Lake Kohangatera

Lake Kohangatera is a typical example of a small, shallow coastal lake. Located in the East Harbour Regional Park on Wellington’s south coast, Kohangatera is the larger of the two Parangarahu Lakes (the other of which is Kohangapiripiri).

Compared to other lakes around New Zealand, Lake Kohangatera is relatively unimpacted and physically unchanged. The plant species diversity and extensive native vegetation has given Lake Kohangatera its reputation as a nationally outstanding example of a ‘healthy’ lake. It also is listed in Greater Wellington’s existing Regional Freshwater Plan as a water body with nationally threatened fish species.

Lake Kohangatera has a total area of 21 hectares; almost twice the size of Kohangapiripiri. However it is a relatively shallow lake, with a maximum depth of 2.1 metres. Land use in the Kohangatera catchment is primarily indigenous forest and scrublands, with regenerating pasture and significant wetland areas towards the north of the lake.

A variety of recreational activities are supported by Lake Kohangatera, including walking, mountain biking, bird watching and duck hunting at specified times of the year. Evidence of Māori huts, ovens and workshop sites can also be seen around the lake, which is considered culturally significant.

LakeSPI monitoring at this site is carried out by the Greater Wellington Regional Council periodically; the last observations were recorded in February 2016. The current ecological condition of the lake is considered “excellent”, meaning that the lake supports a diverse range of native vegetation, with little to no exotic weeds.

Lake Kohangatera is separated from the Cook Strait by a naturally occurring gravel bar. This separation of sea and freshwater has led to a low diversity of native freshwater fish which require access to the sea to complete their lifecycles. However, the lake is thought to drain to the sea via seepage and the breaching of this gravel bar is considered to have increased over the past decade.

Lake Summary

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Scientific data for this lake

This dashboard shows information on the data collected by the regional councils and unitary authorities for two lake water quality and ecological condition measurements. LakeSPI (Lake Submerged Plant Indicators) and TLI (Trophic Level Index). Select an indicator to see the historical monitoring data.

Water Quality

Trophic Level Index (TLI)

This measure is the Trophic Level Index (TLI). The TLI indicates the life supporting capacity of a lake and is based on four water quality indicators.

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Trophic Level Index (TLI) history for this lake

Trophic Level Indicator (TLI) which measures four parameters: water clarity, chlorophyll content, total phosphorus and total nitrogen. From these parameters a TLI value is calculated. In cases where water clarity data is missing a three parameter TLI is calculated. The higher the value, the greater the nutrients and fertility of the water which encourages growth, including algal blooms. As a rule, higher TLI scores mean poorer water quality. View a factsheet on TLI

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TLI history for Lake Kohangatera

Year

What do the icons mean?

Very good water quality. Trophic Level Index of 0-2. Microtrophic lake conditions.

Good water quality. Trophic Level Index of 2-3. Oligotrophic lake conditions.

Average water quality. Trophic Level Index of 3-4. Mesotrophic lake conditions.

Poor water quality. Trophic Level Index of 4-5. Eutrophic lake conditions.

Very poor water quality. Trophic Level Index of greater than 5. Supertrophic lake conditions.

No data available.

TLI history for Lake Kohangatera data table

Year	TLI Score

Year	TLI Score

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Ecological Conditions

Lake Submerged Plant Indicators (LakeSPI)

The LakeSPI status describes the ecological condition of the lake and is based on plants present.

LakeSPI data provided by NIWA

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LakeSPI history for this lake

LakeSPI (Lake Submerged Plant Indicators) is a method of characterising the ecological condition of lakes based on the composition of native and invasive plants growing in them. A higher LakeSPI percentage result is associated with better ecological health:

LakeSPI	N/A
LakeSPI	{{spiData.details.Value}}%

The overall LakeSPI score is calculated using a Native Condition Index ('good' plants) and an Invasive Impact Index (introduced, non-native plants):

Native Condition	N/A
Native Condition	{{spiData.details.NativeIndex}}%

Invasive Impact	N/A
Invasive Impact	{{spiData.details.InvasiveIndex}}%	NA

A higher Native Condition value indicates better ecological condition, but a higher Invasive Impact value indicates invasive plants are negatively impacting native plant communities.
View a factsheet on LakeSPI for more information on these indicators.

LakeSPI
Native Condition
Invasive Impact

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LakeSPI history for Lake Kohangatera

Year

What is this graph showing me?

This graph is displaying the overall LakeSPI score over time. The results denote the ecological condition of the lake.

Excellent ecological health. A LakeSPI score of 75-100%.

High ecological health. A LakeSPI score of 50-75%.

Moderate ecological health. A LakeSPI score of 20-50%.

Poor ecological health. A LakeSPI score of 0-20%.

Non-vegetated. A LakeSPI score of 0% (there are no plants present).

No data available.

LakeSPI history for Lake Kohangatera data table

Sample Date	LakeSPI Status	LakeSPI %	Native Condition Index %	Invasive Impact Index %

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NIWA LakeSPI is licensed under a Creative Commons Attribution-Non Commercial 3.0 New Zealand License 2012. Visit the NIWA LakeSPI website.

LakeSPI information has been provided by NIWA.

Sites

Monitored sites on Lake Kohangatera

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No sites found.