Coasts

Latest news

Seabirds spend nearly 40% of their time on high seas, study finds

4 March 2021

A global effort by seabird researchers, including those from NIWA, has resulted in the first assessment of where the world’s most threatened seabirds spend their time.

Queen of the critters

Feature story

11 February 2021

Sadie Mills has come a long way from scaring the inhabitants of Scottish rock pools. Sarah Fraser explains.

Norse goddess reveals seabed secrets

Feature story

11 February 2021

A large, orange Scandinavian robot gives NIWA’s marine geologists an in-depth look at changes to the seafloor off Kaikōura.

A job for the buoys

Feature story

11 February 2021

New Zealanders and Pacific Island communities are on their way to having the most advanced tsunami monitoring system in the world.

Our work

We need information on the food web structures of our marine ecosystems in order to manage the effects on the ecosystem of fishing, aquaculture and mining, as well as understanding the potential impacts of climate variability and change on our oceans.

Changes in juvenile fish habitats

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.

Coastal adaptation to climate change

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

Plastic pollution processes in rivers

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.

Latest videos

Shifting Sands

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.

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.

No.01 2004

The right time to focus on coasts & oceans

Ocean colour helps fishers

Monitoring Auckland's intertidal zones

A research vessel for all seasons

No.04 2005

Vessels rise to Argo challenge

Tide advice for rescue centre

Picture perfect for port

Sounds surveyed

How green's the bay?

No.05 2005

Big marine farm zone; small effect

Free workshop coming up

Marine Environment Classification launched

Building better offshore mussel farms

Where are the offshore minerals?

No.06 2005

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

No.11 2006

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

Coasts & Oceans Update

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.

No.12 2006

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

Winds & Storms - Looking back at the Wahine Storm

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.

Tsunami

Tsunami is a Japanese word meaning great wave in harbour

Verifying the wave model

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.

Surf zone processes

NIWA coordinates a network of remote video cameras, called Cam-Era, which regularly monitors coastal and river behaviour in real-time.

Sumatra

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) - animation

Solar semidiurnal tide (S2) as an animation.

Waves from Satellites

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) - chart

Solar Semidiurnal Tide (S2)

North Island tidal currents

Twice-daily M2 tidal currents animation around the North Island of New Zealand based on a TIDE2D model.

Maritime Hazards & Support

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.

Lunar Semidiurnal Tide (M2)

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).

Foveaux Strait M2 Tidal Component

This animation shows the chief tidal current in Foveaux Strait. Tidal currents on the west coast of Stewart Island are small, but around the northern and southern coasts of the island and in Bluff Harbour and Oreti Estuary there are strong tidal currents. Overall currents (not shown here) in Foveaux Strait however, are strongly wind-driven with the prevailing wind being from the west. The Southland current, which carries water from the subtropical convergence west of New Zealand, flows through Foveaux Strait.