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Lake Rotoiti at Okawa Bay

This embayment has multiple access point and a popular launching point for boating activities. Lake Rotoiti is popular for water sports and fishing.

Lake Rotoiti is renowned around the world and offers some of the best fishing in New Zealand. The lake provides plenty of opportunity for waterskiing, and if you’re wanting to ski from shore then there are 8 ski-lanes around the lake, from Hot Water Beach to Hinehopu. If you have a boat there are myriads of little bays and beaches all around Rotoiti you can explore. However if you’re relying on a car to get you to a beach you are more limited. Although there are public areas at Okere Falls, Otaramarae and Gisborne Point, the main two public beaches readily accessible by car are Ruato Bay and Hinehopu. Both have picnic areas and Hinehopu has public toilets and also coin-operated bbqs.

Scientific Indicators
Scientific data for this site

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

  • State

    The state is represented by comparison to the National Objectives Framework (NOF) in the National Policy Statement for Freshwater Management 2014

  • 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, quality assurance and the statistical analysis and interpretation of the results presented.

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

Can I trust the data for this site?
Data Collection

Lake water quality is being monitored in this region. Proposed National Guidelines suggest that all councils should monitor lake water quality as part of their State of the Environment Monitoring Programmes, if lakes occur in the region.

State - Sampling

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

State - Quality Assurance - Data Processing

Data at this site has had some form of data processing measures applied. Therefore, the data shown here are more robust than data with no data processing applied.

State - Quality Assurance - Quality Coding

Data shown here hasn’t had any kind of quality coding applied. Therefore, the data shown here is less robust than quality coded data.

Trend - Sampling Frequency

Samples are collected monthly at this site. Therefore, any trends shown here are based on best practice in terms of sampling frequency.

Phosphorus

Total Phosphorus
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State
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Trend
{{trendMsg('TP', TP)}}

Total Phosphorus sample history at this site

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Total Phosphorus samples for Lake Rotoiti at Okawa Bay
mg/m³
Date

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. This data is raw and has not had any methodology applied to it.

Find out about how State and Trend are calculated.

What do the icons mean?

The bands for Total Phosphorus are as outlined in the NOF for freshwater:

A
Lake ecological communities are healthy and resilient similar to natural reference conditions
B
Lake ecological communities are slightly impacted by additional algal and plant growth arising from nutrients levels that are elevated above natural conditions
C
Lake ecological communities are moderately impacted by additional algal and plant growth arising from nutrients levels that are elevated well above natural reference conditions
National bottom line: Annual median 50 mg/m³
D
Lake ecological communities have undergone or are at high risk of a regime shift to a persistent, degraded state, due to impacts of elevated nutrients leading to excessive algal growth and/or plant growth, as well as from losing oxygen in bottom waters of deep lakes

Download data history as a .csv file

Nitrogen

Nitrogen

Total Nitrogen
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State
{{TN.StateScore | uppercase}}
{{stateMsg('TN', TN.StateScore)}}
{{stateMsg('TN', TN.StateScore)}}
Trend
{{trendMsg('TN', TN)}}

Total Nitrogen sample history at this site

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Total Nitrogen samples for Lake Rotoiti at Okawa Bay
mg/m³
Date

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. This data is raw and has not had any methodology applied to it.

Find out about how State and Trend are calculated.

What do the icons mean?

The bands for Total Nitrogen are as outlined in the NOF for freshwater:

A
Lake ecological communities are healthy and resilient similar to natural reference conditions
B
Lake ecological communities are slightly impacted by additional algal and plant growth arising from nutrients levels that are elevated above natural conditions
C
Lake ecological communities are moderately impacted by additional algal and plant growth arising from nutrients levels that are elevated well above natural reference conditions
National bottom line: 750 mg/m³ for seasonally stratified and brackish lakes. 800 mg/m³ for polymictic lakes.
D
Lake ecological communities have undergone or are at high risk of a regime shift to a persistent, degraded state, due to impacts of elevated nutrients leading to excessive algal growth and/or plant growth, as well as from losing oxygen in bottom waters of deep lakes

Download data history as a .csv file

Nitrogen

Ammonia
{{medianValue('NH4N')}}
State
{{NH4N.StateScore | uppercase}}
{{stateMsg('NH4N', NH4N.StateScore)}}
{{stateMsg('NH4N', NH4N.StateScore)}}
Trend
{{trendMsg('NH4N', NH4N)}}

Ammonia sample history at this site

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Ammonia samples for Lake Rotoiti at Okawa Bay
mg NH4-N/l
Date

What is this graph showing me?

This graph is displaying Ammoniacal 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. This data is raw and has not had any methodology applied to it.

Find out about how State and Trend are calculated.

What do the icons mean?

The bands for Ammonia are as outlined in the NOF for freshwater:

A
B
C
D

Download data history as a .csv file

Algae

Algae

Chlorophyll a
{{medianValue('CHLA')}}
State
{{CHLA.StateScore | uppercase}}
{{stateMsg('CHLA', CHLA.StateScore)}}
{{stateMsg('CHLA', CHLA.StateScore)}}
Trend
{{trendMsg('CHLA', CHLA)}}

Chlorophyll a sample history at this site

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Chlorophyll a samples for Lake Rotoiti at Okawa Bay
mg/m³
Date

What is this graph showing me?

What do the icons mean?

The bands for Chlorophyll a are as outlined in the NOF for freshwater:

A
Lake ecological communities are healthy and resilient similar to natural reference conditions
B
Lake ecological communities are slightly impacted by additional algal and plant growth arising from nutrients levels that are elevated above natural conditions
C
Lake ecological communities are moderately impacted by additional algal and plant growth arising from nutrients levels that are elevated well above natural reference conditions
National bottom line: Annual median 12 mg/m³. Annual maximum 60 mg/m³.
D
Lake ecological communities have undergone or are at high risk of a regime shift to a persistent, degraded state, due to impacts of elevated nutrients leading to excessive algal growth and/or plant growth, as well as from losing oxygen in bottom waters of deep lakes

Download data history as a .csv file

Algae

Cyanobacteria
{{medianValue('CYAN')}}
State
{{CYAN.StateScore | uppercase}}
{{stateMsg('CYAN', CYAN.StateScore)}}
{{stateMsg('CYAN', CYAN.StateScore)}}
Trend
{{trendMsg('CYAN', CYAN)}}

Cyanobacteria sample history at this site

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Cyanobacteria samples for Lake Rotoiti at Okawa Bay
mm³/l
Date

What is this graph showing me?

What do the icons mean?

It is important to note that changes to the National Policy Statement for Freshwater Management 2014 were announced in August 2017. The changes have modified the NOF bands for planktonic cyanobacteria. These changes came into effect on 6 September 2017. The data on LAWA has not yet been updated to reflect the new requirements.

The bands for Cyanobacteria are as outlined in the NOF for freshwater:

A
Risk exposure from cyanobacteria is no different to that in natural conditions (from any contact with fresh water)
B
N/A
C
Low risk of health effects from exposure to cyanobacteria (from any contact with fresh water)
National bottom line: 80th percentile = 1.8 mm³/L biovolume equivalent of potentially toxic cyanobacteria OR 10 mm³/L total biovolume of all cyanobacteria.
D
Potential health risks (eg, respiratory, irritation and allergy symptoms) exist from exposure to cyanobacteria (from any contact with fresh water)

Download data history as a .csv file

Clarity

Secchi disc depth
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State
{{SECCHI.StateScore | uppercase}}
{{stateMsg('SECCHI', SECCHI.StateScore)}}
{{stateMsg('SECCHI', SECCHI.StateScore)}}
Trend
{{trendMsg('SECCHI', SECCHI)}}

Secchi disc depth sample history at this site

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Secchi disc depth samples for Lake Rotoiti at Okawa Bay
metres
Date

What is this graph showing me?

What do the icons mean?

The grades for Secchi disc depth are defined as follows:

A
Water clarity is greater than 7 metres in depth
B
Water clarity is greater than 3 metres and less than 7 metres in depth
C
Water clarity is greater than 1 metre and less than 3 metres in depth
D
Water clarity is less than 1 metre in depth

Download data history as a .csv file

Bacteria

E. coli
State
Not measured
Trend
Not measured

Download Data

.ZIP file of lake data.
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.

Recreation
Recreational water quality

Summer Monitoring:

Many councils monitor popular recreational sites weekly over the summer months. This lets swimmers know what the most recent bacteria (E. coli) levels were. Remember, even for sites where the monitoring has shown an acceptable to swim test result, some conditions can make them unsuitable to swim in from time to time and we recommend that you avoid swimming after heavy rainfall for 48 hours.

Overall Recreation Risk:

The Overall Recreation Risk is a guide to give a general picture of water quality at a site over the recreational bathing season. Updated annually, it is calculated from bacteria (E. coli) data collected over the last three years during the summer monitoring months. The Overall Recreation Risk indicator is a precautionary approach to managing health risk and is not designed to represent health risk on a particular day. As such, a site can have an Overall Recreation Risk of ‘Caution’ but still be suitable for swimming some of the time.

See the factsheet on coastal and freshwater recreation monitoring for more information.

  • Summer season monitoring

    A recent snapshot based on a single sample

    NO DATA

    {{sampleComment()}}
    Show more information Hide

    Summer season monitoring history

    • Last 4 Samples
    • All samples this season
    E. coli sampling graph
    E. coli sampling table
    Sample Date Status Result Observations

    What do the icons mean?

    Acceptable – continue routine monitoring
    Acceptable – Alert. Increase monitoring and investigate source
    Unacceptable – Action. Immediate re-sample, public warning issued if required, increased monitoring and investigate source
  • Overall recreation risk

    The long term risk status based on three years of data

    {{rating() | uppercase}}

    {{comment()}}
    Show more information Hide

    Overall recreation risk information

    Human health for primary recreation: overall recreation risk
    Minimum data points required 30 Number of data points available {{dataPoints() | number:0}}
    Lowest E. coli per 100ml value {{minValue() | number:0}} Highest E. coli per 100ml value {{maxValue() | number:0}}
    Hazen percentile result {{hazenResult() | number:0}} Overall recreation risk {{rating()}}

    What do the icons mean?

    VERY LOW RISK
    People are exposed to a very low risk of infection (less than 0.1%) from contact with the water.
    LOW RISK
    People are exposed to a low risk of infection (between 0.1 and 1%) from contact with the water.
    MODERATE RISK
    People are exposed to a moderate risk of infection(between 1 and 5%) from contact with the water.
    CAUTION
    People are exposed to a high risk of infection (greater than 5%) from contact with the water.
    NO DATA
    There are not enough data points (samples) at this site to generate an Overall Recreation Risk result.

This data is collected by trained council staff and analysed by accredited laboratories. Regional Councils are currently reviewing the methodology of how to best calculate recreational water quality. Once new guidelines are established, they will be applied to this data and the appropriate Cawthron Tick will be given.

Recreational activities
Site suitable for these activities
  • Suitable for swimming
See this site