Physiographic Environments of New Zealand

A new landscape classification for water quality that better accounts for the influence of the natural landscape.

A Physiographic Environment is an area of similar landscape characteristics.

What are Physiographic Environments and what do they tell us about water quality?

There are two main factors controlling water quality outcomes – the landscape and us.

Water quality varies widely between regions around New Zealand, even where there are similar land uses and pressures. This is because the natural landscape can have a much bigger influence on water quality outcomes than land use on its own. This means in areas with lots of landscape variation, the effect from similar land use activities can be very different. In areas with little landscape variation, land use pressure is the main control over water quality.

Differences in the hydrological, chemical, and physical processes that occur in the landscape alter the composition of the water as it moves through the landscape. The soil and geology impart a unique chemical signature on the water that it interacts with. By analysing the water chemistry and the combination of landscape processes in the contributing area, it is possible to understand ‘how’ and ‘why’ water quality varies.

Areas with similar landscape factors are likely to respond to land use pressure in a similar and predictable manner. This is the basis of the Physiographic Environments of New Zealand landscape classification for water quality. By understanding the functions that the landscape is performing to minimise the pressures of land use, we can match our land use and management decisions to maintain and improve our freshwater resources.

Physiographic Environments of New Zealand Classification

The Physiographic Environments of New Zealand classification is hierarchical, with a basic 10 Environment Family Classification, and a higher-resolution Sibling Classification, which provides more information over water source and hydrological response (flow pathway), and the role the landscape has in removing or reducing potential water quality contaminants. These environments each have a defining set of landscape characteristics that affect water quality in a predictable manner.

Associated with each classification level are variants. Variants provide additional detail where there is modification of the natural hydrology by artificial drainage, or seasonal and episodic variation in the pathway water takes to leave the land. During heavy rainfall events overland flow may become the dominant pathway or under dry or drought conditions, natural soil zone bypass may occur due to cracking soils. Variants change the predicted contaminant profile for the Physiographic Environment.

Physiographic Environment Families

The summary descriptions provided here are for the Family and Sibling Classes of the Physiographic Environments Classification. For each Environment a video summarises the key hydrological pathway water takes to leave the land, how our actions have modified natural hydrology through drainage, and the inherent risk of contaminant loss from the land. We then match the likely water quality effects in the Physiographic Environment as a result of land use pressure and some best-suited actions to minimise contaminant losses.

Use the information from this section in ACTIONS to learn more about land management strategies and intervention options for reducing contaminant generation and loss.


Variations to the predicted hydrological pathway occur due to human modification of the natural hydrology or seasonal dryness which alters the pathway water takes after rainfall. These variations result in different contaminant risks to water quality and will require different actions to minimise the effects of land use activities.