two soil layers namely capillary and non-capillary layers. The water movement in
the soil layers and land surface (overland flow) is accounted for numerically using a
kinematic wave approach. This model is very good for use in the hill slope and
humid areas like Japan. This study reflects advances on previous studies which for
the most part use a simple hydrological model and assume a steady state condition
in simulating hydrological responses and shallow landslide risk.
The limitation of this study is lack of a detailed deposition map for shallow
landslides. Using only the deposition map for all landslide types makes it difficult to
identify shallow landslides, the most common form of landslide in Japan. Our
hydro-geotechnical model was not constructed for this purpose. The resolution of
DEM is sufficient for shallow landslide risk analysis on a large scale, because we
are not trying to identify the detail basin scale shallow landslide events. In future
100 m mesh land use data will be used as input data. Land use type is also an
important driver of shallow landslide risk.
11.6 Conclusion
We use GIS tools and hydrological modeling linked with a slope stability model to
estimate shallow landslide risk levels. A detailed introduction on the framework of
the GIS process and hydrological modeling for large-scale shallow landslide risk
analysis is presented. Model performance was evaluated with a NSE of 0.93 at the
Arase station and 0.86 at the Senoshita Stations of Chikugo River compared with
the observed discharge. We calculated the shallow landslide risk map in Kyushu
Island, and divided the risk into five levels for better understanding. The central part
of Kyushu Island presented the highest risk levels. In order to capture the intricacy
of many related hydro-geotechnical processes combined hydro-geotechnical
modeling for analysis of large-scale shallow landslide risk. This combined modeling system can be applied in the other large scale study areas for shallow landslide
risk simulation. The results of this study can provide scientific information for
future shallow landslide management to reduce economic loss and contribute to
developing sustainable and survivable societies.
Acknowledgments The authors thanks the supports from the Japan Institute of Country-ology
and Engineering (JICE) Grant Number 13003, Water and Urban Initiative Project at The United
Nations University Institute for the Advanced Study of Sustainability (UNU-IAS), the Kyoto
University Inter-Graduate School Program for Sustainable Development and Survivable Societies
(GSS), MEXT Program for Leading Graduate Schools 2011–2018, Designing Local Frameworks
for Integrated Water Resources Management at the Research Institute for Humanity and Nature
(RIHN), Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research
(A) Grant Number 24248041.
238
P. Luo et al.
the soil layers and land surface (overland flow) is accounted for numerically using a
kinematic wave approach. This model is very good for use in the hill slope and
humid areas like Japan. This study reflects advances on previous studies which for
the most part use a simple hydrological model and assume a steady state condition
in simulating hydrological responses and shallow landslide risk.
The limitation of this study is lack of a detailed deposition map for shallow
landslides. Using only the deposition map for all landslide types makes it difficult to
identify shallow landslides, the most common form of landslide in Japan. Our
hydro-geotechnical model was not constructed for this purpose. The resolution of
DEM is sufficient for shallow landslide risk analysis on a large scale, because we
are not trying to identify the detail basin scale shallow landslide events. In future
100 m mesh land use data will be used as input data. Land use type is also an
important driver of shallow landslide risk.
11.6 Conclusion
We use GIS tools and hydrological modeling linked with a slope stability model to
estimate shallow landslide risk levels. A detailed introduction on the framework of
the GIS process and hydrological modeling for large-scale shallow landslide risk
analysis is presented. Model performance was evaluated with a NSE of 0.93 at the
Arase station and 0.86 at the Senoshita Stations of Chikugo River compared with
the observed discharge. We calculated the shallow landslide risk map in Kyushu
Island, and divided the risk into five levels for better understanding. The central part
of Kyushu Island presented the highest risk levels. In order to capture the intricacy
of many related hydro-geotechnical processes combined hydro-geotechnical
modeling for analysis of large-scale shallow landslide risk. This combined modeling system can be applied in the other large scale study areas for shallow landslide
risk simulation. The results of this study can provide scientific information for
future shallow landslide management to reduce economic loss and contribute to
developing sustainable and survivable societies.
Acknowledgments The authors thanks the supports from the Japan Institute of Country-ology
and Engineering (JICE) Grant Number 13003, Water and Urban Initiative Project at The United
Nations University Institute for the Advanced Study of Sustainability (UNU-IAS), the Kyoto
University Inter-Graduate School Program for Sustainable Development and Survivable Societies
(GSS), MEXT Program for Leading Graduate Schools 2011–2018, Designing Local Frameworks
for Integrated Water Resources Management at the Research Institute for Humanity and Nature
(RIHN), Japan Society for the Promotion of Science (JSPS) Grant-in-Aid for Scientific Research
(A) Grant Number 24248041.
238
P. Luo et al.