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Wellington Region

Groundwater Zone: Ruamāhanga

The Ruamāhanga Groundwater Management Zone lies in the central Wairarapa and is defined by the boundary of the Ruamāhanga River catchment. With an area of 3,555 square kilometres, it is the most significant and heavily used groundwater resource in the region, occupying almost half (44 percent) of the total regional land area. The zone lies beneath the townships of Featherston, Carterton, Martinborough, Greytown and Masterton, as well as the Wairarapa Valley, where the bulk of the region's intensive farming and horticulture takes place.

Fundamentally, the Ruamāhanga aquifer system comprises a single, connected groundwater resource within a closed basin. However, there is a high degree of hydrogeological complexity and unconfined, semi-confined and confined aquifer units are all present. The Ruamāhanga aquifer is recharged both by rainfall and flow loss from the Ruamāhanga River and its tributaries. 

Consents to abstract groundwater from the Ruamāhanga Groundwater Zone make up about 75 percent of the total number in the Wellington region and about 65 percent of the region’s abstraction by volume. Unlike the Kāpiti Coast and Hutt Valley areas where most of the water is taken for municipal supply, the majority of water taken in the Ruamāhanga Zone is used for irrigation. This means that consented water use is highly distributed and the potential for catchment water stress related to cumulative effects is relatively high. 

Management of water resources in the Ruamāhanga Groundwater Zone is focussed on treating surface and groundwater as a single, connected system.  While the zone is split into seventeen sub-zones to help manage allocation limits, the linkage between these zones and surface water bodies is explicitly considered at the whole catchment scale. 


Water Use
Groundwater in this zone

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


Groundwater available: {{waterSource.availableToAllocate}} Irrigation
Town supply
  • Groundwater in this zone
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    Groundwater in this zone

    Accurately estimating the total amount of water available in a groundwater management zone is not currently possible. Regional Councils are working with the Ministry for the Environment on the best way to calculate this figure. We will include these figures on LAWA when they become available. In the meantime, for more information about a particular groundwater management zone, contact your regional council.

  • Water consents: How much water is consented and used?

    Groundwater available to consent

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    Consented water in this groundwater zone

    Use the tables below to look at how much water is available compared with how much is actually consented within this water management zone. Click the plus to expand subzones where available

    Comparing consents and use
    Amount available to consent In this groundwater management zone:
    {{}} {{}}
    available to consent
    Amount consented
    measured and non measured
    Amount used (measured)
    Amount Units Consented or used as a percentage of available
    Total available to consent {{}} {{}} {{}}
    Total consented {{}} {{}} {{}} {{}}
    Total consented and measured {{}} {{}} {{}} {{}}
    Total measured amount used {{}} {{}} {{}}
    Total measured volume used {{}} {{}}

    The table above shows the amount of water that is available for use compared to the amount that has been consented. The �Total Consented� and �Total Consented and Measured� fields are based on percentages of the �Total available to Consent� field. If this field is not populated no data will be displayed. Some consents require actual use to be monitored and this is presented as 'Total measured volume Used' where available.

    Values for water availability have not yet been provided. Greater Wellington Regional Council is in the process (as at June 2015) of notifying a new Regional Plan that will contain proposed allocation limits. When this Plan is notified the proposed limits will be used to update the empty fields.

  • Water consents: How is consented water used?

    Consents by use in this groundwater zone

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    Consented water in this zone

    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}} m3 {{item.numberOfConsents}}
    Total {{}}% {{}} m3 {{}}

    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}} m3/year is consented for hydro-electricity and makes up {{hydroUsage.percentageConsented}}% of the total water volume consented for this region/management zone



Monitored sites in this Zone

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