During the past decade, thousands of Rotterdam building owners installed green roofs on their dwellings — about 330,000 square metres in total, almost two per cent of the city’s 18.5 square kilometres of flat roof space. But where some cities have promoted such projects to improve energy efficiency and absorb carbon dioxide, Rotterdam’s green roof infrastructure is all about water, and keeping as much rainwater run-off as possible out of aging, overtaxed sewers in order to prevent flooding.
About four-fifths of the Dutch port is below sea level. As Paul van Roosmalen, the city official overseeing sustainable public real estate, puts it: “The water comes from all sides” — the sea, the sky, the river and ground water. “It’s always been a threat.” But he also sees an opportunity to use a marriage of technology and green design to elevate the role of rooftops in managing Rotterdam’s water pressures.
While typical green roofs function like sponges and look like gardens, Rotterdam is working with public and private landlords to develop a “green-blue grid.” Instead of simply fitting out roof areas with plantings, these spaces can also be equipped with reservoirs or tanks to retain excess flow — blue roofs. The tanks, in turn, are equipped with electronic drain valves that can be opened and closed remotely, in some cases via a smart phone app.
“The problem,” says van Roosmalen, “is that when they’re full, they’re full.” The city’s vision, he explains, is to develop a system for co-ordinating the water levels in these tanks to help manage sewer capacity. The idea is to link the valve control devices into a grid of blue roofs that function, in effect, like a dispersed network of storm water reservoirs. When there’s rain in the forecast, the reservoirs can be drained automatically. Then, during heavy weather, they can store rainwater, reducing pressure and flooding in the sewer system.
While Rotterdam’s blue-green grid is still far from completion, it may be seen as a compelling example of how a set of technologies can be harnessed to produce what can be described as a smart city solution to a pressing urban problem.
The technological linchpin in Rotterdam’s strategy has been the installation of a highly sensitive weather radar on the roof of the city’s tallest building. The device is capable of detecting rainfall 16 to 20 kilometres away. Remotely operated blue-green roof control systems can be programmed to dynamically respond to those forecasts and release water that sits in the reservoirs. (A similar project, the Resilience Network of Smart and Innovative Climate-Adaptive Rooftops, or Resilio, is underway at several Amsterdam social housing complexes.)
To date, Rotterdam officials are testing a pilot version of this grid, and not just to confirm that the technology works. To scale it up, the city needs to co-ordinate with Rotterdam’s water board, which manages the sewer infrastructure, as well as property owners. The strategy complements other water management planning moves, among them retrofitting public squares with “rain gardens” — i.e., clusters of water-absorbing shrubs and perennials planted in a small depression in the ground. “Instead of making bigger sewer pipes, we made a choice to invest in redesigning public space in a way that contributes to a nicer, better, more attractive district,” Arnoud Molenaar, Rotterdam’s chief resilience officer, told Thomson Reuters last year.
Van Roosmalen adds that a green roof can absorb about 15 millimetres of rain per square metre, whereas a roof with a reservoir can retain 10 times as much. The city’s goal is to convert one million square metres of flat roofs to include water retention systems and solar panels. Aggregated across even a portion of the city’s flat roofs, he says, “it’s a tremendous amount of water.”
The blue-green roof campaign is just one element of a wider set of Dutch policies that are meant to confront the potentially ruinous impact of climate change. The technology “is a means, and not a goal in and of itself,” says Rob Schmidt, the City of Rotterdam’s project manager for smart cities and the digital economy.
The Netherlands’ outlook can also serve as a model for Canadian cities and policy-makers. Dutch governments are by no means indifferent to a potential economic windfall from the urban tech sector and have backed hundreds of smart city or digitization ventures.
But the country situates its smart city technology projects in a broader sustainability agenda. It features extensive public engagement, applied research ventures and public-private partnerships. The Netherlands has set out to promote the circular economy (i.e., ambitious policies to reusing waste and castoffs) and alternatives to private, gas-powered cars. The national government, moreover, works closely with the country’s nine major cities to implement these plans. In Holland, smart city policy isn’t about the tech tail wagging the urban dog.
Some of the earliest applications of smart city technology involved sustainability, and specifically the growing interest in distributed, renewable electricity that began in the 2000s. Conventional electricity grids were linked to large, and often dirty, power sources — coal or gas-fired generators. But as wind power and solar became more economically viable and politically popular, utilities had to figure out how to allow these smaller sources of power generation access to supply the grid. These included homes or flat-roofed commercial buildings fitted out with rooftop photovoltaic solar panels that could generate energy.
In Ontario, the Liberal government’s 2007 pledge to phase out coal forced a push for renewable alternatives. Queen’s Park sought to attract clean energy investors, large and small, with attractive subsidies. The transition turned on the deployment of smart grid technology, including smart meters. These allowed utilities to manage energy drawn from a decentralized set of producers, among them private property owners with solar panels that could feed power into the grid.
Those investments, in turn, paved the way for other conservation-oriented policy shifts, such as time-of-use pricing, which provides ratepayers with a financial incentive to reduce consumption during peak periods. Smart grids also laid the foundation for more electricity-related consumer innovations, such as the wide deployment of electric vehicle charging stations or the installation of backup energy storage devices, such as Tesla’s Powerwall. From a sustainability perspective, smart grid systems only cut overall emissions if utilities phase out or reduce carbon-emitting generation, as Ontario did.
While Canada continues to emit far more carbon than the Netherlands, Holland’s climate policies reflect a great sense of urgency, given its exposure to sea level rise and flooding on rivers that flow into the country from the east. For that reason, adaptation and mitigation are central to plans to future-proof its cities.
Schmidt points out that the Netherlands’ nine largest city-regions collaborate to develop and test approaches and technologies. “We learn from each other how to cope with these so-called smart city projects.” Each city has adopted a policy area: Rotterdam is focused on climate adaptation; Amsterdam, circular economy; Eindhoven, low-carbon mobility and energy transition, and so on.
The national government, has launched an Urban Agenda that involves negotiating “city deals” many involving smart city projects that typically include multiple partners, including research institutions. “Our approach is focused on the opportunity and finding everyone you need to get to a solution,” says Urban Agenda program manager Frank Reniers. “You put them in a room and try to innovate your way out of the problem.”
The Netherlands wasn’t always so collaborative. According to Frank Kresin, dean of the Faculty of Digital Media and Creative Industries at the Amsterdam University of Applied Sciences, Amsterdam in the late 2000s and early 2010s “was doing everything in its power to become ‘smart.’ ” The city’s appetite for tech drove a great deal of investment in automation and digitization.
But the infatuation with these corporate solutions, Kresin wrote in a 2016 study, “had some flaws,” including the risk of excessive surveillance and an unquestioning embrace of the idea that the smart city was “a machine that needs to be optimized, with no consideration or understanding of the organic reality. It wants to maximize efficiency and avoid friction, so it simply and non-negotiably imposes top-down, nontransparent technological solutions.”
Kresin wasn’t the only one concerned about this drift. In the last five or six years, citizens groups, entrepreneurs and academic institutions have pushed Dutch policy-makers and companies to swap out the top-down approach in favour of a more grassroots philosophy that features extensive public engagement, citizen-science projects and applied research.
“The big threat is loss of autonomy,” says Jan-Willem Wesselink of Future City Foundation, a Dutch network of municipal agencies, civil society organizations, universities and technology companies seeking to promote a more democratic approach to smart urbanism that aligns with one of the U.N.’s 17 sustainable development goals (number 11) about resilient, sustainable and inclusive cities. “Does Google or some other company decide how you use the city?”
Kresin describes one early effort at broadening the conversation. In 2014, Amsterdam Smart City, a tech incubator, distributed several hundred “smart citizen kits,” which provided rudimentary sensors to allow people to perform environmental indicator tests on water and air quality around the city. Their findings were fed to the city. While the readings fell short of research-grade data, this experiment in citizen science attracted many participants, generated upbeat media coverage and, in a few cases, led the city to clean up local beach areas. Its popularity also inspired Kresin and some colleagues to establish the Amsterdam Smart Citizens Lab, where civil society groups, academics and government officials work together to find solutions to other urban problems.
The distribution of the kits “was a surprisingly successful project,” says soil chemist Gerben Mol, a resilient cities researcher at Amsterdam’s Advanced Metropolitan Solutions Institute (AMS), a university-municipal government joint venture established to conduct more formal applied urban research.
In recent years, a growing number of Dutch city-dwellers are finding venues to engage in local conversations or projects about how to put urban data and technology to work in addressing the problems they see in their communities — in effect, a cultural, as opposed to corporate or bureaucratic, response.
All this grassroots work has had a bearing on AMS’ work. While some of its research falls under the heading of smart city tech — i.e., data visualization projects — other research initiatives are focused on parallel policy themes, such as the circular economy. One intriguing example: an AMS project that created a composite out of a glue-like bacterial residue and decontaminated wood fibre culled from septic waste (i.e., used toilet paper). A potential application is being tested to use this composite as a binding agent in road asphalt.
There are other more traditional tech ventures, such as Amsterdam Smart City, an incubator with numerous public and private partners, all working collaboratively to benefit the city. The incubator’s community manager Nancy Zikken says the City of Amsterdam has “embraced” TADA.city, a network of European organizations that have pledged to adhere to six core principles for digital city initiatives (inclusive, locally focused, controlled by residents, monitored, transparent and broadly accessible).
She also says that Amsterdam Smart City screens applicants, such as startups, to ensure their proposals align with broader policy goals and have what Zikken calls “social value.” As an example, she cites a firm that recently pitched a parking app that was rejected because it would likely encourage car use in a congested city that wants the opposite. “Most of the companies we’re working with really do see the value of incorporating citizens and using the wisdom of the crowd.”
In Rotterdam, city officials, who are driving the blue-green grid initiative, are also using public education, open houses and other engagement tools to promote these projects, many of which will be installed on privately-owned dwellings, using private capital, if the strategy is to attain sufficient scale to make an impact.
Rotterdam, interestingly, hasn’t created financial incentives. Rather, in discussions with private property owners, city official van Roosmalen says his team stresses the benefits and explains the options for what’s possible, for example combining a rooftop reservoir with solar. “They can pick what they think would add to the quality of their specific land,” he says. But there’s also a more urgent appeal, too. “You can save your city from drowning.”
Next: Civic leaders have more data than ever to guide their decisions, but the tech is not in charge
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