Author(s): Nanako Inokawa; Kenichiro Kobayashi

Linked Author(s): Kenichiro Kobayashi

Keywords: Water gate barrier; Underground flooding; Inundation simulation; Shallow water equation

Abstract: This study aims to clarify the risk of flooding in underground spaces with large elevation differences and the effect of water gate barriers. Underground spaces are often problematic against water-related disasters, especially in urban areas. Many studies have been conducted on the risk of flooding and flooding countermeasures in underground spaces. However, there has been little research on flooding countermeasures focused on elevation differences, although elevation data is important for considering flooding risk and its countermeasures. In this study, we first examined the risk of flooding in the underground space, called “Sanchika” in Kobe, Japan, with high elevation differences. Then we simulated the flooding with water gate barriers and concluded the effect of water gate barriers quantitatively. We used rainfall-runoff model based on 2-dimentional shallow water equation using 1m resolution elevation data. We first simulated the flooding at ground space of Kobe city above Sanchika, approx. 4km x 3km area, giving the rainfall input of 100 year return period, then we transformed the inundation depths at the entrances/exits of Sanchika to the discharges to Sanchika, and carried out the inundation simulation in Sanchika. As a result, the water depth varies greatly depending on elevations. In addition, the effect of water gate barriers becomes significant in the case with water gate barriers at all the exits that have a large amount of total inflow or have a large amount of maximum inflow and a high elevation.

DOI: https://doi.org/10.3850/978-90-833476-1-5_iahr40wc-p0782-cd

Year: 2023