Assessment of meteorological and groundwater drought dynamics and propagation in the Mun River Basin, Thailand | |
| Author | Thapa, Samip |
| Call Number | AIT Thesis no.WM-26-12 |
| Subject(s) | Droughts--Mun River Basin--Thailand Meteorology, Agricultural--Mun River Basin--Thailand Groundwater--Mun River Basin--Thailand |
| Note | A thesis submitted in partial fulfillment of the requirements for the degree of Master of Engineering in Water Engineering and Management |
| Publisher | Asian Institute of Technology |
| Abstract | Drought is a recurring hazard in the Northeast Thailand and affect water resources, agriculture, and livelihoods. The Mun River Basin one of the largest subbasins in the Mekong River System that depends heavily on groundwater to meet water demands during the dry season. However, the link between meteorological and groundwater drought in the basin is not well understood. Sparse and infrequent ground monitoring further limits basin scale assessment and representation of aquifer heterogeneity. This study evaluates the meteorological-groundwater drought dynamics and their controls in the basin from 2002-2024. Meteorological drought was assessed using Standardized Precipitation Evapotranspiration Index (SPEI) at multiple accumulation scales. Groundwater drought was assessed using the satellite derived Groundwater Drought Index (GDI) by leveraging GRACE and GRACE-FO data, combined with soil moisture data from GLDAS Noah LSM. The results were later validated against in-situ observations from 62 monitoring wells from DGR. Drought propagation was examined through lagged correlation, event-based comparison, and autocorrelation analysis. Attribution of groundwater decline was assessed using the time series decomposition, and exploratory land use analysis. The basin experienced three hydroclimatic phases, a dry early 2000s, a sustained wet period (2007-2012) and drying regime post 2014 culminating in the most severe drought of 2019- 2020. Seven major meteorological droughts were identified. After 2014, drought shifted from rainfall-driven events to compound events involving both rainfall deficit and high evaporative demand. Six major groundwater droughts were identified during the study period. Groundwater responded with one-month lag to intermediate scale and a system memory of about 14 months. A key finding was that the aquifer transitioned from buffering meteorological drought to becoming longer and more severe than their atmospheric triggers. Importantly, groundwater storage anomalies showed a statistically significant declining trend while none of the climatic variables did and water demanding land use class increased significantly. This decoupling was inferred as evidence that non climatic factors most likely groundwater abstraction is contributing to the long-term decline. Removal of this trend reduced drought duration by half and fragmented prolonged events into shorter recoverable episodes. Spatially, groundwater drought is primarily controlled where annual rainfall variability is more, while evaporative demand (PET) governs its intensity and persistence. |
| Year | 2026 |
| Type | Thesis |
| School | Faculty of Civil and Environmental Engineering (2026) |
| Department | Other Field of Studies (No Department) |
| Academic Program/FoS | Water Engineering and Management (WEM) |
| Chairperson(s) | Shanmugam, Mohana Sundaram |
| Examination Committee(s) | Shrestha, Sangam;Virdis, Salvatore G.P.;Natthachet Tangdamrongsub;Khadka, Dibesh |
| Scholarship Donor(s) | Thai Pipe Scholarship;AIT Scholarship |
| Degree | Thesis (M. Eng.) - Asian Institute of Technology, 2026 |
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