An Overview of Infrastructure Resilience (Part 1)

Resilience, by definition, means 'the capacity to recover quickly from difficulties' (Lexico). Inherent to this definition is the concept of change, and more specifically, an ability to change in response to a stimulus. From this and in a very broad sense, the speed, efficiency and effectiveness with which a system adapts to stimuli can be interpreted as the degree to which a system is resilient. 

Further to this, in application, there are many components and considerations involved in measuring resilience. The definition above in isolation is only capable of defining the scope of assessment, but not the perspective through which we might want to assess resilience nor the questions we might ask as part of that assessment. It is, therefore, necessary to develop context-specific definitions that subsequently provide this perspective and guide the asking of questions. 

Resilience in a given context seeks to understand two things; the risks to a system, and the vulnerabilities of a system. While in some literature (National Infrastructure Commission 2019), risk management and resilience have been explained as separate properties, it seems counter-productive to maintain this separation as the concepts are not mutually exclusive. Risk management seeks to map and prioritise potential known risks to a system (National Infrastructure Commission 2019), while resilience refers to a broader assessment inclusive of both known risks and unknown risks; the latter driving an introspective focus on system vulnerability in an effort identify the potential impact of an unknown event occurring. 

At any given time, predictions can be made about the future given a discrete set of information. However, these predictions fundamentally can not take into account information not yet received. Because of this, there is a considerable amount of uncertainty surrounding what the future might look like, and as an extension, what conditions a system might have to operate within are. For significant global influences like climate change, a considerable increase in the number of extreme climate events has been observed (Met Office 2020). As climate change progresses, it introduces further uncertainty and a level of unpredictability into future planning; it is because of this that unexpected risks become a significant risk factor to infrastructure systems. 

Another important facet of resilience is understanding the interdependencies between infrastructure elements. Individual pieces of infrastructure may have isolated vulnerabilities, but they may also have system dependants and dependencies. An example of such interdependency might be that of sewage pumping stations on the national power grid. If a significant power outage were to occur, sewage pumping stations may well stop functioning, resulting in the discharge of sewage into local watercourses (US Environmental Protection Agency: Office of Water 2018). This being an obviously undesirable consequence. A diagrammatic representation of such dependencies is presented in the below figure.

Figure 1: Mapping of the cascading effects of infrastructure failure due to interdependence, presented within the 2011 OECD report ’Future Global Shocks’ (OECD 2011).

Technology has also played a significant role in the evolution of resilience. As technology has developed, systems have been empowered to leverage technology both as a mechanism for change within the systems themselves, as well as a way to measure and understand the world in which they operate. Technology provides autonomous and immediate reactivity; for any measurable quantity, a sensor can be attached to a system to measure this quantity, and through an arbitrary amount of computer logic, that system can make decisions based on the quantities state. This ultimately enables systems to become more dynamic and adaptable to changing environmental factors.

Reflecting on a more concrete paradigm of resilience, the National Infrastructure Commission (NIC) has dedicated considerable effort in defining a framework through which the resilience of the UK's infrastructure can be assessed (National Infrastructure Commission 2020). Further to this, the NIC published a series of recommendations to the UK Government in direct response to the needs of the framework they had developed. The framework put forward by the NIC is presented in figure 2. The core elements of the NIC resilience model are (National Infrastructure Commission 2020):

• Anticipate: this is the proactive establishment the right incentives in industry and actively planning for the future.

• Resist: the active response from infrastructure to prevent damage and impact to critical services.

• Absorb: about creating a system that is not simply rigid enough to withstand shocks, but that can minimise the impact of shocks that can not be resisted.

• Recover: the actions and responses to quickly repair and recover from damage caused by the shock.

• Adapt, Transform: longer-term system-wide thinking that seeks to apply the lessons learn from the shock to be better prepared for the next one.

Figure 2: Resilience paradigm set out by the NIC in their report ’Anticipate, react, recover’ (National Infrastructure Commission 2020).

The above defintion extends the original definition of resilience into a practical guide for how resilience should be measured and achieved.

Along similar lines, the Organisation for Economic Co-operation and Development (OECD) significantly explored the topic of infrastructure resilience. In the OECD report ‘Future Global Shocks’ published in 2011 (OECD 2011), the OECD set out their own framework mapping the key element of infrastructure resilience. The OECD model sets out similar stages as the NIC; robustness, redundancy, resourcefulness and adaptability (OECD 2011). While perhaps a more linear approach, as opposed to the sequential steps of the NIC definition, these steps broadly equate to a similar understanding of infrastructure resilience. The US National Infrastructure Advisory Council (and many others; see NIC report appendix (National Infrastructure Commission 2020)) has published equally similar steps as key elements of US infrastructure resilience (Berkeley Iii et al. 2010).

One theme that becomes clear through all of the various resilience frameworks discussed above is the need for specificity and contextual relevance. The concept of resilience is of fundamentally intangible nature, so for a framework to be of any use, it needs to propose a clear paradigm through which resilience can be assessed. Further to this, it is also clear from the literature that it is not sufficient to simply define the measurement criteria for resilience; a path to action must also be created. 

Synthesising the ideas put forward by the above-referenced literature, it is apparent that for a useful definition of resilience, a broader and more practical picture of application must be considered. In particular, the following components seem apparent as the critical elements for definition:

• Paradigm: definition of how to perceive resilience in a given context; the NIC’s anticipate, resist, absorb, recover, adapt and transform is an example of paradigm definition.

• Assessment: how assets are to be assessed against the paradigm elements.

• Scope for Change: for each asset being assessed, a scope for what could be changed to improve the resilience given no constraints.

• Rationalisation: definition of what the constraints are on potential changes; these can then be applied to the scope for change to rationalise and generate feasible actions.

• Action: definition of the action steps to implement the rationalised changes in order to improve the resilience of an asset and the system as a whole.

References

Lexico, “Resilience — Definition of Resilience by Oxford Dictionary on Lexico.com also meaning of Resilience. [Online]. Available: https://www.lexico.com/definition/resilience

National Infrastructure Commission, “Scoping report,” no. September, pp. 1–34, 2019.

Met Office, “How is climate linked to extreme weather? - Met Office,” 2020. [Online]. Available: https://www.metoffice.gov.uk/weather/climate/climate-and-extreme-weather

U S Environmental Protection Agency: Office of Water, “Power Resilience: Guide for Water and Wastewater Utilities”, no. March, 2018.

National Infrastructure Commission, “Anticipate, react, recover,” no. May, 2020. [Online]. Available: https://nic.org.uk/app/uploads//Anticipate-React-Recover-28-May-2020.pdf

OECD, Future Global Shocks, 2011. [Online]. Available: http://public.eblib.com/EBLPublic/PublicView.do?ptiID=767847f%g5Cnhttp:/www.oecdilibrary.org.ezproxy.ub.unimaas.nl/docserver/download/fulltext/4211091e.pdf?expires=1351087982f&gid=idf&gaccname=ocid177396f&gchecksum=6DFDDDE0B397F8814410CAF3C057C19B

A. R. Berkeley Iii, M. Wallace, and NIAC, “A Framework for Establishing Critical Infrastructure Resilience Goals: Final Report and Recommendations,” Final Report and Recommendations by the Council, pp. 1–73, 2010.

This essay has been reproduced from an original written as part of my MRes + PhD programme in Future Infrastructure and the Building Environment: Resilience in a Changing World (FIBE2) at the University of Cambridge.