE HYDRAULIC CONDUCTIVITY WITHOUT ANY WELL? Department of Geological Sciences Faculty of Science, Masaryk University Brno, Czech Republic

2. Hydraulic conductivity k (m/s) • basic hydraulic parameter Darcy´s law flow velocity diferential equations of groundwater flow and/or transport

3. Hydraulic conductivity k (m/s) Methods of determination • Laboratory methods – lab permeameters • Field methods – hydrodynamic testing • Stochastic methods • disadvantages - need of big amount of samples - need of wells and boreholes

4. Methods of determination – LAB PERMEAMETERS • constant head • falling head T i m e i s c r u c i a l, watch for hydraulic gradients ! ! !

5. Methods of determination – LAB PERMEAMETERS • be very carefull with variability of k values in aquifer • need of big amount of samples • concept of REV Representative Elementary Volume

6. Hydraulic conductivity k (m/s) Methods of determination • Laboratory methods – lab permeameters • Field methods – hydrodynamic testing • Stochastic methods • disadvantages - need of big amount of samples - need of wells and boreholes

7. Hydraulic conductivity k (m/s) Is there any other suitable method of k determination? • Can we observe groundwater outside the aquifer? • What is the earth-water balance? • Where does the groundwater discharge? • How is it in surface streams?

8. Boussinesq (1877) – Groundwater flow through a sloping aquifer with the Dupiuts-Forcheimer Assumptions (bed-parallel flow) Water table q Bedrock Channel or stream k = saturated hydraulic conductivity j = drainable porosity h = water table height q = flux J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

9. Boussinesq (1904) – Groundwater flow through a horizontal aquifer Joseph Boussinesq (1842-1929) Watershed or aquifer divide h(x,t) Channel or stream q(t) Impermeable bedrock Solved equation for h(x,t) and q(t) at “late time.” J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

10. Polubarinova-Kochina (1962) – Flow in a horizontal semi-infinite aquifer Channel or stream q(t) Bedrock Solved equation for h(x,t) and q(t) at “early time.” J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

11. Brutsaert and Nieber (1977) Recession Flow Analysis J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

12. From “Q vs. t” to “-dQ/dt vs. Q”… Hydrograph slope J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

13. “Early time” “Late time” Brutsaert and Nieber (1977) – Recession flow analysis J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

14. The solutions for aquifer discharge Early time solution Full solution Late time solution J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

15. Brutsaert and Nieber (1977) – Recession flow analysis ? (From Hewlett,1982) J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

16. Theoretical -dQ/dt vs. Q recession curve J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

17. Brutsaert and Nieber (1977) – Recession flow analysis J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

18. What might cause deviations from the predicted values of 3 and 1.5? 1. Non-uniformity in saturated hydraulic conductivity (k) 2. Aquifer slope (f) Method expanded to non-homogenous, sloping aquifers (Rupp and Selker, Water Resources Research, 2005) J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

19. Theoretical solutions

20. Review… J. Selker, Oregon State University, presentation for lecture in May 2006 in Brno

21. Introduction to the method • simplified geometry of watershed – block-shaped • analysis of the falling limb of hydrograph „early time“ „late time“

22. „early time“ „late time“

23. „early time“ „late time“

26. Theoretical solutions

27. Time- step effect

28. Practical example • small watershed at Uranium minig site Rožná • aquifer composed by crystalline rocks and weathered zone • length of the watershed 600 m, areal extent 0.6 km2 • slope of surface 6 º, thickness of the aquifer 10 m

29. Practical example measured Q represents discharge from the whole aquifer length of the watershed 1800 m areal extent 1.18 km2 slope of surface 6 º thickness of the aquifer 60 m

30. Comparision of results • lab permeameters • 1,8 m 8,8.10-10 m/s • 4 m 2,5.10-6 m/s

31. average hydraulic conductivity value used for the conceptual model of the groundwater flow in Uranium mining site Are the results usable?

32. Literature: • Brutsaert, W. – Nieber, J.L. (1977): Regionalized drought flow hydrographs from a mature glaciated plateau. Water Resour. Res. Vol.3 (3), 637–643. • Mendoza G.F. – Steenhuis T.S. – Walter M.T. – Parlange J.Y. (2003): Estimating basin-wide hydraulic parameters of a semi-arid mountainous watershed by recession-flow analysis. Journal of Hydrol. 273, 57-69. • Parlange, J.-Y. – Stagnitti, F. – Heilig, A. – Szilagyi, J. – Parlange, M. B. – Steenhuis, T. S. – Hogarth, W. L. – Barry, D. A. – Li, L. (2001): Sudden draw-down and drainage of a horizontál aquifer, Water Resour. Res., 37, 2097 - 2101 • Roub, R. – Pech, P. (2003): Hydraulika příklady, Česká zemědělská univerzita v Praze – CREDIT. Praha • Rupp, D. E. – Owens, J. M. – Warren, K. L. – Selker, J. S. (2004): Analytical methods for estimating saturated hydraulic conductivity in a tile-drained field, J. Hydrol., 289, 111 - 127 • Rupp, D. E. and Selker, J. S. (2005a): Information, artifacts, and noise in dQ/dt – Q recession analysis. Advan. In Water Resourc.Res. • Rupp, D. E. and Selker, J. S. (2005b): Drainage of a horizontal Boussinesque aquifer with a power law hydraulic conductivity profile. Water Resour. Res. Vol. 41 • Rupp, D. E. and Selker, J. S. (2006): On the use of the Boussinesq equation for interpreting recession hydrographs from sloping aquifers. Water Resous. Res. Vol. 42   • Selker, J. S. (2006): Unpublished data, lecture in Masaryk university, Brno, Czech Republic.

33. SOLVING THE EFFECTIVE RECHARGE (INFILTRATION) FOR MOST OF MODELS – THE ONLY ENTRY OF GROUNDWATER TO MODEL

34. HOW TO DETERMINE THE EFFECTIVE INFILTRATION? • Calculations from water-balance equations (P, ET, D and SR are known) • Isotope studies • Hydrograph separation based techniques

35. HYDROGRAPH SEPARATION • look for 2 sequential storm events (infiltration) events

36. HYDROGRAPH SEPARATION • look for 2 sequential storm events (infiltration) events • find the master recession curve (MRC) – line, if Q in log scale lucky period

37. HYDROGRAPH SEPARATION R = V2 – V1 Rrecharge volume V1volume of water in aquifer before the precipitation event V2volume of water in aquifer after the precipitation event Q0base flow Krecession index (time of a log cycle of discharge)

38. look for 2 sequential storm events (infiltration) events • apply the MCR curve to infiltration events

39. look for 2 sequential storm events (infiltration) events • apply the MCR curve to infiltration events

40. CALCULATED INFILTRATION RATES • values range widely depending on characteristic of rainfall event

41. CALCULATED INFILTRATION RATES • values range widely depending on characteristic of rainfall event

42. CALCULATED INFILTRATION RATES • values range widely depending on characteristic of rainfall event

43. Practical example

44. Practical example

45. Practical example – impact of land-cover type • St. Anna • agricultural use of main part of the watershed • 1,1 km2 • Wood-tributary • forested watershed • 0,018 km2

47. CALCULATED INFILTRATION RATES • values range widely depending on characteristic of rainfall event • different lengths of events, rainfall intensity • the effective infiltration from 0,6 to 44 % • of the total precipitation in a single rainfall event • that corresponds to the infitration rates from 0,2 to 44 mm • Calculate the average ground water table rise • divide infiltration rates by the effective porosity values • average water table rise from 0,5 to 30 cm after selected infiltration events