Hundreds of Hawke's Bay homes at risk of coastal erosion

Houses and properties in every Hawke's Bay coastal settlement will succumb to rising sea levels and erosion over the next 100 years, a new study claims.

Letters were to be sent to 750 Hawke's Bay landowners today informing them that their property were in a "coastal hazard area" and were likely to be affected by coastal erosion by 2100.

A Hawke's Bay Regional Council commissioned report that cost $85,000 and took nearly two years to complete has predicted the effects of rising sea levels and erosion in 2060 and 2100.

The affected properties, located between Porangahau in the south to Mahia in the north, will now be identified as lying within a hazard area in any Land Information Memorandum (LIM) or Property Information Memorandum (PIM).

Property values may be affected and landowners may find it more difficult to gain building consents or subdivide their land.

They may also find it difficult to insure their buildings against erosion in future.

The report reinforces earlier reports' predictions on the coastal erosion risk in Napier and Hastings and includes the first predictions for the Wairoa and Central Hawke's Bay coastlines.

The report's author, Richard Reinen-Hamill, a consultant at the environmental engineering firm Tonkin and Taylor, presented the report to council yesterday.

Mr Reinen-Hamill said that while scientists were still split over how global warming would affect sea levels, it was known that sea levels had risen by 1.4mm a year over the last century.

"Most scientists agree that sea levels will continue to rise," Mr Reinen-Hamill said.

Areas that will be affected are: Porangahau, Blackhead, Aramoana (including the Shoal Bay development), Pourerere, Mangakuri, Kairakau, Waimarama, Ocean Beach, Clifton, Te Awanga, Haumoana, Clive, Awatoto (including State Highway 2), Westshore, Bayview, Esk River, Whirinaki, Tangoio, Mahia Beach, Oraka Beach, and Mahanga.

Areas where land may be affected but not buildings are: Waipatiki, Aropaoanui, Waikari, Mohaka, Whangawehi, Waihua, Wairoa, Tahaenui, Nuhaka, Waikokopu, and Opoutama.

The report recommends a strategy of "planned retreat" in the threatened areas, which involves phasing out all development in the areas, relocating all threatened buildings, and providing land further inland where existing properties could be relocated.

The regional council has said it was unlikely to build any erosion protection works, such as groynes or seawalls, but will maintain those that exist already.

The council will look at other forms of erosion protection, such as beach renourishment (replacing material that has been eroded) and stricter controls on beach access.

Under the Building Act, district or city councils cannot grant building consents for new buildings unless the council is sure there is enough protection for the building, and the building will not worsen erosion.

The report recommends that any development should maintain the footprint of the existing building.

Councils must also consider any risks facing land that an owner wants to subdivide.

Mr Reinen-Hamill said that indications were that insurance companies would still cover buildings in erosion zones.

"The insurance council is looking very closely at climatic change effects, but it hasn't decided to pull the pin yet," he told councillors.

Over the next three months the regional council and Mr Reinen- Hamill will hold meetings throughout the region to explain the report and answer questions.

- HAWKE'S BAY TODAY