Change in Instant Maximum Flows According to Precipitation and Temperature Differences in the 2025-2055 Period, A Study in Eastern Black Sea Basin

This study was carried out in the Eastern Black Sea Basin, where great loss of life and property was experienced due to heavy rains in the past years. The main purpose of the study is to investigate the effect of climate change on instantaneous maximum flow (Qmax) rates. For this study, four Discharge Observation Stations (DOS) located at different altitudes in the central and eastern parts of the basin were selected: Flow Duration Curves (FDC) were obtained for the reference periods determined by considering the years with the longest continuous recorded data at the selected stations. Flow values corresponding to 95%, 50% and 5% probability of exceeding were obtained from FDCs and were used as estimating parameters for Qmax estimation together with annual average flow, annual total precipitation and annual average temperature data. In the study, forecasting consisted of two stages: calibration and future forecasting. In the calibration, the functions estimating the Qmax of the next year were determined with the data of the previous year by using the data observed in the reference period of the stations (Mean R = 0.975). In the second part, Qmax estimation was made 2025-2055 period using MPI-ESM-MR precipitation and temperature data under the effect of the RCP8.5 emission scenario, where it is reported that the most negative effects of climate change will be observed for the region. The findings obtained from the study showed that precipitation and temperature changes in the basin have statistically significant effects on Qmax, the level of change in the upper basins is limited, and high flow rates that may cause flooding in the lower basins can be observed in the future.