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Ohau

The Ohau River is a river of the Horowhenua District of New Zealand's North Island. It flows from the confluence of two short rivers, the North Ohau River and the South Ohau River. The Ohau initially flows north, turning west to the southeast of Levin. It reaches the Tasman Sea 10 kilometres to the southwest of Levin.

For the latest information on recreational suitability in this catchment visit Horizons' safe swim spot site here.

Sites 5

Monitored sites in the Ohau catchment

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No sites found.

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Scientific Indicators
Scientific data for this catchment

This dashboard shows information on the data collected by the regional councils for water quality indicators, analysed as state and trend.

The state for the catchment is represented by the median concentration for the parameter across all sites within the catchment and then compares that value to the quartiles for all monitored sites in New Zealand.

Click on the parameters state icons to compare this catchment with others in the region.

  • State

    State shows how the median of samples from this site compares to other sites

  • Trend

    Trend shows how the quality of water is changing over time. Depending on the sampling history duration, five and ten year timescales are available:

Can I trust this data?

The Cawthron Institute has worked alongside regional councils to verify the processes and methods used for data collection, laboratory analysis of samples collected and the statistical analysis and interpretation of the results presented.

If all Cawthron ticks are green, then you can trust this data. However, if one or more ticks are orange, then conclusions should be treated with some caution.

For more details on each tick, see our 'Can I Trust This Data?' Factsheet.

Can I trust the data?
Data Collection

All samples were collected using approved field protocols and have been analysed in accredited laboratories. Therefore the data shown here has been collected and analysed following best practice.

State

All samples were collected using approved field protocols and have been analysed in accredited laboratories.

Trend - Adjustment for flow

This data is not flow adjusted. National guidelines suggest that flow-sensitive variables are flow 'adjusted' before trend analysis. Therefore, any trends shown here may be affected by variations in flow across sampling occasions.

Bacteria

E. coli
State
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Trend
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Clarity

Clarity

Black disc
State
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Trend
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Clarity

Turbidity
State
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Trend
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Nitrogen

Nitrogen

Total Nitrogen
State
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Trend
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Nitrogen

Total Oxidised Nitrogen
State
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Trend
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Nitrogen

Ammoniacal Nitrogen
State
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Trend
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Phosphorus

Phosphorus

Dissolved Reactive Phosphorus
State
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Trend
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Phosphorus

Total Phosphorus
State
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Trend
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Download Data

.ZIP file of indicator readings for all sites in New Zealand
Download
Disclaimer

 LAWA Partners shall not be liable, whether in contract, tort, equity or otherwise, for any loss or damage of any type (including consequential losses) arising directly or indirectly from the inadequacy, inaccuracy or any other deficiency in information supplied irrespective of the cause.  Use of information supplied is entirely at the risk of the recipient and shall be deemed to be acceptance of this liability exclusion.