Classification of Land Cover in Kumamoto Area, Japan to Evaluate Infiltration and Surface Runoff

Almost 100% of domestic water is covered by groundwater in the Kumamoto region, Japan. However, in recent years, the groundwater recharge area (particularly paddy fields) has been significantly decreasing, and the groundwater level has been gradually dropping in some places. Aside from this, the groundwater level was abnormally changed as an impact of the 2016 Kumamoto earthquake. Our final goal is to build a model to represent the groundwater level change including the abnormal change. For this purpose, we generated a land cover map by using temporal Normalized Difference Vegetation Index (NDVI) changes based on Landsat-8 satellite images and Geographic Information System (GIS) data. Our classification results well expressed the actual land cover especially around rivers, lakes and buildings compared with the existing land cover map. The calculated infiltration and surface runoff amounts from grasslands with the different land uses indicated the importance of understanding not only land covers but also land uses to evaluate infiltration and surface runoff amounts.