Te Waihora/Lake Ellesmere is a living hāpua/shallow, brackish coastal lake-lagoon that is nationally and internationally significant for its cultural, ecological and economic values.
The catchment, which drains 276,000 hectares, extends from the foothills of the Kā Tiritiri o te Moana/Southern Alps to the Rakaia River, the Waimakariri River, the hills of Banks Peninsula and the plains in between.
It is salty and shallow, with an average depth of 1.4 metres and a maximum depth of around 2.7 metres. It is a brackish coastal lagoon that is termed eutrophic, which means it is rich in plant nutrients.
Internationally, it’s important for its biodiversity and indigenous fish species. Te Waihora is teeming with life and highly productive, but it isn’t as healthy as it should be. There is much work to do.
Explore the scientific data for this lake
- Environment Canterbury monitors water quality at 5 sites around the lake, and one recreational water quality site. Visit Land Air Water Aotearoa's website (LAWA) for the latest water quality data
- Te Waihora covers a total catchment area of 276,000 hectares and is in one of Environment Canterbury's water management zones, Selwyn Waihora. The Selwyn River/Waikirikiri is the main inflowing river, which is itself fed by key tributaries such as the Hororata, Hawkins and Waianiwaniwa rivers
- View the water quality of key tributaries of Te Waihora/Ellesmere catchments by visiting the LAWA website
- In recent years, Waihora Ellesmere Trust has coordinated an annual multi-agency bird count around Te Waihora.
It is widely acknowledged that the ecological health of both the lake and the surrounding tributaries has declined. Since the second half of the 19th century, the lake catchment has been predominantly agricultural. This has led to increasing inflows of nutrients and sediment.
State of the Lake Reports
The following State of the Lake reports have been published by Waihora Ellesmere Trust, with contributions from many agencies and experts.
- 2017 State of the Lake Report
- 2015 State of the Lake Report
- 2013 State of the Lake Report
- Visit the Waihora Ellesmere Trust website to find the 2008 State of the Lake and Future Management Reports
Key turning points for the health of Te Waihora
Key turning points for the health of Te Waihora included the large-scale clearances of bush and draining of wetlands in the 19th century to allow for farming. In the 1960s, the beds of naturally occurring macrophytes (floating or submerged plants) disappeared from the lake.
This happened for a range of reasons including the impact of the Wahine Storm in 1968. This was another turning point for the quality of the lake’s water.
The macrophytes buffer waves, take up nutrients and improve water quality. After their disappearance, the health of the lake and its tributaries declined significantly. Intensification of agriculture including the increase of dairying in this catchment since the 1990s has further increased pressure on the environment.
Climate change and urban development have also contributed to the decline of water quality.
All outcomes of Whakaora Te Waihora will be achieved within the context of Ki Uta Ki Tai (Mountains to the Sea)