Evaluation of the River Discharge Considering Interaction of Surface water and Groundwater in the Yeongsan-Seomjin River in the Republic of Korea Using DWAT (Dynamic Water Resources Assessment Tool, DWAT)

Abstract

The availability of water resources generally refers to the volume of total water resources on the surface, sub-surface, and soil. For a precise assessment of the availability of water resources, it is necessary to secure the accuracy of meteorological forecasts such as precipitation and temperature forecasting and to be able to accurately evaluate the volume of invisible water resources under the surface. Metropolitan areas around large rivers can use water stably even in the event of a drought, but the upstream areas with small and medium-sized rivers are vulnerable to water supply stability in drought season. Therefore, highly reliable evaluation and prediction of river discharge is necessary to prepare comprehensive solutions such as efficient operation of water supply facilities and optimal use of available water resources during drought season.  In this study, river discharge was evaluated for 20-16 standard basins in the Yeongsan-Seomjin river basins, respectively, among major river basins in the republic of Korea. The Dynamic Water resources Assessment Tool (DWAT) was used as a assessment model. DWAT is a water resources assessment tool that can be used free of charge worldwide and can be applied to small and medium-sized river basins for water resource planning and management that considers surface water as well as groundwater and water usage for various purposes. The calibration period was set from 2012 to 2019, and the validation period was set from 2020 to 2021. In addition, simulation accuracy was calculated through a 1:1 comparison of observed and simulated discharge data based on the calibration point, and model efficiency (Nash Sutcliffe Efficiency, NSE)