Flooding processes defended

The council is reviewing if any work needs to be done to mitigate flooding in Doyleston. Photo:...
The council is reviewing if any work needs to be done to mitigate flooding in Doyleston. Photo: Supplied
Selwyn District Council and Environment Canterbury have defended how they responded to the major flooding in the district early last month.

Craig Pauling.
Craig Pauling.
Mayor Sam Broughton and Environment Canterbury chair Craig Pauling have told Emergency Management Minister Mark Mitchell the flooding infrastructure held up, and the processes to manage flooding were up to standard.

They were responding to a letter from Mitchell sent to councils across New Zealand asking them to have a “frank and honest” discussion about responding to flooding.

In his letter he highlighted the flooding in Canterbury, where parts of Selwyn and Banks Peninsula were hit hard.

"No stopbanks were breached or overtopped, and although drainage schemes were overwhelmed in places, they behaved as expected with water entering known ponding areas,” Broughton and Pauling said in a letter sent to Mitchell. 

The district saw two months of rainfall fall in about 48 hours, causing a large amount of flooding, particularly around Ellesmere and Tai Tapu. 

A particular concern among the community was whether Te Waihora/Lake Ellesmere could have been opened ahead of the flooding to reduce the impact. 

Broughton and Pauling told Mitchell even if the lake could have been opened, it would likely have made little difference.

“Unfortunately, sea conditions prior to the event were not favourable, and any opening attempt would have been unsafe and unsuccessful. Had an opening attempt been made a week earlier, it would have closed quickly and likely would have had little effect on water levels during the event.” 

It was noted in the letter that ECan wants the Government to continue to assist with funding for telemetry to monitor river levels and flows. 

"To further support upgrades and strengthen resilience, co-funding with central Government has been sought within the Regional Infrastructure Fund to further accelerate our work.” 

As part of its continued review of the May floods, the district council is paying particular attention to Doyleston, which was one of the worst-hit areas in the district.

On Sunday, council staff met with Doyleston residents to get local knowledge of locations that may have contributed to the flooding.

Staff said it would use that information to establish the next steps for the settlement.