2024 Volume 80 Issue 16 Article ID: 23-16071
In this study, five open levees were assumed to be constructed along the Tedori River, a first-class river in Ishikawa Prefecture, Japan, and inundation simulations were conducted to evaluate the effect of the open levees on reducing economic losses in events of flooding due to levee breach. The simulation results assuming the planned rainfall showed that the potential flood damage was reduced by more than 80 billion JPY (about 87%) depending on the cross-section where the levee breach occurred. On the other hand, discontinuities are formed in the areas where the open levees are constructed. In some cases, without levee breach, inundation occurred even when the flood was at the level where they could safely flow before the construction of open levees. The simulations assuming L1.5 rainfall (rainfall between the planned rainfall and the maximum expected rainfall) also demonstrated the effectiveness of inundation mitigation by open levee, and damage reduction of about 100 billion JPY (about 82%) could be expected. The maximum expected rainfall caused flooding in a wide area even without levee breach, and inundation would have increased if open levees had been constructed.
