All options for plugging leaks come with risk
All options are considered to have some risk, including possible complete failure during repairs, which themselves might not fix the latest leak in a fibreglass joint about 700 metres offshore.
Discussing immediate repairs, council manager asset strategy Catherine Bayly described the outfall as a “live asset” where a shutdown for repairs was only possible for three hours at a time.
“We want to the lowest-risk, least-invasive repairs in the next six months,” she said. “We don’t know how successful it’s going to be.”
The council decided a specialist dive team should be engaged for the job, which could take place in near-zero visibility; that an emergency response plan should be developed for implementation in the event of failure; to apply for a resource consent to cover the situation, and to start planning for early replacement, the cost of which could be up to $40 million.
The repair plan would likely need the construction of a mechanism to pump the wastewater from a leak point through a tube further out to sea.
The planning for the long term is expected to include all possible options, including replacing the outfall with a drying system and disposal of remaining dry matter on land.
With the possibility the outfall has been damaged by impacts, such as fishing vessel anchors and nets, the council, working with the Hawke’s Bay Regional Council, expects to have a “no-go” zone in the area of the repairs.