The major construction project, which has been planned since 2013, will cost $3.1 million more than originally budgeted.
Dunedin City Council water and waste supply capital delivery team leader Dominika Biziak-Kochan said it would result in the recommissioning of the Ross Creek Reservoir, enabling it to act as a backup if the structure over the Taieri River, which supplies Dunedin’s water, failed.
The project would start midway through this month, and was expected to take a year.
"Some favourite areas" would be closed.
"We’ll keep as many tracks as possible open to the public, as we know this is a popular walking and running area.
"We hope people will understand why the work needs to be done."
Members of the public were encouraged to monitor the council’s track app to find out which tracks would remain open in the Ross Creek area, Ms Biziak-Kochan said.
The project would improve dam safety through the removal of trees and the strengthening of the reservoir bank.
The bank would be backfilled, grassed and left to settle.
An overflow channel would also be upgraded and a pipeline built to pump water out of the reservoir, she said.
The reservoir would not be commissioned until a year after completion of the work.
Refurbishment of the reservoir and construction of a pumping station and pipeline from the reservoir to the Mount Grand water treatment plant meant the city would still have a reliable water source in the event of an emergency, Ms Biziak-Kochan said.
In September council water and waste group manager Laura McElhone said the engineer’s estimate for the project was higher than anticipated.
The cost had gone from $3.5 million to about $5.5 million, largely because Otago Regional Council consent for the project involved more work than originally thought.
Access restrictions
Other Dunedin track closures:
• Second Beach track closed until February 7 for track repairs.
• Restricted access on some Signal Hill mountain biking and walking tracks because of fire damage.
• Frasers Gully, upper section closed.
