FUTURE PREDICTION OF RIVER FLOW AND OVERFLOW/EROSION POTENTIAL DUE TO GLOBAL WARMING IN TOYAMA PREFECTURE

Abstract

 In recent years, flood disasters have become more frequent and their scale has been increasing. One of the reasons for this is the increase in rainfall due to global warming, and it is necessary to evaluate future disaster under changing climate. In particular, the rivers in Toyama are known rapid flow and are often erosion, important to predict erosion areas. In this study, rainfall-runoff calculations were carried out for river basins in Toyama using d4PDF to reproduce past conditions, and temperature rise experiments of 2°C and 4°C were conducted to evaluate the effects of inflow, overflow, and possible erosion. As a result of comparison with non-exceedance probability, the flow rate increased by about 1.1-1.7 times when the temperature increased by 2°C and by about 1.3-2.2 times when the temperature increased by 4°C with 150-year probability. In the evaluation of water overflow potential, the number of dangerous areas in the Oyabe River, which has a relatively gentle gradient, increased. The erosion potential of the Joganji River, which has a steep gradient, increased by more than 60% when the temperature was raised by 2°C. the Shogawa and Kurobe Rivers also increased by more than 60% when the temperature was raised by 4°C.