Case Study: Whitfield Stormwater Blocked Drain

Case Study

I was called out to this job to investigate long-term stormwater issues in a property in Whitfield, a leafy residential suburb of Cairns.

The property was a battle-axe block, situated on the lower side of the street, meaning it lacked a direct kerb outlet for stormwater drainage. Instead, the stormwater runoff was directed through a shared easement, a 150mm earthenware pipe running through the neighbour's yard, also servicing their property. Gaining access to this pipework proved challenging, as the only entry point was a kerb outlet across the street.

I began by using my CCTV drain camera to inspect the stormwater system and pinpoint the cause of the blockage. It quickly became apparent that the pipe had completely collapsed about 5 meters from the kerb outlet. This is a common issue in older Cairns suburbs like Whitfield, where earthenware pipes are more prevalent and susceptible to damage from tree roots and soil movement, particularly during the heavy wet season.

We excavated the collapsed section to assess the damage. We discovered that previous work on an adjacent sewer line had likely led to the removal of a 1.5-meter section of the stormwater pipe. While understandable given the sewer repair, the missing section exacerbated the problem. To be fair to the previous plumber, the stormwater pipe was so full of sand and roots, typical in Cairns due to the lush vegetation and clay-rich soils, it likely appeared disused. I repaired this section, allowing me to continue investigating the rest of the system.

Further into the pipe, about 2 meters along, I encountered another significant blockage: the pipe was completely packed with sand and tree roots. After several hours of hydro jetting, I managed to clear approximately 18 meters of the line, extracting a substantial amount of debris.

Then, in classic Friday afternoon fashion, my jetter became firmly lodged about 25 meters into the pipe. With experience in blocked drains, I knew how to handle this. I used my camera to visualize the problem and my locator to pinpoint its exact location for excavation.

The camera revealed a massive tree root, about 50mm thick, had ensnared the jetter head. The root was under a large tree, making extraction difficult. After digging down to the pipe, I carefully cut into it to free the jetter.

I consulted Jetter's Edge for advice on cutting such a thick root, and with a new specialized head, I proceeded cautiously. Using the sewer camera for a clear view, I carefully cut through the root with the jetter.

With the root detached from the tree, I attempted to pull it out, but its length and embeddedness in pipe cracks made it impossible. I employed a block and tackle, anchored to a nearby tree, to generate the necessary 3 tonnes of pulling force to extract the stubborn root.

With that major obstruction cleared, I continued jetting, clearing another 20 meters of sand and roots from the 50-meter run. Finally, with the pipe clear and flowing, I installed a 600mm stormwater pit for easy future maintenance access. The line had several damaged sections, but thankfully, only one had collapsed. While pipe relining would be a worthwhile long-term solution, it exceeded the customer's budget. Instead, we established a maintenance plan to maximize the lifespan of the existing pipework.

This case study highlights the importance of having the right equipment. Without the CCTV camera and locator, identifying the initial collapsed section would have been impossible. We restored a stormwater system that had been non-functional for nearly 15 years, and with ongoing maintenance, we can help our client avoid costly system replacement.

Our team at Oakland Plumbing, with all the equipment and experience needed to fix your blocked drain, proudly served the North Shore for years. We've now brought that same dedication and expertise to Cairns, QLD. For reliable blocked drain service in Cairns, call us on 0466 871 445.

Special thanks to The Jetters Edge for the advice.

https://www.thejettersedge.com.au/