Sam Hawkins' camp flooded during the most recent event and he had to clear out a storm water drain, which was blocked.

Every time rain is forecast, Sam Hawkins clears sand and stones from the stormwater outlet behind his holiday park.

He says the lack of flood mitigation in South New Brighton, in Christchurch's east, is "negligence".

"We have only just signed a long lease with the council and taken over on [May 1] ... we would expect that they would want to do everything in their power to help."

IAIN MCGREGOR/STUFF Alastair Burgess, commodore at the South New Brighton yacht club, surveys erosion near where the proposed new club will be built.

Holiday Park management, as well as the Pleasant Point Yacht Club and South New Brighton Tennis Club, have written to the city council's Coastal-Burwood Community Board to express concerns over a lack of flood mitigation and erosion.

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The letters come after Southshore residents were left "very, very angry" work was not done to protect their suburb – where houses, gardens, garages and sheds were inundated with water – before flooding in late-July.

DAVID WALKER/STUFF An aerial photo from Bexley looking towards South New Brighton and Southshore, with Mount Pleasant and Redcliffs in the background.

Holiday park management wrote they had to clear a stormwater outlet and hire pumps to stop the campsite flooding during heavy downpours of July 21.

Meanwhile, the Pleasant Point's commodore said allowing part of the estuary edge to "naturalise" could jeopardise the club's new $1.5 million clubrooms.

The city council said a report had been prepared summarising measures that could be available to protect the South New Brighton area from flood water inundation.

Hawkins said water from the Avon-Heathcote Estuary started to ingress into the rear of the camp during July's flood event. Contractors built a temporary bund to stop the water.

Hawkins and the park's groundsman braved the conditions to unblock a stormwater outlet themselves.

The outlet was a "constant issue".

"We go down before it rains . . . to go and clear the sand and stones out.

"You know the kids whistle's they get at birthday parties that unfurl when they blow it? It's the same design as that, but in a sandy area and you know what water does to sand, it pushes it up and blocks it.

"It stops that opening and stops the stormwater leaving basically," Hawkins said.

In their letter, park management said they believed it was "negligence not protecting the land since the earthquake".

City council land drainage manager Keith Davison​ said the South New Brighton Reserves Development Plan envisaged a new stopbank between the holiday park and the estuary.

"This was already in the investigation stages prior to the flood events of July 21-22, 2017. Those events meant this work has been expedited.

"A report to council currently being prepared will likely outline options for the construction of this," Davison said.

The council was confident rubber valves on the stormwater outlets were "fit for purpose under normal rainfall conditions".

"The stormwater outlets are necessarily underwater at high tide, and some sand does build up around them.

"This is not generally a problem in normal conditions as the rainfall can reside in the pipe and push its way out on a low tide.

"During heavy rain, and especially combined with a high tide, water will pond in low spots until the tide recedes and the pipes can drain," Davison said.

In his letter, Pleasant Point Yacht Club commodore Alastair Burgess addressed erosion along the shoreline of South New Brighton Park.

The club's old headquarters, at Rat Island, were wrecked during the September 2010 earthquake and it was fundraising to build new facilities at the park.

It was "alarmed" its $1.5 million could be in jeopardy should the city council allow the area to "naturalise".

Davison said the council recognised allowing the estuary edge to naturalise meant "some change to the location of the current shoreline and shared use track".

"However, allowing naturalisation would be accompanied by a management and monitoring plan which would track the progression of the naturalisation.

"It is likely this proposal will be tabled at the next council meeting with the flood protection options," he said.

Hard engineering had been considered, but was not the preferred option partly because it was expensive.

"The estuary edge at this point is also subject to multiple hazards, not just erosion.

"For instance, in another earthquake hard engineering defences would be far more likely to be damaged than a natural edge," Davison said.

They would compromise the area's natural character and likely be unsustainable given predicted sea-level rise impact in the area, he said.

In his letter, South Brighton Tennis Club president Mark Condon expressed concern over "constant flooding of our facilities since the earthquakes".

Since September 2010, the club's courts and clubrooms had flooded five times.