Impact of Storm Surge Runup in Small and Medium Rivers on Urban Inundation Characteristics

Key Points

• The study aims to evaluate how river representation affects urban inundation characteristics during storm surges.
• Utilized the SuWAT model to perform storm surge inundation calculations.
• Focused on urban areas around the Tamagawa and Nogawa rivers in Ota, Tokyo.
• Assessed the impact of river geometry and compound flooding on inundation.
• Analyzed timing differences between peak surge and river discharge.
• Inundation area increased by approximately 25-36% when the Nogawa river geometry was included.
• Earlier flooding times were observed, particularly upstream of Nogawa.
• Smaller timing differences between surge and discharge peaks resulted in larger maximum inundation areas.
• Predictions indicate that climate change will shorten peak timing differences, increasing flooding risks.