The level of Te Waihora/Lake Ellesmere is managed by periodically opening the lake to the sea. This happens two or three times each year to manage for a range of values, including wildlife, wetland vegetation and fish habitat, mahinga kai, customary fisheries, water quality, summer levels, land inundation, waterway networks and infrastructure, and fish migration.
The lake is currently OPEN to the sea.
The calm average level of the lake as recorded on Friday 11th August was 0.64m.
Leigh Griffiths, from ECan’s Engineering section, wrote on October 17, 2016:
For the first time we were able to capture some aerial footage as the lake was opened on 28 September 2016. You can view the footage here. For me, the footage demonstrates the scale and dangers of the job we face when opening. Hopefully people can appreciate that when the sea is bigger (it was relatively calm that day) the safety concerns and problems we can face even accessing the site.
Q: What was the lake level reading before this one?
A: 0.60m, calm average, on Monday 7th August 2017.
Q: When was the lake last opened to the sea?
A: The lake was opened on 25th July 2017 and has remained open since. The cut is approximately 25m wide.
Q: What are the potential lake opening levels?
A: Between 1 August to 31 March the minimum level the lake may be opened is 1.05m. Between 1 April to 31 July the minimum level the lake may be opened is 1.13m. Primarily for fish migration purposes, the lake may also be opened ‘at any level’ between 1 April to 15 June and 15 September to 15 October. (Note: in practical terms, ‘any level’ is a level above 0.90m – below this level the engineers do not believe they can physically get the lake open).
Q: Where can I find the new resource consent for 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.