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In Kumamoto, Japan flood risk information is made available on several websites. In the event of heavy rainfall, local citizens need to access these websites and make household-level decisions. It is difficult for citizens to monitor all these sites, analyze and make effective decisions. Evacuation orders are issued by the local government who then filters the information to the relevant multiple stakeholders and local citizens. This takes time and reduces the response lead time of citizens especially in fast-onset floods. There was a therefore a need for illustrative integrated approaches, integrating these data sets.

Using precipitation, river water and tide level data, user-friendly real-time graphs were set up for the Shirakawa River, Kumamoto, Japan. Flood data were collected and used to create numerical simulations, and electronic community-based hazard maps were created.

The data gathered from the July 2012 flood event were used as a demonstrator, illustrating a flood event, as well as how to utilize the information provided on user-friendly real-time graphs’ website, to determine the location, future time and possibility of flooding. Additionally, an electronically generated flood hazard map-making process was developed for distribution across Japan.

These illustrative approaches are relatively new and have only been tested and evaluated in communities across Kumamoto, Japan. As such, it is too early to determine robustness and generalized applications worldwide, especially in data-scarce countries and communities. Improvements and maintenance are ongoing.

These illustrative approaches can be adopted and utilized in cities and communities around the globe, thereby helping in overall disaster risk-reduction initiatives and better flood risk management strategies.

These illustrative approaches are new to Kumamoto City and Japan. These provide citizens with user-friendly real-time graphs that can be accessed anytime and used in flood hazard preparations, warnings, response or recovery.

This study aims to answer the following questions: what is the time scale in which areas downstream are affected by significant rainfall upstream, which areas are first affected, which areas are most affected, how effective is the current warning system in allotting an appropriate amount of time for evacuation, what has been the response time thus far utilizing the current warning system, how can this response time be im-proved using numerical simulation were addressed. The accu-rate prediction of floods and potential inundated areas is crucial for effective flood risk management and this paper analyses the model created for the July 12, 2012 Kumamoto flood event.

Using GIS, LIDAR, SIS and levelling field survey data, the inundated areas were mapped; the sequence of events and the distribution of flood waters were recreated using numerical analysis and modelling. The inundated areas generated by the model were then compared to the actual inundated areas.

The Tatsuda Ichi Chome area was completely inundated within 40 minutes of the first pooling of flood waters, whereas the Tatsuda Jin area was completely inundated within 20 minutes of the initial pooling of flood waters.

This research provides empirical evidence of flood impacts and highlights the benefits that can be derived from incorporating accurate flood modelling results into flood risk management systems, as well as extends the methodological approaches of flood risk management.