Geophysics used to help find good quality groundwater in the Vientiane Plain, Lao PDR

Summary Lao PDR is a poorly developed country, with a large rural population which relies heavily on agricultural production. The Vientiane Plain is one of the most important and largest agricultural production areas with plans to expand the area under irrigated agriculture. Historically, surface water has been used because of its relative abundance with limited consideration to use groundwater. Where groundwater development has occurred for irrigation there is little or no management, and what little there is, is based on very poor hydrogeological information. A lack of knowledge of where to site wells has led to well failure and poor water quality. This project was initiated through the Society of Exploration Geophysics - Geoscientists without Borders Program to: teach local scientists, both university-based, as well as from the government, about the latest in hydrogeophysical technology and how it can be used in the Lao PDR. Specifically we looked to apply hydrogeophysical techniques to characterise the hydrogeology of the Vientiane Plain; to evaluate the quantity and quality of groundwater that may be available; and to enhance the scientific knowledge of local resource users. Two field trips were undertaken in 2018 and 2019 to conduct workshops and training with in-country government department officials and students from the Laos University. Results from the project identified and mapped highly conductive zones related to saline geological features which would be unsuitable locations for well locations for groundwater irrigation.