Changes to the beach may affect the ability of living things there to obtain food and find shelter

Pollution from Fox Glacier landfill washed down to the coast, NZ

The beach environment undergoes not only the diverse, regular daily and seasonal changes of conditions but also the unpredictable changes due to extreme weather, unusual tides and the impact of people.

Water and wind are two of the most powerful agents of change in nature. Waves can move great quantities of beach material, sand and shingle and wear away cliffs and rock. Wind can create and reshape sand dunes (tāhuahua). Like waves, wind can also wear away cliffs and rock and even uproot seaside plants.

River flood events can send huge amounts of water down rivers, carrying debris such as trees, branches and silt downstream. This debris can change the river’s course leaving tidal mudflats high and dry. The debris left over from logging operations known as slash can smother beaches and river banks causing problems for the inhabitants of river valleys and the seashore.