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Southland region

Surface Water Zone: Waiau Surface Water Zone

The Waiau surface water zone extends from below the Manapouri Lake Control, where the Mararoa River joins the Waiau River, down to the Waiau Mouth at Te Waewae Bay. The western boundary of this zone includes the eastern fringes of Fiordland National Park. This area is well known for its rugged and isolated mountainous country and very high rainfall.

Prior to being harvested for hydroelectricity generating purposes in the early 1970’s, the Waiau River was New Zealand’s second largest river in terms of discharge. Even with more than 500 cubic metres/second (cumecs) of water being diverted through the Manapouri Power Station at West Arm to Deep Cove, the Waiau River is still an impressive river, with a mean annual flow of 144 cumecs. In summer, the Waiau River downstream of the Manapouri Lake Control must maintain a flow of at least 16 cumecs to help sustain aquatic habitat and the renowned brown and rainbow trout fishery that exists in the river. Environment Southland has several permanent water level and automatic rainfall recording sites that provide hydrological and floodwarning information. At Sunnyside, near Blackmount, a permanent water level recorder has monitored the water level and flow of the Waiau River for more than 35 years. The Waiau surface water zone is deemed to be fully allocated due to the generation of hydro-electricity within the Waiau catchment. All remaining water in the Waiau surface water zone is required to stay in the system to ensure that the minimum flows for the Waiau can be maintained, ensuring protection of the aquatic habitat.

Water Use
Surface Water in this Zone

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


Rainfall {{waterAvailable.rainfall}} Runoff to sea {{waterAvailable.runoff}} Surface Water available: {{waterSource.availableToAllocate}} Irrigation
Town supply
  • How much surface water is there in this zone?

    Rainfall and flow in this surface water zone

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    Rainfall and runoff

    Relative breakdown 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 water management zone receives each year and how much of that flows out to sea. These are approximate figures only.

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

    Surface water available to consent

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    Consented water in this surface water 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 surface water 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.

  • Water consents: How is consented water used?

    Consents by use in this surface water zone

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    Consented water

    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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