Eketahuna’s oxidation pond treatment system. PHOTO/TOM TAYLOR
TOM TAYLOR
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While heavy rainfall batters the region, causing slips and damaging roads, an unexpected result of the severe weather has been repeated requests for residents to conserve water.
In the past week, Greytown and Featherston residents have had to limit their use of water, while to the north of the region, Eketahuna residents have had to boil their water after heavy rainfall affected their water supply.
Last week, high river levels and torrential rain resulted in high levels of cloudy water in the bores supplying Greytown and Featherston.
Wellington Water asked the residents to conserve water until further notice.
Drinking water chief adviser Laurence Edwards said the cloudy water had resulted in an unexpected interruption to water supply, and reservoirs had dropped to low levels.
“Because of this, the treatment plant supplying Featherston and Greytown needs time to recover,” Edwards said.
Wellington Water had lifted the initial restrictions with water running clear and reservoirs at normal levels.
However, on Sunday, after another bout of heavy rainfall, Wellington Water again asked Featherston and Greytown residents to conserve water.
“This is similar to the events last week which resulted in an unexpected interruption to the water supply,” Edwards said.
“To prevent this from happening again, we’re asking the community to help by limiting water use as much as possible until further notice.”
The Featherston and Greytown water supply came from four bores next to the Waiohine River, north of Woodside.
Another groundwater bore in Memorial Park, Greytown, supplied water to Greytown only.
A Wellington Water spokesperson said there had been six occasions since the beginning of the year where rainfall had caused high levels of cloudy water in the bores.
“Each bore reacts differently, and the cloudiness of the water in each bore may be impacted to different extents.”
The spokesperson said that on Sunday, two out of the four bores were still able to provide water.
“Supply was not interrupted, but having several bores down meant added pressure on the system to meet demand for Featherston and Greytown.
“This is why we were proactive in asking residents to help us by using as little water as possible.”
Three reservoirs contained the water supply for the two towns: a 750,000-litre tank shared by both towns, a 450,000l tank for Greytown, and another 450,000l tank for Featherston. The tanks normally operated at 75-95 per cent full.
Although the reservoirs were now back to normal levels, restrictions would remain in place for residents.
A Wellington Water and South Wairarapa District Council project planned to increase water storage at the treatment plant, which would increase available water.
“This will allow us to manage high demand events for an extended period regardless of river conditions,” the spokesperson said.
Meanwhile, in Eketahuna, a precautionary boil water notice has been in place since Monday.
In a media release, Tararua District Council said heavy rain had resulted in dirty source water.
The water treatment plant could not guarantee the complete treatment of contaminants throughout the network.
Infrastructure general manager Chris Chapman said the main risk to residents was that the water in the network was no longer chlorinated.
“Because of the turbid river water source, any sediments that remain in the water following the treatment plant will consume the chlorine, so we cannot guarantee that water will remain chlorinated throughout the reticulation network for protection against possible contaminants.”
No E-coli had been detected in the water supply.
Chapman said before this week’s event, there were no records of a boil water notice on the Eketahuna water supply.
He said upgrading Eketahuna’s water treatment plant would provide additional filtration of the water, enabling more effective treatment when heavy rainfall impacted the river source water.
The council were to provide an update on the situation yesterday.
