A new approach to flood risk assessment in Asia-Pacific region based on MRI-AGCM outputs

Abstract

Abstract:Climate change is anticipated to escalate flood impacts, and thus it is important to assess flood risk closely in terms of extent and location. This study aimed to assess present and future flood risks, particularly flood risk change, over the Asia-Pacific region with consideration of climate change impacts by using a topography-based analysis method. By analyzing the output of the super-high-resolution global atmospheric general circulation model, it was found that future flood risk will increase in response to extreme rainfall under climate change. Results of this study also indicated that flood risk will further increase in the far future than in the near future . Analyses of inundation area and flood inundation depth (FID) also showed upward trends; most of flood plains in the AsiaPacific region may experience a 0-50cm increase in FID.

Effectiveness of water infrastructure for river flood management – Part 1: Flood hazard assessment using hydrological models in Bangladesh

“…In the Bangladesh portion of the GBM basin, the 0.45 km FID model simulated the flood water level and estimated potential flood inundation depth and area using flood peak discharges of a selected return period produced at each BTOP grid (Kwak et al, 2012). The FID model is a GIS-based model developed from about 0.5 km HydroSHEDS data set (Lehner et al, 2008) and converts flood peak discharges to flood river water levels using a synthetic rating curve developed with Manning's equation (Kwak et al, 2012).…”

“…The FID model is a GIS-based model developed from about 0.5 km HydroSHEDS data set (Lehner et al, 2008) and converts flood peak discharges to flood river water levels using a synthetic rating curve developed with Manning's equation (Kwak et al, 2012). The FID simulated flood water levels of the 10-year return period discharge were considered as DWLs, which include height of embankments.…”

“…Kwak et al (2012) assessed flood inundation depth and area maps in Asia-Pacific region including the GBM river basin using GIS-based flood inundation depth (FID) model with flood peak discharges of the global 20 km BTOP model, which is distributed hydrological model calibrated at the Mekong River basin (Takeuchi et al., 2008). Winsemius et al (2013) used 50 km hydrological model PCR-GLOBWB globally including the GBM basin to estimate flood discharge and flood inundation, but they also did not conduct model calibration with the observed river discharges.…”

Effectiveness of Water Infrastructure for River Flood Management: Part 2 – Flood Risk Assessment and Its Changes in Bangladesh

“…From the results of flood hazard assessment described in Part 1 of this study, we selected 50-year flood as extreme events based on MRI-AGCM3.2S (SRES A1B scenario) precipitation for the present and future climates simulated with a distributed hydrological Block-wise TOP model (BTOP model: Takeuchi et al, 2008) and the GIS-based Flood Inundation Depth (FID) model (Kwak et al, 2012). Then, nationwide flood risk change between the present and future climates was estimated in terms of flood hazard (inundation area, depth and frequency) and exposure (affected people and agricultural damages).…”

“…Especially, Asia is disproportionally influenced by the impacts of flood disasters (WWAP, 2009). For instance, Kwak et al (2012) demonstrated that the Asian region would be at a higher flood risk throughout the 21st century than ever before, because more extreme rainfall would lead to increase of flood inundation depth in many areas.…”