Environment Canterbury is defending its handling of the Lake Ellesmere opening, saying it followed all required procedures and acted as soon as conditions allowed.

Farmers contacted chrislynchmedia.com accusing the regional council of moving too slowly, worsening flood damage on surrounding land.

However, General Manager Hazards Leigh Griffiths said the lake opening process is jointly managed by Environment Canterbury and Ngāi Tahu, and governed by the National Water Conservation Order and a suite of resource consents.

“There are specific conditions that need to be met before Lake Ellesmere can be opened.”

Griffiths said consultation to open the lake began on Monday 28 April and was completed the following day.

A joint decision to proceed with the opening was made on Tuesday 30 April once the lake level reached the required 1.13 metres.

“We can only open the lake once a joint decision has been made, and the lake height reaches a minimum of 1.13 metres (from 1 April to 15 June).

The lake conditions were not met until Tuesday 30 April.”

Griffiths said that while the decision was made as quickly as possible, sea conditions have since made an opening attempt unsafe and likely ineffective.

“The success of a lake opening depends heavily on favourable weather conditions.

Wind strength, wind direction, sea swell, wave directions and the tides are all factors that can affect openings,” she said.

“In difficult weather and adverse sea conditions, multiple attempts may be necessary, and a successful opening may take weeks or even months to achieve.

An opening is considered ‘successful’ when it persists for at least four days, the amount of time required on average to lower the lake level below the opening threshold.”

“Machinery has started earthworks on site,” Griffiths said.

“In current conditions, however, an opening would not be successful (the cut from the lake to the sea would fill in) and it is also unsafe for people to operate machinery in the surf zone.”

She said the lake will be opened to the sea as soon as weather and sea conditions allow. “This is likely several days away at the earliest.”

The situation has sparked wider frustration across Banks Peninsula, with residents also questioning the timeliness of action at Lake Forsyth, managed by Christchurch City Council.

Lake level data for Lake Ellesmere is available on Environment Canterbury’s website.