Abstract

The analysis results and quality evaluation of underground water in Hà Tĩnh coastal area showed groundwater here is affected by the intrusion of sea water as well as economic and social activities. In central plains and coastal areas, chloride and total dissolved solids are relatively high and tend to increase during dry seasons. The process of limestone, granite leaching and their dissolves into groundwater causes increases in total hardness. The aquifer has nitrogen concentration higher in rainy season, but other indicators are less volatile and below pollution limits. Based on water chemical analysis in Holocene and Pleistocene aquifers, there are 03 water quality levels: very good quality distributed mainly in 590 km² sandy-soil coastal and the western area; good water quality distributed in 890 km² central plains and the average water quality accounts for 505 km². Overall, fresh groundwater sources have quality assurance for water supply and irrigation demand.