Design of preliminary groundwater monitoring networks for the coastal Tra Vinh province in Mekong Delta, Vietnam

• DOI: 10.1016/j.ejrh.2023.101425
• Publication Date: 2023-05-20T04:13:13Z
• Authors: Pham Van Tuan; Yangxiao Zhou; Tibor Stigter; Dang Van Tuc; Dao Hong Hai; Bui Tran Vuong
• Keywords: Physical geography; Saltwater intrusion; Environmental science; Machine learning; Groundwater; Biology; Water Science and Technology; Coastal groundwater; QE1-996.5; Ecology; Monitoring network design; Hydrology (agriculture); Geology; FOS: Earth and related environmental sciences; Watershed Simulation; Computer science; 6. Clean water; Water resource management; GB3-5030; Groundwater models; Kriging; Geotechnical engineering; Hydrological Modeling and Water Resource Management; 13. Climate action; Kriging interpolation; FOS: Biological sciences; Environmental Science; Physical Sciences; Overexploitation; Aquifer

Abstract This study designed and assessed preliminary monitoring networks to fulfill the urgent need for essential information to formulate plans for sustainable groundwater resources development and management in the coastal Tra Vinh province of Vietnam. Groundwater overexploitation has resulted in aquifer depletion and saltwater intrusion, predominantly originating from formation water trapped in clays from past marine transgressions. A limited number of monitoring wells is operated and is insufficient to delineate the cone of depression and fresh/salt water interfaces. Since data from the existing monitoring were insufficient to explore variogram analysis and subsequent Kriging interpolation for the network design, groundwater flow and saltwater transport models were constructed to create groundwater level and salinity distributions. We followed an iterative procedure to select monitoring locations based on the contour maps of groundwater levels and total dissolved solids (TDS) constructed from the groundwater models. Priorities for the locating groundwater level monitoring wells were targeted in areas with cones of depression and boundaries, while priorities for salinity monitoring were given to coastal zone and fresh/saltwater interfaces. The standard deviation of Kriging interpolation error was used to assess the quality of the designed monitoring networks. Once the designed networks are implemented, observed data from the networks will provide valuable information for sustainable groundwater resources management in Tra Vinh province.