The recent flooding in the top half of the South Island is horrible for all concerned and our hearts go out to those who have been impacted.
This incident has been one of many high-profile floods over the last couple of years across Aotearoa and climate change projections indicate that as a country we can expect more extreme weather events.
When engineers design infrastructure, one of the first things we assess is risk – especially from natural hazards like flooding. Yet, many property buyers overlook this critical factor. Here’s why you shouldn’t:
1. Site selection is everything
Civil and environmental engineers use topographic data, hydrological models and historical flood maps to determine safe building zones. If a site is prone to flooding, it’s often deemed unsuitable for critical infrastructure. However, there are many properties already located in these areas which were built well before we know what we do now, so do your homework.
2. Structural integrity and long-term costs
Flooding doesn’t just damage furniture – it undermines foundations, corrodes materials and accelerates structural decay. Even minor, repeated flooding can lead to major repair bills and insurance hikes. As the frequency of climate related incidents occur you may even struggle to secure insurance in the future.
3. Risk is quantifiable – and avoidable
Engineers use return periods (e.g., 1-in-100-year flood) to estimate flood likelihood. This doesn’t mean it only happens every 100 years. These periods aren’t just theoretical – they’re based on real data. If your future home is in a floodplain, the risk is measurable and real.
4. Resilience is cheaper than recovery
Designing for resilience – like elevating structures or using flood-resistant materials – is far more cost-effective than rebuilding. But the best resilience strategy? Avoid high-risk zones altogether.
5. Health risk
Homes that have been previously flooded and are damp can lead to health complications such as respiratory issues (especially for those with asthma or allergies). Floodwaters often contain sewage, chemicals and other hazardous substances which may have some residue impacts.
Bottom line:
Before you buy:
A great property isn’t worth the risk of being underwater – literally.
Davis Ogilvie (DO) is a multidisciplinary consultancy that provides comprehensive engineering, surveying and planning services, as well as specialist expertise in civil, geotechnical and structural engineering, resource management and environmental sciences.
With a legacy of over 90 years, we have a wealth of local knowledge and experience, with South Island offices in Christchurch, Nelson, Greymouth, and Timaru. Whether it is a multidisciplinary or a standalone project, we can help.
From dirt to development, resilience to recovery, DO provides collaborative efficient solutions. DO delivers.
