Lower-cost option for sewerage in Central Otago

Tim Cadogan

About $5 million could be saved with a "plan B" Clyde sewerage system that would involve piping being installed from Clyde to the Alexandra plant, Central Otago Mayor Tim Cadogan says.

The price of building an entire new system had been estimated at about $34 million, Mr Cadogan said. At present, all Clyde properties had septic tanks, and there was no town sewerage system.

Mr Cadogan said the situation of Clyde having no reticulated sewerage system could not continue as the town expanded.

"The simple fact of the matter is that the council will be forced by the Otago Regional Council and/or the Government at some stage to face the sewerage situation in Clyde, and that the day of reckoning will be coming sooner rather than later.

National water policy standards and regional urban water discharge standards will force the issue. On top of that, the lack of a proper system puts significant restraints on Clyde's ability to grow commercially or residentially."

Mr Cadogan said the $34 million initially proposed was a "staggering amount of money".
However, investigations had shown a "lower-cost option" might be available, using an expanded Alexandra plant and "taking advantage of the opportunity presented by the Lake Dunstan Water Supply pipeline taking water from Clyde to Alexandra".

This option could cost about $29 million, and would have the additional advantage of being done in stages.

"It is common sense that there are significant savings to be made by putting a second pipe in the ground at the same time as the water pipe is put in. If this course of action is taken, a staged implementation of reticulated sewerage in Clyde could see the commercial and older area of the township off septic tanks within 3 to 5 years.

A second phase of implementation would cover all but the newer parts of Clyde within 12 to 15 years, with the final part, being the parts of Clyde with modern septic tank systems such as Sunderland Estate and the northwest side of Shield St, being completed within 28 years. This allows the community to address the high-use, high-risk areas first, while staggering the cost of the total project."

Mr Cadogan said that, regardless of which option was pursued, the Clyde sewerage project would be "the biggest infrastructure project in Central Otago's history".

More precise figures for both options were being worked out and there would be full consultation,  he said. The timeframe for investigations and consultation was not confirmed, but he expected it would take place as part of next year's long-term plan process.

pam.jones@odt.co.nz