Experts say Auckland sewer sinkholes are caused by aging infrastructure

Author: Reissa Almeida royal bank of new zealand

An environmental ecologist says problems with old infrastructure need to be urgently addressed if Auckland is to avoid further water pollution.

Hundreds of liters of sewage per second are being pumped into Waitemata Harbor after a 13-metre-deep sinkhole opened in Parnell a week ago and tons of debris have been cleared from the clogged pipe.

Watercare has postponed the laying of temporary pipes until Tuesday to reduce wastewater overflows.

The pipeline is expected to be commissioned on Monday, but Watercare said crews spent the day preparing the ground.

Dr Mike Joy, a senior researcher in ecology and environmental sciences at the University of Victoria, said the problem was not new.

“This is in the news because it’s a big deal, but Auckland’s broken infrastructure, like many New Zealand cities, has been leaking wastewater for a long time, and in much smaller quantities.

“I’ve seen a lot of broken pipes and slow discharges into streams over at least the last two decades.”

He said the problem was caused by aging infrastructure that was never updated.

“This is just the peak of ongoing failures in critical wastewater infrastructure. “Some of these pipes and networks are ancient and Auckland is growing at an incredible rate but can’t keep up. “

Watercare said hundreds of liters of waste per second were being pumped into Waitemata Harbor before the bypass was completed.

“Wastewater volumes in this part of the network fluctuate throughout the day, increasing during wet weather and decreasing during dry weather.

“We do not have a flow meter at the overflow location so our best estimate of the overflow volume is a few hundred liters per second. “This is a significant overflow and we are doing everything we can to end this situation as quickly as possible. “

Joy said the pollution could have severe impacts on marine life.

“Nutrients in (sewage) can cause algae blooms in ports and waterways, limiting available sunlight and causing a lack of oxygen in the water.

“Human waste tends to be very high in some unusual things like estrogen, some hormones and nettles, and often there’s also industrial waste that goes into these wastewater systems.

“This could cause big problems for aquatic balance.”

He said aquatic life can have devastating consequences.

“Shellfish can accumulate wastewater pathogens, which can survive longer in the shellfish.

“So even if water quality tests come back clear of the pathogen and it’s safe to swim again, high levels of potentially dangerous pathogens may still be present in the shellfish for a longer period of time.

“It is still unsafe for long-term consumption.”

Joy said the problem still exists and needs to be addressed urgently to avoid causing greater environmental damage.

“This is not the only place where wastewater leaks into the port, there are many others. Some of it tends not to flow directly into the port, but into the streams that flow into the port, so when heavy rainfall occurs, they get washed away.”

He said the government should take precautionary measures.

“We have this tendency not to take any action until a problem occurs. Everyone knows how dangerous this is and we should upgrade our wastewater infrastructure so it doesn’t happen again.

“We need to start thinking longer term, climate change is here.”

“Stay away from water” – National Public Health

A global study by the World Health Organization (WHO) estimates that bathing in polluted oceans causes 250 million cases of gastroenteritis and upper respiratory illness each year.

The Group of Experts on Scientific Aspects of Marine Environmental Protection (GESAMP) said most diseases are caused by pathogens.

“They cause a variety of acute illnesses, including diarrhoea, cholera, dysentery, typhoid and hepatitis A.

“Pathogenic bacteria can survive in the ocean for days to weeks, while viruses can survive in water, fish or shellfish for several months. Hepatitis viruses can survive in the sea for more than a year,” it said.

Auckland’s 24 inner-city beaches have been closed to swimming due to wastewater overflows.

Te Whatu Ora National Public Health Northern Regional Health Officer Dr David Sinclair said the number of illnesses caused by exposure to contaminated water was concerning.

“If people enter the water, they can contract many types of skin infections, eye and ear infections, and respiratory infections.

“Of course, they could also develop gastroenteritis from any gastrointestinal bacteria present in the water at the same time. This is contagious and could lead to an outbreak.”

He said water activities should be avoided, as well as allowing pets to swim.

“It is best for people to stay out of the water until things return to normal, including paddling and kayaking.

“Pets are just as susceptible to infection as humans, so it’s best to keep them away.”

Fishing is not recommended.

“Especially shellfish fishing because they absorb nutrients from sewage for quite some time,” Sinclair said.