This blog has been written by a member of the Newground Flood Team.
Our need to develop land for infrastructure is decreasing the amount green space available for surface water to drain naturally. This is a problem which will only increase in the future as approximately 83% of the UK population currently live in towns and cities, which is up from 80% in 2007.
Urban areas are growing, and with that growth comes more concrete, roads, and buildings, which reduce the amount of green space available for rainfall to drain naturally into the ground. As more land is developed, managing surface water is becoming increasingly difficult, especially during heavy rainfall events.
In fact, around 83% of the UK population now live in towns and cities, up from 80% in 2007. And with approximately 17,000 hectares of undeveloped land being built on every year, according to DEFRA’s 25 Year Environment Plan, the need for sustainable, resilient solutions is more important than ever.
Blue-Green Infrastructure (BGI) refers to natural and semi-natural systems used to manage water in urban environments. Instead of relying entirely on traditional concrete (‘grey’) drainage systems, BGI works with nature to control rainwater, reduce flood risk, and improve environmental and community wellbeing.
Together, they help slow down surface water runoff, allow water to infiltrate into the ground and reduce pressure on drainage systems.
Historically, new developments have relied on conventional (‘grey’) drainage solutions like gullies, pipes, culverts and channels to move water quickly away from roads and buildings. But during intense or prolonged rainfall, these systems can become overwhelmed, increasing the risk of surface water flooding.
That’s where blue-green infrastructure comes in, by keeping water closer to where it falls, it reduces the chance of overwhelming sewers and watercourses downstream.
Both types of infrastructure are designed to attenuate flow before it enters a watercourse and provide areas where water can be stored, infiltrated and harvested for re-use. A benefit of blue-green infrastructure features are that they act as natural cleaning agents, reducing the amount of contaminants and sediment in surface water runoff through settlement or biological breakdown of pollutants. New developments provide better opportunities to apply and utilize blue-green infrastructure, as retrofitting into existing developments may not be possible due to land constraints. Blue-green infrastructure also fits within the scope of natural sustainable drainage systems (SuDS) and can help to reduce surface water runoff in the urban environment.
Blue-green infrastructure offers far more than just flood protection. Here are some of the key benefits:
1. Reduces Surface Water Flooding
By soaking up or storing rainwater, BGI reduces the volume of water entering drains and sewers. This is especially important during heavy rainfall and storms.
2. Improves Water Quality
Features like wetlands and vegetated swales help filter out pollutants, improving the quality of water that eventually reaches rivers or groundwater.
3. Boosts Biodiversity and Wildlife Habitats
Green spaces provide important habitat for birds, bees, insects, and other wildlife, helping support biodiversity in urban areas.
4. Creates Attractive, Usable Public Spaces
Parks, green corridors, and planted areas improve the look and feel of neighbourhoods, making them more pleasant places to live and work.
5. Improves Air Quality
Trees and plants absorb airborne pollutants, helping to clean the air and reduce health risks from vehicle emissions and industrial activity.
6. Supports Climate Resilience
By managing heat and water naturally, BGI helps towns and cities adapt to climate change, especially as extreme weather becomes more frequent.
As urban populations grow and climate change brings more intense rainfall, blue-green infrastructure will be essential for keeping our towns and cities liveable and flood-resilient. It’s also a cost-effective way to deliver multiple environmental, social and economic benefits at the same time.
New housing and infrastructure developments offer the best opportunity to install blue-green features from the start. Retrofitting existing areas can be more difficult due to limited space and higher costs, but even small-scale changes like adding rain gardens, green roofs or tree planting can make a big difference.
Blue-green infrastructure is also a key part of Sustainable Drainage Systems (SuDS). If you’re interested in learning more about how SuDS work and their role in flood management, download our guide below.
Download our ‘Introduction to SuDS’ booklet here.
Blue-green infrastructure helps us manage water more naturally while improving the places we live. As climate pressures and urban growth increase, it’s clear that these systems are no longer just “nice to have” – they’re essential for building healthy, flood-resilient and climate-ready communities.
By planning for nature-based solutions now, we can reduce future flood risk and create cleaner, greener spaces for everyone.
Download our Blue-Green Infrastructure resource here.
Sources: Statista.com
