22 May 2024

Irate residents allege council inertia on drainpipe maintenance caused flooding

3:28 pm on 22 May 2024
New Brighton flooding

Heavy rain caused parts of New Brighton to flood on Tuesday. Photo: Supplied / Kim Money

Frustrated residents of a coastal community in Christchurch believe a lack of drainpipe maintenance is leaving the area needlessly exposed to flooding.

A bout of heavy rain in the city on Tuesday morning resulted in shin-deep flooding for parts of the seaside suburb of New Brighton.

The flooding had subsided within a couple of hours after local authorities rushed to clear outflow pipes which had left parts of Marine Parade and Pacific Road awash.

Flooding in New Brighton in Christchurch on 21 May 2024

A New Brighton resident stands in floodwaters on the corner of Marine Parade and Pacific Road on Tuesday. Photo: Supplied / Celeste Donovan

Affected roads had reopened by the afternoon.

An update from Christchurch City Council staff that day explained leaf fall had blocked some sumps which slowed the drainage of surface water.

"Out east we are aware of a couple of locations where surface flooding occurred, however, contractors were onsite early this morning managing traffic and clearing the key outfalls.

"Once this occurred the water drained away quickly."

Some residents RNZ spoke to explained this was an occurrence which had become the norm when the area received heavy rainfall.

But the North Beach Residents Association's chairperson Kim Money said the lack of maintenance for sand-blanketed outfall pipes could leave homes vulnerable.

"It will go into houses," she said.

"It's certainly something that frustrates me immensely because I understand it is something that is a relatively easy fix.

"The longer it takes the council and [Citycare] to come and clear the outpour drains on the beach, the larger the buildup of water on Marine Parade.

"It needs to be addressed straight away... it affects residents all the time."

New Brighton flooding

An outflow pipe at New Brighton beach in 2023. Photo: Supplied / Kim Money

Money explained the buildup issue was symptomatic of an "accreting" shoreline.

A NIWA report commissioned by the Christchurch City Council in 2018 suggested the majority of the city's coastline was experiencing accretion, where the shoreline builds up as the coast advances seaward.

"As soon as we get those ocean outfall pipes covered in sand, the water just can't get out from the street," Money said.

New Brighton flooding

An outfall pipe at New Brighton beach submerged in sand. Photo: Supplied / Kim Money

"The frustrating thing is that this whole thing is avoidable, by clearing the outfalls before the rain comes."

Money said a proposed extension of the outflow pipeline at Cygnet Street could mitigate some of the problem, or reallocating the maintenance burden to coastal community park rangers.

The council said in a statement the surface flooding was due to leaves blocking grates and the ocean outfall being covered in sand.

Contractors were on site at around 8.30-9am and cleared the grates and ocean outfall at the end of Cygnet Street. The surface flooding was all cleared before midday.

Prior to any significant events council contractors proactively clear key drains, grates and outfalls.

"When we clear the outfalls along the coast our contractors need to do this following a high tide as if we do this at the wrong stage of the tide then they will just get covered in sand again," a council spokesperson said.

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