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This study evaluated temporal and spatial variability of groundwater and stream water fluxes using multiple temperature time series. The study area is located in Inbuk stream, Gangwon Province, Republic of Korea. Total annual precipitation was 698.5 mm in 2014 (1210.5 mm, over the last 30 years). For the study, temperature loggers were installed at depths of 0.1, 0.2, 0.3, 0.4, and 0.5 m at five points with at 10 m intervals (IST1, IST2, IST5, and IST6) in the streambed. Temperature data was continuously measured every two-hours from June 1 to November 30, 2014. Vertical fluid flow (seepage flux) were calculated using the VFLUX program, which uses temperature time series data measured at different depths by temperature loggers in the hyporheic zone. The results of flux calculations Inbuk stream show that vertical flux rates at four locations are generally upwelling condition in the dry season and downwelling condition in the wet season. This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2015R1A4A1041105). [ABSTRACT FROM AUTHOR]

The objective of this study is to examine groundwater responses before and after the November 15, 2017 Pohang earthquake (Mw=5.4) in a coastal area of Korea. The earthquake caused devastating damages to many buildings in the city. For this study, groundwater monitoring data (water level, electrical conductivity, water temperature) were obtained for January 2016 to February 2018 from the national groundwater monitoring stations, the rural groundwater monitoring wells, and the seawater intrusion monitoring wells and they are located within 25 km from the epicenter. There are eight national groundwater monitoring stations (PSG, PYI-D, PYI-S, PGB-D, PGB-S, PJH, PDH, PGR), five rural groundwater monitoring wells (PH1, PH2, PH3, PH4, PH5) and four seawater intrusion monitoring wells (GG1, GG2, YI1, YI2). Six of the monitored wells showed groundwater level decreases of 9–81 cm and two of them exhibited a recovery to the previous level within three days while the remaining wells did not. And six monitoring wells showed EC changes to the earthquake with -1,274–161 μS/cm. In addition, three wells showed discernible groundwater temperature fluctuations of -0.2–0.3oC. Here, we found the magnitude of groundwater level change is decreasing with distance of the monitoring wells from the epicenter. Some detailed analyses on the relationship between the responses and a variety of hydrogeological parameters deserve a further study. This work was supported by the Energy Efficiency & Resources of the Korea Institute of Energy Technology Evaluation and Planning (KETEP) grant funded by the Korea government Ministry of Trade, Industry and Energy (No. 20183010111860) and by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2015R1A4A1041105). [ABSTRACT FROM AUTHOR]

Seasonal fluctuation in groundwater level (below the ground surface) and water quality variables are mainly attributed to climatic conditions, soil characteristic, drainage method, and management practices. Groundwater degradations and high nitrate values have taken considerable attention in the Republic of Korea. Water management practices needs to be based on results of monitoring of groundwater level and water quality variables. We studied spatial variations based on temporal fluctuations of groundwater level (GWL), and water quality parameters including pH, electrical conductivity (EC), and nitrate (NO3). These contents were monitored from year 2011 to 2014 in 70 groundwater wells of an agricultural region in Korea. The monitoring of contents was done in field and collected data after laboratory analysis, was analyzed by using geostatistical modeling and mapping techniques. Seasonal variations in GWL during the period of four years of monitoring were ranged 2.91–5.17 m and 2.80–4.08 m in wet and dry seasons, respectively. The variations in pH value for the same period ranged 6.55–7.50 and 6.69–7.82 in wet and dry seasons, respectively. The fluctuations in EC values ranged 125–604 μg/cm and 80–272 μg/cm in wet and dry seasons, respectively. The values for NO3 in groundwater ranged 12.87–34.40 mg/L and 9.46–38.80 mg/L during the wet and dry seasons. The GWL shows strong spatial dependence, while pH and EC show strong to weak spatial dependence. The groundwater NO3 shows partial spatial dependence with decreased values in 2014 compared to the values in 2011. This finding is attributed to improved agricultural practices and change in land use pattern from white radish and cabbage to orchards and ginseng fields. This work was supported by the National Research Foundation of Korea (NRF) grant, funded by the Korean government (MSIT) (NRF-2015R1A4A1041105) and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Education (NRF-2018R1D1A1B07047200). [ABSTRACT FROM AUTHOR]

Water is an essential element for all organism, including human. There are anaerobic organisms in nature, but no organisms hate water. As time goes on, the interest and need for such water management is increasing worldwide. Seawater is the most abundant on the Earth's water and accounts for more than 95% of the total. But this is the salty water that humans can not drink. So, even if most of the water is seawater, it is important to manage the fresh water that humans can drink. Uses in which water is used in human life are various such as agriculture and living water. Therefore, the purpose of this study is to contribute to the management of groundwater used in everyday life. Groundwater can be largely divided into quantity and water chemistry. Of these, interest in this study is related to water chemistry and is water temperature. Groundwater chemistry can be changed by temperature change. So, we want to predict changes in the future by analyzing past groundwater temperature changes. Box plot was used as the study method. This makes it is easy to see the yearly change visually. In this box, displays 25% to 75% of the total data distribution. Also, values outside the minimum (25% – 1.5 × IQR) and maximum (75% + 1.5 × IQR) range are designated and excluded as outliers. The line in the box represents the median, which is not necessarily located in the middle of the box. This study used water chemistry data from 2011 to 2015. The result of this study suggests that groundwater temperatures have risen over the past five years, and that this can increase in the future. This research was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2015R1A4A1041105). [ABSTRACT FROM AUTHOR]

The international lack of water is publicly known. Over time, interest in groundwater and surface waters has increased for domestic use as drinking water and agricultural water. Due to the impacts of climate change, floods, landslides, droughts and other disasters related to water are becoming more and more important, and the need for water resources planning and management is emphasized. This study was aimed to assess the trend of groundwater quality in Korea. We also investigated the main drivers behind the trend and are attributed to rock-type and land use. Data was collected for 10 years from groundwater quality monitoring in Korea. Twelve water quality parameters were analyzed year by year. The collected data was statistically analyzed using a nonparametric method (Mann-Kendall trend test, M-K trend test). In addition, normality was analyzed by histogram (K-S test / Kolmogorov-Smirnov test or S-W test / Shapiro-Wilk test) and box plot. The Mann-Kendall trend test used the data for more than 5 years to identify the trends. The results were displayed on the map of the whole country, showing trends by regions. All of the water quality parameters were not statistically normal as a result of verifying the normality of the whole data through P-value in the histogram. Also, it was not normally distributed as a result of verifying the normality of yearly collected data through box plot. As a result of testing the normality of the M-K trend test using P-value, the T and HCO3- increased nationwide, and the pH, Eh and NO3- decreased nationwide. While, Cl-, Mg2+ and SO42- increased in the central area and decreased in the south. Potassium decreased markedly in the south, and EC and Ca2+ showed no regional trends. The reason for the regional difference was thought to be the influence of the rock type of the area where the irrigation had been installed, and it was affected by the land use. This work was supported by the National Research Foundation of Korea (NRF) grant funded by the Korea government (MSIT) (No. NRF-2015R1A4A1041105). [ABSTRACT FROM AUTHOR]