Manawatū-Whanganui region

Groundwater Zone: Whanganui Groundwater MZ

The Whanganui Groundwater Management Zone encompasses 938 km2 of the coastal area surrounding Wanganui city. Located at the northern portion of the Manawatu-Whanganui sedimentary basin, shallow wells of less than 30 m depth intercept Late Quaternary deposits. Deeper wells of up to 600-700 m depth intercept confined water-bearing marine sand and shell sediments of the Nukumaru Group, deposited between 2.4 and 1.63 million years ago. Estimated recharge of this zone is 266 M m3/year.

Groundwater sourced from the deeper Nukumaru Group sediments provides for Wanganui's municipal needs, which accounts for around 75% of groundwater use in the Whanganui GMZ. At present, around 62% of total annual allocable groundwater is consented for use, with an estimated annual usage of approximately 14 million cubic metres (32% of total available allocation).

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
{{waterUsage.irrigationLabel}} Industrial
{{waterUsage.industrialLabel}} Stock
{{waterUsage.stockLabel}} Hydroelectrical
{{waterUsage.hydroLabel}} Town supply
{{waterUsage.drinkingLabel}}

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.

Total allocation is calculated as Daily Max Volume over 100 days for irrigation takes and Max Daily Volume over 365 days for all other uses. Estimated Annual Allocated Volume (EAAV) is calculated to determine a conservative maximum usage that may occur in a dry year and assumes that (1) for consents authorising abstraction during the irrigation season the EAAV can be calculated by assuming that, on average over a year, water is used for 100 days at 80% of the maximum consented daily abstraction rate; and (2) for consents for full year abstractions, the EAAV can be calculated by assuming that, over a year, water is used for 365 days a year at 50% of the maximum volume.

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: {{item.data.totalAvailableAmount}} {{item.data.totalAvailableUnits}} 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	{{item.data.totalAvailableAmount}}			{{item.data.totalAvailableAmount}}	{{item.data.totalAvailableUnits}}
Total consented	{{item.data.totalConsented.amount}}			{{item.data.totalConsented.amount}}	{{item.data.totalAvailableUnits}}	{{item.data.totalConsented.percentText}}
Total consented and measured	{{item.data.totalMeasured.amount}}			{{item.data.totalMeasured.amount}}	{{item.data.totalAvailableUnits}}	{{item.data.totalMeasured.percentText}}
Total measured amount used	{{item.data.totalAmountUsed.amount}}	{{item.data.totalAvailableUnits}}	{{item.data.totalAmountUsed.percentText}}
Total measured volume used	{{item.data.totalAnnualVolumeUsed}}	{{item.data.totalAnnualVolumeUnits}}

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.

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}}	-	-	No data available		{{item.breakdownPercentage}}%	{{item.totalVolume}} m³	{{item.numberOfConsents}}
Total	{{waterUsage.total.percentageConsented}}%	{{waterUsage.total.totalVolume}} m³	{{waterUsage.total.numberOfConsents}}

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

Allocation for existing hydroelectricity generation is excluded because, while it is still part of the overall allocation framework, it sits outside of the core allocation limits (i.e. the core allocation limits were set after the existing hydroelectricity take volumes).

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Monitored sites in this Zone

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