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Waimakariri River Catchment

The Waimakariri River is located in Environment Canterbury's Waimakariri management Zone. It is a large braided alpine river, flowing 151 km from the Southern Alps across the Canterbury Plains to the ocean. The river rises on the eastern flanks of the Southern Alps, eight kilometres southwest of Arthur's Pass. For much of its upper reaches, the river is braided, with wide shingle beds. As the river approaches the Canterbury Plains, it passes through a belt of mountains, and is forced into a narrow canyon (known as the Waimakariri Gorge), before reverting to its braided form to travel across the plains. 

The Waimakariri enters the Pacific Ocean north of Christchurch, near the town of Kaiapoi. Geological evidence indicates that the river mouth has in the past been very mobile, and at times the river flowed through the current location of Christchurch City. Geological evidence also suggests that the Waimakariri flowed into Lake Ellesmere, south of Banks Peninsula.

In Māori, Waimakariri has several meanings, one of which is "river of cold rushing water".
Many tributaries flow into the lower reaches; e.g. the Cust, Cam and Kaiapoi Rivers. The upper headwaters of the Waimakariri are covered by a mixture of native and exotic vegetation with relativity low level landuse activity. In the lower reaches, agricultural intensification and demand for water abstraction has developed rapidly in recent years.

Six sites are monitored on the Waimakariri River as part of Environment Canterbury's state of environment monitoring programme. A further seven tributary streams are also monitored under the programme.

The upper reaches of the Waimakariri River have low dissolved nutrient concentrations, bacteria levels and good aquatic life supporting values (temperature, dissolved oxygen). Concentrations of nutrients and bacterial indicators increase in the lower catchment. This is most likely due to cumulative effects from surrounding landuse pressures (both agricultural and urban) and slightly poorer water quality from inflowing tributaries, such as the Cam and Kaiapoi Rivers. Trends from the last 10 years of monitoring tributary rivers such as Cam, Cust, Ohoka and South Branch/Otukaikino show improving water quality.

Sites 35

Monitored sites in the Waimakariri River Catchment catchment

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Scientific Indicators
Scientific data for this catchment

This dashboard shows information on the data collected by the regional councils for water quality indicators, analysed as state and trend.

The state for the catchment is represented by the median concentration for the parameter across all sites within the catchment and then compares that value to the quartiles for all monitored sites in New Zealand.

Click on the parameters state icons to compare this catchment with others in the region.

  • State

    State shows how the median of samples from this site compares to other sites

  • Trend

    Trend shows how the quality of water is changing over time. Depending on the sampling history duration, five and ten year timescales are available:

Can I trust this data?

The Cawthron Institute has worked alongside regional councils to verify the processes and methods used for data collection, laboratory analysis of samples collected and the statistical analysis and interpretation of the results presented.

If all Cawthron ticks are green, then you can trust this data. However, if one or more ticks are orange, then conclusions should be treated with some caution.

For more details on each tick, see our 'Can I Trust This Data?' Factsheet.

Can I trust the data?
Data Collection

All samples were collected using approved field protocols and have been analysed in accredited laboratories. Therefore the data shown here has been collected and analysed following best practice.


All samples were collected using approved field protocols and have been analysed in accredited laboratories. Therefore the data shown here can be trusted.

Trend - Adjustment for flow

This data is not flow adjusted. National guidelines suggest that flow-sensitive variables are flow 'adjusted' before trend analysis. Therefore, any trends shown here may be affected by variations in flow across sampling occasions.


E. coli



Black disc





Total Nitrogen


Total Oxidised Nitrogen


Ammoniacal Nitrogen



Dissolved Reactive Phosphorus


Total Phosphorus

Download Data

.ZIP file of indicator readings for all sites in New Zealand

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