Lake Pounui

Lake Pounui is a moderately shallow lowland coastal lake situated in the foothills of the Rimutaka Range in the Southern Wairarapa.

As opposed to other lakes in the Wellington Region, Lake Pounui has a high diversity of native fish species, with recent surveys identifying abundances of threatened species such as Giant kōkopu and Longfin eels. A large part of the Pounui catchment area is protected under the QE2 National Trust Open Space Covenant, due to its diversity of native vegetation and significant indigenous ecosystem values. Lake Pounui is also listed in Greater Wellington’s existing Regional Freshwater Plan as a catchment with nationally threatened fish.

Lake Pounui is the second largest and deepest lake monitored by the Greater Wellington Regional Council (GWRC), with a total area of 46 hectares and a maximum depth of 9.6 metres. The surrounding area is largely comprised of indigenous forest, with small areas of pastoral land to the north and south-western sides of the catchment. Lake Pounui is privately owned so access for contact recreation is generally limited to the land owners.

GWRC has carried out periodic monitoring of macrophyte community structure using the LakeSPI index since 2011. Assessments of ecological condition in Lake Pounui have placed it in the “moderate” category, with an increase in invasive vegetation in the past four years, including toxic algae blooms. However, Lake Pounui has a relatively diverse native vegetation structure, with the presence of all key native community types recognised by LakeSPI. The fact that it is almost completely unmodified, leading to a high diversity of native fish species, makes it relatively rare compared with other lowland coastal lakes around New Zealand.

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 Pounui

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 Pounui 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 Pounui

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 Pounui 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 Pounui

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No sites found.