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O autor teve o privilégio de participar no XIII Encontro Nacional de Riscos que se realizou na cidade do Funchal em Fevereiro de 2020 sob a designação genérica de “Madeira Região Resiliente”. O presente texto é um resumo da sua apresentação com o título “Resiliência e Gestão do Risco” a qual incidiu nos seguintes tópicos: Etimologia e divulgação do termo resiliência; Definição e conceptualização de uma métrica de resiliência; e Resiliência e Gestão do Risco.

Adaptation to climate change is a process that should engage different participants, including not only researchers and technicians but also other stakeholders and local individuals, and, therefore, it is important to understand their beliefs on the local effects of climate change. Recent studies illustrate a linear relation between coastal distance and scepticism, which is lower in coastal zones than in inland. A possible explanation is that people living inland do not experience (or do not perceive) particular natural hazards as being caused by climate change, or attribute the natural hazards to other causes, apart from climate change. This might influence the relative importance of dealing with direct anthropogenic effects and planning adaptation to climate change. Therefore, the goal of this work was to explore this effect by comparing beliefs on the local effects of climate change in Aveiro region (Portugal), specifically in Baixo Vouga Lagunar (BVL, located in the inner side of Ria de Aveiro Coastal Lagoon, 10 km distance from the coast) with the nearby coastal zone between Esmoriz and Vagueira settlements. Stakeholders were interviewed and local individuals were surveyed in order to explore causal attributions towards relevant local environmental problems and compare with data available from the coastal zone. Natural hazards concerned flooding in BVL and shoreline retreat in the coastal zone. Results suggest that in BVL both stakeholders and local residents did not attribute local natural hazards mostly to climate change. However, in the coastal zone, local natural hazards were indeed mostly attributed to climate change. This attribution to climate change was further correlated to a higher risk perception of natural hazards in the coastal zone but not in BVL. Thereby, it is important to consider distance from the shoreline in order to promote local processes of adaptation to climate change. info:eu-repo/semantics/publishedVersion

Hydraulic systems are dynamically susceptible in the presence of entrapped air pockets, leading to amplified transient reactions. In order to model the dynamic action of an entrapped air pocket in a confined system, a heuristic mathematical formulation based on a conceptual analogy to a mechanical “spring-damper“ system is proposed. The formulation is based on the polytropic relationship of an ideal gas and includes an additional term, which encompasses the combined damping effects associated with the thermodynamic deviations from the theoretical transformation, as well as those arising from the transient vorticity developed in both fluid domains (air and water). These effects represent the key factors that account for flow energy dissipation and pressure damping. Model validation was completed via numerical simulation of experimental measurements.

An abnormal accident with no flow in a pumping system occurred with a large displacement of the pipe system. A slow closure of an isolation valve installed in a large suction pipe was the main action. As soon as the valve was closed the 1.6 m diameter pipe moved and the pipe supports were broken, presenting an expansion joint almost fully opened and the main pipe almost broken. This was a critical event that took place in one of the most important pumping stations of the water supply system in Lisbon. In order to avoid future accidents, a detailed analysis was developed as a priority in order to identify the cause of this event. The paper describes the event and the methodology followed in order to fully validate the diagnostic and the proposed chain of events that caused the pipe movement. The process included a careful, in situ observation of the system, hydraulic and structural analyses and some site tests. Ironically, the explanation of abnormal events can give the opportunity to better understand the operation of water supply systems. Weak points in the design and in the operation can then be detected and future accidents can also be avoided.

Coastal risk is already high in several parts of the world and is expected to be amplified by climate change, which makes it necessary to outline effective risk management strategies. Risk managers assume that increasing awareness of coastal risk is the key to public support and endorsement of risk management strategies – an assumption that underlies a common worldview on the public understanding of science, which has been named the deficit model. We argue that the effects of awareness are not as straightforward. In particular, awareness of coastal hazards might not lead to more technically accurate risk perceptions. Based on research on risk perception normalization, we explored the hypothesis that coastal risk awareness reduces coastal risk perception – in particular the perceived likelihood of occurrence of coastal hazards – through its effect on reliance on protective measures to prevent risk. Individuals can rely on protective measures, even when those are not effective, as a positive illusion to reduce risk perception. This effect might be stronger for higher probability hazards and for permanent residents of costal zones. Data from 410 individuals living in coastal zones corroborated most of our expectations. Global results demonstrated a risk normalization effect mediated by reliance on current measures. Additional analyses made clear that this effect occurred in 2 of the 5 high-probability hazards (flood and storm), and not in the low-probability hazard (tsunami). Normalization might be more likely among high-probability hazards which entail catastrophic and immediate impacts. This effect was also found among permanent residents, but not among temporary residents. Results imply that coastal risk management might benefit from (a) taking risk perception normalization effects into account, (b) tailoring strategies for permanent and temporary residents and (c) promoting a higher public engagement, which would facilitate a more adaptive and effective coping with coastal risk than the use of positive illusions. info:eu-repo/semantics/acceptedVersion

The fundamental background of the solution for the steady-state flow in pressurized water closed-loop pipe systems, without any reservoirs in-between, is presented in this paper. The use of the steady-state mass balance and energy equations to calculate discharges and heads in this type of hydraulic system leads to an undetermined problem. The way to solve this indeterminacy is to consider an additional continuity equation associated with the difference between initial and final conditions, taking into account fluid compressibility and pipe-wall deformability. A complete formulation is derived considering pressure and temperature changes in the hydraulic system. Simplified formulae are presented for isothermal flows in simple systems and multiple closed-loops with pipes in series and in parallel. This problem can also be solved by a pseudotransient analysis technique applied to steady-state conditions. Proposed solutions for this problem are applied to steady-state flows and tested for different system configurations.

Reliable and quick techniques are needed to locate and estimate leaks in pressurised pipe systems in order to reduce water loss as much as possible. The aim of the present paper is to show that the...

The most severe hydropower transients are induced in long hydraulic circuits due to extreme operating conditions. A computational model was developed in order to on one hand ensure waterhammer system control and, on the other hand, provide a more reliable and easier analysis for different specific speed turbines and alternative solutions of the system as a whole, through interaction between different hydraulic components. In reaction turbines, runaway conditions and guide vane closure cause significant discharge variations and pressure fluctuations that can affect the design of conveyance systems. A new approach for groups modelling as dynamic orifices concept was developed enabling the characterisation of the integrated system. The simulation results were compared with laboratory tests. This model can be used in the initial stages of civil works design as an efficient way to better characterise the hydrodynamic behaviour of the system when equipped with reaction turbines.

Hydraulic transients that naturally occur in pressurised pipe systems propagate back and forth and carry information about different features of the systems, like bursts or leaks, changes of pipe diameter or material, tee-junctions, local head losses, air pockets, closed valves or pipe branches. The aim of the current paper is the report and analysis of different characteristic pressure traces associated with different pipe system features, whose detection, in the transient pressure signal, allows its identification and approximate location. Transient events analysed herein were artificially generated in different experimental facilities and real life systems by the fast closure of side discharge or in-line valves. Transient pressure data were collected at several locations, with and without bursts, air pockets, changes in pipe diameter/material and branches. Different transient pressure traces were observed and are reported: a burst creates a pressure drop; a dead-end reflects totally incident waves; a diameter decrease induces a pressure peak; an air pocket creates a pressure drop followed by an increase; different pipe materials have different pressure wave shapes and damping. Analyses carried out were aided by two diagnosis support tools: a hydraulic transient simulator and an inverse transient solver. Collected data were compared with the results of numerical simulations obtained by running a transient solver incorporating the accurate description of these phenomena in multi-pipe systems, and an excellent agreement was obtained. An inverse transient solver was applied for the evaluation of the location and size of bursts and air pockets, and it successfully estimated them, providing that an accurate transient solver was used, the evaluation was carried out simultaneously with calibration, and the transient event was created by a fast linear flow change. Conclusions are drawn concerning the importance of considering these phenomena since the design phase until system operation and future expansion. Transient-based techniques are particularly important for the diagnosis, monitoring and control of existing water supply systems, not only to identify abnormal features and estimate their approximate locations, but also for a better understanding of the causes of pipe bursts induced by transient events. This paper was presented at the 8th Annual Water Distribution Systems Analysis Symposium which was held with the generous support of Awwa Research Foundation (AwwaRF).