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Tasman region

Water Quantity

In the Tasman Region rivers and groundwater respond quickly to rain and drought. Therefore water demand is highly seasonal and is greatest in the eastern regions which have the highest population and intensive horticultural areas.

The varied topography and patterns of precipitation in the Region combined with the complex geology creates unique patterns of water availability and demand. 70% of the Region is comprised of conservation land with annual precipitation levels up to 6000mm, while only 5% is flatter lowlands with precipitation totals down to 900mm.

The lowland areas in the eastern regions have the highest population and industrial concentrations as well as intensive horticulture areas such as pipfruit, market gardens, vineyards, berries and hops. Much of this water demand is met from the groundwater which is linked closely to surface water sources.

Thus high abstraction rates pose risks to maintaining instream river flows as well as positive aquifer pressure to limit salt water intrusion at the coast. Detailed water management plans for these areas are designed to ration water abstraction during periods of high demand and low availability so as to protect the river flows and aquifer integrity. The Waimea area has an over allocated water resource and hence water rationing is a routine practice during most summer months. The Waimea Community Dam is now in the commissioning phase and once operational hopefully beginning of 2024, will store water in the winter to be released in the summer to augment river flows and reduce the frequency of water rationing.

The regions to the northwest and south are generally wetter and are dominated by dairy farming. Traditionally irrigation in these areas has been limited, but in the last decade water demand has begun to grow.



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.

  • 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.

    Catchments with operative regional plans have integrated water allocation rate for aquifers and rivers. The allocation rates varies between catchments depending on river flow and/or groundwater level triggers. In catchments without operative plans the default allocation for rivers of regional significance is 10% of the 1 in 5 year 7day MALF. Therefore it is not possible to separate total amount allocatable from surface water and groundwater.

  • 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
Groundwater management zones in the Tasman region

Select the groundwater management zone you'd like to see information on by clicking the buttons below or navigate using the map.