Introductory Chapter: Critical Infrastructure – Modern Approach and New Developments

1. Introduction

Disaster Risk Reduction aims at decreasing the damage caused by natural hazards, such as earthquakes, floods, droughts, and landslides, by implementing prevention and response measures. According to a 2022 report [1], 80% of cities have been affected by significant climate change hazards represented by extreme heat (46%), heavy rainfall (36%), drought (35%), and floods (33%). This set of hazards affects the complex system of the built environment and results in interrelated consequences at different scales ranging from single buildings to urban spaces and territorial infrastructures. Since it is not possible to reduce the severity of natural hazards, the main opportunity for lowering risk lies in reducing vulnerability and exposure. Vulnerability and exposure are related to urban development choices and practices that weaken the system’s robustness. This volume reviews recent insights from risk identification and reduction to preparedness and financial protection strategies and proposes new approaches for better critical infrastructures and built environment protection.

Global warming and natural disasters are becoming more frequent and devastating to life and infrastructures. There are two types of natural disasters: uncontrollable and controllable. Uncontrollable disasters include earthquakes, tsunamis, windstorms, hurricanes, and others, for which the event’s evolution is determined by nature, and when the disaster strikes, our responses are limited to early warning and repair actions. Controllable disasters are those like wildfires, floods, and pandemics, for which, in addition to early warning and repair actions, we can also modify the evolution of the event (e.g., wildfires, pandemics).

In addition to natural disasters becoming more prevalent, Critical Infrastructure and Systems are becoming increasingly interconnected, and the need to design for robustness and resiliency against man-made and natural threats has become a critical problem in our society [2]. An example of interdependent systems includes the electrical system that supplies the telecommunication system, which allows the mobile transmission, stoplights, light detectors, and railways that compose the modern transportation sector. If the electricity supply is not available, then the operations of these other systems will also be impacted.

2. System resilience

Although there are several definitions of resilience, we could define resilience as the capacity of a system to anticipate critical events and maintain operations during and recover from these events. In engineering literature, resilience plays a decisive role in studying critical infrastructure systems. However, most research regarding the resilience of critical infrastructure systems focuses on single, isolated systems, such as the electric grid, transportation, or water, without consideration of surrounding systems. Since Critical infrastructures are interdependent, these models fail to ensure the resilience of specific systems.

Based on the definition above, to strengthen resilience, it is necessary to improve the risk culture and strengthen the integration of resilience in the strategy process. Risk management includes five pillars: preparedness, mitigation, response, recovery, and evaluation. Preparedness refers to planning, training personnel, and providing educational activities regarding potentially disastrous events. Mitigation refers to actions to prevent or reduce the disasters’ cause, impact, and consequences. The response phase occurs in the immediate aftermath of a disaster. When a disaster occurs, actions are taken to save lives, treat injuries, and minimize the effect of the disaster. During the recovery period, restoration efforts occur concurrently with regular operations and activities. Finally, evaluation includes actions to review the response effectiveness and reactions.

Technology, modelling, and simulation techniques can play a large role in analyzing resilience and estimating risk, and then implementing actions capable of lessening the consequences of disruptive events on lives and property. Regardless of the type of disaster, the timeline of a disaster can be divided into three periods: pre-disaster (preparedness and mitigation), during the disaster (response and recovery), and post-disaster (evaluation).

Figure 1 [3] shows the various stages involved in recovering a system damaged by a disaster, from preparation to recovery. The post-disaster period can be divided into immediately after a disaster, days after, weeks after, and months after. As shown in Figure 1, much effort should be put into the response immediately after the disaster (where most lives are at stake) and in optimizing the response in the early stages. Reinforcement of the system before the disaster happens increases the robustness of citizens and infrastructures. Reinforcement includes the preparation of the citizens in how to protect their lives during the event, reinforcement of buildings and homes, and reinforcement of the critical infrastructures (CIs). Similarly, being ready to increase robustness immediately after the disaster strikes has a strong influence on the overall consequences of the disaster. The decisions on prioritizing the assets to be reinforced more for a given CI budget will depend on the role of that asset in preventing loss of life and restoring the quality of life after the disaster.

Figure 1.

Time stages of resilience.

A targeted and prioritized response as early as possible after the disaster (optimized response curve in Figure 1) requires knowing where the victims are located, the severity of their injuries, the transportation time, and the availability of treatment in the hospitals. The subsequent short-term and mid-term periods after the disaster focus on recovering infrastructure to restore people’s well-being to a minimum level. The actions during the first days after the disaster will considerably impact the total time until a minimum functionality of the system is achieved. This period can be shortened from several weeks to a few days by increasing the efficiency of the response.

3. Preparation for the next disaster

The knowledge and information gained during the short- and mid-term periods of the response and restoration of a disaster should be used for the long-term planning of reinforcing the system before the next disaster. In addition, this rebuilding period should be used to bring the system to higher levels of robustness than before the previous disaster occurred.

Each disaster period requires quantitative metrics to assess the cost-benefit analysis for preparation and response. Cost-benefit analysis is difficult to make in the case of disasters. First, there is the cost of human lives, which is very difficult to quantify in economic terms. The cost of infrastructure recovery can be quantified in terms of direct repair and replacement costs. In addition to life and property, the quantification of the costs should include the loss of quality of life until the system recovers a certain level of functionality. In the case of some disasters (e.g., wildfires or floods), there is also the long-term cost of damage to the environment.

Sophisticated simulation tools exist today that can make use of the new advanced technologies to make more informed and effective decisions in emergency environments. A typical workflow for the use of these tools is as follows. First, predict the evolution of the disaster from the physics of the phenomenon and sensor measurements. Second, predict the damage expected to be caused by the advancing disaster. Third, play What-if scenarios with possible responder actions and choose the action that will result in the best possible outcome.

Advanced prediction and optimized management tools can greatly reduce the consequences of loss of human lives and property. These advanced modelling and response tools can be used at all stages of the disaster, from reinforcing the system before the disaster by performing what-if scenarios and identifying the vulnerabilities to restoring the infrastructure in the shortest amount of time.

The Chapters in this book present strategies for responding to natural disasters and making use of available technological and simulation advances to minimize their consequences.