Millions of dollars could be saved by harnessing technological advances to simplify construction of the Tauranga City Council's $102 million Southern Pipeline.
The council yesterday backed a major re-think of how the sewage pipeline could be built in the environmentally sensitive harbour crossing to Matapihi.
Instead of focusing on 1st Ave as the crossing point, the council has decided to pursue options that include the previously rejected idea to thrust the pipeline under the harbour from Memorial Park.
This would mean departing from the consented plan for a submarine crossing just under the bed of the harbour - from 1st Ave to the Matapihi bridge railway embankment.
A total of $41 million has been spent to get the pipeline from Maleme St to Memorial Park and the council now faces costs of $60 million to complete the job to the Te Maunga sewage treatment works.
The pipeline was needed to service the growing southern end of Tauranga because the current pipeline to the Chapel St works was already under so much pressure that raw sewage overflowed in heavy rain out of a manhole at Glasgow St and entered the Waikareao Estuary.
Councillors were told that if a direct link from Memorial Park was viable, it would potentially not only be millions of dollars cheaper but avoided the disruption to residents and downtown businesses of laying the pipeline up Devonport Rd from Memorial Park.
Project manager Richard Myers said that technology had improved since 2007 when council was unable to consider direct drilling (thrusting) the pipeline under the harbour.
The council yesterday agreed that when it went out to contract for the job, it would be on the basis of a design/build contract covering not only a crossing from 1st Ave but also from Memorial Park. The exact route and construction method would be determined by the industry.
Council city services manager Ian McDonald said council could deliver significant savings by testing the market. Pressed by councillor Catherine Stewart to say how much, he said it could be millions.
However, departing from the consented plan would require either a change to the existing consent or a new consent from the regional council. The council was told the cost of obtaining these consents would be small compared to the savings.
Construction of the Matapihi to Te Maunga section of the pipeline was due to go to tender in March/April, with work beginning in July.