What is a sponge city and how can they help mitigate flooding?

With flash flooding fast becoming a major risk to the UK’s capital, calls have been made for London to become a ‘sponge city’ in order to protect the 615,000 workers and assets that could be at risk.

The Greater London Authority (GLA) believes that flooding has become the main environmental risk to London’s infrastructure, businesses and residents with around 1 in 6 UK properties currently in peril. Climate change and the increasing challenges posed by significant storms such as Kathleen, Isha, Jocelyn, and Henk could see this figure grow substantially in the future according to scientists.

By association, flooding can reduce the value of a property by 30% in severe cases so in the current climate, there is a growing need for data to facilitate better informed decisions regarding risk. As of January 2024, it is already a requirement to disclose material information regarding flood risk under IFRS S2. These new disclosures may present opportunities for increasing stakeholder transparency, identifying risks to assets / insurance policies and building portfolio resilience. 

Flood risk mitigation has therefore never been more important to consider, and techniques such as sponge cities are being discussed by authorities and flood risk consultants, like us, as a way of future proofing cities. 

What is a sponge city?

The term sponge city brings together green spaces, permeable surfaces, and water retention areas to absorb and manage rainwater. This process helps to reduce the risk of surface water flooding created by too much water deluging the drains and water courses. Natural filtration systems in sponge city infrastructure can also improve the quality of stormwater runoff, reducing pollution in rivers and streams long term.

How would the implementation of sponge cities affect ESG (Environmental, Social and Governance)?

Incorporating more green spaces, wetlands, and water bodies within the city enhances urban biodiversity, providing habitats for various species. Sponge cities also promote the reuse and recycling of rainwater, contributing to more sustainable water consumption practices.

Socially, increased green spaces and recreational areas could improve the well-being and mental health of residents. Better flood management systems increase the city’s resilience to extreme weather events, protecting communities and infrastructure.

Implementing sponge city principles would require updates to urban planning and building regulations, promoting sustainable development practices. Surface water drainage systems (SuDS) is an example of a mitigation measure that is already being enforced in the UK planning system.

Transforming London into a sponge city aligns with ESG principles by promoting environmental sustainability, improving social well-being, and fostering robust governance practices. This holistic approach to urban development can serve as a model for other cities in the UK and worldwide.

Understanding your flood risks

GeoSmart Information is calling on businesses, asset managers and planners to ensure that future-proofing against flooding is both an ESG and a best practice decision for every business. Flood water needs to have somewhere to go to and by providing suitable SuDs policies with every new and existing property where possible, we are ensuring that flooding doesn’t need to be such a challenge. 

GeoSmart can help with understanding the flood risks to every single building in the UK, now and in the future. We are the only flood risk company that takes into account groundwater and can fully advise on how a business can mitigate their risk whilst also utilising SuDS effectively. 

For further information and to understand your flood risk, get in touch with GeoSmart.