Assessing Future River Environments in the Seomjin River Basin due to Climate Change

Environmental impacts in the Seomjin River Basin were evaluated based on watershed characteristics and climate change using Representative Concentration Pathway 4.5 and 8.5 scenarios provided by the Korea Meteorological Administration. Future dam and tributary inflow from 2000 to 2100 were estimated using a hydrology model. Dam safety evaluation and downstream flow duration curve analyses were performed using a hydraulic structure operation model based on hydrology model flow results. Water quality trends were analyzed through a seasonal Kendall test method using 19 years of water quality data. Dam discharge, tributary inflow, and water quality estimated by hydrology, hydraulic structure operation, and water quality model were used to analyze future influences on water quality trends. New guidelines for managing river environments and climate change issues are provided, allowing a preemptive response. The inflow increase during the flood season was smaller than that during the dry season because of climate change. Furthermore, the water stage of Seomjin or Juam Dam exceeded the designed flood level. It is therefore necessary to study the long-term effects and changes in water quality with regards to future flow rate changes.