What is freshwater?

Freshwater refers to water from rivers, lakes, reservoirs, underground streams, and other sources. Water is continually evaporated from the oceans and then returned to the land as ice, snow, or rain. Ice and snow melt from mountains to release freshwater to our rivers, streams, lakes, and to resupply underground streams.

New Zealand's freshwater habitats range from glaciers and seepages in the mountains, down to lowland rivers and streams that flow into estuaries. They include lakes, rivers, streams, some wetlands, cave systems, geothermal areas and underground aquifers.

Importance of freshwater habitats

Freshwater ecosystems contribute to biodiversity, the economy, recreational opportunities, cultural significance and our well-being.

Freshwater is used by a wide variety of native plants and animals. Some of these are unique to New Zealand and often highly specialised to the habitats they are found in.

Tangata whenua have strong links to water. Awa (river) are an important part of whakapapa (geneaology) and freshwater sustains taniwha and protects wāhi tapu (sacred areas). Awa also provide valuable resources such as mahinga kai (harvesting), harakeke (flax) and habitat for species of cultural importance (e.g. tuna/eels).

Threats and pressures

Our freshwater ecosystems are impacted by a number of pressures. These include land use change and intensification, deforestation, drainage, reduced flows, pollution, sedimentation, nutrient enrichment and spread of invasive species.

These pressures have had significant consequences for our freshwater species, which are vulnerable to habitat loss and degradation, competition and predation from invasive species, overharvest and interbreeding.

Freshwater pests including koi carp are found in and threaten our freshwater ecosystems.

The CRESP research programme addresses four pressures on New Zealand’s freshwater ecosystems.