The current underground system in Ōwairaka was built in the 1950s and combines stormwater with wastewater (sewer). It is at the end of its design life and needs to be replaced. Over the next approximately year and half, we’ll be putting in a new network that separates stormwater from wastewater flow. We'll install new pipes that will be dedicated to stormwater and upgrade the existing pipe to contain only wastewater.
Works started in November 2019 and the whole project is expected to be completed mid-2021.
Construction will take place in the roadway of many of Ōwairaka's streets. Stage B is currently happening on Hendon Ave and Range View Road. It will continue in these locations in early 2020, progressing onto Stewart Road, Alan Wood Reserve and Olympus Street. In the second half of 2020, works will move onto Dunkirk and Alamein Terraces, parts of Hargest and Cassino Terrace.
We will keep residents in the immediate vicinity of upcoming works informed ahead of time.
Separating stormwater and wastewater will help to manage wet weather flooding and overland flow in the area. It will also reduce wastewater overflows into Oakley Creek, improving public health and environmental quality of the creek and its surrounds. The project will also greatly reduce the risk of pipeline failure in the future, and increase the network capacity to better serve the area's growing population.
Modernising this infrastructure will also equip the neighbourhood for new housing to be built, faster.
To install the new stormwater alignment we need to undertake a significant amount of rock excavation. Ōwairaka is a neighbourhood built on basalt - a very hard volcanic rock, and this needs to be broken and removed to complete the project. This rock breaking will largely be done in one of two ways – by using a hydraulic pick (jackhammer), and by using expanding grout to fracture the rock. The basalt will then be excavated and repurposed, new stormwater pipes installed, and the old pipeline upgraded for containment of wastewater.
Two crews will be doing this work simultaneously in separate locations to maximise efficiency, with drainlayers following closely behind.
The rock breaking process can generate significant noise and vibration. We’ve elected this approach for the main pipelines in the roadway as it's the most efficient construction method providing the shortest timeframe of disruption. It is also the area of works that is furthest away from private property so the noise and vibration effects are minimised by distance. For the lateral pipelines that head towards property boundaries, we’ll largely fracture the rock using expanding grout poured into drill holes in the rock. You will experience some noise and vibration from initial drilling into the rock, but overall it is quieter than the jackhammer method.
Stage A is complete. Stage B started on the 20th of November 2019. The actual rock breaking and trenching is estimated to average progress of 5 metres per day. We estimate the entire project will take approximately 18 months to complete.
The rock breaking will create noise and vibration and our overall trenching and drainlaying works may temporarily affect access to your driveway. When your street and driveway is directly affected we will provide notice in advance. Traffic management will be in place to allow us to complete all work safely and this often involves one lane closures with stop/go controls.
We aim to complete the project efficiently whilst also working with you to minimise the disruption caused.
Our traffic management plans are staggered and reviewed based on what layouts are required in each location for us to undertake work safely. The work itself means that we can usually operate with at least one lane of the road open. Should there be any road closures or significant diversions, we will provide advance notice to surrounding residents.
Working hours are 7.30am – 6.30pm Monday to Friday, and 8am – 6pm on Saturdays. Wherever possible we will use Saturdays to carry out quieter activities.
We would very much like to hear from you if you are regularly home during weekdays. While we want to complete this project as quickly and efficiently as possible, we're also committed to working with our neighbours to help minimise disruption. Please call us on 0508 PIRITAHI or email firstname.lastname@example.org.
No, but we are undertaking additional work to upgrade the lateral pipes towards property boundaries that can be connected to private households at a future date. This may be beneficial to residents wanting to improve stormwater and sewerage connections from their properties and can be arranged at their cost.
We will update residents in the vicinity of upcoming construction by delivering information to their letterbox. We encourage residents in the area to sign up here to receive future updates about this project and Piritahi's other land development and infrastructure works in the neighbourhood.