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Canterbury region

Water Quantity

Canterbury is highly reliant on its abundant freshwater resources for driving agricultural productivity, tourism, industry and supplying drinking water to a spatially diverse rural and urban population.

Canterbury, as the largest region in New Zealand, has the largest water resources and also the highest water use.  It is estimated that around 70% of irrigated land in New Zealand falls within the Canterbury region.  Groundwater is used extensively for irrigation and drinking water supply across the Canterbury Plains and in other inland basins. 

The majority of surface water is found in 7 major alpine rivers (Waitaki, Rakaia, Waimakariri, Waiau, Rangitata, Hurunui and Clarence).  These rivers come from high rainfall areas in the Southern Alps, often with extensive snow and ice fields sustaining flows through the summers.  These rivers are also an important source of groundwater recharge for the Canterbury Plains.  Smaller rivers derive from the foothill mountain ranges (e.g. Pareora, Opihi, Orari, Selwyn, Ashley, Waipara and Conway rivers) which are lower rainfall areas and the rivers often reach very low flows in the summer. 

A third set of rivers and streams are the groundwater derived spring fed streams found near the coast (e.g. Ohapi Creek, Harts Creek, Avon, Styx and Cam Rivers).  These spring fed streams sustain flows through most summers but are also the most affected by extensive groundwater usage.  Water allocation is managed in Canterbury through the region-wide Land and Water Regional Plan and a series of sub-regional chapters which set out the allocation regime (i.e. minimum flows, total volume available etc.). 

The planning framework is underpinned by the non-statutory Canterbury Water Management Strategy (CWMS) which divides the region into 10 water management zones and are run by Water Management Zone Committees.  The CWMS sets out a series of economic, social, cultural and environmental targets, including improving water quality in lowland streams and increasing irrigated area across the region.

Regional Summary
Water quantity data in this region

Regional councils collect information about how much water is available and manage resource consents for those wishing to take water from rivers or groundwater supplies. Use the buttons below to view regional information on: how much water is available, where it comes from and how its used.


Rainfall {{waterAvailable.rainfall}} Runoff to sea {{waterAvailable.runoff}} Groundwater available: {{waterSource.groundwater}}
{{waterSource.groundwaterPercentAvailable}}% of total available
Surface Water available: {{waterSource.surfacewater}}
{{waterSource.surfacewaterPercentAvailable}}% of total available
Town supply
  • How much water is there in this region?

    Rainfall and runoff in this region

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    Rainfall and runoff

    Relative Volume Source Volume
    Rainfall total:
    {{waterAvailable.rainfall }}
    rainfall Rainfall Total {{waterAvailable.rainfall}}
    Runoff total:
    {{waterAvailable.runoff }}
    runoff Runoff to sea {{waterAvailable.runoff}}

    The table above shows the average amount of rainfall the region receives each year and how much of that flows out to sea. These are approximate figures only.

    N.B. the total runoff is calculated as precipitation minus evaporation, therefore it is both groundwater and surface water outflows (NIWA figures from National Water Physical Stocktake 1995-2010)

  • Water consents: where does water come from?

    The split between surface water and groundwater

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    Consented water by source

    Relative volumes
    Amount available to consent Surface water:
    available to consent
    available to consent
    Volume consented Surface water:
    volume consented
    volume consented
    Source Amount available to consent Volume consented Consented as a percentage of available
    surface water ground water {{item.source}} {{item.amountAvailable}} {{item.volumeConsented}} {{item.percentageConsented}}
    {{}} {{}} {{}} {{}}

    The table above shows how much water is available to use compared with the amount that is actually consented for use. It also shows how much of this water is surface water and how much is groundwater.

    The amount of surface water available to allocate in the Canterbury region cannot be calculated easily as each river and sub-region has a different flow allocation regime

  • Water consents: How is water used?

    Consents by use in this region

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    Annual consented water use by type

    Overall annual volume for {{waterAvailable.year}}
    Relative breakdown
    Activity Percentage of total consented Total volume Number of consents
    {{item.displayText}} {{item.displayText}} - - No data available {{item.breakdownPercentage}}% {{item.totalVolume}} {{item.numberOfConsents}}
    Total {{}}% {{}} {{}}

    The above table shows the proportion of water consented for irrigation, industrial, stock, town supply and other. It excludes hydro electricity. In this region/management zone {{hydroUsage.totalVolume}}/year is consented for hydro-electricity and makes up {{hydroUsage.percentageConsented}}% of the total water volume consented for this region/management zone

Surface Water Zones Groundwater Zones