Evaluation of change in groundwater storage and its drivers in the transboundary Cambodia-Mekong River Delta Aquifer in Lower Mekong Region | |
| Author | Upadhyay, Surabhi |
| Call Number | AIT Thesis no.WM-22-09 |
| Subject(s) | Groundwater--Storage GRACE (Artificial satellites) Transboundary pollution--Lower Mekong Region |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Science in Water Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Agricultural, domestic, and industrial sectors have become increasingly reliant on groundwater use, and some of the questions that arise include: How can we estimate groundwater storage? What volume of groundwater has been depleted? What causes spatio-temporal variability in depletion? Is it possible to manage groundwater on a regional scale? The Gravity Recovery and Climate Experiment (GRACE), a state-of-the-art remote sensing tool, has made it possible in monitoring groundwater storage anomalies, in areas with a lack of observed monitoring stations. The performance of GRACE has not been examined in the transboundary Cambodia-Mekong River Delta aquifer, where groundwater has been extensively used for agricultural and domestic purposes. In this study, we (a) evaluate the performance of GRACE data with the PCRaster Global Water Balance (PCR-GLOBWB) model and in-situ groundwater observations. (b) analyze the trend in groundwater storage change over 15 years from 2002 to 2017, and (c) identify potential drivers of groundwater storage change. GRACE-derived groundwater storage anomalies and those obtained from the PCR-GLOBWB model (r > 0.7, RMSE < 15) and observed groundwater observations (r>0.8, RMSE<15) are in good agreement demonstrating the significance of satellite observation in assessing aquifer-wide groundwater resources. Among three different GRACE-Mascon products evaluated, GWSA derived from Goddard Space Flight Center (GSFC) outperformed in the study. A declining trend of about 0.68 cm/year in groundwater storage with a total volume loss of 18.28 km3 was observed in the aquifer. The influence of abstraction (46%) and precipitation and evapotranspiration (31%) on groundwater storage were dominant in the Mekong River Delta, Vietnam, compared to land use change (23%). If the declining trend persists in the upcoming years, it might affect the domestic and agricultural sectors in the aquifer. Therefore, this study shows the potentiality of GRACE in capturing groundwater storage change in a data-scarce region which will be a basis for the formulation of groundwater management strategies and policies to reduce groundwater stress in the region. |
| Year | 2022 |
| Type | Thesis |
| School | School of Engineering and Technology (SET) |
| Department | Department of Civil and Infrastucture Engineering (DCIE) |
| Academic Program/FoS | Water Engineering and Management (WM) |
| Chairperson(s) | Shrestha, Sangam;Shanmugam, Mohana Sundaram (Co-chairperson) |
| Examination Committee(s) | Babel, Mukand S.;Ho Huu Loc;Sarawut Ninsawat |
| Scholarship Donor(s) | Anat Arbhabhirama;Asian Institute of Technology Scholarships |
| Degree | Thesis (M. Sc.) - Asian Institute of Technology, 2022 |