Coasts

NIWA answers a wide range of scientific questions using ocean modelling. These models can be linked to well established weather forecasting models to predict ocean temperature, sea level and the dispersal of pollution.

This system is based on these papers.

This is a user guide on non-native fish, reptile, invertebrate, algal and plant species that are recorded in New Zealand freshwaters.

An explanation of how New Zealand beach types are classified and mapped and how the different beach types and their associated hazards are identified.

A tide-dominated system, with a narrow reflective high-tide beach composed of coarse sediments, fronted by wide (100's to several 1000's of metres), low gradient (

Reflective + sand flats beaches have a small steep (3-10°), very low-energy high-tide beach composed of coarse sand, fronted by flat featureless sand flats up to several hundred meters wide and composed of finer sand.

Ultradissipative beaches have a relatively straight, steep, cuspated high tide beach, and a low gradient concave, featureless, wide (averages 400-500 m) intertidal zone.

Reflective + bars & rips beaches have a relatively straight, moderately steep, narrow, and coarser sand, cuspated high-tide beach, fronted by a lower gradient, relatively featureless intertidal zone.

This is the lowest energy of the tide-modified beaches and also has the coarsest sand.

Dissipative beaches are characterised as being high energy beaches with a wide surf zone (300-500 m) including two to three shore normal bars and troughs, and a low-sloping and wide beach face consisting of fine sand.

Low tide terrace beaches are composed of fine to medium sand and have a moderately steep beach face joined to an attached bar or shallow terrace that is often exposed at low tide.

Bars transverse (perpendicular) to and attached to the beach separated by distinct rip troughs at 150-300 m spacing.