NGHIÊN CỨU ĐÁNH GIÁ TRỮ LƯỢNG KHAI THÁC NƯỚC DƯỚI ĐẤT CÁC DẢI CỒN CÁT VEN BIỂN TỈNH HÀ TĨNH PHỤC VỤ CẤP NƯỚC SINH HOẠTCHO VÙNG KHAN HIẾM NƯỚC

Abstract

The assessment of the groundwater quantity in coastal sand dunes to supply for the water scarcity areas in the Northern Central region is very necessary and a pilot assessment conducted for the coastal area of ​​Ha Tinh province is presented in this article. An analytical method used to determine the exploitable quantity of grid cell basis has been programmed for numerical calculation. The results show that groundwater in the sand dunes of Ha Tinh province in an area of ​​about 95 km² can provide about 10,390 m³/day during 27 years of exploitation under the most unfavorable condition without rainwater. The average exploitation volume from the coastal sand dunes is 109.69m³/day/km², equal to approximately one-fourth of the rainwater of 395.78m3/day (infiltration rate is 10%). The exploitation of groundwater from the sand dunes has a role that promotes the rate of rainwater infiltrating into groundwater, increasing the volume of groundwater quantity in the area compared to those areas without groundwater extraction. The results of this assessment are of great practical significance in the development of master plans of groundwater exploitation in the water scarcity areas in the Northern Central region and this is a basis to assess salinity intrusion and spreading of pollutants in the groundwater of the coastal sand dunes into the groundwater exploitation systems as well as predict and propose measures to prevent salinity intrusion and pollution.