Te Waihora /Lake Ellesmere is currently OPEN to the sea.
Te Waihora was opened briefly to the sea on two separate occasions over the weekend however rough sea conditions and large swells prevented the opening cut from surviving the high tide.
A further attempt to open Te Waihora to the sea was made this morning, Monday 5th May 2025 at 10am, on the outgoing tide.
The main cut is still developing, and the channel will continue to widen provided that conditions remain favorable for the opening cut to survive several tidal cycles.
Anyone going on site is reminded the lake opening site is a controlled Health and Safety area with significant risks.
All visitors must report to Site Supervisor Mike Hyett or Dan Meehan on arrival.
The calm average level on Monday 5th May at 08:00am was 1.63m.
Q: What was the lake level reading before this one?
A: 1.14m. The wind affected average level as at 0800 hrs on Wednesday 30th April 2025.
Q: When was the lake last opened to the sea?
A: The lake was mechanically opened on 9th November 2024 and closed naturally on 23rd November 2024.
Q: At what levels can the lake be opened to the sea at this time of year?
A: From 1st April to 15th June : Anytime (to assist fish passage) – otherwise 1st April to 31st July: 1.13m.
24/7 access to Te Waihora/Lake Ellesmere water levels:
Te Waihora/Lake Ellesmere levels are now available on our river flow data web page. These levels are average readings taken from the two gauges around the lake, one at Taumutu and the other at Seabridge Road/Nutts Cut.
Please note that wind effect should be considered when interpreting this raw data. The wind information is currently not provided on the public web page; however, it may be requested by contacting Customer Services.
Click this link to go to the average lake level data webpage – https://www.ecan.govt.nz/data/riverflow/sitedetails/168307
Or, navigate to the site named Te Waihora/Lake Ellesmere (Average) from ECan’s river flow data webpage – https://www.ecan.govt.nz/data/riverflow
For more information on the mechanical opening of Te Waihora/Lake Ellesmere, please visit our web page here: https://ecan.govt.nz/your-region/your-environment/river-and-drain-management/opening-te-waihoralake-ellesmere/
An artificial opening of Te Waihora/Lake Ellesmere is governed by the Lake Protocol which outlines the procedure around exercising the consent which lists key values of the lake to be considered in the decision making. A decision to open the lake is only made when the representatives in the Protocol Group have been consulted. Currently, the Protocol Group is consisted of the following organisations: (Fig 1).
The next regular update will be on Monday the 12th of May 2025. Please do not hesitate to contact me if you have any questions.
Q: Where can I find the resource consent for the lake opening?
A: The Hearing Commissioners decision on the new joint resource consent application by Te Runanga o Ngai Tahu and Environment Canterbury was received on Wednesday 22 January 2014. The decision was to grant the application for a period of 15 years subject to a suite of mitigation measures. You can read the decision here: RMA92023020 Decision – Final
Q: What lake opening investigations are being carried out as part of Whakaora Te Waihora?
NIWA and the University of Canterbury have investigated options for an engineered lake level. As part of this project a website has been created which summarises the options that have been considered over the years. There is further information here.