During heavy rain, Gisborne's wastewater network discharges treated waste and raw sewage into city rivers. Photo / Liam Clayton / The Gisborne Herald
During heavy rain, Gisborne's wastewater network discharges treated waste and raw sewage into city rivers. Photo / Liam Clayton / The Gisborne Herald
A scheme to stop sewage gurgling up on to Gisborne properties has been heralded a success during a council meeting this week.
The DrainWise programme renews wastewater pipes and works with property owners to reduce the amount of rainwater getting into the wastewater system.
If too much stormwater gets in, it can cause sewage to overflow onto property and into waterways.
One way to stop this from happening is to open valves and discharge the wastewater into the river.
Councillor Larry Foster said when a heavy rain event happened a couple of weeks back and the valves did not open, it was “a great recognition that the DrainWise project is working”.
Water manager Leo Kelso agreed there was a lot of positive work happening in the drainworks space. The team had focused on the Kaiti area initially, because of the renewals work on the pipelines.
Kelso said it was a complicated process as there were multiple contributors that impacted on the wastewater network.
“There’s the pipe age and infrastructure, the inflow and direct feeds from housing, and localised flooding that blocks gully traps when it comes through.
“Kaiti has been a focus in terms of those conceptions, and going forward it remains a focus, but in balance with other aged infrastructure, which also contribute to overloading the network that compounds that situation [in Kaiti],” he said.
A large part of the network crossed on a similar path from Kaiti and inhibited its ability to move through to the plant, Kelso said.
Gisborne District Council lifelines director Tim Barry said: “You’ve got to look around and see where you can have the most influence. For this programme, it is an ongoing and long-term project that looks at getting the most for the dollar,” he said.
The DrainWise programme collaborates with property owners to mitigate sewage overflows into waterways and properties.
Kelso said there were years of work to complete and last year hindered the ability to do work.
“In our world, there’s a certain window of opportunity to do this work, which is in spring and summer.
“That is why you have to do the legwork upfront so that you can get those projects through,” he said.
A part of the DrainWise programme was working with private property owners to fix the issues.
Barry said the work had to be mutually agreed and that could be tricky for some.
“It’s initially on them and many can’t afford to do it ... then we have to figure out a way of potentially funding it ourselves.
“So there is a bunch of work outside of identifying and getting the outcomes we want,” he said.
$2.239 million has been spent on wastewater pipeline renewals of the $2.426m budget. This includes urgent pipe relining in Stanley Rd and a replacement of a deteriorated manhole in Custon House St.
$130,000 has been spent on wastewater pump station renewals of the $313,000 budget, including pumps purchased for Dunstan Rd pump station.
$368,000 has been spent of the $448,000 budget on renewing stormwater pipes to improve network performance. This includes the Disraeli/Childers Rd stormwater channels, a project on 158 Stout St, and Ngaio St pipe relining.
$261,000 spent of $833,000 budget on the public drains on private property part of the DrainWise programme, which aims to extend the public stormwater network to reduce water flow from entering the sewage system.
LDR is local body journalism co-funded by RNZ and NZ On Air
