Analysis of physical mechanisms of human body instability for the definition of hazard zones present in emergency action plans of dams. Case study: Santa Helena Dam, Bahia

Luan Marcos Da Silva Vieira,André Luiz Andrade Simões,Andrea Sousa Fontes

doi:10.1590/2318-0331.241920180185

Luan Marcos Da Silva Vieira, André Luiz Andrade Simões + Show 1 more

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https://doi.org/10.1590/2318-0331.241920180185

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Abstract

ABSTRACT The impacts caused by flood waves due to dam ruptures usually cause irreversible damages to the resident population, and, the loss of body equilibrium in floods contributes to aggravate this scenario. In this context, this work aimed to analyse the influence of consideration of physical mechanisms that cause instability in the human body on the definition of hazard zones. Therefore, it was developed simulation of the propagation of the flood wave due to the hypothetical rupture of Santa Helena Dam in Bahia, using the hydrodynamic model HEC-RAS. The results of flow velocities and heights were related and compared to different criteria of hazard zonings and mechanisms that cause body instability. It was verified that the consideration of instability mechanisms of the human body can contribute to hazard management, through the knowledge of areas in which different individuals may topple or slide. It was confirmed that in supercritical flow regimes is more likely for the individual to slide and that in subcritical regimes the individual will topple. Moreover, the consideration of parameters such as buoyancy force and the angle related to the human body's adaptive ability in a flooding influence on the definition of zones.

Highlights

IntroductionThe occurrences of failures and dam breaks generally unleash several damages to current population downstream valley, specially by flood waves and inundation caused by those disasters. Kobiyama et al (2006), Freitas and Ximenes (2012), Quiroga et al (2016) cite some possible consequences that may happen: damaging of the environment and infrastructure; health and mortality of human beings and animals; interruption of services; and disserving local economy.Such phenomena are characterized for generating high flow velocities and water height, that compromise human security and result in the imbalance of the human body, which, in some cases, only slides, while others topple, possibly disabling the person and resulting in drownings.According to ICOLD (1998), parts of the methodologies that guide the study on dam breaks are: elaboration of rupture hydrographs; the knowledge about induced waves dissemination; mapping flood zones; and, the creation of Emergency Actions Plans.Mapping susceptible areas to flooding is part of the Emergency Actions Plans (EAP), and it is a largely used and useful alternative in hazard studies (MONTE et al, 2016)
The main target of this study is to evaluate the occurrence of physical mechanisms of human body instability, due to the hypothetical rupture of Santa Helena Dam, in Bahia, as a means of contribution to define risk zones required in Emergency Actions Plans of dams
The methodology of this study was structured in three steps: (i) Presentation of equations that physically describe instability mechanisms of the human body; (ii) Simulation of the flood wave downstream valley from Santa Helena Dam, on the bi-dimensional hydrodynamic model HEC-RAS 5.0; (iii) Elaboration of hazard maps against inundations, zoned based on presented criteria by the USBR (1988), the Brazilian legislation and the consideration of physical mechanisms that cause the instability of the human body

Summary

Introduction

The occurrences of failures and dam breaks generally unleash several damages to current population downstream valley, specially by flood waves and inundation caused by those disasters. Kobiyama et al (2006), Freitas and Ximenes (2012), Quiroga et al (2016) cite some possible consequences that may happen: damaging of the environment and infrastructure; health and mortality of human beings and animals; interruption of services; and disserving local economy.Such phenomena are characterized for generating high flow velocities and water height, that compromise human security and result in the imbalance of the human body, which, in some cases, only slides, while others topple, possibly disabling the person and resulting in drownings.According to ICOLD (1998), parts of the methodologies that guide the study on dam breaks are: elaboration of rupture hydrographs; the knowledge about induced waves dissemination; mapping flood zones; and, the creation of Emergency Actions Plans.Mapping susceptible areas to flooding is part of the Emergency Actions Plans (EAP), and it is a largely used and useful alternative in hazard studies (MONTE et al, 2016). Kobiyama et al (2006), Freitas and Ximenes (2012), Quiroga et al (2016) cite some possible consequences that may happen: damaging of the environment and infrastructure; health and mortality of human beings and animals; interruption of services; and disserving local economy. Such phenomena are characterized for generating high flow velocities and water height, that compromise human security and result in the imbalance of the human body, which, in some cases, only slides, while others topple, possibly disabling the person and resulting in drownings. These maps contribute on the evaluation of damages and the establishment of communication procedures with the authorities, so they can plan their actions of rescue and improve the management of hazard and land use, defining evacuation routes and alert systems that are adequate (VISEU, 2006)

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