[A-HW22] Material transportation and cycling in watershed ecosystems; from headwaters to coastal areas

[AHW22-P15] Estimation of Landuse Change Impact on Water Budget in Higashihiroshima Catchment using SWAT

*Sharon Bih Kimbi¹, Kunyang Wang¹, Shin-ichi Onodera², Ichirow Kaihotsu¹, Shingo Nozaki², Yusuke Tomozawa² (1.Graduate School of Integrate Arts and Sciences, Hiroshima University, 2.Graduate School of Advanced Science and Engineering, Hiroshima University)

Keywords:Landuse , Water Budget, Hydrology, SWAT

Increasing population growth with rapid changes in social and economic standards have led to increasing demand in settlements or agriculture areas. To use water resources sustainably, it’s important to understand the quantity of water resource both Spatially and temporally. The Soil and Water Assessment Tool (SWAT) model was used to analyse watershed hydrology and variability of streamflow in the Higashihiroshima catchment area. The statistical model performance, which measures the coefficient of determination (R²) and Nash-Sutcliffe Efficiency (NSE) were used to evaluate the correlation between the observed and simulated daily streamflow. The preliminary result shows a good agreement between the observed and simulated flow. Both NSE and R² were found to be greater than 0.7 for the calibration and validation period. The analysis was performed on two different land-use maps (1987 and 2009) to determine the effect of urbanization on the hydrology of the watershed specifically water budget. Landuse change has a profound impact on runoff hydrographs. Increased impervious surfaces are a common cause of increased peak-runoff volumes. This condition will increase erosion, sedimentation on the water body, decreasing water resources, increase agricultural pollutant, landslide and decrease agricultural production.


This study is supported by JSPS (Japan Society for the promotion of Science)