Abstract:
Background In recent years, due to the poor service condition and frequent extreme rainfall weather during flood season, the check dams are in the risk of breach while bringing comprehensive benefits, which causes a great threat to the life and property of downstream people and the protection of the ecological environment. Therefore, it is urgent to propose a quantitative calculation method for the loss from check dam system breach under extreme rainfall conditions.
Methods This study was based on the FT-IWHR program for the risk analysis of dam system failure using the "Genealogy Method", the DB-IWHR program for dam breach flow calculation, and the one-dimensional flood routing calculation program. It proposed a comprehensive calculation method for the entire process of check dam system failure and subsequent flood routing. By integrating the Li-Zhou method for estimating life loss, it constructed a calculation methodology for assessing the impact of dam breach that encompasses life loss, economic loss, and social-environmental impact.
Results Based on the calculating method system proposed in this study, an application study was carried out on the check dam system in Xiwuselang basin. The results show that the warning time has a great impact on the number of life loss. Under full warning and no warning, the number of life loss is about 10 times different, and the loss increases sharply after the rainfall exceeds 100-year return period. This dam system is mainly breached by small and medium-sized check dam.
Conclusions The proposed calculation method for breach loss can achieve rapid quantitative evaluation of the loss from check dam system breach, and provide technical support for the safe operation of check dams and reinforcement of dangerous dams. It is suggested that the Xiwuselang basin should do a good work in preventing and controlling the risk of small-and medium-sized check dam breach.
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