Tests for construction of proposed Ocean Outfall
29 April 2005
Tests for construction of proposed Ocean Outfall to begin
Preparations for the proposed construction of an ocean outfall to discharge Christchurch’s treated wastewater out to sea, begin on Monday when OCEL consulting engineers will commence geotechnical tests along the proposed outfall pipe route within the ocean.
John Moore, the City Council Implementation team leader, Asset Management, says the work is part of Council efforts to meet a timetable to build the Ocean Outfall under the Environment Court timetable, issued as part of the Estuary Discharge consent.
This means that, while the Council still awaits a decision from Environment Canterbury, Banks Peninsula District Council, and Christchurch City Council on resource consents to build, operate and maintain the Ocean Outfall, it must progress preparations for construction.
“We’re confident of getting resource consent, but there may be a number of conditions that may have to be determined. While we still await the decision, we have to start looking at preparatory work for construction and that’s why tests are starting as part of contract preparation work ,” Mr Moore says.
Senior OCEL engineer Gary Teear says the work, starting Monday, late afternoon, will take about three to four days, with a day and half spent at each of three sites where standard penetration tests will be carried out along the outfall route. In addition, water-jet probing will also take place at 10 locations along the alignment.
“We’ll be carrying out a training exercise with the divers at the Christchurch Yacht Club on Monday, where we’ll have a 5m-high frame that carries a winch and drilling gear, to familiarise them with what we want them to do and the way it all works,” Mr Teear says.
A helicopter will be used to fly the frame out from the yacht club to the first location, and also transfer the frame between locations. The noisiest part of these trips would be when the helicopter picks up the frame from the yacht club area to take it out to the first site, Mr Teear says.
Two 9m boats would be used to support the sub-sea operation once the 5m frame is in place on the seabed. Surf inflatable boats will also be used to carry gear and support the work, he says.