Many cities are turning to green infrastructure solutions that utilize nature’s ecosystem services in the management of water resources and associated climatic risks.
By Robert C. Brears
Green infrastructure 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 on the streets, sidewalks, and rooftops – it collects oil, litter, and other pollutants as it runs off city surfaces into waterways). Green Infrastructure enables cities to capture and clean this stormwater, ensuring that the waterways are healthier; with reduced potential for flooding (green infrastructure 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; with enhanced resilience to climate change (green infrastructure can use excess water as a resource for communities and natural habitats). Green infrastructure also helps cool cities during extreme heat events; with reduced sewer infrastructure cost (green infrastructure 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; and increases green space for communities and wildlife (green infrastructure provides multiple mental and physical health benefits to communities as well as provides a sanctuary for urban wildlife and pollinators).
Santa Monica 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.
Oslo Restoring its Nature
Oslo has 10 main waterways that run through its urban areas. Up until recently, the city’s waterways were considered problematic for sewage and an obstacle to the development of land. As such, large sections of waterways flow through pipes and culverts. However, these have predefined capacities and with more frequent and heavier rainfall from climate change, urban flooding will become an increasing challenge. Oslo has decided to restore its waterways by reopening closed rivers and streams where possible to handle stormwater more efficiently, as well as create recreational spaces for people and facilitate increased habitat for biodiversity. One example is the Teglverksdammen Project which is a reopening of around 650 meters of the stream Hovinbekke. The project has been planned and designed as a natural cleaning system with several sedimentation basins, a stream with water rapids, a small lake, and shallow waters with dense vegetation. Stormwater from a nearby school is also safely led into the newly reopened stream.
Vancouver’s Green Future
In Vancouver, over half the city is made up of impervious surfaces resulting in runoff carrying pollutants into local waterways as well as overwhelming the combined sewer system during heavy rainfall periods. Vancouver’s goal is to capture and treat 90% of its average annual rainfall by using green infrastructure practices on both public and private land. One project contributing towards this target is the 63rd Avenue and Yukon Street Boulevard Improvements project which has been identified as an opportunity to increase access to green space, enhance rainwater management, and improve neighborhood amenities. The boulevard will feature sidewalks, seating plazas, bike racks, a drinking water fountain, and lush rain garden beds that will contribute to cooling down the surrounding area during extreme heat and provide clean water, air, and lush nature in urban spaces for the community and nature.
Meaningful Educational and Job Opportunities
Green infrastructure initiatives also provide meaningful educational, employment, and community-building opportunities.
With climate change making heavy downpours and the risk of flooding more likely, Anglian Water in the UK is looking at Blue-Green Infrastructure 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 green infrastructure project at a primary school has a rain garden as well as a weather station to help the children monitor the climate at school.
Philadelphia has embarked on a green infrastructure program that protects local communities from excess stormwater runoff while providing new green job opportunities. A key part of the green infrastructure upgrade of the city is that small, local firms are encouraged to bid on and build green infrastructure. 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 green infrastructure maintenance jobs.
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 green infrastructure to improve local waterways.
Green infrastructure contributes to the development of climate resilient, educated, and engaged communities.
Robert Brears is the author of Urban Water Security, Founder of Mitidaption, and Our Future Water.
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