Coasts

Latest news

Two reports released today by NIWA and the Deep South National Science Challenge reveal new information about how many New Zealanders, how many buildings and how much infrastructure could be affected by extreme river and coastal flooding from storms and sea-level rise.

NIWA puts a lot of things in the ocean—instruments tied to moorings, floats that dive up and down measuring what’s going on in the water, and video cameras that monitor fish.

Huge mudslides from November’s earthquakes have wiped out all organisms living in the seabed of the Kaikōura Canyon.

New Zealand continues to punch above its weight in global environmental issues, with three Kiwis seeking a positive change to our oceans in Washington this month.

Our work

NIWA is looking for people who have had a long association with the Hauraki Gulf or Marlborough Sounds to help them with a research project on juvenile fish habitats.

NIWA is developing guidelines and advice to help coastal communities adapt to climate change.

Most of the plastic in the ocean originates on land, being carried to the estuaries and coasts by rivers. Managing this plastic on land before it reaches the river could be the key to stemming the tide of marine-bound plastics. The aim of this project is to understand the sources and fate of plastic pollution carried by urban rivers using the Kaiwharawhara Stream as a case study.
Seagrass beds form an important undersea habitat for small fish, seahorses and shellfish in New Zealand.

Latest videos

Shifting Sands - Tsunami hazard off Kaikoura, NZ

Dr Joshu Mountjoy discusses NIWA's work in assessing the tsunami hazard just south of Kaikoura. 

Find out more about this research. 

Antarctic Coastal Marine Life in a Changing Climate

NIWA marine ecologist Dr Vonda Cummings discusses the likely effects of climate change on marine invertebrates living on the seafloor of the Ross Sea coast.

Next Stop Antarctica

Our Far South is an expedition that aims to raise New Zealanders' awareness of the area south of Stewart Island. Gareth Morgan, Te Radar, scientists and 50 everyday Kiwis are onboard to learn and then share their experience. This is the first video produced by them, showing some of the highlights of the trip so far.

Rivers: the land-coast connection

Rivers: the land-coast connection

Gravel extraction, Waimakariri River, Canterbury. (Photo: above, Graham Fenwick, NIWA)

(Photo: above, Alistair McKerchar, NIWA)

NIWA scientists are developing models to predict the impact of changes in river sediment loads on coastal erosion. Rivers are a key connection between the land and the sea, carrying sand, gravel, and cobbles down river, and depositing them at the coast. This material is then redistributed and groundup by waves and currents.

What risk to human health?

What risk to human health?

Sequence of calculations to model health risks at a beach, either from swimming or from consumption of raw shellfish.

One of the direct consequences of land-based activities on the coast is the discharge of treated sewage into the sea. Pathogens (bacteria, protozoa, and viruses) in sewage can pose a risk to human health, through people swimming in polluted areas or eating contaminated shellfish.

Special Issue - Effects of land-based activities on the coastal environment

Special Issue – Effects of land-based activities on the coastal environment
New Zealand’s coastline is increasingly affected by land-based activities, particularly intensified agriculture and nitrate runoff, sewage disposal, coastal subdivision and sediment runoff, and heavy metal and contaminate runoff from urban centres into estuaries. Such issues are the focus of increasing and better environmental management practice.

The right time to focus on coasts & oceans

Ocean colour helps fishers

Monitoring Auckland's intertidal zones

A research vessel for all seasons

Vessels rise to Argo challenge

Tide advice for rescue centre

Picture perfect for port

Sounds surveyed

How green's the bay?

Big marine farm zone; small effect

Free workshop coming up

Marine Environment Classification launched

Building better offshore mussel farms

Where are the offshore minerals?

Modelling aquaculture effects in the Firth of Thames

To San Diego, via Chile

Habitat map for taiapure

When paua seek a home

Hear world experts on seafloor mapping

Ocean Survey 20/20 gets underway

What happens to nutrients in estuaries?

Sophisticated sonar for marine habitat mapping

Ashley Estuary in good shape

Bounty and Antipodes Islands surveyed

Up until November 2008, this was a joint quarterly update from the National Centre for Coasts and the National Centre for Oceans. The publication facilitates public, industry, and governmental access to NIWA's expertise and knowledge in coastal and ocean research.

Better tools mean improved knowledge and services

Smart buoy for coastal monitoring

A flexible way to model sediment dispersal

Getting intimate with aquatic sediments

GeoEel sees beneath the seafloor

Winds & Storms

Looking back at the Wahine Storm

Looking back at the Wahine Storm
Historical records of pressures, winds and waves have been collected for Cyclone Giselle, more widely know as the Wahine storm, after the Inter-island ferry TEV Wahine that sank off Wellington Heads with the tragic loss of 54 lives. The storm on 9 to 10 April 1968 caused winds of up to 150 km per hour at Wellington Airport and high seas and storm tides occurred along the east and south coasts of the North Island as the storm tracked south.

Waves

Wave climate around New Zealand

Wave climate around New Zealand
NIWA has recently implemented a large wave model (NIWAM) for the oceans around New Zealand. This is based on WAM, a 3rd generation model which accommodates the processes of wind generation, white-capping and bottom friction, and includes a direct estimate of non-linear energy transfer through four-wave interactions. NIWAM has been established on a 1.125° resolution grid (see image below) covering the Southwest Pacific, New Zealand, Australia and the Southern Ocean.

Verifying the wave model
The results from the model hindcast have been compared with data from wave buoys deployed at various times in the past at several sites around New Zealand (shown below).

Foveaux Strait Buoy
This was located in 100 m water depth. Model results were corrected for the effects of limited fetch to the coast before comparison with the data (shown below, click to enlarge).

Mangawhai Buoy
This was located in 30 m water depth, in a site sheltered by surrounding land, and affected by refraction of waves over the seabed topography the variable depth.

Tsunami

Gisborne Wharf during the 1960 Chile tsunami - Click to enlarge

International tsunami response sign

What are they?
Tsunami is a Japanese word meaning “great wave in harbour” Tsunami are temporary oscillations in sea level with periods longer than wind waves or swell, but shorter than ocean tides. Tsunami are usually created by a sudden movement or rupture of the ocean floor, such as from earthquakes, underwater landslides and underwater volcanic eruptions. They occur a few times a year, but generally we don’t notice them.

Surf zone processes

Cam-Era coastal network

Cam-Era coastal network
NIWA coordinates a network of remote video cameras, called Cam-Era, which regularly monitors coastal and river behaviour in real-time. Initial funding from the Ministry of the Environment helped demonstrate the potential of remote video cameras for monitoring medium- (over days) to long-scale change (over months) on sandy and muddy coastlines. NIWA has installed the core components of a network of computer-controlled video cameras around New Zealand.

Sumatra tsunami recorded at 1-minute sampling intervals at 9 sites:
a) Date/time in NZ Standard Time (UTC+12), with earthquake (EQ) time shown.
b) Elapsed time in hours since the earthquake occurred.

Sumatra tsunami recorded at 5-minute sampling intervals at 19 sites:
a) Date/time in NZ Standard Time (UTC+12), with earthquake (EQ) time shown.
b) Elapsed time in hours since the earthquake occurred.

Tsunami run-up height reached up to 12 m in Khao Lak (Thailand) as shown by damage to tiles on roof.

Solar semidiurnal tide (S2) as an animation.

Waves from Satellites
Waves are available from a number of satellite sensors, including radar altimeters and synthetic aperture radar (SAR).

A radar altimeter aims a narrow beam directly downwards. From the spread in the return signal, the wave height can be measured.

Solar Semidiurnal Tide (S2)
Twice-daily M2 tidal currents animation around the North Island of New Zealand based on a TIDE2D model.

This map links to graphs showing the tidal range across the whole of 2010 to give people an indication of when the tides are larger or smaller relative to the Moon cycles, and also when the tides are really low for collecting kaimoana!

Tidal and surface currents - besides tidal height, the NIWA tide model of New Zealand's EEZ also produces tidal currents. For the first time, a detailed overall picture has emerged of the strength (speed) and direction of tidal flows on the continental shelf and around various islands, headlands and straits.
Animation of the lunar semidiurnal tide (M2) in New Zealand.
Diurnal Tide (K1)

Hazard planning, awareness and building resilient communities

Sea level on the move?
Effect of global warming
Educational CD-ROM “New Zealand’s Sandy Coasts”
Coastal & Storm Hazards Workshop

Sea level on the move?

Long-term sea level varies at timescales of years, decades and centuries. Before the long-term trend in sea-level rise can be obtained from any sea-level record, we must understand the fluctuations that occur over years and decades. The longest sea-level record in New Zealand is from the Port of Auckland (click to see accompanying figure).

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All staff working on this subject

Principal Scientist - Coastal and Estuarine Physical Processes
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Principal Scientist - Ecosystem Modelling
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Coastal and Estuarine Physical Processes Scientist
Hydrodynamics Scientist
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Principal Scientist - Marine Ecology
Senior Regional Manager - Wellington
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Marine Invertebrate Systematist
Principal Scientist - Marine Ecology
Fisheries Acoustics Scientist
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Physical Oceanographer
Principal Scientist - Coastal and Estuarine Physical Processes
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Marine Biologist (Biosecurity)
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Marine Ecology Technician
Hydrodynamics Scientist
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Fisheries Scientist
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Marine Ecology Technician
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Principal Technician - Marine Geology
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Principal Technician - Fisheries
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