Updated – 06:02PM – Thanks to David Lee and WCC:
Received an update last night from Councillor David Lee.
From David Lee:
The emergency repair work was successful with about 1/4 (500-600 m3) of the estimated 2000 m3 of wastewater being discharged to sea. See WCC officer’s update below.
Work to repair the leaking wastewater main at Owhiro Bay began around 1am on Friday morning. The pipe was reconnected by Friday afternoon, and the discharge to coast stopped at about 2.30pm.
By Saturday the water was clear, and preliminary results show water quality quickly returning to normal.
In the end an estimated 500-600 cubic metres was discharged to sea. This is a lot less than the 2,000 or so that we were originally looking at, and was achieved through a non-stop chain of sucker trucks transferring wastewater from near the discharge point, to the network on the Kilbirnie side.
Wellington Water was also able to install a valve in the new section, which should improve our ability to manage future maintenance.
The rāhui will remain in place until further notice – likely the middle of next week, depending on water testing results. We’ll keep you posted on these
The Esplanade, Owhiro Bay – Emergency wastewater repair
You might have heard about our need to make an emergency repair to a pressurised wastewater main, and that this will mean a discharge of wastewater to the sea. Quite a few people are quite energised by this event – quite rightly so – and are wondering how it could happen.
Discharging to sea is not something we want to do either. Usually when we carry out emergency repairs on the wastewater network, we’re able to manage the interruption in service by temporary storage, diverting the flow, or using sucker trucks.
But the pipe is a big one, and it’s long. It carries wastewater from Brooklyn all the way up to a tunnel that passes beneath Mount Albert, on its way to the treatment plant at Moa Point.
In this case, despite all our normal methods and a few others, the volume involved is too much to manage. We’ve managed to reduce what we think will discharge to around 1,000 cubic metres of water. The alternative would be for this to overflow onto the street – but that would end up going down the stormwater system and out to sea anyway.
How can this happen? To avoid any kind of overflow in a wastewater network, you’d need to have a failsafe system, or duplicate pipes. That’s not practical. The cost to duplicate all the trunk wastewater mains in the city would be in the 10s if not 100s of millions of dollars. Wastewater network overflows happen in every city. The best thing you can do is design for them – to control where the water goes, and so minimise the risk to human and environmental health and safety. That said, we do need to make sure we’re on top of our proactive maintenance.
A few other things to note. This is not an ongoing situation – it’s a one off emergency. Advice we’ve received is that the wastewater will clear quickly once it reaches the ocean, and there will be no lasting impact.
We’re also really grateful we’ve had enough time to work with our iwi partners to perform a rāhui, and with health and environmental authorities to get their advice. Kura Moeahu led the laying of the rāhui at Owhiro Bay which will extend from Lyall Bay to Tapu Te Ranga. Kura was assisted by Alishia Moeahu, Pekaira Rei, Kurt Komene and accompanied by other members of Taranaki Whanui and Wellington Water staff, including the Acting CEO Audrey Scheurich and GM Gary O’Meara.
We’ve contacted residents living directly opposite the chamber where the leak is, who will be most affected by the work. We haven’t been able to directly contact all residents who will be affected by the discharge – we know that will be thousands of people. But we hope they’ll understand the need to carry out the work as quickly as possible.
Best wishes to the crew working on the repair. They know how important it is to get this done safely, quickly, and to get it done right.
Previous Update – Wellington City Council/Wellington Water
An update from Wellington water regarding the wastewater discharge at Owhiro Bay.
Thanks also to Paul Eagle and Wellington City Council for the open communication.
Not good at all – here’s the latest just through from David Chick, Chief City Planner at the council:
From: Betsie Lotter On Behalf Of David Chick
Sent: Thursday, 3 August 2017 4:44 PM
To: GRP: Councillors
Cc: ‘Alexander van Paassen’; Sam Lister; Richard MacLean; GRP: Executive Leadership Team (ELT)
Subject: Wastewater main repairs – Owhiro Bay
Just to keep you informed regarding the Wastewater pipe repair works at The Esplanade, Owhiro Bay:
• Strong engagement with Iwi has taken place.
• It has been confirmed that works would start at 2am on Friday morning.
• Wellington Water is gearing up for the work on the wastewater main repair at The Esplanade and are dropping the letters below this afternoon.
• FYI – The area they are working is pretty much opposite Dive Wellington
• The sump truck discharge point is in Kilbirnie (due to the pipe shutdown) – Residents might wonder what is going on.
Wastewater repairs – The Esplanade at Owhiro Bay
Update for residents
Dear Resident/Business Owner
You may have heard about the emergency work we’re carrying out on the main wastewater pipe on The Esplanade.
To minimise the impact on the environment, we need to start work urgently. We will begin around 2am tomorrow (Friday) morning, and there will be activity at the site from midnight tonight. There will be noise from the vehicles and contractors arriving on site and sump trucks operating.
We apologise in advance for any disturbance, however this emergency work needs to be completed as soon as possible in the interests of health and safety.
If you have any questions, please contact Sam Lister at Wellington Water on 04 912 4400, or Alex van Paassen on 027 232 1677.
Wastewater pipe repairs – Update for residents
Wellington Water is carrying out some emergency wastewater pipe repairs in Owhiro Bay. We are using sump trucks to minimise the impact on the environment, which will discharge into the manhole near 256 Coutts Street overnight tonight.
We anticipate this will create some noise in your area and apologise for any disturbance, however this emergency work needs to be completed as soon as possible in the interests of health and safety.
If you have any questions, please contact Sam Lister at Wellington Water on 04 912 4400, or Alex van Paassen (027 232 1677).
Chief City Planner | | Wellington City Council
E David.Chick@wcc.govt.nz | W Wellington.govt.nz | |