This video shows a groundwater study in Mekong Delta with:
Research Title: Groundwater Flow System at Coastal Region of Soc Trang Province, Southern Vietnam
Author: Tran Dang An – University of Tsukuba, Japan
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In coastal regions, ground water quality and quantity are frequently affected by many complicated factors, including salt intrusion, surface water pollution, unsustainable management and overexploitation. Therefore, understanding groundwater flow systems in these areas is essential for the optimal use and management of water resources, particularly within the context of climate change.
In the Mekong Delta, especially, in coastal regions like Soc Trang province, which lack water supply system, groundwater is the most important fresh water resource for domestic, industrial, agricultural and aquaculture purposes. However, groundwater quality has seriously deteriorated due to intensive extraction, acid sulphate soil, diffuse pollutants in wet weather and reverse salt intrusion in the dry season. This study presents a case study of coastal areas of Soc Trang province, Southern Vietnam. The aim of this research is to characterize groundwater flow systems and hydrogeological processes, which govern groundwater characteristics in coastal aquifers of the Mekong Delta.
Field surveys, chemical analysis and statistic analysis techniques were performed in this study. The field surveys were carried out in the dry and rainy seasons between 2013 and 2014. Water samples were collected following seasonal characteristics and tidal regime. The main water parameters: Temperature (T0C), pH, Dissolved Oxygen (DO), Electrical Conductivity (EC) and Total Dissolved Solids (TDS), were measured on-site using portable meters. Bicarbonate (HCO3- was analyzed by; inorganic ions: sodium (Na+), potassium(K+), calcium(Ca2+), magnesium(Mg2+), nitrate (NO3-) chloride (Cl-) and sulphate (SO42-) were analyzed by Ion Chromatography (IC) and Inductively Coupled Plasma (ICP), while stable isotopes oxygen-18 and ditium were analyzed by Mass spectrometry.
The results show that (i) groundwater between aquifers shows different hydro-geological processes, mainly affected by dolomite dissolution at middle and lower Pleistocene aquifer, and deeper aquifers involve in calcite, anhydrite and halite saturation; (ii) the groundwater flow system has changed tremendously due to intensive exploitation; (iii) some parts of middle Pleistocene aquifer that close to Tran De estuary of the Mekong Delta may be affected by saline water diffusion or saline water leaching within aquifers. This demonstrates the fact that excessive pumping activities and extreme reduction of water recharge into coastal aquifers are the main causes of disturbance groundwater flow systems and expanding saline boundary in this site. Therefore, appropriate regulations on exploiting groundwater and integrated water resources management within watersheds should be promptly considered in order to prevent groundwater contamination and use sustainably the water resources in the context of rapid socio-economic development, imbalance water uses in the Mekong River Basin and the unpredictable impacts of climate change.
KEYWORDS: Soc Trang, Groundwater flow system; hydro-geochemical processes