Australian Water Management Review Vol 2 2013 | Page 49

Aussie pipes receive trenchless overhaul
As Australia’s assets age, councils and utilities are faced with mounting pressures to renew and repair critical infrastructure as it comes to the end of its useful life. Here, we take a look at some of the major pipe rehabilitation projects undertaken by Sydney Water, Queensland Urban Utilities and the North Burdekin Water Board, and the various technologies the water authorities have used to restore assets.

I

Sliplining saves time and money in Queensland
TS Trenchless recently provided a costsaving alternative to North Burdekin Water Board when rehabilitating a 900 mm and 1,350 mm diameter watermain at the Rocks Pump Station in Ayr, Queensland.

The completed works.

North Burdekin Water Board (NBWB) own and operate the Rocks Pump Station located in the Queensland town of Ayr. The station pumps water from the Burdekin River via two separate 165 m lengths of 900 mm and 1,350 mm reinforced concrete pipelines and discharges it into the nearby Sheep Station Creek, which forms the start of the open channel irrigation distribution system. The Board had experienced significant pipework leaks from both pipelines due to deteriorated rubber rings in the pipework joints. An internal CCTV inspection and condition assessment of the pipeline also identified a number of joints had root penetration, with some showing signs of separation. To add to NBWB’s concerns, a number of pipework sections were showing longitudinal or circumferential cracks. NBWB requested tender submissions from suitably qualified contractors to reline the pipes with a cured-in-place pipe (CIPP) structural liner, which

included the significant restriction of an extremely tight program window of 18 days. This was the length of time the mains could be shut down, which could only be changed in the event of weatherinduced impacts, due to the critical supply of irrigation water and existing contracts in place with users. In addition, the works were adjacent to Little Salt Pan Creek, which meant there was an increased environmental focus on the project.

The ITS Trenchless project team noted that the pipelines carried raw water from the Burdekin River, and thus any design had to take into account the amount of sand and silt in the water and the abrasion effects on the potential liner. The design also had to take into account both 24 m head of positive pressure and negative pressure of -8 m head of the pumps, and any solution had to carry a 50-year design life.
Australian wat e r m a n a g e m e nt r e vie w 43