Cities are turning to Blue-Green Infrastructure solutions that utilize ecosystem services in the management of water resources while providing multiple co-benefits.
Blue-Green Infrastructure (BGI) is a strategically planned network of natural and semi-natural areas that are designed and managed to deliver a wide range of environmental, economic, and social benefits. These benefits include:
- Improved water quality: When rain falls on a city’s surfaces (streets, sidewalks, and rooftops), it collects oil, litter, and other pollutants as it runs off city surfaces into waterways. BGI enables cities to capture and clean this stormwater, ensuring waterways are healthier
- Reduced potential for flooding: BGI slows down and holds stormwater allowing it to soak into the ground. This helps reduce the volume of water entering the sewer system and prevents flooding
- Enhanced resilience to climate change: BGI can use excess water as a resource for communities and natural habitats. BGI also helps cool cities during extreme heat events
- Reduced sewer infrastructure cost: BGI reduces the volume of water entering the sewer system by returning water to the natural water cycle. This increases the lifespan of the sewers and reduces infrastructure maintenance costs
- Increased green space for communities and wildlife: BGI provides multiple mental and physical health benefits to communities as well as provides a sanctuary for urban wildlife and pollinators
Turning stormwater into a resource
The City of Santa Monica, in partnership with the Santa Monica Malibu Unified School District and the Metropolitan Water District of Southern California, has constructed the Los Amigos Park Storm Water Harvesting and Direct Use Demonstration Project. The project involves capturing stormwater runoff from a storm drain near the park, pre-treating flows with a hydrodynamic separator, storing flows in a subsurface storage system, and treating the water with ultraviolet light before use for indoor flushing and park irrigation, both of which currently use potable water. The project stores around 53,000 gallons of urban runoff and offsets up to 550,000 gallons of potable water per year, ensuring urban runoff can become a resource rather than a waste that carries pollution into Santa Monica Bay. In addition to reducing the amount of polluted runoff going into the ocean, the project demonstrates to the wider community the benefits of capturing and using urban runoff and stormwater for uses that do not require potable water. Overall, the project contributes towards the city’s wider goal of reducing water use by 20% and being 100% water self-sufficient by 2020.
Incentivizing BGI on private property
New York City’s BGI aims to reduce combined sewer overflows into New York Harbour, in addition to providing multiple benefits including urban heat island reduction, and more habitat for birds and pollinators. To incentivize BGI retrofits on private property, the city’s Department of Environmental Protection (DEP) is releasing a Request for Proposals to procure a Program Administrator to launch and administer a new BGI Private Incentive Retrofit Program. The five-year contract will have a value of $43-$58 million with a goal of retrofitting 200 greened acres. DEP has also released a streamlined fast-track review process for private green roof projects funded through its Green Infrastructure Grant Program. The funding schedule sets reimbursement rates for green roof projects based on growing media depth and planted area. These upfront reimbursement rates eliminate uncertainty over how much funding is available for potential projects and by giving this information to applicants in advance it means DEP can fast-track green roof grant applications, with anticipated design approval within 90 days from the submittal date.
A green Lego city
To raise awareness of the issues of stormwater quality and surface runoff, Melbourne Water has developed the Water Smart City Model. This model is an educational activity suitable for all ages which can be used at community events and festivals. The activity involves the audience building a model city with roads and buildings made from Lego building blocks. Food dye, representing pollutants, is placed on the city and rainfall is simulated over the model, carrying the pollution over the impervious surfaces and into the ‘bay’. A variety of features including rain gardens, rainwater tanks, swales and rooftop gardens are then added. Pollution is again added to the model and rain simulated. The amount of surface runoff is significantly decreased due to the retention capabilities of the new features, reducing risks of flooding. Pollution is also captured in the features so the water flowing into the ‘bay’ is cleaner.
Meaningful educational and job opportunities
BGI initiatives also provide meaningful educational, employment, and community-building opportunities, including:
Tools to educate young children
With climate change making heavy downpours and the risk of flooding more likely, Anglian Water in the UK is looking at BGI solutions to not only reduce and slow down the rainfall entering the sewers but to also use them as tools to educate young children on the environment and water cycle. For example, a BGI project at a primary school has a rain garden as well as a weather station to help the children monitor the climate at school.
Creates opportunities for minority and women-owned businesses
Philadelphia has embarked on a BGI program that protects local communities from excess stormwater runoff while providing new green job opportunities. A key part of the BGI upgrade of the city is that small, local firms are encouraged to bid on and build BGI. This creates more opportunities for minority and women-owned businesses to be involved. The city is also working with non-profit organizations to train at-risk youth for BGI maintenance jobs.
Youth changing their local environment for the better
Greenspace Scotland is supporting youth groups to engage with others in their communities to take action to improve the environmental quality, biodiversity, playability, and vibrancy of neighborhoods. Seed grants are available to support Young Placechangers (between the ages of 12–25) who want to change their local environment for the better. The scale of projects eligible for funding can range from local greenspaces and community gardens right up to neighborhood-level initiatives such as implementing BGI to improve local waterways.
Blue-Green Infrastructure contributes to the development of climate, resilient, educated, and engaged communities.