From rising sea levels to so-called heat islands, the challenges facing the world’s major cities as a result of climate change are daunting to say the least. But some municipal responses – especially those spearheaded by architects and designers – have been as creative as the problems are formidable. Think city parks turned reservoirs, urban forests on demand, even a redirected river. What follows are a few of the initiatives that five threatened yet ambitious metropolises have effected or are exploring to engender civic resilience, with designers leading the charge.
Among Beantown’s coordinated efforts to preserve its historic waterfront: buried bulkheads, “living edges” and other discreet yet effective infrastructure
When it comes to protecting cities from rising tides, few pieces of infrastructure are as effective as seawalls — stone, steel or concrete barriers that repel ocean water just as the ramparts of medieval castles once thwarted enemy invaders. There is nothing subtle, however, about a seawall: It’s hard infrastructure that very much looks like hard infrastructure. “Who wants to be on an urban waterfront and see a giant wall blocking the harbour?” says Pippa Brashear, a planning principal at Scape Landscape Architecture. “Think about what that does to people’s experiences and to the cultural identity of a city.”
To help formulate a plan for Boston, which they dubbed the Resilient Boston Harbor Vision, Brashear and her team at Scape studied the waterfront and came up with renderings — she calls them “vignettes” — depicting flood defences that are well-integrated into their surroundings. In some vignettes, the seawall hangs back, buried beneath a green berm that’s tucked behind an expansive beachfront. In others, it is replaced — or enhanced — by a “living edge,” often including a salt marsh that extends into the harbour, absorbing and calming the waves.
Boston is known for its Harborwalk, a waterfront promenade (still under construction) that follows the shoreline, linking wharves, piers and famed historic sites. As Scape envisions it, the Harborwalk skitters, floats and dances, sometimes cantilevering out past a seawall, sometimes stepping overtop a terraced seaside bulkhead. At other times, it flanks elevated roadways or piers, which are mounted on stilts to sit safely above the waves.
These vignettes aren’t blueprints but templates. As part of the city’s wider Climate Ready Boston initiative, each of Beantown’s neighbourhoods — from historically Irish South Boston to the Italian North End — will have to reimagine its own waterfront. Scape has given them a range of options to choose from. “We’ve created a suite of techniques,” says Brashear. “Boston is a city of beaches, marshes and promenades. We want it to stay that way.”
In the Danish capital, a historic park is redesigned to include built-in flood absorption — without infringing on any of its charm
“Everybody in Copenhagen remembers where they were on July 2, 2011,” says Flemming Rafn, cofounder of the design practice Tredje Natur. On that day, the Danish capital saw a flood so severe that it turned streets into canals and temporarily transformed the city into a Scandinavian Venice. To avoid a repeat of that catastrophe, the municipality sought to build new infrastructure that would absorb or store floodwater at the low points of various rain catchment areas. One such region, however, was already occupied by Enghaveparken, a neoclassical park with fountains, promenades and sports amenities, plus two pavilions and a bandstand by modernist legend Arne Jacobsen.
“In theory, we could scrape off the entire surface of the park and lower everything,” says Rafn, whose firm won the commission to turn the site into a flood zone. But that, of course, was out of the question. Instead, Rafn redesigned the park’s hockey quad, fountain and rose garden so that each now sits several metres below grade.
During so-called 10-year storms, water will flow — via a network of gutters — into these sunken areas individually, flooding the hockey quad first, then the fountain and then, finally, the rose garden. During 100-year storms, however, the entire park will become a basin, as its perimeter is now bounded by movable walls containing subterranean concrete shafts outfitted with buoyant steel boxes. When floodwater surpasses the rose-garden level, it will enter the boxes at select entry points and cause the walls to float upward, sealing the perimeter and creating enough of an enclosure to hold more than 22,000 cubic metres of water. (Jacobsen’s pavilions and bandstand would remain above the deluge.)
Until recently, such occurrences would have been rare, but those 10-year storms may soon be annual events and 100-year storms could happen several times a decade. The new Enghaveparken is built to manage such phenomena but not to hide them. When the space suddenly transforms into the world’s largest bird bath, the effect should be profound. “The design evokes the transformative power of water,” says Rafn. “It also invites people to reflect on where that water came from. If we don’t see the physical consequences of climate change, we will have a difficult time grasping it.”
A plan to renaturalize a vital urban waterway will restore a river delta to its former pristine state — and create a new island in the process
The mouth of Toronto’s Don River, where the 38-kilometre waterway empties into Lake Ontario, was once a shaggy marshland. In the 1880s, however, developers began filling it in, transforming a porous ecosystem into a hard surface suitable for loading docks and power plants. The natural delta no longer exists. As it approaches its southern terminus, the Don now takes a hard westward turn into the Keating Channel, an artificial canal that flows into the lake. During rainy seasons, the water hits this right-angle juncture at high speeds, causing the river to back up — and effectively making the Port Lands where the Don meets the lake a flood plain, much of it unsuitable for housing.
In 2014, the city hired urban planner Melanie Hare, a partner at the consultancy Urban Strategies, to head up a design team for the unlikely landform that will result from a proposed renaturalization of the Don’s base: a new island. (“Right angles?” says Hare. “Rivers never do that.”) Under the renaturalization scheme, the Keating Channel will still exist, but the Don itself will travel south into a restored delta before meandering west to the lake. The banks of the new mouth will be soft, deep and grassy — designed to hold and absorb floodwaters. And the new waterway, when it’s completed in 2024, will carve out a chunk of land — 35-hectare Villiers Island — from the Toronto lakefront.
This is something novel: a whole new space, in crowded downtown Toronto, zoned for residential use and designed almost entirely from scratch. The island will have mixed-used amenities (making driving unnecessary) and a district energy source (specifically a power generator that serves multiple dwellings at once and is therefore more efficient than the one-furnace-per-household model). Its streetscape will be laid out like a theatre, with the highest seats in the back: Low-rise houses will absorb southern winter sun, while the taller buildings stand unobtrusively behind them.
Villiers Island will also have what Hare calls “a green skirt.” “Almost all the land on the periphery will be open park space,” she says. “This will give Torontonians a chance to reacquaint themselves with their harbourfront.” The original Port Lands were a reclamation — an attempt to snatch a parcel of land back from the lake. The new island will also be a reclamation, albeit of a different kind: It’ll transform a mere location into something more like a destination.
In one of Asia’s most populous cities, improving air quality means conjuring an instant urban forest, complete with two million trees
The western bank of the Huangpu River in Shanghai is home to some of the most beloved neighbourhoods in China, from the Bund to the French Concession. But, until recently, the eastern bank was less iconic. When Richard Mullane, a principal at the international architecture and design studio Hassell, toured the area in 2016, he saw decaying industrial buildings and vacant lots. How, he wondered, might one turn such a sprawling brownfield site into a landmark worthy of its neighbour?
The plan that Mullane and his team have devised involves trees — lots of them. More specifically, it calls for removing the area’s concrete, capping any contaminated areas with landform and then planting some two million specimens, effectively creating a forest in the heart of the metropolis. When it comes to climate mitigation, trees are among the most sophisticated technologies going, converting carbon dioxide into oxygen, releasing water vapour (thereby cooling the surrounding landscape) and purifying air (a major advantage in a city that has seen deadly clouds of smog).
As envisioned by Hassell, the soil in the Huangpu East Bank Urban Forest, as the initiative has come to be known, will function as a natural berm if the river overflows its banks; during heavy storms, the trees and the parkland they’ll sit in would absorb stormwater on the land side as well. But the forest isn’t just green space. When it’s finished, it’ll feature a promenade that snakes through the trees, bridging canals and occasionally giving way to urban follies–cum–outdoor classrooms.
The trees, moreover, will be arranged to dramatic effect. Some parts of the forest will be lined with Japanese elms and Chinese maples, the leaves of which change colour in the fall; others will contain Yulan magnolias, which blossom in spring. At select intervals, parks, performance venues and cafés will materialize. “We were drawn to the forest concept because we could carve urban space out of it,” says Mullane. “The bank was wide and open, but we found a way to make it intimate, tactile and human.”
To address rising sea levels along a storied coast, designers are proposing a string of “collection and connection points,” each of them contributing to region-wide resilience
Since its postwar heyday, the concept of “urban renewal” has acquired a bad reputation, recalling a hubristic era in which city planners attempted to fix urban problems by imposing grandiose schemes. None of that flies anymore. Most urbanists now agree that good city-building must be participatory and flexible, engaging communities directly. But how does one create sensitive, community-level designs when the biggest problem of our time — climate change — requires a coordinated response?
This was the question that Kristina Knauf, an architect at Rotterdam-based MVRDV, contemplated when participating in the Resilient by Design Challenge — a competition, funded by the Rockefeller Foundation, to come up with smart resiliency schemes for the San Francisco Bay Area. Working with a team led by the international firm Hassell, Knauf helped develop a new concept: collection and connection points. These areas consist of an upper community hub (that is, a “collector” area, on high ground) and a lower hub (a “connector” area, adjacent to the waterfront, that’s linked to the upper hub by a creek, canal or street).
Both hubs encompass public spaces containing whatever amenities the community needs — parks, fire halls, cafés, libraries. They are also built to collect and channel floodwater from the high-ground hub to a reservoir at the low point, adjacent to the Bay. (After it has been cleaned, the water can then be released, gradually, into the sea.)
Based on this concept, the Hassell-led team subsequently came up with a specific collect-and-connect design for South San Francisco, an industrial region containing a waterway called Colma Creek. The plan proposes widening and greening the creek, which connects Orange Memorial Park (a green space on high ground) to the shoreline (where a new park containing flood-management measures and spaces would be built). It also calls for creekside promenades, a pool and playgrounds.
But this is just one variation on a highly adaptable theme. Any community can adopt the connection–collection prototype according to its needs. Each iteration, done in its own way and on its own timeline, would contribute to wider resilience. “We are creating guidelines and toolkits,” Knauf explains, noting that insensitive, large-scale planning rarely gets public buy-in. “You need to invite residents to take action on their own.”