Study Report on the Improvement of Efficiency of Emergency Construction Conducted in Response to Levee Breaches (Draft) Released
The risk of large-scale flood disasters due to typhoons and torrential rains is increasing, as highlighted by recent levee breach disasters. However, even if the river level is high, such as immediately after a failure, it should be possible to reduce flooding water, and thereby mitigate damage by the flood, by sealing the opening effectively at an early stage. Nevertheless, the development of emergency sealing construction technology has not seen much progress because (a) available construction materials and methods are limited, as this type of construction is carried out in emergency situations, (b) not enough knowledge has been accumulated due to the low frequency of such works conducted, and (c) the mechanism of widening of levee breaches is still unclear. There is an urgent need to establish effective disaster mitigation technology against levee failure disasters.
In order to address this challenge, the Hokkaido Regional Development Bureau (HDB) of the Ministry of Land, Infrastructure, Transport and Tourism, and the Civil Engineering Research Institute for Cold Region (CERI) have jointly conducted a levee breach experiment with a full-scale water channel, Chiyoda Experimental Channel, and developed a numerical calculation model based on the experimental results to clarify the mechanism of widening of levee breaches. The HDB and CERI have also systemically promoted other research activities as well, including a study on techniques to reduce flooding water to mitigate damage after a breach, and a study on an efficient construction material installation method.
In this post, we will introduce the content of the Study Report on the Improvement of Efficiency of Emergency Construction Conducted in Response to Levee Breaches (Draft), which comprehensively covers the studies conducted to propose damage mitigation technology for levee breaches.
Summary of the Study Report
The structure of the Study Report is summarized in Figure 1. First, we conducted case studies and interviews with those involved in emergency construction in recent levee breach cases in Hokkaido Prefecture to gain some insights and identify challenges. Then we identified the key points in addressing these challenges. Next, we conducted a levee breach experiment with a full-scale levee, Chiyoda Experimental Channel, and developed a numerical calculation model. Based on the results of the experiment and calculation, we identified the influence of the channel characteristics on the widening of the levee breach and developed an approach to disaster response measures that can effectively tackle such phenomenon. In addition, in order to improve the efficiency of emergency construction in disaster situations, we examined the work process of material installation using heavy machinery, as illustrated in Figures 2 and 3. In the final phase, we carried out a simulation of a real river levee breach and determined the damage mitigation effect of the emergency construction methods that we proposed.
A part of this Study Report is used as a reference material in simulations of emergency levee breach measures conducted by various flood control offices across Japan.
How to Obtain the Study Report
The Study Report on the Improvement of Efficiency of Emergency Construction Conducted in Response to Levee Breaches (Draft) can be downloaded for free from the website of CERI River Engineering Research Team.
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(Contact: River Engineering Research Team, CERI)