Abstract
Under changing climate, increasing groundwater use has risen the concern for groundwater quality variations over recent years, to maintain a healthy ecosystem. The objectives were to identify trend of temporal variations in groundwater quality and its suitability for different uses in Republic of Korea. Water quality data were collected from 198 monitoring stations of Groundwater Quality Monitoring Network (GQMN), annually for the period of ten years (2008–2017). Non-parametric trend analysis of a Mann–Kendall test and Theil–Sen’s slope was done on groundwater physico-chemical data of ten years. Groundwater suitability evaluation was done for use in main sectors including domestic (drinking) and agriculture (irrigation). For drinking suitability analysis, results were compared with World Health Organization (WHO) and Korean Ministry of Environment (KME) established guidelines. For irrigation suitability evaluation, electrical conductivity (EC), Sodium Adsorption Ratio (SAR), percent of Na+, Residual Sodium Carbonate (RSC), US Salinity Laboratory (USSL), and Wilcox diagram were used. Most significantly, water type belongs to Ca-HCO3 and Ca-SO4 types, but a small proportion belongs to Na-CO3 and Na-Cl types. Approximately, 96% and 93% of groundwater samples are suitable for drinking, based on WHO and KME guidelines, respectively. Around 98% and 83% of groundwater samples are in suitable range for irrigation use, based on USSL and Wilcox diagrams, respectively.
Highlights
Groundwater is one of the major sources of drinking and irrigation water all over the world [1,2].In the Republic of Korea, increased annual precipitation associated with the increase in intensity, frequency, and duration of monsoon’s precipitation in summer season, and decreased precipitation during other seasons have effects on water resource management [3]
The study area has a humid continental-subtropical climate which is affected by the East Asian monsoon and most of the annual precipitation are extreme during three months of the summer season [24]
The data for average annual precipitation and temperature was measured from a network of 102 weather stations under Automated Synoptic Observing System (ASOS), in Korea
Summary
In the Republic of Korea, increased annual precipitation associated with the increase in intensity, frequency, and duration of monsoon’s precipitation in summer season, and decreased precipitation during other seasons have effects on water resource management [3]. This increasing variable and extreme precipitation are making the country more susceptible to flood and drought hazards [4,5]. 13% of the total annual agricultural, domestic, and industrial water supplies are based on groundwater [8]. The major use of groundwater is for agricultural (51.2%) and domestic (39%) purposes [9]
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