The North South Interconnection System Project (NSISP) was a crucial component of SA Water’s Network Water Security Program. This long-term strategy aimed to deliver an integrated solution for water transfer and distribution in Adelaide to 2050.

Adelaide’s water resources are predominantly located in the southern suburbs. Previously there was limited capacity to transfer this water to the expanding northern suburbs. With the addition of a non-climate dependent source of water in the desalination plant in Adelaide’s south, SA Water needed the ability to transfer up to 167 ML/day of water from the plant across the metropolitan network.

 

Creating a More Flexible Water Supply

NSISP connected Adelaide’s water supply from south to north by upgrading existing infrastructure as well as installing new infrastructure. This was the largest water supply upgrade ever undertaken in Adelaide. It included these components:

• Four new pipelines totalling 23 kilometres
• Three new pump stations in residential areas (Clapham, Wattle Park and Gilberton)
• Four new pressure control stations
• Four treatment facilities

In total, infrastructure was modified or installed at more than 150 locations across Adelaide to create a more flexible water supply.

 

Multidisciplinary Expertise in a Single Team

The WaterLink JV, a joint venture between WSP, MWH and Tonkin Consulting, partnered with SA Water to form the Integrated Project Team that delivered NSISP. WaterLink was responsible for the concept design, engineering and specialist project services in the areas of construction, project controls and environmental services and approvals.

 

Working with the Community to Identify Benefits

As the project impacted residential and commercial districts, stakeholder engagement was important to the successful delivery of the project. WSP’s team supported SA Water’s Stakeholder Engagement Manager to deliver an integrated approach and ensure the design process considered community issues and maximised community benefits.

Initially, the community had concerns about the location and design of the above-ground infrastructure, such as pumping stations and pressure-reducing valve stations. By identifying these concerns early on, we addressed them in the design. The team demonstrated a high degree of flexibility, working within stringent design criteria relating to noise, footprint and visual amenity established during the community consultation phase.

 

Managing Ageing Infrastructure

In some cases, we were working on constrained sites, on heavily trafficked roads, near rail corridors and residential housing. At times, we were also working with infrastructure that was up to 100 years old or facilities (such as on-line storages) where minimal alterations were possible. In these cases, the team created designs that provided as much functionality as possible without making significant changes to existing infrastructure.

 

Applying the Latest Technology

GIS mapping solutions (such as ArcReader and web-based mapping applications) supported the decision-making, data management and visualisation on this project with timely and accurate spatial data. The team gathered and mapped vast and complex underground services information across the entire city. This provided a truly collaborative knowledge sharing solution.

We also developed innovative practices, such as introducing new control systems that use real-time data, to enable better decision-making and to maximise the efficient use of resources. Operators can now more accurately forecast demand and complete operational what-if scenarios. The control system includes a distribution optimisation tool, which improves the operation of bulk water transfers and production from water treatment plants.

 

Minimising Construction Impacts

We created a construction methodology that was compatible with the ongoing operation of the existing network. For example, at the Clapham Pump Station, we designed it to enable commissioning and testing while the existing facility remained online.

Working in residential and commercial districts of Adelaide’s inner suburbs, where possible, we used trenchless tunnelling technology to deliver underground pipelines with minimal disruption to the community and environment. Micro-tunnelling enabled us to install the infrastructure under major road intersections.

 

Interconnectivity to Drought-Proof the City

We completed the final NSISP construction and commissioning packages in mid-2013. The co-location of the Integrated Project Team fostered a close working relationship that ultimately contributed to the successful delivery of the project within the timeframe and budget. Our strong community approach helped to reverse the initial negative sentiment about the project. Rather than simply being an infrastructure upgrade, NSISP became a valued community asset.

The NSISP has transformed how Adelaide’s water supply system functions and operates. The project has connected the northern and southern water supply networks, permitting Adelaide to make the best use of its metropolitan distribution network and securing the city’s future water supply.