ABSTRACT Starting from a resilience assessment of Harare's water supply, the system interactions of the city’s water management arrangements are explored through a series of causal loop diagrams. These are based on economic, physical, commercial, environmental, and social subsystems and the reinforcing and balancing loops that influence key variables of interest in each are identified. The analysis identifies a series of shortcomings including a weak provider-customer relationship, limited governance capacity, inadequate coordination and integration between key players, shortfalls in physical supply and critical infrastructure, environmental degradation, and a lack of disaster response and recovery measures. A series of strategies are proposed as intervention actions that target the areas of potential leverage identified in the causal loop analysis, including improving customer-provider relationships; increasing coordination, collaboration, and integration; developing physical and informational infrastructure and enhancing environmental protection and rehabilitation. The impacts of these strategies are highlighted as strengthening key elements of the causal loop diagrams and addressing the resilience gaps identified. The systems mapping approach reveals that key issues are large-scale, cross-sectoral, and compounding. Remediation strategies must therefore also be multi-faceted and holistic in scope.

ABSTRACT Two different applications of Jaynes’ maximum entropy framework, maxEnt, are given. The purpose is to show how maxEnt stimulates questions about the relations between the formal structure of the maxEnt model and the practical, possibly political, considerations which arise when deciding the objective function and the constraints. While these points do not lead to computationally complicated models they do raise important questions about the relationship between model form and the environment in which it is used. The first example is from urban and transportation planning. The use of maxEnt to derive the allocation of trips, the gravity model, brought benefits of clarity but also raised an important question with policy implications: should journey cost rightly be a behavioural constraint in the model or should it be considered an output? The policy implications are discussed. The second case was initially stimulated by personnel selection and raises the possibility that it is not always clear what maxEnt should be optimising, what should we be minimally discriminating about? The issue is quite general and is illustrated by the choice of a scheme for water resource allocation.

ABSTRACT China is a large industrial country where tropical meteorological disasters occur frequently. Therefore, natural-technological (Natech) risk cannot be ignored. Assessing the social vulnerability of an industrial city prone to tropical meteorological disaster-induced Natechs is urgent. To analyze the social vulnerability of such cities, we propose a Bayesian network (BN)-based method to model the social vulnerability framework. Natech is characterised by high-consequence and low-probability. The industrial cities in Southeast China are selected as a case study. The Monte Carlo method simulates the data generated in industrial cities suffering from tropical disaster-induced Natechs, and the conditional probability tables of BN descendant nodes are obtained by the expert scoring method. After sensitivity analysis, we conclude that the ‘catastrophic index of tropical cyclones,’ ‘population density,’ and ‘prevention capacity’ have important impacts on social vulnerability. Human traits, the social environment, and the economy play important roles in social vulnerability assessments. Therefore, reducing the catastrophic index of tropical cyclones and population density and strengthening prevention capacity management measures are necessary. Some suggestions obtained after sensitivity analysis can assist governments in improving disaster prevention and mitigation abilities and formulating urban planning policies for sustainable development. Highlights Industry city’s vulnerability analysis for Natural-technological (Natech) accidents A social vulnerability assessment framework for sustainable development A Bayesian network combined with the Monte Carlo simulation data and expert judgment Risk management for high-consequence and low-probability events

ABSTRACT Engineering structures consume a significant fraction of resources and contribute to greenhouse gas emissions worldwide. A conducted literature review shows that most existing approaches to improve the environmental performance of structures concern the adoption of decisions during the conceptual design stage (e.g. on the choice of material), often in connection with life cycle assessment. However, approaches for addressing environmental objectives in practice are often hampered by economic interests pursuing short-term profit. Moreover, such approaches are rather descriptive and lack criteria for assessing the acceptability of specific solutions. Sustainable development of our built environment requires hence a shift of paradigm on how engineering structures are designed. In this paper it is claimed that this should be approached at the strategical level of structural design codes, which contain the rules that support everyday engineering decisions in regard to structural safety and functionality. The paper discusses the reasons why these rules as conceived do not foster an optimal use of materials and explores possibilities for savings of resources and greenhouse gas emissions through modifications of these rules. The potential of risk-informed decision approaches in this context is highlighted and illustrated by a case study – the design of steel beams in building structures.

ABSTRACT Numerical modelling consists of simulating with informatic technologies the conditions of experiments that would require big resources in terms of time and costs. For example, structural engineering considers numerical models of structures because otherwise it would be too expensive to build and destroy a building to study its behaviour under collapse conditions. In this regard, numerical modelling has become a valid alternative to physical experiments since they fall within the scientific method as they need validation that consists in discarding models when the results are not considered reliable. The criterion of falsification is therefore the basis of the selection process not of the ‘most truthful’ model, but of the ‘model least’, that is, less affected by errors. The paper discusses the sources of errors at the base of numerical models by proposing the importance of validation as the application of the falsification method proposed by Karl Popper.

ABSTRACT Civil infrastructures have historically been developed as highly centralised, extensive, and complicated systems. Electricity, water, buildings, transport networks, and communication systems are each delivered separately. Recent advancements in the development of energy micro-grids have opened the possibility of localised, intensive, and complex, nature-based infrastructure ecosystems. Designed at the scale of a village, such systems would integrate different types of infrastructure. For example, an energy micro-grid can provide electricity to buildings, power electric vehicles and cycle water through a precinct. In turn, the water system can store energy and irrigate a diverse, regenerative food system. Providing housing close to food production reduces transport costs, supply chain losses and packaging. The significant land area required for each village would result in a dispersal of populations, creating networks of villages, each with integrated infrastructure ecosystems. This challenges the orthodoxy in town planning and regional economics that accepts ever-increasing urbanisation. To synthesise ideas developed in different disciplines we adopt the epistemology of consilience. That is, a conclusion can be confirmed when different disciplines arrive at that same position. We show that literature in town planning, regional economics, ecological economics, and public health all support the argument for dispersal reached through civil engineering systems.

ABSTRACT A utilidor is a ‘system of systems’ infrastructural solution to the ‘subsurface spaghetti’ problem resulting from direct burial of utility transmission infrastructure beneath the public right of way (PROW). The transition from direct burial to utilidors in older, dense American cities has generally not occurred, despite the potential to increase system performance in a long-term, financially and environmentally sustainable manner, because it would require reform of local planning practices and of utility pricing to support financing within a complex regulatory system. Utilidor adoption in New York City (NYC) would be a significant local infrastructure transition, amplifying the need for locality-based research, that would occur while each utility sector undergoes its own infrastructure transitions, thereby increasing the level of regulatory complexity. This paper applies transitions analysis, recursive collective action theory, and capacity to act analysis to NYC’s experience with its PROW subsurface spaghetti problem and utilidor implementation to demonstrate a place-based methodology that identifies specific sources of resistance to innovative subsurface design and feasible pathways for resolving them. This methodology would be transferable for application to other American cities or classes of American cities to supplement the limits of generalised subsurface and subsurface resource integration research for practitioner application.

ABSTRACT The world faces grave problems stemming from environmental issues, but apocalyptic disaster is not inevitable. The problems arise primarily from human failure to understand the issues and act collectively to deal with them. Any solution must therefore address human factors. This paper considers two: a lack of clarity in thought, aims and action, and the destructive nature of unconstrained conflict at all levels, particularly between groups of all sizes. The first can be helped by the discipline of systems engineering which aims to achieve clarity in complex situations, and the second can use the clarity of understanding to help groups interact while having an attitude of both collaboration and competition. Means of achieving clarity are discussed. Examples demonstrate how clarity has cut through difficult problems and also, in some detail, how, in a major project management situation, a clear-thinking approach brought normally competing groups to work together in such a way that they had to simultaneously collaborate and compete to the delight of the clients and the mutual benefit of all. It can be done and catastrophe avoided.

ABSTRACT To add to the engineer’s toolkit for the twenty-first century challenges, we demonstrate a novel systems model for understanding urban impacts. The model captures interdependencies between different interconnected systems (or sectors, e.g. recreational services or public healthcare) in cities, from the tangible (e.g. resources such as roads) to the more intangible (e.g. outcomes such as the sustainable economy). The model is hazard-agnostic in that it can be modified to capture the impacts of different shocks on tangible parts of the system and how these cascade through to more abstract and high-level city tasks and outcomes. This paper demonstrates three hypothetical scenarios (a flood, drought, and pandemic) and their impacts on a generic UK city. Using the network analysis, impacts can be tracked and interpreted to help prioritise requirements for resilience-building. We propose this new tool be taken up and tested by others working to address global challenges such as the Sustainable Development Goals and grappling with the interconnectedness of urban systems.