Analysis of water budget through measurement of groundwater flux using seepage meters at Osongji in Jeonju-si

Despite increased interests in groundwater-surface water interaction, there have been few studies that directly measure groundwater fluxes into/out of surface water body in Korea. In this study, groundwater fluxes were measured using seepage meters and analysis of water budget was conducted at Osongji, Jeonju-si. The fluxes of groundwater were measured by installing seepage meters at four locations in the upstream of the pond and the flow rate of surface water was measured using a flow meter at the downstream outlet of the pond. Measurements were made once or twice a week for about 3 months from June to August in 2018, and were made three times a week during the rainy season of July. The average groundwater flux in the upstream of the pond was 0.41 L/m²d∼4.13 L/m²d, indicating that only groundwater influx occurred. The surface water outflow rate at the downstream outlet was measured as 32∼8774 L/d. When the groundwater flux in the upstream to the surface water outflow rate in the downstream was compared, the average ratios at the four locations were 12.49, 7.56, 2.46, and 0.60, respectively. This means that the groundwater influx to Osongji is considerably larger than the outflow of surface water when precipitation and evaporation rates are not taken into consideration. Also, in case that Osongji has a year-round consistent water volume, it implies that there might be groundwater outflux around the pond. This study shows that measurement of groundwater and surface water fluxes using seepage meters and flow meters can contribute to analyzing water budget in surface water bodies like ponds.