Flood Update

People should prepare to face further days of surface flooding and a sewerage and stormwater system under pressure as more rain is forecast for later this weekend.

Marlborough District Council assets and services manager Mark Wheeler says the prolonged rain is causing the problems, leaving no chance for anything to dry out.

“Today, rivers peaked around lunchtime but the situation is very slow to improve because the ground is absolutely soaked and the run-off is just not stopping. We need a decent break from the rain before the situation will change.”

He said residents should not be surprised if early next week’s forecast rain means there is a re-run of the street flooding due to the overloaded stormwater and sewerage systems.

“Our maintenance teams have been working hard on the clean up today, both at private addresses and on the streets. But the soil can’t absorb any more rainfall so we’ll very quickly be back at an overflow situation again if we get further deluges.”

By mid-afternoon, when calls from the public tailed off, about 130 calls about the sewage and stormwater network had been received by the Council’s maintenance team.

However Council Operations and Maintenance Engineer Stephen Rooney said his team was preparing to gear up again to handle the impact of more rain, forecast from Sunday.

People should expect low lying water on their lawns to remain for some time yet, said Mr Rooney.
“The groundwater levels are extremely high and the water has nowhere to go. Even where land does seem to be draining, surface flooding is likely the next time it rains.”

Mr Rooney says Blenheim’s sewerage system dates back to the mid-1930s and, while sewer infrastructure is generally expected to last for 80-100 years, parts of the system are beginning to show their age.

“We know that in some parts of the network the groundwater is infiltrating the sewers. Under normal circumstances we manage that through an infiltration programme which deals with any major leaks.

However the experience of these last few days confirms the need for a plan Council already has in place to rehabilitate the sewer mains in Bank Street and McLachlan Street between Fulton Street and Old Renwick Road.”

Over the last two days special pumps had been put in place in these areas to take the pressure off the sewerage system by pumping the overflow directly into the stormwater system.