New stormwater system supports healthier harbour

 

Stormwater management is an important part of Port of Tauranga’s efforts to help improve the health of Te Awanui Tauranga Harbour.

“The health of Te Awanui Tauranga Harbour is crucial to our community and our region, so it’s an ongoing focus for us here at the port,” says Port of Tauranga’s Environmental Manager, Joey McKenzie.

While the Port continues to meet all of its resource consent conditions, the team is continuously seeking ways to improve. 

“We extensively monitor both stormwater and harbour water, to gather data and identify opportunities for improvement,” says Joey.

The team’s ongoing analysis, alongside some robust brainstorming and problem-solving, has resulted in several initiatives and infrastructure upgrades at the port’s Mount Maunganui wharves over recent years.

“To prevent contaminants entering the harbour, we have increased the use of vacuum sweeper trucks and installed large filtration chambers to screen solids like bark,” Joey says.

“We’ve also installed fender plates along the wharf edge to cover gaps between our wharves and working bulk vessels, so solids don’t fall into the water.”

These efforts reached a new level recently when the port launched its biggest infrastructure project to date to improve water quality – an expansive new stormwater treatment facility at the Mount Maunganui wharves.

The innovative new system features a custom-built above-ground tank holding up to one million litres of rain, and a clarifier to clean stormwater before it flows into the harbour.

Joey, who first initiated the idea for the system, says in the research phase, automated sampling machines were used to collect stormwater throughout multiple rain events.

“Through sampling we could identify the ‘first flush’, which is the dirtiest part of stormwater at the start of a rain event,” he says.

“This new infrastructure means we can now capture the first flush and pump it into our holding tank. At maximum volume this would take 24 hours to drain through the clarifier, with the cleaned water then flowing through to Te Awanui.”

As part of the project, the port’s electrical team built a substation to house the switchboard for the new treatment system. The equipment can be operated remotely and all parts of its performance monitored in real time.

Chief Executive Leonard Sampson says the new stormwater system is an example of the port’s approach to “do more than simply what is required.”

“While we continue to comply with our resource consent conditions, our new stormwater treatment system has been an innovative, and substantial, undertaking for our business.

“From conception, to design, then building and testing, our people have worked hard to find solutions and ensure the success of this important environmental project.”

Joey and his team are excited to see the new system in action and say learnings from this project will help them develop stormwater management options for other priority areas of the Mount Maunganui wharves.

“It seems strange to say this in the sunny Bay of Plenty, but we’re looking forward to a bit of rain!”