The dive boat on Wednesday at the area of an outfall leak near Awatoto. Photo / Paul Taylor
The dive boat on Wednesday at the area of an outfall leak near Awatoto. Photo / Paul Taylor
Divers working from a boat off the Awatoto coast south of Napier have begun an intensive examination of the city's ageing underwater wastewater outfall.
The work, involving a crew of seven from New Zealand Diving and Salvage Ltd, follows the discovery of two leaks in the 1.54km pipe, installed 48years ago and carrying treated wastewater out to sea.
The first leak was discovered at a join in the pipe about 700m offshore in 2018, and another closer to shore was found in April this year.
The Napier City Council
in June adopted several recommendations, including starting to plan for "early" replacement of the outfall to minimise risks and to increase levels of service, in line with improvements to the Wastewater Treatment Plant onshore.
Members of the dive crew line up on their boat in the Napier inner harbour before heading for a day's work on the outfall. Photo / Supplied
A Wastewater Treatment and Outfall Master Plan has been developed to determine future requirements for the full replacement of the outfall, likely to cost between $20 million and $40 million.
The council says a detailed investigation is needed to make sure the preferred option is the right one, and that there can be a more accurate estimate of cost.
The information is likely to be available by the end of the financial year in June.
The current project is weather-dependant and expected to take a month, starting with an inspection of the diffusers at the end of the outfall, before work begins on the first of the leaks.
The repair has been planned for the past three months, involving the council, Hawke's Bay Regional Council, the Harbourmaster, environmental agencies, iwi and other affected parties.
More information about the replacement is expected
next year. The city council has allocated $2 million for the repair and $2 million to create storage for wastewater at the treatment plant to allow future shutdowns for maintenance and repairs, and aid management of stormwater.
The costs for the repair and the new storage is funded from reserves so there is no effect on rates.
The outfall pipe has been in place since 1972 and the first leak was where a fibreglass joint was installed in 1984.
The council has spent close to $1 million on proactive maintenance of the outfall in the past two financial years.
