A pump malfunction on Tuesday night has again left the council and residents dealing with a distasteful discharge.
RAW sewage was released into the Waimata River near Russel Street in Gisborne on Tuesday night because of a pump malfunction. The council was alerted at 8.40pm to a fault with the Russell Street pump station, where about six cubic metres of wastewater had leaked into the river.
A media release sent to The Gisborne Herald nearly 24 hours after the malfunction said people were advised to avoid swimming, paddling or gathering seafood from the Waimata and Turanganui Rivers for up to five days following the sewage leak.
Operations group manager Barry Vryenhoek said he was extremely disappointed the systems to prevent sewage from overflowing had failed.
“There was a fault in the level of the sensors that trigger the pumps to operate and a mechanical fault with the emergency release valve,” he said.
“We’re responsible for making sure the system works and we apologise that this has happened. The leak was sporadic over two hours and the tide was going out when it occurred, so it’s likely that any contamination has been diluted and dispersed.”
Samples of the water have been taken from the river at Russell Street, Grant Road and Gladstone Road Bridge to test for bacteria levels and the results will be back on Friday.
“We will let the community and water users know when the levels have returned to normal.?
A notice of the discharge was emailed out to interest groups and on the council’s website and social media, and signs were put up at public access points yesterday afternoon.
Engineers stopped the discharge within an hour.
“We would like to thank the two people who reported the discharge so that our contractor was able to fix the problem quickly.”
The pump station has a back-up storage tank that collects any overflow from the station. The emergency release valve from this tank to the river was faulty and was replaced.
“Alarm systems and mechanical functions at all other pump stations are also being checked.”
Earlier this year, human error caused a pump station overflow in the Wainui Stream, after which the council put in place stringent procedures.
“The pump stations undergo maintenance weekly and scheduled upgrades are being made,” Mr Vryenhoek said.
“We are taking this very seriously, the water utilities team are assessing the circumstances of this fault and how we’ll prevent it from occurring again.”
A discharge like this is prohibited under the new Freshwater Plan regulations and environmental services staff are investigating if any enforcement action is necessary.