Vol.15 No.3 - September 2007

Coastal hazard causes and drivers and those affected by climate change. The growing popularity of a coastal lifestyle and the increasing risk of natural hazards are on a collision course.

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This acoustic profile of the seabed between White Island and the Bay of Plenty coast illustrates some of the 300 active submarine faults identified by NIWA within the tectonic rift that extends from Lake Taupo to north of New Zealand.
Seafloor image of the Boo Boo Fault (the sharp break across the image) displacing the seafloor in southern Cook Strait.

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The 1995 flood in Alexandra highlights the costs of flooding. (Photo: Otago Regional Council)
High-resolution modelling can find the weakness in a town’s flood defences.
Close match between modelled (top image) and actual flooding in a bend of the Clutha River.
Alistair McKerchar and Graeme Smart explain how new models are refining the process of predicting damaging floods. To avoid flood damage we need to keep people and property out of the path of floods.

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Parking beside the River Leith proved precarious as floods tore through Dunedin in 2006. (Photo: NIWA)
Precipitation forecasts from NZLAM for the 6-hour period ending at 1800 NZST on 29 November 2006.
Quantitative streamflow forecasts for the Buller River at Te Kuha for the high-flow event on 29–30 November 2006.
Year after year, people across New Zealand face the threat of damaging floods.

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Aftermath of the Taranaki tornadoes. (Photo: Peter Scantlebury, New Plymouth District Council)
Sitting astride a tectonic plate boundary in the Southern Ocean’s ‘roaring forties’, New Zealand is exposed to a wide range of geological and weather-driven hazards. Events such as storms, floods, and coastal inundation directly affect people, property, and economic activities, and we’re all affected indirectly when insurance rates rise to spread the risk.

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Community opinion can be divided – and negative environmental outcomes emerge – when rock seawalls built to protect ocean-front property from erosion restrict access along the shore and change the amenity value of a public beach. (Photos: Jim Dahm)
Does involving local people in reducing coastal hazards lead to better environmental outcomes?

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A female bristleworm (Perinereis amblyodonta) from Wellington Harbour. (Photo: Geoff Read)
New Zealand's treasures of the sea Did you know?
The world’s largest lobster – the packhorse rock lobster – is found along the northeast coast of the North Island. It can weigh up to 20 kg. Maui’s dolphin, which lives only in New Zealand waters, is facing extinction.

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At Wellington Airport, Kevin McGill checks an automatic rain gauge. (Photo: Alan Blacklock)
Stricter air-quality requirements will help improve the tunnel experience.

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Knowledge for customary coastal and kaimoana management
Sir Tipene O’Regan’s keynote address stressed informed debate.

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Kina (sea urchins) produce their hard exoskeleton from carbonate dissolved in the ocean. (Photo: NIWA)
The joinery factory had to be abandoned as the cliff erosion advanced. (Photo: Mark Dickson)
Ocean acidification workshop Since the Industrial Revolution, the world’s oceans have absorbed more than a third of the carbon dioxide released into the atmosphere by man. This has reduced the buildup in the atmosphere, and so decreased the rate at which climate change is occurring.

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Lesieli Kolo and Hugh Clearkin show us some sponges they have in their classroom. (Photo: Amy Shanks)
Emily Webster holding a northern tuatara (Sphenodon punctatus punctatus) during her visit to Little Barrier Island. (Photo: Sally Richardson)
When is a sponge not a sponge? Do you know what sponges are? Plants. Sponges. Things with holes in them. Do you know what this is?

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Doug sizing up a South Island beach at Okarito. (Photo: Andy Short, Sydney University)
Departing Nui Atoll in Tuvalu. (Photo: Ursula Kaly, Tautai Ltd)
Coastal engineer Doug Ramsay casts a practised eye over the foreshore, on the lookout for potential hazards. Lured from his Scottish east coast origins by New Zealand’s friendlier climate, Doug is NIWA’s coordinator of the Natural Hazards Centre and a coastal hazard consultant, roles that find him at beaches all around New Zealand and the Pacific, assessing risks of erosion and inundation.

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Surf Life Saving. (Photo: Surf Life Saving New Zealand)
Model output shows rip current development. The shoreline is at the base of the image (red).
The arrow points to a rip current at Piha Beach. (Photo: Surf Life Saving New Zealand)
A large part of Surf Life Saving New Zealand’s rescue and safety interventions are in response to rip currents.

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Modelled results: maximum water surface elevation showing wave focusing behind Motiti Island.
This graph compares past wave heights from the geological record with maximum wave heights predicted by the model for different locations along the Bay of Plenty coastline.
By comparing the record of past events with results from a computer model, James Goff and Roy Walters are discovering how tsunamis could affect the Bay of Plenty in the future. Beyond its obvious blessings of fine weather and beautiful scenery, the Bay of Plenty on the North Island’s east co

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One of NIWA’s aims with this magazine is to contribute to science education in New Zealand. To this end we distribute Water & Atmosphere without charge to New Zealand high schools. Articles are assigned ‘Curriculum Connections’ to indicate which of the NZ NCEA Achievement or Unit Standards they can complement as a classroom resource.

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The ‘chain of risk’. RiskScape works by running through a sequence of steps, from hazards and exposure through to vulnerability and potential losses, before determining risk.
Homes and property destroyed by floodwater and debris at Matata, Bay of Plenty, in May 2005. (Photos: Alan Blacklock)
Further detail on the project can be found on the RiskScape website: www.riskscape.org.nzA similar project by Geosciences Australia is also underway. See: www.ga.gov.au/urban/projects/nrap
Be prepared!

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What a satellite ‘sees’: a visualisation of the brightness temperatures measured by the NOAA15 Advanced Microwave Sounding System (AMSU) at 89 GHz (one of 20 channels in this instrument).
NIWA’s ’all-hazards’ environmental forecasting framework.
NZLAM: Low cloud and mean sea-level pressure (hPa) and NZLAM: Low cloud and mean sea-level pressure (hPa)
Michael Uddstrom, Hilary Oliver, Phil Andrews, Stuart Moore, and Vanessa Sherlock explain how state-of-the-art meteorological forecasting supports a raft of models for the hazards c