SWIM20 June 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

SWIM20 June 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

SWIM20 June 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

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

SWIM20 June 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

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

SWIM20 June 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 S1 Saltwater Pumping Control F2 Freshwater Pumping S2 Saltwater Pumping Control

SWIM20 June 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

SWIM20 June 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 …

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

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

SWIM20 June 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)

SWIM20 June 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

SWIM20 June WATER RESOURCES SYSTEMS GROUP DEPT.OF CIVIL ENGR, DONG-A UNIVERSITY Calibration of Intrinsic Permeability Calibration Result Intrinsic Permeability Fitness 11.26E E E E E E E E E CompressibilityFitness 11.00E E E E E E E E E Calibration of Compressibility calibrated parameters

SWIM20 June 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)

SWIM20 June 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)

SWIM20 June 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

SWIM20 June 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

SWIM20 June 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

SWIM20 June 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

SWIM20 June 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

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