Risk-informed design: Navigating uncertainty before the full picture is clear

Decisions made early in the design of buildings and urban environments can influence conditions that contribute to disaster risk. Yet these decisions often begin before a complete picture of risk is available.  

In my work as a built-environment sustainability practitioner, I have found that the environmental evidence available at this stage can still inform decisions — not because it provides a complete risk assessment, but because examining different sources together can reveal what we know, what the evidence suggests, and what still needs investigation.  

When two maps change the question  

Rainwater analysis is a good example.  

Early in a project, I may work with environmental data showing where water is likely to accumulate during heavy rainfall, alongside information about streets, landscaped areas, and other site conditions.  

Looking at one source in isolation can lead quite quickly from an identified problem to a proposed response. But built environments function as interconnected systems. Cross-referencing different sources of spatial information can reveal relationships that are not visible when each source is considered separately, and those relationships may change the question the design team needs to ask.  

A landscape map shows where landscaped areas are located, and a water accumulation map shows where water collects. However, if the two maps are compared, one might wonder: why does water still collect even though there are abundant landscaped areas nearby?  

One possible explanation is that runoff has difficulty reaching the landscape. Site information may reveal curbs, differences in level, or other physical barriers that interrupt the flow.  

The available evidence does not prove that this is the cause. But it changes the direction of the investigation. Instead of immediately asking whether more green space is needed, the design team can first examine whether existing landscaped areas are effectively connected to the places where water accumulates.  

The interpretation changes if water accumulation also appears within landscaped areas. This may suggest that storage, infiltration, or drainage capacity also needs to be examined. Yet information about soil permeability, precise site levels, or drainage capacity may not be available at this stage.  

That does not mean the progress on the project has to stop. The evidence may already be enough to identify water management as a design priority, preserve space for possible measures, or avoid decisions that could make runoff more difficult to manage. But it may not yet be enough to determine which intervention is appropriate.  

Improving connections between hard surfaces and landscape, introducing bioswales — vegetated depressions designed to slow, filter and temporarily retain stormwater — or using blue-green roofs may all become relevant responses. Which approach is appropriate will depend on what further investigation reveals. 

What can the evidence support now?  

This is one of the difficulties of designing for a changing climate: decisions begin before every uncertainty has been resolved.  

Cross-referencing different sources help clarify the boundary between what the available evidence can support, what remains a possible explanation, and what still requires investigation. Looking at interconnected conditions may also reveal underlying issues that a single source alone would not show. 

The aim is not to force a conclusion from incomplete information, but to understand what can reasonably be decided now and what should remain open. 

From environmental evidence to risk-informed decisions  

This is where I see a connection with disaster risk reduction.  

Environmental evidence alone does not provide a complete picture of disaster risk .  

Understanding risk also requires considering hazards, who and what may be exposed, the conditions that make them vulnerable, and the capacities available to manage and reduce risk.  

My work takes place early in the project cycle, while buildings and urban environments are still being shaped. I use “risk-informed design” here to describe bringing risk considerations into that process early enough to influence decisions, without treating preliminary environmental analysis as a complete risk assessment. This use is closely related to UNDRR's broader emphasis on integrating disaster-risk considerations into planning and investment decisions .  

Before committing to a specific design intervention, I ask three questions  

• What can we confirm from the existing evidence?  
• What possible interpretations might emerge by comparing different sources of evidence? 
• What still needs to be discussed or investigated before we reach a stronger conclusion or decide on the next step?  

Risk-informed design under uncertainty is not about immediate conclusions, but about a more informed reasoning process behind decisions. Through this process, project teams can recognize possible risk implications, consider potential consequences of decisions, and formulate open questions to carry into the next project phases.  

Sometimes the most useful result of environmental analysis is not an immediate solution, but a more precise question.

Kaiqi Yang is a built-environment sustainability practitioner and researcher focused on advancing climate and sustainability transitions through knowledge mobilization, practice innovation, and the redesign of professional processes. With a background in architecture and urban design, she explores how environmental evidence and sustainability knowledge can move across disciplines, organizations and contexts, and be translated into actionable strategies and better decision-making