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Rangitāiki at Matahina Dam

The sparkling blue waters of Lake Matahina, 30km from Whakatāne, sit between steep bush-clad hills. The lake is formed by a hydro-electric dam. It offers excellent family kayaking and is an ideal spot for training. From the dam, kayak up the lake. On the right, towering rock cliffs soar high over the water. Try paddling near to the base and call  "hello": several spots return an excellent echo. After about an hour's easy family kayaking you'll reach a tree-covered island. You can paddle either side. Another easy hour and you're near the lake head. There's parking and a toilet at the dam. Try fishing from the shores of the lake or in the river below the race.

Water Quality
Water quality data for this site

This dashboard shows information on the data collected by the regional councils and unitary authorities for water quality indicators, analysed as state and trend. Select an indicator to see the historical monitoring data.

  • State

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

    This site is a {{siteDescription}} site. Currently showing the state of this site compared to:

  • The state is also represented by attribute bands in the National Policy Statement for Freshwater Management 2020 for some indicators.

  • Trend

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

The state is also represented by attribute bands in the National Policy Statement for Freshwater Management 2020 for some indicators.


Bacteria

E. coli
{{medianValue('ECOLI')}}
State
{{stateMsg(ECOLI.StateScore)}}
State
{{ECOLI.NofBand | uppercase}}
Attribute Band
N/A
Attribute Band
Trend
{{trendMsg(ECOLI)}}

Sample history at this site

Showing:
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E. coli samples for Rangitāiki at Matahina Dam
n/100ml

What is this graph showing me?

This graph is displaying E. coli concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard.  Find out about how State and Trend are calculated.

Monitoring data are displayed from 2004 onwards (where available).  Data displaying from the current year (2024) may not have gone through council quality assurance processes and should be treated as unverified.  

 

What do the attribute band icons mean?

The bands for E. coli are as outlined in the National Policy Statement for Freshwater Management 2020

A
For at least half the time, the estimated risk is <1 in 1000 (0.1% risk). The predicted average infection risk is 1%*.
B
For at least half the time, the estimated risk is <1 in 1000 (0.1% risk). The predicted average infection risk is 2%*.
C
For at least half the time, the estimated risk is <1 in 1000 (0.1% risk). The predicted average infection risk is 3%*.
D
20-30% of the time, the estimated risk is >=50 in 1000 (>5% risk). The predicted average infection risk is >3%*.
E
For more than 30% of the time, the estimated risk is >=50 in 1000 (>5% risk). The predicted average infection risk is >7%*.
* The predicted average infection risk is the overall average infection to swimmers based on a random exposure on a random day, ignoring any possibility of not swimming during high flows or when a surveillance advisory is in place (assuming that the E. coli concentration follows a lognormal distribution). Actual risk will generally be less if a person does not swim during high flows.
 Download data

Suspended Fine Sediment

Clarity
{{medianValue('BDISC')}}
State
{{stateMsg(BDISC.StateScore)}}
State
{{BDISC.NofBand | uppercase}}
Attribute Band
N/A
Attribute Band
Trend
{{trendMsg(BDISC)}}

Sample history at this site

Showing:
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Clarity samples for Rangitāiki at Matahina Dam
metres

What is this graph showing me?

This graph is displaying Black Disc readings over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard.  At some sites Black Disc is not measured - here the calculation of the state attribute band for Clarity (suspended fine sediment) has used Clarity measurements converted from Turbidity data (where available).  Find out about how State and Trend are calculated.

Monitoring data are displayed from 2004 onwards (where available).  Data displaying from the current year (2024) may not have gone through council quality assurance processes and should be treated as unverified.  

 

What do the attribute band icons mean?

The bands for Clarity (suspended fine sediment) are as outlined in the National Policy Statement for Freshwater Management 2020

A
Minimal impact of suspended sediment on instream biota. Ecological communities are similar to those observed in natural reference conditions.
B
Low to moderate impact of suspended sediment on instream biota. Abundance of sensitive fish species may be reduced.
C
Moderate to high impact of suspended sediment on instream biota. Sensitive fish species may be lost.
National bottom line: Numeric attribute state by suspended sediment class: 1 = 1.34, 2 = 0.61, 3 = 2.22, 4 = 0.98
D
High impact of suspended sediment on instream biota. Ecological communities are significantly altered and sensitive fish and macroinvertebrate species are lost or at high risk of being lost.
 Download data
Turbidity
{{medianValue('TURB')}}
State
{{stateMsg(TURB.StateScore)}}
Trend
{{trendMsg(TURB)}}

Sample history at this site

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Turbidity samples for Rangitāiki at Matahina Dam
 NTU
FNU

What is this graph showing me?

This graph is displaying Turbidity levels over the selected time period. You can adjust this period by changing the dropdowns. 

Yellow coloured bars on the graph represent turbidity values measured in NTU. These records form the basis for the state and trend indicators displayed on the dashboard. Some councils now also measure turbidity in FNU.  The FNU data (blue coloured bars) are not used by LAWA for the state and trend indicators.  Find out about how State and Trend are calculated.

Monitoring data are displayed from 2004 onwards (where available).  Data displaying from the current year (2024) may not have gone through council quality assurance processes and should be treated as unverified.  

 

Nitrogen

Total Nitrogen
{{medianValue('TN')}}
State
{{stateMsg(TN.StateScore)}}
Trend
{{trendMsg(TN)}}

Sample history at this site

Showing:
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Total Nitrogen samples for Rangitāiki at Matahina Dam
mg/L

What is this graph showing me?

This graph is displaying Total Nitrogen concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard.  Find out about how State and Trend are calculated.

Monitoring data are displayed from 2004 onwards (where available).  Data displaying from the current year (2024) may not have gone through council quality assurance processes and should be treated as unverified.  

 

Total Oxidised Nitrogen
{{medianValue('TON')}}
State
{{stateMsg(TON.StateScore)}}
Trend
{{trendMsg(TON)}}

Sample history at this site

Showing:
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Total Oxidised Nitrogen samples for Rangitāiki at Matahina Dam
mg/L

What is this graph showing me?

This graph is displaying Total Oxidised Nitrogen concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard.  Find out about how State and Trend are calculated.

Monitoring data are displayed from 2004 onwards (where available).  Data displaying from the current year (2024) may not have gone through council quality assurance processes and should be treated as unverified.  

 

Dissolved Inorganic Nitrogen
{{medianValue('DIN')}}
State
{{stateMsg(DIN.StateScore)}}
Trend
{{trendMsg(DIN)}}

Sample history at this site

Showing:
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Dissolved Inorganic Nitrogen samples for Rangitāiki at Matahina Dam
mg/L

What is this graph showing me?

This graph is displaying Dissolved Inorganic Nitrogen concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard.  Find out about how State and Trend are calculated.

Monitoring data are displayed from 2004 onwards (where available).  Data displaying from the current year (2024) may not have gone through council quality assurance processes and should be treated as unverified.  

 

Ammoniacal Nitrogen
{{medianValue('NH4')}}
State
{{stateMsg(NH4.StateScore)}}
State
{{NH4.NofBand | uppercase}}
Attribute Band (toxicity)
N/A
Attribute Band (toxicity)
Trend
{{trendMsg(NH4)}}

Sample history at this site

Showing:
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Ammoniacal Nitrogen samples for Rangitāiki at Matahina Dam
mg/L

What is this graph showing me?

This graph is displaying Ammoniacal Nitrogen concentrations over the selected time period.  These monitoring data have not been pH adjusted.  You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard.  Find out about how State and Trend are calculated.

Monitoring data are displayed from 2004 onwards (where available).  Data displaying from the current year (2024) may not have gone through council quality assurance processes and should be treated as unverified.  

 

What do the attribute band icons mean?

The bands for Ammonia (toxicity) are as outlined in the National Policy Statement for Freshwater Management 2020

A
99% species protection level: No observed effect on any species tested.
B
95% species protection level: Starts impacting occasionally on the 5% most sensitive species.
National bottom line: Annual median 0.24 mg NH4-N/L. Annual 95th percentile 0.40 mg NH4-N/L (milligrams ammoniacal-nitrogen per litre). Note 1 mg/l = 1 g/m3
C
80% species protection level: Starts impacting regularly on the 20% most sensitive species (reduced survival of most sensitive species).
D
Starts approaching acute impact level (ie risk of death) for sensitive species.
 Download data
Nitrate Nitrogen
{{medianValue('NO3N')}}
State
{{stateMsg(NO3N.StateScore)}}
State
{{NO3N.NofBand | uppercase}}
Attribute Band (toxicity)
N/A
Attribute Band (toxicity)
Trend
{{trendMsg(NO3N)}}

Sample history at this site

Showing:
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Nitrate Nitrogen samples for Rangitāiki at Matahina Dam
mg/L

What is this graph showing me?

This graph is displaying Nitrate Nitrogen concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard.*  Find out about how State and Trend are calculated.

*For sites where there are not enough Nitrate Nitrogen data available, Total Oxidised Nitrogen (TON) data have been used instead to calculate state and trend.  

Monitoring data are displayed from 2004 onwards (where available).  Data displaying from the current year (2024) may not have gone through council quality assurance processes and should be treated as unverified.  

 

What do the attribute band icons mean?

The bands for Nitrate (toxicity) are as outlined in the National Policy Statement for Freshwater Management 2020

A
High conservation value system. Unlikely to be effects even on sensitive species.
B
Some growth effect on up to 5% of species.
National bottom line: Annual median 2.4 mg NO3-N/L. Annual 95th percentile 3.5 mg NO3-N/L (milligrams nitrate-nitrogen per litre). Note 1 mg/l = 1 g/m3
C
Growth effects on up to 20% of species (mainly sensitive species such as fish). No acute effects.
D
Impacts on growth of multiple species, and starts approaching acute impact level (that is, risk of death) for sensitive species at higher concentrations (>20 mg/L)
This attribute measures the toxic effects of nitrate, not the trophic state. Where other attributes measure trophic state, for example periphyton, freshwater objectives, limits and/or methods for those attributes may be more stringent.
 Download data

Phosphorus

Dissolved Reactive Phosphorus
{{medianValue('DRP')}}
State
{{stateMsg(DRP.StateScore)}}
State
{{DRP.NofBand | uppercase}}
Attribute Band
N/A
Attribute Band
Trend
{{trendMsg(DRP)}}

Sample history at this site

Showing:
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Dissolved Reactive Phosphorus samples for Rangitāiki at Matahina Dam
mg/L

What is this graph showing me?

This graph is displaying Dissolved Reactive Phosphorus concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard.  Find out about how State and Trend are calculated.

Monitoring data are displayed from 2004 onwards (where available).  Data displaying from the current year (2024) may not have gone through council quality assurance processes and should be treated as unverified.  

 

What do the attribute band icons mean?

The bands for Dissolved Reactive Phosphorus are as outlined in the National Policy Statement for Freshwater Management 2020

A
Ecological communities and ecosystem processes are similar to those of natural reference conditions. No adverse effects attributable to dissolved reactive phosphorus (DRP) enrichment are expected.
B
Ecological communities are slightly impacted by minor DRP elevation above natural reference conditions. If other conditions also favour eutrophication, sensitive ecosystems may experience additional algal and plant growth, loss of sensitive macroinvertebrate taxa, and higher respiration and decay rates.
C
Ecological communities are impacted by moderate DRP elevation above natural reference conditions. If other conditions also favour eutrophication, DRP enrichment may cause increased algal and plant growth, loss of sensitive macroinvertebrate and fish taxa, and high rates of respiration and decay.
D
Ecological communities impacted by substantial DRP elevation above natural reference conditions. In combination with other conditions favouring eutrophication, DRP enrichment drives excessive primary production and significant changes in macroinvertebrate and fish communities, as taxa sensitive to hypoxia are lost.
 Download data
Total Phosphorus
{{medianValue('TP')}}
State
{{stateMsg(TP.StateScore)}}
Trend
{{trendMsg(TP)}}

Sample history at this site

Showing:
–
Total Phosphorus samples for Rangitāiki at Matahina Dam
mg/L

What is this graph showing me?

This graph is displaying Total Phosphorus concentrations over the selected time period. You can adjust this period by changing the dropdowns. These records form the basis for the state and trend indicators displayed on the dashboard.  Find out about how State and Trend are calculated.

Monitoring data are displayed from 2004 onwards (where available).  Data displaying from the current year (2024) may not have gone through council quality assurance processes and should be treated as unverified.  

 

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