The Dunedin City Council announced yesterday the completion date on the $6.1 million refurbishment of the 150-year-old facility would be extended because excavation work on the dam had taken longer than expected.
Council planning and delivery manager Jared Oliver said as well as the added excavation work, poor weather and archaeological discoveries had delayed the project.
It had been expected to be finished by February.
Mr Oliver said the work would now be finished by the middle of 2018.
"At the moment were looking at sometime in July for everything to be finished."
To ensure the strengthened dam would be stable enough, contractors needed excavate deep enough to remove the old embankment material, he said.
"Once we started digging down what we found was the material was still unsuitable and we basically needed to keep digging down until we found suitable material."
Mr Oliver said he did not have the exact figure but there would be an added cost to the project.
"It will have an impact on the cost of the project, which overall will probably be in the order of six to seven million."
The spillway on the Rockside Rd side of the dam crest still needed to be widened to cope with flows from the reservoir after heavy rain. People in the area were likely to notice some minor ground shaking and noise while during the work, Mr Oliver said.
The track along the Burma Rd side of the dam crest had been reopened after being closed for a pipe to be installed, and two-thirds of the base of the dam had been filled with new material.
After construction finished the dam would be left to strengthen for a year then refilled.
During that time the area would be restored as a recreational area for the city.
Some landscaping work would be done and the council would look at incorporating works of art in the area.
The reservoir would be reopened to the public once the work had finished and it was safe to do so.
The project is part of the council’s security of supply strategy to ensure the city has water supply options if there are problems getting water from Dunedin’s main water sources at Deep Creek and Deep Stream.
