Week in Review

Home is where the water is

As the country recovers, how will life and the services we need change? Part one of a new series on New Zealand infrastructure.

Back in the mid-2000s, the developers of Auckland's Stonefields housing project had a brilliant idea. They would take the excess rain water that was automatically - and annoyingly - pooling at the bottom of the former quarry site and would recycle it back into the new homes.

Each house would have a 'third' water pipe - not just the usual ones for drinking water going in and wastewater going out, but also an extra one bringing treated rainwater run-off from the Stonefields basin and making it available for residents to flush their toilets and water their gardens.

Instead of storm water being a problem for the development, it was to be an asset. Early plans touted the system as a landmark in sustainable housing and a bargain for homeowners in terms of reduced water bills.

All the original Stonefields homes were built with the third pipe in place, waiting for the whole network to be operational. More than $7 million was invested in the system.

And then, in 2014, the project was shelved. Auckland’s water supplier Watercare, which had inherited management of the scheme after the SuperCity merger, said it was dangerous and uneconomic. Stormwater would pick up all sorts of nasty stuff on its journey to the collection point - from dog poo to leaked car oil, Watercare said. Treating and then pumping it to the 2500 or so homes in the development would cost five times more than just bringing in town supply drinking water and filling toilets with that.

"There was the risk people would inadvertently drink from the non-potable supply, concerns about cross connections in private plumbing, and the high cost of maintaining such a network," Watercare's Mel Verran says.

The 'third pipe' was uneconomic at Stonefields, but a system of rock gardens and stormwater ponds (above and below) provide rain water management and flood protection. Photos: Tim Murphy.

Residents were up in arms for a while - after all, they had bought into the forward-thinking vision when they signed up for a home in the new development.

And then the project quietly died. No one wanted to pay five times as much for recycled water as town supply, no matter how environmentally sound the former was. As a NZ Herald editorial writer wrote at the time: “The Stonefields idea would be money down the drain.”

“More water falls on Auckland than the city can use.” NZ Herald editorial, 2014

But there was another reason the project seemed crazy to many in 2014. And that was the perceived wisdom, as that Herald editorial writer put it, that “More water falls on Auckland than the city can use.” And that “Thanks to the Waikato River, Auckland will never be short of water.”

Just six years on, that view seems almost laughable.

Auckland’s water storage is 45 percent this week, compared with a historic average of 77 percent at this time of year, and Auckland has imposed stage 1 water restrictions for the first time since the 1993-94 drought. Other regions are faring even worse.

At the same time, flooding appears to be hitting the country with increasing regularity. The Coromandel was deluged by rain over Queen’s birthday weekend and low-lying areas like Nelson and South Dunedin are regularly underwater.

Meanwhile, sea level rises threaten $1.4 billion-worth of water-related infrastructure, including many of our sewage treatment plants.

Richard MacGeorge is a former infrastructure finance specialist at the World Bank, and is now lead special advisor to the chief executive at Infracom, the New Zealand Infrastructure Commission - Te Waihanga.

At a personal level, he wonders if it isn’t time to reconsider our national and regional water infrastructure? Not tomorrow, and not all at once, but should we be trying to take some of the load off our aging system of pipes and treatment stations by moving, albeit gradually, towards a more local, even household-level water system?

He says Infracom, created in September 2019 to provide support to agencies and local authorities in planning and delivering major infrastructure projects, is interested in ensuring governance and regulation within the water sector creates the incentives for it to be agile, adaptable and resilient so that new solutions can bubble through.

But how do we do it?

Aging infrastructure

The history of reticulated water supplies is almost as old as the history of New Zealand as a British colony. The first dam, at Ross Creek outside Dunedin, was finished in 1867, after local residents described the existing water supply to the city as little better than sewage. 

From the early days of colonial settlement, Dunedin had problems with its water supply. Photo: Toitū Otago Settlers Museum

Diseases associated with dirty water and open sewers, including typhoid, cholera and dysentery, were rife in all the main cities in the 1860s and 1870s. Supplying cheap, clean water, and dealing with sewage, was a necessity.

And since it costs money to pump water uphill, but going down is cheap, a largely gravity-based networked water infrastructure system has developed for our major towns and cities, with dams in the hills feeding pipes bringing water downhill to our homes, and more pipes taking waste and rainwater down again to be dealt with or discharged, normally at an outflow or sewage works on the coast - the lowest point. 

Stormwater outlet, Petone. Photo: Emily Greenberg, Wellington Water Limited

A century and a half after engineers first started designing water infrastructure, New Zealand has well over $20 billion of stormwater and wastewater assets alone, including 24,000 kilometres of sewage pipes, more than 3000 pumping stations, and over 17,000 kilometres of stormwater networks. 

But much of this infrastructure is aging. And the system could be more efficient, MacGeorge says.

“Technology changes things.” 

As do earthquakes, increasing climate change-related drought and flooding risks, rising sea levels, and the burgeoning population.

Pipes leak and break, sewage overflows contaminate beaches, sea level rise will eventually flood our coastal sewage treatment plants, and our dams are already struggling to provide enough water at certain times.

The 2017 Climate Change and Stormwater and Wastewater Systems report paints a tough picture of a water network "not designed for the challenges climate change will bring, from sea level rise to the predicted changes in precipitation frequency and intensity".

"The increase in extreme rainfall events will add stress to the system by overwhelming the networks, restricting opportunities for maintenance, and increasing the occurrence of infiltration of wastewater into stormwater," says report co-author Professor Iain White of Waikato University.

Meanwhile "drought brings its own problems, disrupting gravity systems by slowing flow and leading to blocked pipes. Particularly lengthy droughts can also affect wastewater treatment processes, creating functional and safety concerns.”

Richard MacGeorge, lead special advisor to the chief executive at Infracom. Photo: Supplied.

MacGeorge says there will be re-imagining of the whole water cycle in the future. “We could be thinking about a different possibility. For example, maybe, some of our urban rainwater could be collected on roofs, either at the household or the community level and more of our storm and wastewater could be treated and disposed of locally, so less has to be done centrally.

“That might reduce the amount of investment that’s required in our water network.

"Whatever solutions are best, the regulatory settings need to be enabling."

But where to start?

In Christchurch, it started with the 2010 and 2011 earthquakes, which left some bits of the city higher than they used to be - sometimes by a lot; other bits fell. 

And in a relatively flat city reliant on gravity for a functioning water system, that mattered. Even a few millimetres rise or fall can make a big difference to a well-flowing pipe, even when that same pipe doesn’t get broken - which many, many of them did.

It was tough, says David Adamson, general manager city services for the Christchurch City Council. But it was also an opportunity. As Christchurch rebuilt, the city had the option to think differently around some of its water infrastructure.

Christchurch City Council's David Adamson. Photo: Supplied

Like stormwater: Could the city use green spaces - wetlands, rain gardens and grassy run-off areas to absorb and filter more rain water close to where it fell, so less had to be got rid of through pipes?

Or sewage: Could small holding tanks with pumps serving individual houses or a small handful of properties provide resilience in the system?

The answer in some cases was “yes”, Adamson says. And where existing infrastructure had been seriously damaged, the cost of a new solution was often comparable to the cost of repair.

One of the most innovative projects, under construction at the moment, will use heat exchange technology to harness energy from two local sewer mains to heat the water at the new Metro aquatic centre. 

Another project, being proposed to Government under the shovel-ready scheme, is to install a smart water network for Christchurch, allowing monitoring of consumption patterns, water pressures and much more.

It’s frustrating, and exciting, Adamson says. On the one hand, technology developments present possibilities for a smarter, more locally-focussed water system. But on the other hand infrastructure is expensive, there’s a vast number of existing pipes and plants that can’t just be abandoned, and the city is strapped for cash, particularly post-Covid.

The complexity of water

Water is unlike almost any other infrastructure resource, in that planners have to deal with the issue of too much water, as well as too little.

You don’t often hear about problems of too much electricity, too much rail, or too many schools. But too much water can be as big a problem as too little. 

Too much water

And it’s here that local, and even household-level infrastructure solutions can play a big part. 

Dr Rob Bell, a principal scientist at Niwa, the National Institute of Water and Atmospheric Research, spends a lot of time thinking about the problems of too much water.

“New Zealand has tended to have a laissez-faire approach to water: if we have too much, we just get rid of it into waterways or into the sea.

Hard surfaces like roads and buildings stop water being absorbed when it rains. Photo: Niwa

“But as cities increasingly deal with the impact of flooding, there’s a whole new paradigm coming through, around working with water, rather than fighting it. Part of that is water-sensitive urban design.”

The problem with cities is they are full of hard surfaces - roads, buildings, car parks etc - which don’t absorb water when it rains. Instead when there’s a big storm, water overpowers the drainage system, causing flooding, not just of water, but of all the bad stuff that lies around on the roads - plus, sometimes, sewage.

Water-sensitive urban design is about introducing surfaces at a local level that absorb water as it falls, or holds it for a while until the storm has passed and then releases it slowly into the stormwater system or even allows it to soak into underground aquifers, where it can be used in the future.

Rotterdam, a port city in the already low-lying Netherlands, is 80 percent below sea level and is expected to lose another metre of land by the end of the century. Unsurprisingly, it has become a leader in water-sensitive urban design. The port city has 'water plazas' - contained areas that serve as playgrounds or basketball courts when it’s dry, but storage lakes when it’s wet, allowing the water to seep away slowly.

When it's dry, it's a basketball court, when it's wet it's flood protection. Photo: Supplied

The city also gives subsidies to people who convert their roofs into rooftop gardens which absorb rainwater and delay peak water discharge during storms.

This sort of planning is happening in New Zealand too. New subdivisions and large areas of roads are being built with ‘swales’ - wide channels filled with grass or other plants, which soak up water, filter out contaminants as they go through, and then allow the water slowly back into the water system.

Roadside swales in Hobsonville absorb and filter water during rain. Photo: Supplied

Stonefields and other new developments are built with stormwater ponds, where rainwater can collect during bad weather.

Stonefields' stormwater ponds also serve as recreational areas for locals. Photo: Tim Murphy

But John Mackie, acting chief executive of Water NZ, a sustainable water management not-for-profit, would like to see practical stormwater solutions in people’s homes as well.

He says the sort of street-level rainwater collection envisioned at Stonefields is problematic - “all that does is pick up cigarette butts and dog poo and brake linings and dump it into a waterway somewhere”. 

But gathering water off people’s roofs doesn’t come with the same problems.

Instead there are a range of new technologies available, including filter pods, which can be dug under people’s gardens or communal areas. They take rainwater from the roof, potentially via a rainwater tank that can be used for toilets and outdoor watering. Once the tank is full, the rest of the water goes into the pod and is filtered slowly through into the groundwater system.

“The other thing you can do is use permeable paving. It’s like a paving system, but the water goes through it, down into the collection system. It doesn’t run off into the street. 

“These are technologies being used all over Europe and it’s a good solution because you avoid having to build big diameter stormwater infrastructure.”

Rain gardens, like these ones at Auckland's Wynyard Quarter, are a part of water-sensitive urban design. Photo: Auckland Council

Andrew Chin, Auckland Council’s Healthy Waters strategy manager, says water-sensitive urban design is now an important part of the Auckland Unitary Plan, and he would like to see more household-level measures to take the pressure off the existing networked infrastructure.

Auckland Council's Andrew Chin

Individual rainwater retention tanks are an important part of the picture, he says, but while they are compulsory in new developments, retrofitting them into existing buildings has been difficult because city planning rules treat tanks in the same way as small buildings, so they need neighbour consent and to meet rules around boundaries.

“We need installing a tank to be a permitted activity in far more situations than now,” Chin says. That means cutting through the red tape and getting clear guidelines around what’s allowed and what isn’t.

Retro-fitting water tanks can sometimes get mired in red tape. Photo: Auckland Council.

Chin started his career in the water sector during the 1994 drought when, like now, the problem was too little water, not too much. For a while after 1994, water was top of mind. And then it rained and everyone forgot about the problems.

With parts of New Zealand locked in one of the worst droughts ever, and with climate change potentially bringing both more droughts and more storms, communal forgetfulness mustn’t happen this time, he says.

“We need water resilience.” 

Droughts could become more frequent with climate change. Photo: Hawkes' Bay Te Mata Peak, Ian Garside, Water NZ

Too little water

Water resilience is something Dr Margaret Leonard, senior scientist at the Institute of Environmental Science and Research (ESR), has spent many years looking at.

Dr Margaret Leonard, senior scientist at the Institute of Environmental Science and Research (ESR). Photo: Supplied.

And she says there are several things that can be done at a local or household level to help manage water shortages. 

Or perhaps more urgently they are needed to manage water peaks - those times, as she describes it, when it’s 7.05am and half the country flushes the toilet and then turns on the shower. 

Those peaks are expensive - like with peak electricity, our water network needs enough capacity in its pipes to cope with this sort of hard use - even when it’s only for an hour or so each day. 

Enter water-holding tanks. No one Newsroom spoke to seemed to think people in the city should be drinking water from their roofs - although around 400,000 people in rural areas do so. 

But what if we all had a storage tank that filled slowly during the night ready for the morning onslaught?

“You’d be drawing off that tank for your shower, perhaps, and then it would fill up. If it rained, that would be nice, but if it didn’t [or if there were concerns about quality of supply] the tank would be filled from the potable supply, but at a time when not everybody was using the water."

Rainwater tanks help build resilience into the water system. Photo: Auckland Council.

But like the problems at Stonefields, retrofitting water storage and reuse systems is expensive, Leonard says.

Overseas research suggests without subsidies or rebates it’s uneconomic for people to install systems to collect rainwater and to reuse grey water for the garden and toilet. (Grey water is what comes out from household sources like sinks, dishwashers, washing machines, and showers.)

In most circumstances water is just too cheap, so the payoff period is just too long.

But no one wants to provide the subsidies. The economic model means it’s mostly not in the best interests of a water supply company to invest in anything that discourages people from using water; meanwhile councils question whether ratepayers should be subsidising installation of a water conservation system where the eventual winner is the individual homeowner - in terms of lower water bills. 

The benefits of regulation

It’s easier when new houses are being built - you just make sustainability mandatory. Kapiti Coast did just that in the early 2000s. Strong population growth, combined with longstanding water supply issues, saw the council introduce some simple measures, which have in some cases halved the amount of town supply water new houses use.

From February 2008, all new homes built on the Kapiti Coast had to install either a 10,000 litre rainwater tank to supply toilets and outside taps, or a fresh greywater garden irrigation system and a smaller 4500 litre rain tank supplying toilets and outdoor taps. 

The rain tanks are linked up to the main water network, so if levels in your tank drop too low, they get topped up with potable water. 

A Water NZ study found that “at first glance the properties look similar to other areas, with established gardens, and little evidence of the water-saving systems that are installed. 

“However, these properties are typically only placing half the demand on the infrastructure.”

And having their own water supply also made the houses more resilient in the event of a disaster like an earthquake, the report found. 

Smart metering

Smart metering is another household-level solution that could have a significant impact on how much water we use, Leonard says. While a lot of New Zealanders have smart electricity meters, and that’s spawned innovation in pricing and technology, water has never been enough of a problem in New Zealand to justify the expense of installing the devices.

In fact, many parts of New Zealand aren’t metered at all.

Smart meters can produce savings even in areas that had ordinary meters before, Leonard says. That's because they tell a householder how much water they are using and when, and because they pick up leaks more quickly.

Earlier this year, Singapore announced it will roll out 300,000 smart water meters by 2023, as it tries to cut water use.

Trials showed smart meters cut people’s water consumption by 5 percent on average.

And the inland New South Wales town of Dubbo, where storage lakes fell to 3.9 percent full late last year, started installing smart meters this month. They are also looking at 5-10 percent savings. 

But smart metering is expensive. Replacing existing meters with smart ones in Dubbo (population less than 40,000 people) will cost A$4.5 million.

The fraught issue of sewage

Meanwhile, if the drought is an imminent crisis - particularly in super-dry areas like Dubbo - the impact of climate change on our sewerage infrastructure is what John Mackie calls “a slow-moving train wreck”. 

Because sewage treatment is almost always at the lowest point of a water infrastructure system, treatment ponds and plants are mostly on the coast. As sea levels rise, that’s increasingly going to be a problem.

According to a Local Government NZ report by environmental and engineering consultancy company Tonkin + Taylor released in January 2019, just half a metre of sea level rise could impact $1.4 billion of water infrastructure, including treatment plants, storm and wastewater pipes, and pump stations.

That’s more than the combined national replacement value for exposed council-owned roading and building infrastructure. 

Most sewage treatment plants are on the coast, like this one in Tauranga. Photo: Alan Ludlam, Tauranga City Council

“We’ve got time to respond,” Mackie says, “but as these assets come to the end of their useful lives, before you go replacing like for like, you’d be thinking ‘Okay, should we be looking at something more resilient that will resist climate change as well as earthquakes, weather events, storm surges and tsunamis’.

“Rather than having large-scale wastewater treatment plants, we could look at different alternatives, like more decentralised infrastructure.” 

Water NZ's John Mackie has experience of the devastation earthquakes and other natural disasters can cause to water infrastructure. Photo: Supplied.

Mackie says the Christchurch earthquakes made much of the city’s gravity sewerage system unusable, and experts sat around to talk about what to do. Among the options: repair the existing infrastructure, or replace a centralised system with a series of smaller, community-based treatment plants. 

In the end, the decision was to go with the status quo. The city was in crisis and everyone wanted to get portaloos off the streets as soon as possible.

But if the same thing happened again, or if you were starting from scratch with sewerage infrastructure, the outcome might be quite different, Mackie says.

“With some of the treatment technologies we have now, like membrane filtration, micro filtration, and reverse osmosis, you can get some very high-quality water coming out of them, and some of these plants have a small footprint.”

Imagine warehouse-sized treatment plants dotted around a city and dealing with sewage from anything from a dozen to 1000 houses. The high-quality treated water could then be filtered back through the ground into an aquifer, providing water that can be reused, rather than sending it all out to sea.

It’s not impossible that will be the future, Mackie says, as sewage treatment plants around the country need replacing.

Local resilience

In the meantime, the Christchurch rebuild has already put local resilience into the sewerage system. In areas where land had moved so much that a gravity-based network was no longer possible, small sewage storage tanks were dug into the ground in front of people’s homes. These tanks collect the sewage from a handful of homes and then pump it into the network system.

The cost of the electricity for the pumps is negligible - somewhere around $20 a year, Mackie says. And homes get the resilience of having around 1000 litres of storage on site, if there’s another disaster.

“If you have a power cut or an earthquake and you are cut off from the system, your toilet still works. It gives you that ability to survive a disaster. It also means you aren’t transporting a lot of rainwater with the sewage, as you would in a conventional sewerage system. Because it’s all pumps, you only need small diameter pipes, so the infrastructure is less costly, and you’ve got less water to treat at the other end.”

So why aren’t these sorts of solutions more widespread right through the water network?

It’s that small problem called ‘embedded infrastructure’. 

“New Zealand has something like $54 billion worth of assets tied up in water and wastewater treatment plant,” Mackie says. “That represents about $11,000 of investment already spent for every man, woman and child in the country.”

Water equity

It’s a very complicated situation, and change isn’t going to happen overnight, says Infracom’s Richard MacGeorge.

It’s important customers have choice, including to use any technologies that are available - whether it’s rain water tanks, smart meters, or storm and waste water disposal - to cut their water bills or meet their environmental goals.

But it’s also important that technology isn’t just available to wealthy customers. The equity issue that’s playing out with solar panels and people’s electricity supply will come to the water network as technology and regulation develops.

“Embedded infrastructure is a problem everybody shares, because everybody is paying for existing systems. If other technologies are developed where consumers, having choice, decide to go off the system, then that raises the average cost of the network to other users.

"And that raises questions of equality because the poor don’t necessarily have the same choices,” MacGeorge says. 

That’s where the government comes in - setting a framework which sends signals to the market around using less - or reusing - water, controlling peak usage, and disposing of water more sustainably. And making the same choices available to everyone.

“Regulation should enable consumer choice, equity, and sustainability of our water resources,” MacGeorge says.

But sending the right signals is tough under the present economic and regulatory system, because utilities are mostly incentivised to sell more water and to take more storm and wastewater away.

“There can naturally be a conflict between a water company’s commercial needs and the public interest, or that of the environment," MacGeorge says. 

Take the "third pipe" idea at Stonefields. In that case, at least in part, expensive embedded assets in the form of Auckland’s existing water and stormwater infrastructure, made a new, innovative, environmentally-friendly solution five times more expensive than the status quo. 

Economically, it was a no-brainer to scrap it.

It’s always going to be a trade-off for policy makers, MacGeorge says, and transformational change isn’t easy, or fast.

But in the end, as Niwa's Rob Bell says, we’ve got to think differently.

Niwa's Dr Rob Bell says we have to work with water, not fight it. Photo: Supplied.

“Rather than fighting water and trying to get rid of it as quickly as possible, we should be trying to work with it, so not as much is going into the pipes. Instead of simply making the pipes bigger to cater for more water or more waste, we need to look at what we can do upstream that can reduce the flow or even out the peaks that swamp the whole system.”

Will this happen? Will we all start to play more of a part in our water infrastructure? MacGeorge hopes so.

“I’m not painting a picture of what I predict is going to happen. But what I’m suggesting is as time goes by there will be possibilities to do things differently. For us to assume how we've done things in the past will be how we'll do them in the future is a risky approach.

“We need to be prepared for our water services being delivered in different ways, and possibly down to the household level, where the need for network infrastructure is much reduced and the need for capital investment in that infrastructure is much lower too.

“And that capital investment can then be reapplied to other social activities, so we are all the winners for it.”

Talking about other social activities: the $7 million already embedded in the Stonefields water collection infrastructure before the idea was abandoned - that wasn’t wasted. The water goes to keep the greens green at the Remuera golf course.

Good job.

The ‘Beyond the new normal’ infrastructure series is a content partnership between Newsroom and Infracom (NZ Infrastructure Commission, Te Waihanga). Infracom seeks to lift infrastructure planning and delivery to a more strategic level and by doing so, improve New Zealanders’ long-term economic performance and social wellbeing. It is developing a 30-year strategy for infrastructure and invites input from anyone interested in the future of New Zealand’s infrastructure.

Newsroom would like to thank the following people for their input into this article: Christchurch City Council general manager city services David Adamson; Niwa chief scientist Rob Bell; Auckland Council head of healthy waters strategy Andrew Chin; Stonefields Residents Association board member Kerry Laing, ESR senior health and environmental scientist Margaret Leonard; NZ Infrastructure Commission’s lead special advisor to the CEO Richard MacGeorge; Water NZ acting CEO John Mackie, and Environmental Defence Society chief executive Gary Taylor. Also thanks to Water NZ for allowing us to use photographs from its 2020 photography competition.

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