As weather patterns evolve and climate-related risks intensify, the construction sector must rethink how it assesses flood exposure. South Africa is on the cusp of yet another unprecedented weather cycle. The World Meteorological Organisation (WMO) predicts a moderate-to-strong El Niño event developing between now and August 2026.
Climatologists warn this could rank among the strongest events on record. It could supercharge global weather extremes and increase the likelihood of excessive droughts and floods.
A changing climate risk landscape
Recent events demonstrate just how rapidly these risks are evolving. Severe flooding in parts of the US over the past year caused widespread damage to infrastructure, disrupted transport networks and displaced communities. Meanwhile, across Europe, record-breaking temperatures exceeding 40°C have disrupted power generation, damaged infrastructure and overwhelmed healthcare systems.
Closer to home, recent flooding in the Western Cape resulted in an estimated R9 billion in damages. It impacted more than 22,890 homes and 230 roads. South Africa is actively transitioning from a wet La Niña phase into a developing El Niño weather pattern. While drought impacts are expected to be felt primarily across the summer rainfall regions of the country’s central and northern interior, localised flood risks remain concentrated along the eastern coastline and the southern Cape.
For the South African construction sector, this shifting climate outlook raises important questions around the reliability of historic flood data for future infrastructure plans. While there is a growing recognition that the risk environment has shifted, the implementation of mitigation measures remains inconsistent. In many instances, the industry still responds reactively rather than fully integrating mitigation into planning and design. As a result, projects face increasing exposure to weather-related disruptions. These disruptions can affect timelines, increase costs, and ultimately challenge insurability.
The construction sector must therefore recognise that historic flood data alone may not fully reflect emerging risks. Designing for today’s conditions requires a shift in approach. Site-specific hydrological studies must be undertaken to ensure that designs properly account for both current and future water behaviour.
Designing for future water behaviour
From an engineering perspective, these studies provide a clear picture of water movement. They enable teams to design appropriate foundations, drainage systems and protective measures from the outset.
From an insurer’s point of view, they provide confidence that teams have taken all reasonable steps to account for potential flooding. This makes it easier to assess and price risk accurately.
Contractors should also incorporate measures such as freeboard. This involves elevating structures above anticipated flood levels and adding an additional buffer against extreme weather. These types of risk mitigation interventions are critical in minimising the likelihood of water ingress. They also limit the extent of damage when flooding occurs.
The consequences of underestimating water risk during construction can be severe. Poor stormwater planning can lead to site flooding, erosion and even the washout of works. This risk is particularly significant during the early stages of a project, before permanent drainage systems are in place.
Beyond the direct impact on infrastructure, these conditions can pose significant safety hazards. They can put individuals at risk of injury or, in extreme cases, even loss of life. These risks often intensify when teams inadequately consider changing rainfall patterns and increased runoff. Without effective stormwater management throughout the construction process, projects become significantly more vulnerable. This management must continue throughout construction, rather than only feature in the final design.
Lessons from construction claims
Our claims data reflects these challenges. A recurring issue involves the underprediction of the volume of water passing over construction sites. This often links to the absence of proper hydrological studies. In addition, poorly sealed building envelopes can allow water to penetrate structures during rainfall. This can result in internal damage, rework and delays.
Poor sequencing of works can further exacerbate risk. Incomplete drainage systems or changes in site levels may inadvertently redirect water flow at critical stages. These risks highlight why historic flood data should inform planning without becoming the sole basis for assessing future flood exposure.
Overall, there is a clear trend of increasing frequency and severity of water-related claims. Losses often escalate from relatively minor damage to major events.
Beyond individual project design, site layout and runoff management also play a decisive role in mitigating risk. Effective site planning should account for how water enters, moves through and exits a site. This ensures that runoff moves safely without creating downstream impacts.
Managing runoff across the project lifecycle
Common shortcomings, such as inadequate stormwater capacity or poor grading, can significantly increase vulnerability. Even well-designed solutions can be undermined by last-minute design changes or poor maintenance of drainage systems.
Addressing these risks requires collaboration across the construction value chain. Developers, engineers, contractors, insurers and municipalities all have a role to play. Municipalities, in particular, can strengthen outcomes by making hydrological studies a mandatory component of development approvals. They can also improve outcomes by maintaining stormwater infrastructure more effectively.
While capacity constraints are a reality, a more consistent, risk-focused approach to oversight can make a meaningful difference. Such an approach can also help ensure that historic flood data supports, rather than limits, more forward-looking risk assessments.
Insurers are also increasingly focused on shifting the conversation from reactive claims management to proactive risk mitigation.
From insuring risk to managing it
By engaging with clients early in the project lifecycle and raising awareness of potential exposures, insurers can help encourage stronger risk assessments and more resilient design decisions. Pricing signals and underwriting discipline further reinforce the importance of adequate planning and risk management.
This approach is becoming central to how construction risk is managed. There is a growing emphasis on working closely with clients to identify vulnerabilities early, support more robust planning and encourage the adoption of resilience measures.
The approach is rightly shifting from simply insuring risk to actively partnering with clients to manage and reduce it.
 |
 |
| Mark Barrow | Head | Construction and Engineering | mail me | | Jonathan Kaiser | Head | Claims | mail me | |
| | Santam | | |
