groundwater salinity simulation of a subsurface reservoir in penghu island (pescadores), taiwan...
TRANSCRIPT
![Page 1: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/1.jpg)
GGroundwater Salinity Simulation of roundwater Salinity Simulation of A Subsurface Reservoir in Penghu IsA Subsurface Reservoir in Penghu Is
land (Pescadores), Taiwanland (Pescadores), Taiwan
GGroundwater Salinity Simulation of roundwater Salinity Simulation of A Subsurface Reservoir in Penghu IsA Subsurface Reservoir in Penghu Is
land (Pescadores), Taiwanland (Pescadores), Taiwan
•Professor Yih-Chi TanProfessor Yih-Chi Tan •Department of Bioenvironmental Systems EnDepartment of Bioenvironmental Systems Engineering, National Taiwan Universitygineering, National Taiwan University•Director, Hydrotech Research InstituteDirector, Hydrotech Research Institute
![Page 2: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/2.jpg)
INTRODUCTION INTRODUCTION
Chi-Ken subsurface reservoir Chi-Ken subsurface reservoir The subsurface reservoir is located in ChThe subsurface reservoir is located in Ch
i-Ken Basin,i-Ken Basin, Pescadores (a group islands Pescadores (a group islands
located at western part of Taiwan, betweelocated at western part of Taiwan, betwee
n Kinmen and Taiwan) n Kinmen and Taiwan) The reservoir has had the salinity problem since The reservoir has had the salinity problem since
19911991
Chi-Ken subsurface reservoir Chi-Ken subsurface reservoir The subsurface reservoir is located in ChThe subsurface reservoir is located in Ch
i-Ken Basin,i-Ken Basin, Pescadores (a group islands Pescadores (a group islands
located at western part of Taiwan, betweelocated at western part of Taiwan, betwee
n Kinmen and Taiwan) n Kinmen and Taiwan) The reservoir has had the salinity problem since The reservoir has had the salinity problem since
19911991
![Page 3: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/3.jpg)
![Page 4: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/4.jpg)
INTRODUCTION
annual average temperature is 23.3annual average temperature is 23.3ooCC average moisture is 80~85%average moisture is 80~85% annual average rainfall is 913 mmannual average rainfall is 913 mm annual average ET rate is 1575mmannual average ET rate is 1575mm no single river in the basin; the major recharge of no single river in the basin; the major recharge of
groundwater is by infiltration of rainfallgroundwater is by infiltration of rainfall
annual average temperature is 23.3annual average temperature is 23.3ooCC average moisture is 80~85%average moisture is 80~85% annual average rainfall is 913 mmannual average rainfall is 913 mm annual average ET rate is 1575mmannual average ET rate is 1575mm no single river in the basin; the major recharge of no single river in the basin; the major recharge of
groundwater is by infiltration of rainfallgroundwater is by infiltration of rainfall
![Page 5: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/5.jpg)
INTRODUCTIONINTRODUCTION
basin area of the subsurface reservoir is basin area of the subsurface reservoir is 2.14 km2.14 km22
discharge of groundwater is 1.27discharge of groundwater is 1.27××101066mm33 annual planning water supplies is annual planning water supplies is
7.97.9××101055mm33
![Page 6: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/6.jpg)
Chi-Ken subsurface reservoirChi-Ken subsurface reservoir
North-west toward south-eastNorth-west toward south-eastNorth-west toward south-eastNorth-west toward south-east
![Page 7: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/7.jpg)
Chi-Ken subsurface reservoirChi-Ken subsurface reservoir
south toward north south toward north south toward north south toward north
![Page 8: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/8.jpg)
What is subsurface reservoir?
subsurface reservoirsubsurface reservoir
![Page 9: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/9.jpg)
Possible salinity reasons of subsurface reservoirPossible salinity reasons of subsurface reservoir
shortage of rainfall shortage of rainfall leakage of the subsurface barrier causes the leakage of the subsurface barrier causes the
intrusion of seawaterintrusion of seawater Percolation from weathering basaltPercolation from weathering basalt
![Page 10: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/10.jpg)
NUMERICAL MODELNUMERICAL MODEL NUMERICAL MODELNUMERICAL MODEL
GMS (Groundwater Modeling System)GMS (Groundwater Modeling System)define soils layer datadefine soils layer data hydro-geological parametershydro-geological parameters initial conditionsinitial conditions boundary conditionsboundary conditions generation of three dimension meshesgeneration of three dimension meshes
![Page 11: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/11.jpg)
NUMERICAL MODELNUMERICAL MODELNUMERICAL MODELNUMERICAL MODEL
A three dimension FEMWATER(Yeh , 199A three dimension FEMWATER(Yeh , 1996) numerical model is adapted to find the po6) numerical model is adapted to find the possible leakage position of the subsurface barssible leakage position of the subsurface barrier and location of seawater intrusion by corier and location of seawater intrusion by comparing the different possible leakage simumparing the different possible leakage simulated result with the observations lated result with the observations
![Page 12: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/12.jpg)
Boundary of the modelBoundary of the model
![Page 13: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/13.jpg)
Location of subsurface barrierLocation of subsurface barrier
Subsurface barrierSubsurface barrier
![Page 14: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/14.jpg)
HYDRO-GEOLOGICAL LAYERING HYDRO-GEOLOGICAL LAYERING
1.The upper layer is white middle to grossly 1.The upper layer is white middle to grossly coralline sand with screenings coral, coralline sand with screenings coral,
2. The middle layer is gray loam sand, 2. The middle layer is gray loam sand, 3. The substratum layer is brownness clay,3. The substratum layer is brownness clay, 4.the bottom layer is weathering basalt 4.the bottom layer is weathering basalt The major aquifer is in the upper and middle The major aquifer is in the upper and middle
layerslayers
![Page 15: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/15.jpg)
HYDRO-GEOLOGICAL LAYERINGHYDRO-GEOLOGICAL LAYERING
![Page 16: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/16.jpg)
HYDRO-GEOLOGICAL LAYERINGHYDRO-GEOLOGICAL LAYERING
![Page 17: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/17.jpg)
determine the leakage position by numerical modeldetermine the leakage position by numerical model
According to the observation data from TaiAccording to the observation data from Taiwan Water Supply Corporation (1998), the wan Water Supply Corporation (1998), the possible leakage positions of the subsurface possible leakage positions of the subsurface barrier are:barrier are:the interface between barrier and basltthe interface between barrier and baslt the leakage of the subsurface barrierthe leakage of the subsurface barrier
![Page 18: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/18.jpg)
determine the leakage position by numerical modeldetermine the leakage position by numerical model
three hypothetical leakage casesthree hypothetical leakage cases Case A1Case A1:: leakage position is in the bottom leakage position is in the bottom
part of the barrierpart of the barrier Case A2Case A2:: leakage position is in the middle leakage position is in the middle
part of the barrierpart of the barrier Case A3Case A3:: leakage position is in the upper part leakage position is in the upper part
of the barrierof the barrier
![Page 19: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/19.jpg)
Cross –section of barrierCross –section of barrier
![Page 20: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/20.jpg)
Case A1Case A1:: leakage position is in the bottoleakage position is in the bottom part of the barrierm part of the barrier
![Page 21: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/21.jpg)
309100.00 309200.00 309300.00 309400.00 309500.00 309600.00
2618650.00
2618700.00
2618750.00
2618800.00
2618850.00
2618900.00
2618950.00
2619000.00
2619050.00
2619100.00
The distribution of the chloride concentration for A1case The distribution of the chloride concentration for A1case
matches with the observed valuesmatches with the observed values
309100.00 309200.00 309300.00 309400.00 309500.00 309600.00
2618650.00
2618700.00
2618750.00
2618800.00
2618850.00
2618900.00
2618950.00
2619000.00
2619050.00
2619100.00
Groundwater levels distributionGroundwater levels distribution Chloride concentration distributionChloride concentration distribution
Case A1Case A1:: leakage position is in the bottoleakage position is in the bottom part of the barrierm part of the barrier
![Page 22: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/22.jpg)
Case A2Case A2:: leakage position is in the middle leakage position is in the middle part of the barrierpart of the barrier
![Page 23: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/23.jpg)
309100.00 309200.00 309300.00 309400.00 309500.00 309600.00
2618650.00
2618700.00
2618750.00
2618800.00
2618850.00
2618900.00
2618950.00
2619000.00
2619050.00
2619100.00
The numerical result for chloride concentration with The numerical result for chloride concentration with 1000ppm of A2case and A3case are not comparable to the 1000ppm of A2case and A3case are not comparable to the observed dataobserved data
309100.00 309200.00 309300.00 309400.00 309500.00 309600.00
2618650.00
2618700.00
2618750.00
2618800.00
2618850.00
2618900.00
2618950.00
2619000.00
2619050.00
2619100.00
Chloride concentration distributionChloride concentration distribution Groundwater levels distributionGroundwater levels distribution
Case A2Case A2:: leakage position is in the middle leakage position is in the middle part of the barrierpart of the barrier
![Page 24: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/24.jpg)
Case A3Case A3:: leakage position is in the leakage position is in the upper part of the barrierupper part of the barrier
![Page 25: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/25.jpg)
309100.00 309200.00 309300.00 309400.00 309500.00 309600.00
2618650.00
2618700.00
2618750.00
2618800.00
2618850.00
2618900.00
2618950.00
2619000.00
2619050.00
2619100.00
The inland chloride concentration of A2case and A3case is The inland chloride concentration of A2case and A3case is
lower than the observed datalower than the observed data
309100.00 309200.00 309300.00 309400.00 309500.00 309600.00
2618650.00
2618700.00
2618750.00
2618800.00
2618850.00
2618900.00
2618950.00
2619000.00
2619050.00
2619100.00
Chloride concentration distributionChloride concentration distribution Groundwater levels distributionGroundwater levels distribution
A3A3:: leakage position is in the upper leakage position is in the upper part of the barrierpart of the barrier
![Page 26: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/26.jpg)
CONCLUSIONSCONCLUSIONS CONCLUSIONSCONCLUSIONS
By assuming the leakage position is in the By assuming the leakage position is in the bottom of barrier, the numerical result bottom of barrier, the numerical result predicts values closer to the observation predicts values closer to the observation than the other assumption. It showed that than the other assumption. It showed that the most possible leakage position is at the the most possible leakage position is at the bottom of the barrier.bottom of the barrier.
![Page 27: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/27.jpg)
CONCLUSIONSCONCLUSIONSCONCLUSIONSCONCLUSIONS
The research applied three dimension The research applied three dimension FEMWATER and GMS as an interface to FEMWATER and GMS as an interface to input parameter. The simulation of water input parameter. The simulation of water level and chloride concentration already level and chloride concentration already shows the real situation, and the result can shows the real situation, and the result can be applied to the future study of the Chi-be applied to the future study of the Chi-Ken subsurface reservoir salinity problems.Ken subsurface reservoir salinity problems.
![Page 28: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/28.jpg)
The governmentThe government decided to rebuild another decided to rebuild another cutoff to prevent sea water intrusion, and it cutoff to prevent sea water intrusion, and it has been finished in last year.has been finished in last year.
It is very important that is to continue It is very important that is to continue monitoring the water quality and preserve monitoring the water quality and preserve the limit water resources in this island.the limit water resources in this island.
![Page 29: Groundwater Salinity Simulation of A Subsurface Reservoir in Penghu Island (Pescadores), Taiwan Professor Yih-Chi TanProfessor Yih-Chi Tan Department of](https://reader035.vdocuments.site/reader035/viewer/2022062404/551bf16b550346c3588b65e3/html5/thumbnails/29.jpg)