[A-HW24] Material transportation and cycling at the land-sea interface: from headwaters to the ocean

[AHW24-P07] Estimation of suspended sediment discharge in Takahashi River using Soil and Water Assessment Tool

*Nang Yu War¹, Shin-ichi Onodera¹, Mitsuyo Saito², Yuta Shimizu³, Kunyang Wang¹, Yusuke Tomozawa¹ (1.Graduate School of Advanced Science and Engineering, Hiroshima Universiity, 2.Graduate School of Environmental and Life Science, Okayama University, 3.Western Region Agricultural Research Center, National Agriculture and Food Research Organization)

Keywords:SWAT, suspended sediment , Takahashi river

Takahashi river in Okayama Prefecture encountered serious flooding due to the heavy rainfall and long-time precipitation over 48 hours, resulting in the damage of river banks, and loss of lives, in 2018. This study models the streamflow and suspended sediment transport in the Takahashi river using the Soil and Water Assessment (SWAT) model. Takahashi watershed covers about 2638 sq km. The SWAT model was simulated using the 30 m resolution SRTM Digital Elevation Model (DEM), land cover from Ministry of Land, Infrastructure, Transport and Tourism National Land Numerical Information, and weather data from the Japan Meteorological Agency. Precipitation, temperature, and wind speed data from 7 weather stations, relative humidity, solar radiation data from 3 weather stations (1980-2021) were used as the weather data inputs for the SWAT modeling. The observed streamflow data from the Sakazu station and the water quality data from Kasai Weir were used for the model calibration and validation.