Coffs Harbour is the main regional centre of the Coffs Coast. The region is renowned for its ecological diversity – half of the Local Government Area is dedicated as reserves, parks, national parks and state forest holdings – and is bounded offshore by the Solitary Islands Marine Park.

The city encompasses a total area of 1,174 sq km of land stretching from Red Rock South to Bundagen and west past Brooklana and Lowanna.

Across this area, the council is responsible for 617 km of water pipeline (100–600 mm diameter), 494 km of sewer pipeline (150–600 mm), 114 km of sewer rising mains (50–600 mm diameter) and 160 km of stormwater mains.

Covering so many assets keeps the water infrastructure management team busy. In terms of asset management, the council is involved with water main renewals, sewer main renewals, CCTV inspection of newly-constructed and existing sewer mains, hydrant and valve maintenance, and jetting of repeat chokes.

Article continues below…

Trenchless Technology has an important role to play in this asset management program. The main techniques used by council are underboring, CCTV inspections, smoke testing and vacuum e-ducting.

According to Simon Thorn, Executive Manager Operations, Coffs Harbour Water, the recent addition of council’s CCTV Pipeline Inspection Van and Vac-U-Digga has transformed the way council maintains its assets. The CCTV crawler gives staff eyes under the ground to enable an accurate diagnosis of the problem and what the best method of fixing it is. The Vac-U-Digga has improved efficiencies as well as work safety and has been used for pipe locations, potholing services including fibre, cleaning of hydrant pits and valve pits, trenching and jetting of conduits.

Mr Thorn says “Trenchless Technology will be playing an increasing role in the maintenance of our ageing system, due to the increasing environmental and social pressures.”

A recent example of a trenchless project the council undertook involved rectifying two low spots in a 280 OD PN16 HDPE gravity sewer main, which was recently constructed by an underbore. The sags were 35 mm and 100 mm below the designed invert level, meaning they would accumulate fat and silts and cause ongoing blockages if not resolved. Uretek were engaged to inject an expanding resin material 1 m below the pipe to raise it to the desired level. Council’s CCTV crawler was used to determine when the pipe was at the correct invert level and when to stop injecting the resin.

The council also engages a number of under road borers to deliver water and sewerage projects. These include Grafton Under Road Boring, Coffs Harbour Under Road Boring and other specialist contractors for major projects. Clearflow Specialised Services also deliver patch repair solutions to failed mains, bends and junctions.

Maintenance and rehabilitation is what council spends a considerable portion of its sewerage and water budgets on. In 2009–2010 Coffs Harbour Water carried out CCTV inspections of 13.25 km of newly-constructed and existing sewer main.

According to Mr Thorn, the Trenchless Technologies to be used in a given situation are selected by determining the method that is best suited, based on whole-of-life cost, environmental and social outcomes.

The main challenges for the provision of water/wastewater services in the region are the ageing infrastructure, stormwater inflow and infiltration, and an ageing workforce (which raises concerns that significant experience and knowledge could be lost in the coming years).

But despite the challenges, on this Coffs Harbour Water is clear; their main priority is ensuring that all customers, both external and internal, are satisfied with the service provided and ensuring that everything is carried out safely and professionally.