Risk Assessment of Dam-Breach Flood Under Extreme Storm Events

Xiajing Lin,Guoqing Wang,Denghua Yan,Guohe Huang,Xiong Zhou

doi:10.3389/fenvs.2021.742901

Abstract

In recent years, as a result of increasingly intensive rainfall events, the associated water erosion and corrosion have led to the increase in breach risk of aging dams in the United States. In this study, a hydrodynamic model was used to the inundation simulation under three hypothetical extreme precipitation-induced homogeneous concrete dam-breach scenarios. All hydraulic variables, including water depth, flow velocity, and flood arriving time over separated nine cross-sections in the Catawba River, were calculated. The hypothetical simulation results illustrate that the impact of Hurricane Florence’s rainfall is far more severe over the downstream of hydraulic facilities than that of the Once-in-a-century storm rainfall event. Although Hurricane Florence’s rainfall observed in Wilmington had not historically happened near the MI Dam site, the river basin has a higher probability to be attacked by such storm rainfall if more extreme weather events would be generated under future warming conditions. Besides, the time for floodwaters to reach cross-section 6 under the Hurricane Gustav scenario is shorter than that under the Once-in-a-century rainfall scenario, making the downstream be inundated in short minutes. Since the probability can be quantitatively evaluated, it is of great worth assessing the risk of dam-break floods in coastal cities where human lives are at a vulnerable stage.

Highlights

Heretofore, about 87,000 dams have been built in the United States, which control 600,000 miles (970,000 km) of rivers (Figure 1) (Infrastructure Report Card, 2017)
Most dams in the United States have been built for nearly 100 years or even more, and thousands of dams have been listed as high-risk dams, all of which are facing the risk of failure (Chen and Hossain, 2019)
Once-in-a-Century Storm Rainfall Induced Dam Break Flood Scenario The intensity–duration–frequency curve (IDF curve) is an engineering mathematical function based on time series, which links rainfall intensity with its duration and frequency

Summary

Introduction

Heretofore, about 87,000 dams have been built in the United States, which control 600,000 miles (970,000 km) of rivers (Figure 1) (Infrastructure Report Card, 2017). Most dams in the United States have been built for nearly 100 years or even more, and thousands of dams have been listed as high-risk dams, all of which are facing the risk of failure (Chen and Hossain, 2019). Extreme rainfall events, such as hurricanes, tropical cyclones, and typhoon-induced precipitation, may attribute to dam failures and lead to devastating inundation disasters (Hill and Lackmann, 2011). Such dam failures including overtopping and piping failures frequently occurred when the accumulated floods came from the high stage level of the river.

Objectives

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Results

Discussion

Conclusion