Strong stormwater flows on some Lyttelton streets

Lyttelton residents have been warned to expect stormwater flows on some streets as urgent work to repair a blocked drain continues.

Christchurch City Council contractors have been working to excavate the collapsed and blocked brick barrel stormwater drain on Oxford St, between Ripon and Exeter Sts, after a sump collapsed into it.

Workers will need to dig about 5.5-6 metres down to reach the pipe.

Council head of three waters Helen Beaumont said stormwater upstream of the blocked section of pipe will be pumped away, diverting it from reaching the blocked area.

The stormwater will be diverted down St Davids, Oxford and Exeter Sts.

Beaumont said there will be heavy stormwater flows running down those streets. Temporary traffic measures will be in place to prevent people from accessing the area and sandbags are being deployed around certain properties as additional protection.

"We will be working closely with Fire and Emergency New Zealand to monitor the situation."

The Metservice issued an orange rain warning for parts of Canterbury, including the plains north of Ashburton, the foothills, and in and around Christchurch, from 1am Wednesday to 6am Thursday.

"Expect 110mm to 160mm of rain to accumulate, especially north of Christchurch. Peak rates of 15 to 25 mm/h. Note, heavy rain is expected to ease north of Christchurch after midnight Wednesday," the Metservice said.

Beaumont asked residents who live around the Lyttelton area to expect heavy stormwater flows down the streets.

"We’re pumping the stormwater upstream of the broken pipe onto surrounding streets to divert around houses so please be aware of this if you see a large amount of water going down these streets.

"We’re asking all residents living on Oxford Street, downstream of Rippon Street, to not park their cars on the road from this evening onwards.''

Deputy Mayor Andrew Turner said the council has plans in place to handle the heavy stormwater levels expected.

"You may see our staff and contractors on the ground today and tomorrow distributing sandbags or setting up pumps or traffic measures. With the heavy rain expected, we are taking all precautions we can to ensure that the stormwater is diverted as best as possible and any surrounding properties and buildings are protected.”

The blockage will take a number of days to clear.