Archives of Mining Sciences

Abstract

BacBinh is a sand dune area located in the southern part of central Vietnam. This area is confronted with a lack of water supply. The project aims to investigate the site for artificial recharge (AR) and the management of aquifer recharge (MAR) in the sand dune area. The geological setting of the area is characterised by ryo-dacitic bedrock, which forms steep isolated hills (up to 300 m a.s.l.) overlain by a Pleistocene-Holocene marine sand dunes plateau (up to 200 m a. s. l.). This is represented by prevailing white fine sand (Pleistocene) and prevailing red sand (Holocene), which occurs extensively in the coastal area. The hydrological and geological conditions are investigated by collecting all existing data of aerial and satellite photos, rainfall statistics, morphological/geological/ and hydrogeological maps for acquisition and interpretation. The field geophysical surveys are carried out for the location of groundwater aquifers to site selection, monitoring and operation of groundwater recharge. Hydrochemical and isotopic characterisation of surface water and groundwater in different periods showed that the sand dunes aquifers, with electrical conductivity ranging from 100 to 400 μS/cm, are composed of different water types, characterised by complex mixing processes. The site chosen for the artificial recharge, where 162 days of pumping tests have been carried out, proved that the use of the bank filtration technique has considerably improved the quality of water, which was originally highly contaminated by E-coli bacteria. The well field developed within the present project is now capable of supplying 220 m 3 /day of good water quality to the HongPhong community, BacBinh district, which were recurrently affected by severe droughts.