By Ashley Karen
Checking for black flags on the Safeswim website may stand as reasonable protection, but Aucklanders should have more enthusiasm to take a dip at the city’s beaches when Watercare’s Central Interceptor wastewater tunnel is finished.
Water quality has been an obstacle emphasized by January’s flooding and Cyclone Gabrielle, after which many beaches had warnings for weeks.
Nigel Varcoe, the Commercial manager, articulated that was precisely what the Central Interceptor was pointed to alleviate.
He stated: “Central Interceptor is designed to prevent contaminated water entering the harbor,”
“Our ultimate objective is to clean up our beaches.”
In central Auckland’s more aged areas, an integrated network of pipes bears both stormwater and wastewater.
Regardless, during severe rainfalls, the volume of stormwater can surpass the pipes’ capacity, resulting in wastewater overflowing into streams and creeks and contaminating them.
Varcoe declared in the recent intense rain, even the Central Interceptor would have overflowed, yet, it will be able to avoid the vast majority of incidents.
“We’re cleaning up 90 percent of Auckland’s overflows in this part of the isthmus, so 90 percent of what happens at the moment would have been cleaned up; what happened earlier this year is a bit exceptional.”
While the City Rail Link, another of Auckland’s main tunnelling projects, had blown out in budget by a billion dollars, Varcoe was sure that the Central Interceptor would still come in within its initial funding of $1.2 billion.
He claimed: “We’re on track for that at the moment.
“We had significant contingencies put aside for unforeseen events, and so for the moment, we’re still on track against that number.
“However, with Covid-19 delays, the completion date would be blown out slightly – pushed back from 2025 to 2026.”
The Central Interceptor’s TBM Hiwa-i-te-Rangi has advanced its most in-depth point at the moment, excavating 115 meters under Hillsborough after crossing the Manukau Harbor from Māngere.
Michele Petris, the tunnel manager, stated in spite of all the problems thrown at his team by the pandemic, they were making satisfactory advancements.
“It was very complicated to get the people into the country, specialized people, to work.
“But with all these problems, if you look 360 degrees at the picture, we’re going pretty well.”
On 16th March, the tunnel boring machine would have finished 5km of its 15km trip from the Māngere wastewater treatment plant to Grey Lynn. Petris stated the TBM was tunnelling 20-25m per day.
“For the length we have, it’s a good production. We expect to continue like this, with this average, until we reach May Rd.”
The May Rd landmark, the halfway point of the project, was now 2.5km away.
Almost in August, the team and all their equipment would require to migrate there from Māngere.
Petris pointed out that despite the great move, the instruments would not be down for long, with excavating towards Grey Lynn probably to continue in November.
“Once we reach May Rd, the first section of the tunnel will be stripped to reuse all the rails, lighting, supports, and everything, so we can deliver the first section of the tunnel as soon as possible.”
In addition, Watercare lodged resource consent to develop the tunnel route from Grey Lynn to Point Erin, to capture the mixed stormwater and wastewater streams from the Saint Mary’s Bay and Herne Bay areas.
16 Central Interceptor sites have now opened across the city, allowing for links to the principal pipeline to advance.
At one of these sites, Domenica, a micro-tunnel boring machine, was just one week out from finishing a secondary tunnel that would operate from Miranda St, Avondale to May Rd, in Mt Roskill.
Bhargava Jinukula, the senior project manager, declared that even if residents had shown so much interest in the project, the team had tried to minimize disruption.
Meanwhile, he claimed that when the project was finished, the advantage to citizens would be obvious.
He added: “They will see a lot less contamination of the beaches of Auckland and probably enjoy more time on the beaches when it’s a clear day like this.”
