Five Blue-Green Infrastructure Projects Making a Splash
Published on February 10, 2020
Cities around the globe are increasingly incorporating nature as an intentional element of urban planning. As the effects the climate crisis begin to make themselves known – often in the form of increased rainfall, flooding, droughts and extreme heat – city planners are realizing how integral nature is as a tool to adapt to the climate crisis.
This is where Blue-Green Infrastructure comes in. Blue Green Infrastructure (BGI) projects can be an important part of city planning across all sectors. BGI projects are, at their core, environmental components and natural assets that are integrated into an urban landscape (buildings and public spaces) to create and promote more sustainable ecosystems. They can be small-scale - think rain barrels or small green roofs - or large - like living walls and gigantic stormwater catchments.
Here are five Blue-Green Infrastructure projects from around the globe that are making a splash.
Green City, Clean Waters in Philadelphia
Philadelphia receives over one million gallons of rainfall per acre annually. Though nowhere near the rainiest of US cities, the city has received a reputation for struggling with stormwater management. A focus during the last century on covering up industrial waste and river systems by bridges and roads has left the city with few natural places to absorb rainwater. As a result, billions of gallons of untreated stormwater would rush out from the city, which had serious environmental impacts as the water eroded natural habitats and carried industrial waste right towards municipal water supply.
In 2011, the city entered in a 25-year agreement with the US Environmental Protection Agency to tackle this problem. Over 2.4 billion USD in public funds, with billions more from private funders, propelled the city towards implementing a “citywide mosaic of green stormwater infrastructure,” with the intention to create the largest system of its kind in the country. Through hundreds of projects forged through numerous public/private partnerships, the city has created over one thousand “greened” acres to restore the natural precipitation cycles and systems of the area. Ranging from simple to complex, these greened acres can absorb billions of gallons of rainfall annually, with the added bonus of creating outdoor green spaces for the public to enjoy.
Green Your Laneway in Melbourne
In 2017 Melbourne embarked on four pilot projects to “green your laneway,” a natural makeover for the city’s central laneways that lacked green space. As temperatures and hot days increase in across Australia, green infrastructure can be a handy tool to help regulate temperatures, support stormwater filtration, provide shade, and improve air quality.
After the city mapped over 200 laneways in the Central Business District, the city focused on four high potential for greening: Meyers Place, Coromandel Place, Guildford Lane and Katherine Place. In laneways where it wasn’t always possible to install green infrastructure like living walls, as a city known for its extensive public art, they opted to bring in artists to paint nature inspired public murals to compliment the other greenery. Using a combination of stormwater tanks, green roofs, green walls, and rain gardens they completely transformed these public urban laneways into verdant sanctuaries in the heart of the city.
Cloudburst Masterplan in Copenhagen
In 2011, Copenhagen was hit by a one-in-a-thousand year rainstorm, known as a cloudburst. Over the course of two hours, 150 mm of rain came down on the city, leaving low laying areas under a metre of water. This devastating storm left 50,000 homes without power and caused damage to infrastructure upwards of 1 billion USD, affecting multiple jurisdictions throughout the city and surrounding regions. Weather models and assessments indicated that what used to be a rare weather event was predicted to happen far more frequently, and Copenhagen couldn't take that risk. They sprang into action, following a six step procedure to undertake detailed data collection and analysis and map out Blue Green Infrastructure projects to completely overhaul their stormwater and flooding management.
In order to mitigate costs, they came up with solutions that were dual purpose, one such example being stormwater pools. These pools doubled as recreational sites for the public during most months of the year, and used to capture and hold stormwater only during extreme weather events. They set up detention roads that would both absorb water through greenery and divert excess water to Sankt Jørgen Lake. Since they managed to lower the lake level at the same time, it had much greater capacity to absorb rainwater with new overflow pipes constructed. The Danish example has been so successful, they have since developed an award-winning, universally applicable cloudburst toolkit.
Rain City Strategy in Vancouver
Following the lead of cities like Copenhagen, Vancouver has built upon previous Green Infrastructure urban planning efforts to formalize their Rain City Strategy in 2019. As one of the rainiest cities in Canada and one of the first to declare a climate emergency, the city knows it is imperative to use rainwater as a valuable resource and design the city to be rain sensitive. The strategy has three main goals: improve and protect water quality, create resilience and enhance livability. This strategy marks a paradigm shift that brings together city planners across all sectors to practically address climate change with the urgency that is required. With an ambitious target to capture, clean and manage at least 90 per cent of their annual rainfall volume, Vancouver is slated to implement a number of actions related to streets and public spaces, buildings, sites, parks and beaches.
Some of the BGI projects include rainwater tree trenches on roadways to absorb rainfall, green roofs, absorbent parks and wetlands as well as permeable sidewalks. There are a number of anticipated benefits to a the prioritization of BGI, including reducing the volume of rainwater that enters city sewers, improve air quality and reduce pollution, mitigate urban island heat effects and increase green space in the city. This strategy is also a way to build stronger and more equitable nation-to-nation relationships with the Musqueam, Squamish, Sechelt and Tsleil-Waututh Nations on whose traditional territories Vancouver is situated. There is a great deal to learn from Indigenous knowledge systems and land management and the Rain City Strategy is an opportunity for shared stewardship of those lands.
Garden City and Global HydroHub in Singapore
Singapore is an inspiring example of intensive BGI. B being an island, it has long faced unique challenges to urban planning and infrastructure, having had to sacrifice most of their green spaces to development to support a growing population through the 20th century. For Singapore, one of the greatest climate risks is the possibility of mega-droughts, whereit has had to import water from neighbouring countries for decades to augment their supply. Back in the 1970s and again in the early 2000s, Singapore launched massive campaigns to remodel their city into a leading example of green infrastructure and smart water management, earning its nickname The Garden City.
Now a Global HydroHub, it integrates three key strategies: collect every single drop of rainwater, reuse water indefinitely, and desalinate seawater. Two-thirds of the city surface is now able to capture rainwater and convey most of that water through various tunnels to 18 reservoirs. They have also built a number of desalination plants to treat seawater, with many more in the works. They have also pushed the notion of livable density, making green buildings mandatory since 2008 and making all new developments require plant life. They have one of the largest green walls in the world - boasting 5,300 square-metres - located at the Singapore Institute of Technical Education’s College Central. The green space that was lost has now been brought back, vertically. Some of Singapore's recent plans include creating almost 650 km of walking and cycling paths throughout the city.