Hydrogeological reconnaissance of Sukhuma District, Champasak Province, Southern Laos

摘要

Sparse hydrogeological data is a significant limitation to the study of groundwater in many areas. The objective of this study was to assess the hydrogeology in Sukhuma District of Champasak Province in Southern Laos where such a limitation occurs. The connection between surface water and groundwater was assessed by comparing groundwater levels and river bed elevations. Groundwater recharge was estimated by the water table fluctuation method. The feasibility of remote sensing to address data limitations for the future study of groundwater in the region was also investigated by comparing the Mekong River flow and rainfall data with the Equivalent Water Height derived from the Gravity Recovery and Climate Experiment; soil moisture data obtained from the Global Land Data Assimilation System was also compared with rainfall and groundwater levels in Sukhuma District. The results show that some parts of Khamouan River bed are disconnected from the water table during the dry season, whereas the river bed is fully connected to the water table during the wet season. However, in the Pheung River, which flows into the Khamouan River upstream of the river gauge, the groundwater level is fully disconnected from the river bed in the dry season and partially connected in the wet season. Groundwater recharge estimates vary according to the specific yield values used for the aquifer. The comparison between in-situ hydrological measurement and remote sensing data provides insights into the general hydrogeological conditions. The comparison also provides useful information for future studies of the hydrogeology in Sukhuma District and Southern Laos, where field observation data are sparse, to support sustainable groundwater development in the region.