Once, cities were a testament to our ability to conquer nature. Concrete islands sprang up in the most inhospitable climates and we developed new ways to isolate the environments in our buildings from the world outside.
Over the past few years, that trend has started to reverse itself. This began as an effort to reduce the impact of our day-to-day operations on the world — think carbon credits and renewable energy — as well as the incorporation of sustainable features like green roofs and office gardens to bring a little nature back to bleak urban settings. But these types of installations only affect small pieces of real estate.
There’s currently a movement underway to push these efforts even further, combining everything we know about incorporating green features with central planning in the hopes of making cities more comfortable and more efficient — restoring a sense of balance to our cities to make them work and feel better. These efforts can even help reduce urban flooding, which is why some of the locales implementing the changes are known as “sponge cities.”
A RIVER RUNS THROUGH IT
The sponge city concept started in China, which has 450 million inhabitants living and working in cities — many of which were suffering from unprecedented flooding. They took a cue from nature, which absorbs excess water rather than force it to transit over land. What this means for new construction is less concrete and more permeable materials.
Planners also researched what to do with the water that can’t be soaked up like a sponge, discovering that connecting rivers and streams created greater flow, giving rainfall somewhere to go other than up.
PARKS AND SWALES AND FACADES, OH MY
Where China and Singapore are scaling up water recycling and purification, some cities like Berlin are requiring rainwater to be managed by properties on-site. Germany has developed a reputation for aggressive environmental protection policies, and incorporating these practices and porous building materials are just the start of the absorption protocol.
At street level in Germany, urban wetlands and swales complement green facades and roofs — holding water until it can evaporate naturally, which is where it starts to get really interesting. Anybody that’s gone for a hike in the woods on a hot day can tell you how effective plant transpiration is at cooling the surrounding areas. Adding greenery to cities on a large scale replicates this system and helps combat the urban “heat island” effect, which can be responsible for a nearly five-degree temperature increase over the surrounding area.
That means buildings don’t have to work as hard to achieve a comfortable temperature inside and engineers can incorporate more natural, unfiltered air that occupants find refreshing (remember that stale feel lots of offices had in the ‘90s?).
PREPARING FOR TOMORROW’S CITY
If these “sponge cities” sound a little too good to be true, that’s because in some ways they are. Requiring new construction to incorporate green features and handle runoff on-site is costly, driving up the price of new buildings and spaces in them. Chinese President Xi Jinping initially allocated $50-$100 million for each sponge city project, which only covered about 20% of expenses. Compounding that effect, plots must be set aside for plants and trees, taking up potentially valuable revenue for the city.
That’s a lot to ask for something still largely in development. Cities like Berlin and Singapore still struggle with flooding, and underground infrastructure can significantly inhibit how much soil is available to absorb precipitation.
But while there are still some kinks to work out, owners might consider incorporating a few of these strategies in the live-work-play developments coming online. The initial cost might be higher than traditional options, but they can contribute to an environment that makes tenants happier and lowers operating costs.
All the different “greening” strategies work in concert, which means that the more you implement the greater the impact. Across a portfolio, it isn’t difficult to see how the savings can add up (to say nothing of the value of an image as an eco-friendly company or city).