08 April 2016

Matt Winthrop

Engineering Insight: Sharing the Water Supply

  • Installation of a hydro-electric generator in the Wainuiomata-Orongorongo Water Catchment Area. Photo: Wellington Water.
  • The Macaskill water storage lakes in Upper Hutt supply drinking water to the Hutt Valley, Porirua and Wellington. Photo: Wellington Water.
  • Stormwater entering a local creek. Photo: Wellington Water.
  • Moa Point Wastewater Treatment Plant, Wellington. Photo: Wellington Water.

Several urban authorities have joined forces to form an integrated platform for managing the delivery of water, wastewater and stormwater services across the Wellington metropolitan region. It’s the first time such a model has been put into effect in New Zealand and – as the architects of this regional initiative hope – it could be a game-changer.

Where in urban New Zealand do you even need to think twice about where your water comes from and how it got there? Certainly not in Wellington, where in spite of the engineering challenges of a topsy-turvy urban spread and susceptibility to natural disaster, water is delivered safely and smartly via the region’s 6,500-kilometre-long water network.

This fundamental but essentially hidden service is the responsibility of Wellington Water, the second-largest public water infrastructure management company in the country. As the council-controlled custodian of the region’s water assets, the company operates water treatment and supply, stormwater and wastewater services.

Comprising approximately $5 billion in assets, the region’s three waters networks had, until recently, fallen under the remit of 14 individual management plans. These were split between each of the five councils within the region (Wellington, Porirua, Hutt City, Upper Hutt and Greater Wellington Regional). It made sense from a local perspective; each unique community had its own water management requirements.

But, as Mark Kinvig, Wellington Water’s Group Manager of Network Strategy and Planning, says, there were clear benefits for the region in taking a different approach. “We were interested in looking at policies and practices across each of the five councils to identify how to optimise our planning, rather than having five different approaches,” he says. “The thinking was our planning needed to be based around catchments, not on where the city boundaries were. It would also be much more viable for the councils to have common ways of managing their networks – from both operational and investment perspectives.

“Long-run value for money is our focus – that’s what we’ve got to demonstrate back to the councils. But it’s not just about cost. Many other dimensions come into play. We need to work with contractors and consultants in a different way to get better outcomes in health and safety, in how we procure services, in the standards we set and the goals we want to achieve for the region’s communities. One area we’re working on is developing consistent policies and engineering standards, so everyone – from contractors to suppliers to consultants – is working to the Wellington region’s way of doing things.”

“One area we’re working on is developing consistent policies and engineering standards, so everyone is working to the Wellington region’s way of doing things.”

Reaping the benefits of integration

Wellington Water was established in 2014 following the merger of Greater Wellington Regional Council’s water supply group with Capacity Infrastructure Services. A newly-formed committee of shareholder council representatives set strategic priorities for the new business. As the committee mapped out key water issues, it became increasingly clear how much more could be achieved collectively rather than individually. One of these issues was the need to roll all the region’s individual asset management plans into one long-term vision. Mark says the key was to identify priorities for each of the councils and to link them in an integrated way that would still achieve their own outcomes.

Each of the councils has its own strategic goals, its own processes. The challenge was to find commonalities on which everybody at the table could agree. “We needed to drive consistency,” Mark says. “Where people were used to working in a particular way, we wanted to bring out the best in the councils as we built a unified way forward.”

He says community education is a clear example: “By working together with the same vision, we can pool resources to maximise the value of campaigns to improve public awareness about the three waters – for example, correctly disposing of waste liquids by not putting them down the stormwater drain, not flushing disposable wipes etc. It’s about what we can do at a regional level to get the maximum value from the public spend.”

One of the councils’ main priorities is ensuring the water network’s resilience. Mark says the key questions are how seismically resilient does the region’s water infrastructure need to be, how much will it cost and how quickly does it need to happen? He says: “Because Wellington Water looks after the bulk water network as well as the reticulation system in the cities, we’re basically managing the whole picture – from the catchment all the way to the customer. Having combined, regional resilience means we can plan holistically, not just consider part of the network on a council-by-council basis. That means working for the good of the region rather than just from an individual council perspective.”

Such thinking makes even more sense, he says, when you consider the large urban migration of tens of thousands of commuters from the outer suburbs into central Wellington and back again every weekday. “By making the networks supplying water into Wellington’s central business district more resilient, we can provide an economic benefit to the region as a whole, to the people who work downtown but live out of the city.”

Rob Blakemore, Wellington Water’s Chief Advisor of Asset Management, says having a co-ordinated regional strategy is especially important given the inherent difficulties in maintaining water infrastructure and monitoring its performance. “Most of Wellington Water’s assets are underground,” he says. “This means we have to use a variety of techniques to predict deterioration in performance and to maintain the services the public can rightly expect. It’s not like being able to drive down the road and see where the potholes are.”

Then there’s the complexity of the network. The water infrastructure in the four cities is of varying ages, with some late 19th century-era pipes still in the ground and working well, and others having a much shorter life span. Due to material shortages following World War II, for example, asbestos cement pipes were commonly used in state housing developments. Rob says the trouble is the life cycle of this material is coming to its natural end right about now. “It’s a worldwide issue. Unless we do some smart thinking, combining our strengths to optimise investment so we can better understand the performance of these assets and what needs to be done, we face some serious problems.”

“Unless we do some smart thinking, combining our strengths to optimise investment so we can better understand the performance of these assets and what needs to be done, we face some serious problems.”

Planning a regional approach

This new approach to water will be captured in a regional asset management strategy. The first phase of the plan has been drafted, providing the concept of a regional approach over the next 30 years. It sets out three-waters services delivery across the region, covering key parts of the picture: where money will be spent, the projected future costs of maintaining the network, the planned response to major water issues, and how performance will be measured. It also outlines the region’s primary strategic goals, developed in collaboration with the councils, which are linked to key outcomes: safe drinking water, respect for the environment, and resilience.

The plan will evolve over time – as strategic imperatives, council priorities and community expectations change – but will still be grounded by those common outcomes. Rob says these are critical to the regional plan: “Once you have a common aspiration, you can drive common behaviours. While recognising differences exist between the councils, we need to look at the shared goals and technical challenges common to the region and, often, to the nation.”

Rob points to the pay-off of a whole-of-region approach in being able to use utilities much more efficiently – such as the region’s four wastewater treatment plants. One serves Porirua and Tawa (part of Wellington City); another serves both Hutt and Upper Hutt cities; while Wellington City has two. “They all have an issue with the disposal of treatment plant biosolids in some form. Often it goes to landfill. Having a whole-of-region plan means being able to more effectively concentrate efforts on disposal options that have environmental, social and community benefits.

“It means we can use assets more efficiently. We might be able to transport biosolids between regions, and have joint operational plans. We can test and plan for regional environmental outcomes so future investment is going where it will get the best return. Previously, these would have been treated separately.”

Rob says the model allows thinking that goes beyond political boundaries. If successful, it could serve as a model for other regions. But he’s the first to admit many Wellington Water customers aren’t likely to even be aware of the issues surrounding water, wastewater and stormwater services in their region, nor what’s been done to secure their water for the future. “We’re a hidden service. There’s a perception of value, that water costs nothing because it falls from the sky. We could argue that even if water as an untreated commodity is free, there are still costs involved in providing clean water and disposing wastewater around the clock. Water networks really are very efficient delivery services when you think of what you might pay a courier company to deliver a parcel to your house, for example, or the effort needed should the network fail.”

Having an integrated long-term plan, he says, will allow that value to be maximised region-wide for decades to come.