Groundwater recharge in Mekong River Delta: An application of the water-table fluctuation method in the Long Xuyen Quadrangle and the Ca Mau Peninsula

Abstract

Local groundwater recharge was determined using the Water Table Fluctuation method in the Long Xuyen Quadrangle and the Ca Mau Peninsula to refine existing estimates in a range of aquifer lithologies in light of climate change. The approach takes advantage of long term monthly water level records of Vietnam by Division of Water Resources Planning and Investigation for the South of Vietnam. An analysis of water levels in eight observation wells during four climatically distinct years (2005, 2009, 2013, and 2020) was used in combination with the monthly meteorological data. Groundwater recharge was estimated by the Water Table Fluctuation method to vary from 95.7 to 150.4 mm/year and account for 5.3 to 7.5% of the total rainfall. The estimates fall within the range of values used in regional-scale recharge models and demonstrate the potential of the Water Table Fluctuation method for resolving spatial and temporal variations of groundwater recharge.

Keywords

• groundwater recharge
• water-table fluctuation
• climate change
• mekong river delta