What does urban security encompass today? Alongside the protection of residents, infrastructure, data, and service continuity, issues that only a few years ago were seen primarily as environmental, technical, or operational are becoming increasingly relevant. Water is one of them.

In June 2025, the European Commission adopted the European Water Resilience Strategy, placing water within the broader context of resilience, security, preparedness, and the competitiveness of the European economy. This marks an important shift in perspective. Water availability is not simply a matter of water resources. It is a prerequisite for the functioning of industry, energy, healthcare, fire protection, essential supplies, and the day-to-day operation of cities.

The security question, therefore, is not simply “Will we have enough water?”
A more precise question is: Which functions within a city or region critically depend on it, what reserves does the system have, and what happens if today’s operating conditions change?

This is where the difference between sectoral management and genuine resilience becomes apparent. Individual parts of the system have their own owners, operators, regulations, and plans. National authorities address issues at the state level, water utilities operate infrastructure, river basin authorities manage water resources, and cities are responsible for their services and crisis management. Each actor may perform its role correctly, yet gaps can still emerge between individual areas of responsibility—gaps that no one addresses as part of the system as a whole.

This is a typical challenge of complex systems: risk arises not only from the failure of an individual component, but also from the interdependencies between components that no single actor owns or manages.

For cities and regions, the objective is therefore not to take over the specialist responsibilities of water utilities or national authorities. They do, however, need to understand their own territory as a system. Which services must continue to operate even when resources are constrained? Where does backup capacity exist? Where are there critical dependencies on a single source, infrastructure asset, or operator? Which constraints can be managed operationally, and which require strategic decisions?

The time dimension is equally important. Many security issues today are assessed according to their immediate urgency. For long-term risks, this can be misleading. Water scarcity, ageing infrastructure, dependence on a limited number of suppliers, or shortages of specialist expertise may not emerge suddenly. Over time, however, they can gradually erode system reserves and reduce the room for manoeuvre when additional pressure occurs.

Resilience therefore requires not only response plans, but also scenario planning, adequate reserves, and an understanding of critical dependencies. The aim is not to predict a specific crisis. It is to prepare systems so that when conditions change, every deviation from the norm does not automatically become a crisis.

This perspective also has direct implications for urban development. A new neighbourhood, industrial site, energy project, hospital, or data centre is not merely an investment in buildings and technology. It creates new demands on infrastructure and introduces new dependencies. Strategic planning should therefore consider not only today’s capacity, but also whether critical resources and services are sufficiently robust throughout the life cycle of the planned investment.

Water is a useful starting point, but it is far from the only example. The same approach can be applied to dependencies on navigation and timing services, the availability of critical raw materials, the concentration of supply chains, energy interdependencies, specialist expertise, or technological platforms without which the functioning of modern cities is becoming increasingly difficult to imagine.

We are interested in the systems that modern cities depend on, how those systems are interconnected, and what happens if one of them can no longer operate at the level we have come to rely on.

In our view, these are precisely the kinds of questions that form part of the practical foundations of safe and resilient cities. Not because every potential risk requires a new strategy, document, or standalone programme, but because cities need to be able to distinguish between issues that can remain within sectoral management and those that require a shared, cross-sectoral perspective.

The world is changing faster than infrastructure, strategic plans, and investment cycles. This makes it all the more important to retain the ability to address issues that may not yet feature prominently in security strategies, but which could significantly reshape the conditions in which cities operate within just a few years.