1. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY applicability of two-phase numerical model for controlling saltwater intrusion at pumping wells - laboratory & field experiments Namsik PARK, Sungyun KIM, and Lei Shi Dong-A University, Korea

2. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY contents 1. objectives 2. sharp-Interface Model 3. laboratory experiments 4. field experiments 5. concluding remarks

3. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY 1. objectives Investigate the applicability of a sharp- interface numerical model for estimating salinity against experiments

4. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY Seawater Freshwater 2. sharp-interface model

5. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY estimation of salinity assuming At pumping wells Transmissivity-wegithed contribution of fresh and salt waters At EC sensors Constant transition-zone thickness Linear variation of salinity within transition zone

6. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY Cross-Section sand tank Laboratory Experiment 3. laboratory experiments

7. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY Comparison of numerical & experimental result Scenario Pumping rate (ml/min) Saltwater content(%) Length of saltwater wedge(cm) NumericalExperimentalNumericalExperimental F2 Freshwater Pumping 71.30 25.023.7 S1 Saltwater Pumping Control 2.199.48100 F2 Freshwater Pumping 70.270 24.824.5 S2 Saltwater Pumping Control 0.898.65100

8. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY 3-Dimensional sand tank Sand tank length (x)1.75 m Width (y)1.60 m Thickness of sand0.58 m Freshwater level0.358 m Saltwater level0.340 m Saltwater density1040 kg/m 3 Laboratory Experiment

9. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY Comparison of numerical & experimental result Experimental resultNumerical result Time (hr) Salinity (ppm) Normalization of salinity Time (hr) Salinity (ppm) Normalization of salinity 01540101677.861 0.814100.9078012.41312.40.712655 1.7512700.8085114.81080.170.530067 2.811400.7163127.2920.860.404811 3.8510600.6595749.6799.470.309365 5.658100.4822712706.180.236013 ….. 28.853080.12624133.59441.80.02815 31.82700.09929136.01436.010.023595 32.952560.08936238.4430.260.019074 34.852380.07659640.79424.540.014578 46.81550.0177343.2418.870.010123 48.51450.01063845.59413.250.0057 50.81400.007092484090.002359 54.91300524060

10. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY Experimental Watershed 4. field experiments

11. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY FE mesh developed around the well - Domain Size : 400mX400m - Node : 1089 - Element : 1024 modeling domain

12. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY preliminary pumping test Pumping Test 144m 3 /80min Monitoring - Water level - EC values at pump outlet & sensors at (-25 & -28m)

13. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY E L E V. (m) Time(min) EC (mS/cm) EC (mS/cm) Time(min) E L E V. (m) Time(min) Water level (O1 well) Water level (OA1 well) EC Values EC2 observation & calibrated results predicted observed EC1

14. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY Calibration of Intrinsic Permeability Calibration Result Intrinsic Permeability Fitness 11.26E-130.1485 22.26E-130.1102 33.26E-130.0774 44.26E-130.0737 55.26E-130.078 66.26E-130.0851 77.26E-130.0914 88.26E-130.097 99.26E-130.1018 CompressibilityFitness 11.00E-090.0799 22.00E-090.0781 33.00E-090.078 44.00E-090.0786 55.00E-090.0792 66.00E-090.0798 77.00E-090.0804 88.00E-090.0809 99.00E-090.0814 Calibration of Compressibility calibrated parameters

15. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY Pumping scenario Pumping & Monitoring wells validation experiment O1 (-10m) Pumping: 37m 3 /day (0-2,270min) O1 (-40m) Pumping: 79m 3 /day (1,172-2,270min)

16. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY pumping E L E V. (m) Time(min) Water level -22m EC (mS/cm) Time(min) EC (mS/cm) predicted observed Time(min) EC at Pump outlet Contamination due to over-exploitation Control of Saltwater wedge EC (mS/cm) Time(min) -30m EC (mS/cm) Time(min) -15m results – observed & computed EC Values O1 (-10m) Pumping: 37m 3 /day (0-2,270min) O1 (-40m) Pumping: 79m 3 /day (1,172-2,270min)

17. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY 5. concluding remarks A two-phase numerical model can estimate salinity at pump outlet & sensors with reasonable accuracy

18. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY 5. concluding remarks A two-phase numerical model can estimate salinity at pump outlet & sensors with reasonable accuracy handle a wide range of practical problems

19. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY 5. concluding remarks A two-phase numerical model can estimate salinity at pump outlet & sensors with reasonable accuracy handle a wide range of practical problems A simulation-optimization model based on the two-phase numerical model can be used for optimal development and management of groundwater in coastal areas

20. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY ACKNOWLEDGEMENT This research was supported by a grant (code # 3-3-3) from the Sustainable Water Resources Research Center of the 21st-Century Research Program. Future Plan A beta version of the simulation-optimization model shall be released to develop case studies. We are willing to work with those interested (nspark@dau.ac.kr).

21. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY Thank you! ACKNOWLEDGEMENT This research was supported by a grant (code # 3-3-3) from the Sustainable Water Resources Research Center of the 21st-Century Research Program. Future Plan A beta version of the simulation-optimization model shall be released to develop case studies. We are willing to work with those interested (nspark@dau.ac.kr).

22. SWIM20 June 23-27 2008 WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY 1. Introduction Freshwater pumping causes upconing Saltwater pumping causes “downconing”