Assessment of the need and potential for groundwater artificial recharge based on the water supply, water demand, and aquifer properties in a water shortage region of South Korea

Abstract

Artificial recharge is increasingly necessary to ensure sustainable groundwater supplies and meet the needs of a growing population and crop cultivation in the age of climate change. In this study, artificial groundwater recharging using surplus water resources within the local area is considered for a water shortage area during a drought season, Shingok village, Hongsung-gun, South Korea, that lacks water sources. Based on an analysis of the monthly supply and demand with the water budget method, the current water supply is determined to be entirely dependent on groundwater wells, and water shortages occur in May (approximately 6446 m3) when rice planting begins. The surplus groundwater, which is the amount of natural recharge minus the present usage, and stream discharge are sufficient from December to June, so they are considered source waters for artificial recharge. A depth of 6 ~ 19 m is suggested as the main target region for recharge based on the composition of strata and the vertical distribution of the hydraulic conductivity, which was investigated with electric resistivity survey, drilling, and pumping test methods. Considering the permeability of layers, a vertical well, by which water can infiltrate directly into the target strata, is proposed as the main injection structure, and a ditch is also suggested as an auxiliary system to improve the effect of injection over a broad area. In the future, a detailed design for the injection scenario, injection facility, well and ditch arrangements, and pumping facility will be established through numerical modeling, field injection tests, etc. If it is impossible to obtain water from a long distance, an artificial recharge system based on local water sources may be an appropriate method of securing water considering the storage capacity of permeable strata.