Almost 18,000 properties across Wairarapa have been identified as potentially exposed to flooding during a severe or 1-in-100-year flood event, according to figures released by Greater Wellington Regional Council (GWRC).

The numbers were obtained under the Local Government Official Information and Meetings Act, but how they are presented — and what they actually mean for residents today — deserves closer examination.

What the Numbers Actually Show

GWRC estimates 17,800 properties could be affected in a major flood scenario:

• Masterton: ~9,400 properties

• South Wairarapa: ~5,300 properties

• Carterton: ~3,100 properties

These figures include urban, rural, residential, and commercial buildings. Importantly, they represent exposure, not guaranteed damage.

In other words, a property being “at risk” does not mean it will flood tomorrow — or even within the next decade.

Climate Change and Long-Term Projections

GWRC’s modelling looks far into the future. Council officials say that by the year 2110, nearly half of all buildings in parts of South Wairarapa and Masterton could be exposed if nothing changes.

That includes:

• Around 60% of commercial buildings in South Wairarapa

• Around 70% of commercial buildings in Masterton

These projections assume:

• No major upgrades to flood protection

• Continued development in flood-prone areas

• No retreat from high-risk zones

That context is often missing in headlines.

What About the Cost of Flooding?

GWRC has completed a detailed flood damage assessment for Masterton, which estimates:

• $8.1m to $16.7m in damage under present-day conditions

• $21.5m to $42.3m when climate change impacts are factored in

These estimates include:

• Building repairs

• Vehicle damage

• Contents loss

• Clean-up costs

• Temporary relocation

• Rural land impacts

However, no equivalent cost studies have yet been completed for Carterton or South Wairarapa, meaning regional financial risk remains partly unknown.

How Does This Compare to Wellington?

For perspective, a Tonkin + Taylor flood exposure report prepared in 2022 found that about 31% of the wider Wellington region’s population and buildings could be exposed during a 1-in-100-year flood event.

That means Wairarapa’s exposure is not unique, but part of a wider regional challenge.

Which Towns Are Most Affected?

Four major towns — Featherston, Greytown, Carterton, and Masterton — face flood risk from rivers in the Ruamāhanga Valley.

Martinborough sits higher, but is frequently cut off during floods, disrupting:

• Emergency access

• Tourism

• Local businesses

• Daily travel for residents

Coastal catchments are also vulnerable, as seen during Cyclone Gabrielle, which caused serious flooding around Tinui.

What Is Being Done Right Now?

GWRC says it is actively managing flood risk through:

• Flood modelling and hazard mapping

• Emergency management planning

• Maintaining and upgrading flood defences

Current projects include:

• Waipoua River urban flood planning (Masterton)

• Exploring nature-based flood solutions

• Reviewing the Lower Wairarapa Valley Development Scheme

Following Budget 2024, the Government and Kānoa agreed to co-fund 16 flood resilience projects:

• 15 sites across Wairarapa

• 1 site in Ōtaki

These projects aim to protect homes, infrastructure, cultural sites, and local economies.

Is the Media Scaring Residents — or Informing Them?

This raises a key question for readers:

Are headlines warning that “thousands of homes are at risk” helping communities prepare — or creating unnecessary fear?

The data itself is legitimate. But when long-term projections and worst-case scenarios are presented without clear timelines or probability, it can feel alarming.

There is a difference between:

• Risk awareness, and

• Fear-based framing that drives clicks

So the real question may not be whether flooding is a risk — but how responsibly that risk is communicated.

What Residents Should Take Away

• Flood risk is real, but largely long-term and conditional

• Exposure does not equal certainty

• Significant mitigation work is already underway

• Better local planning decisions matter more than panic

Understanding the numbers — not just reacting to them — is key.