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Piako River at Kiwitahi

There is water quality, flow and ecological information collected at this site on the Piako River situated at Kiwitahi. This site is open with a 1 metre wide fenced buffer either side of the stream and no riparian plantings to speak of. The site is often choked with macrophytes (aquatic plants) especially over summer before winter floods remove some growth from the soft, silty riverbed.

There is water quality, flow and ecological information collected at this site on the Piako River situated at Kiwitahi. This site is open with a 1 metre wide fenced buffer either side of the stream and no riparian plantings to speak of. The site is often choked with macrophytes (aquatic plants) especially over summer before winter floods remove some growth from the soft, silty riverbed. The majority of the catchment (84%) upstream from this point is pasture land with the majority being dairying with a small amount used for stock finishing. In the headwaters there is native forest which makes up 14% of the catchment landuse above this site. From here the stream flows toward Morrinsville and across the pasture dominated Hauraki Plains and the Kopuatai Peat Dome to Ngatea before entering the Firth Of Thames.

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 Piako River at Kiwitahi
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
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State
{{stateMsg(BDISC.StateScore)}}
State
{{BDISC.NofBand | uppercase}}
Attribute Band
N/A
Attribute Band
Trend
{{trendMsg(BDISC)}}

Sample history at this site

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Clarity samples for Piako River at Kiwitahi
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
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State
{{stateMsg(TURB.StateScore)}}
Trend
{{trendMsg(TURB)}}

Sample history at this site

Showing:
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Turbidity samples for Piako River at Kiwitahi
 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
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State
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Trend
{{trendMsg(TN)}}

Sample history at this site

Showing:
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Total Nitrogen samples for Piako River at Kiwitahi
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 Piako River at Kiwitahi
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 Piako River at Kiwitahi
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 Piako River at Kiwitahi
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
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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 Piako River at Kiwitahi
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 Piako River at Kiwitahi
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
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State
{{stateMsg(TP.StateScore)}}
Trend
{{trendMsg(TP)}}

Sample history at this site

Showing:
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Total Phosphorus samples for Piako River at Kiwitahi
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.  

 

 Ecology
Ecological data for this site

This dashboard shows information on macroinvertebrate data collected by regional councils and unitary authorities.  Select an indicator to see the available historical results.

Select a time period

  • 10 years
  • 15 years

Macroinvertebrates

MCI
{{medianValue('MCI')}}
State

{{nofDisplayGradeEcology(MCI.NofBand)}}

Attribute Band
Trend
{{trendMsg(MCI)}}

Sample history at this site

Showing:
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MCI samples for Piako River at Kiwitahi
MCI score

What is this graph showing me?

This graph is displaying MCI scores over the selected time period.  You can adjust this period by changing the dropdowns.  These records for the basis for the state and trends displayed on the dashboard.

Find out about how State and Trend are calculated.

What do the attribute band icons mean?

The bands for MCI are as outlined in the National Policy Statement for Freshwater Management 2020

A
Macroinvertebrate community indicative of pristine conditions with almost no organic pollution or nutrient enrichment.
B
Macroinvertebrate community indicative of mild organic pollution or nutrient enrichment. Largely composed of taxa sensitive to organic pollution/nutrient enrichment.
C
Macroinvertebrate community indicative of moderate organic pollution or nutrient enrichment. There is a mix of taxa sensitive and insensitive to organic pollution/nutrient enrichment.
National bottom line: MCI score 90
D
Macroinvertebrate community indicative of severe organic pollution or nutrient enrichment. Communities are largely composed of taxa insensitive to inorganic pollution/nutrient enrichment.
 Download data
QMCI
{{medianValue('QMCI')}}
State

{{nofDisplayGradeEcology(QMCI.NofBand)}}

Attribute Band
Trend
{{trendMsg(QMCI)}}

Sample history at this site

Showing:
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QMCI samples for Piako River at Kiwitahi
QMCI score

What is this graph showing me?

This graph is displaying QMCI scores over the selected time period.  You can adjust this period by changing the dropdowns.  These records for the basis for the state and trends displayed on the dashboard.

Find out about how State and Trend are calculated.

What do the attribute band icons mean?

The bands for QMCI are as outlined in the National Policy Statement for Freshwater Management 2020

A
Macroinvertebrate community indicative of pristine conditions with almost no organic pollution or nutrient enrichment.
B
Macroinvertebrate community indicative of mild organic pollution or nutrient enrichment. Largely composed of taxa sensitive to organic pollution/nutrient enrichment.
C
Macroinvertebrate community indicative of moderate organic pollution or nutrient enrichment. There is a mix of taxa sensitive and insensitive to organic pollution/nutrient enrichment.
National bottom line: QMCI score 4.5
D
Macroinvertebrate community indicative of severe organic pollution or nutrient enrichment. Communities are largely composed of taxa insensitive to inorganic pollution/nutrient enrichment.
 Download data
ASPM
{{medianValue('ASPM')}}
State

{{nofDisplayGradeEcology(ASPM.NofBand)}}

Attribute Band
Trend
{{trendMsg(ASPM)}}

Sample history at this site

Showing:
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ASPM samples for Piako River at Kiwitahi
ASPM score

What is this graph showing me?

This graph is displaying ASPM scores over the selected time period.  You can adjust this period by changing the dropdowns.  These records for the basis for the state and trends displayed on the dashboard.

Find out about how State and Trend are calculated.

What do the attribute band icons mean?

The bands for ASPM are as outlined in the National Policy Statement for Freshwater Management 2020

A
Macroinvertebrate communities have high ecological integrity, similar to that expected in reference conditions.
B
Macroinvertebrate communities have mild-to moderate loss of ecological integrity.
C
Macroinvertebrate communities have moderate-to-severe loss of ecological integrity.
National bottom line: ASPM score 0.3
D
Macroinvertebrate communities have severe loss of ecological integrity.
 Download data
  • Taxonomic richness

    The median of the last 5 years of data

    {{medianValue("TaxaRichness")}}
    Taxonomic richness is the number of different taxa present in an ecological community identified to the best possible level.

    Taxa richness history at this site

    Showing:
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    Taxa richness for Piako River at Kiwitahi
    Number of taxa

    What is this graph showing me?

    This graph is displaying Taxonomic richness over the selected time period.  You can adjust this period by changing the dropdowns.  These records for the basis for the state displayed on the dashboard.

  • Percent EPT richness

    The median of the last 5 years of data

    {{medianValue("PercentageEPTTaxa")}}
    EPT are macroinvertebrates that are sensitive to water pollution. These are Ephemeroptera (mayfly), Plecoptera (stonefly) and Trichoptera (caddisfly).

    EPT history at this site

    Showing:
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    Percent EPT richness for Piako River at Kiwitahi
    EPT %

    What is this graph showing me?

    This graph is displaying percent EPT taxa over the selected time period.  You can adjust this period by changing the dropdowns.  These records for the basis for the state displayed on the dashboard.
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