Flood risk is soaring in parts of London. Here’s where
More than 1,000 properties were flooded in London in 2021, resulting in insurance losses of more than £281 million. Record-breaking floods continue to affect England.
13 per cent of properties in the capital were classed as being at high or medium risk of flooding. Life-threatening warnings could soon become a reality, especially for people living in low-lying land next to the River Thames in east London.
Boroughs such as Tower Hamlets, Newham and Hackney were built on former marshland. These areas must have originally absorbed water naturally, but were used for urban development.
More than 85 percent of London’s marshes were lost in the 20th century. London has lost the natural buffer that helps water drain away. As sea levels rise and storm surges become more widespread, the risk of flooding increases.
London is one of the most urbanized cities in the world, with 78 percent of the land being urban. Thanks to important impermeable surfaces consisting of concrete, asphalt and roofs, water is prevented from leaking into the ground. Rapid surface water flow puts a strain on drainage systems, and surface water runoff flooding is one of the biggest threats to east London.
Large-scale infrastructure and tidal flood defenses such as the Thames Barrier protect London from large-scale river flooding, but they cannot prevent surface water flooding from localized storms.
As these structures age, maintenance costs also increase. Relying solely on them is a risky strategy for the future, especially as storm surges become more intense due to climate change.
Specialist organizations such as the Environment Agency monitor water quality in rivers to reduce the risk of infection when water is contaminated.
However, many areas of east London have Victorian sewer systems designed to receive much less rainfall, so these systems can easily be overwhelmed. This means that the likelihood of sewage contamination increases in these areas. It is estimated that around 39 million tonnes of untreated sewage is discharged into the River Thames every year.
East London also faces high levels of deprivation. Many people lack the resources to deal with flooding and possible water pollution, often because they are constrained by socioeconomic inequalities.
About the authors
Ravindra Jayaratne is Reader in Coastal Engineering at the University of East London.
Maciej Pawlik is a PhD Researcher in Risk and Disaster Reduction at UCL.
This article was first published by. Speech and is republished under a Creative Commons license. Read original article.
High child poverty rates in east London boroughs such as Tower Hamlets (47%), Newham (45%) and Hackney (45%) mean flood preparations are often overlooked.
In addition to strengthening infrastructure and physical barriers, there are also natural ways to manage flood risk.
Our research shows that combining nature with urban infrastructure increases the protection capacity and flood resilience of an urban river such as the River Thames. Preliminary insights from our ongoing social research suggest that creative ways to engage with people can help them better understand and support natural flood solutions.
natural obstacles
Planting suitable wetland species along streams and canopies helps delay surface water runoff by up to 90 percent. Instead of releasing water immediately like impermeable surfaces such as concrete and asphalt, plants absorb and release water within a few hours. This slows the flow of water into the drainage system and reduces the risk of overclogging of sewers and pollution leaks.
There are hundreds of green roofs at bus stops in the Netherlands. Data shows that every square meter of green roof cover absorbs 20 liters of water, reducing the amount of water entering sewers.
More natural solutions like this can also improve air quality, attract pollinators, and provide shade (which prevents the sun from heating buildings or walkways).
Green roofs on bus stops have now become a common sight in some UK cities, including Brighton and Cardiff. Introducing them to east London would be a good first step.
One of the charity-led initiatives, East London Waterworks Park, involves the rewilding of a former warehouse. By converting concrete-covered land into swimming pools with reeds for filtration, this project provides more space to retain flood water and a place for local people to socialize and interact with nature.
At London’s Queen Elizabeth Olympic Park, a former site of construction rubble has been transformed into a large-scale sustainable urban drainage system. This involves creating open spaces interspersed with natural features such as reed beds, wetlands, and swales (marsh channels) that slow the flow.
This helps slow the flow of water into rivers, especially during heavy rains. Studies show that improved water management in the park has saved 4,000 homes from flood risk since it opened in 2014.
London’s population is growing. This constrains resources and exacerbates the effects of increasing urbanization. Socioeconomic inequalities increase the level of vulnerability of London’s population. Flood risk is not just an environmental problem, it is a national security threat.
Incorporating nature into urban resilience plans helps reduce risk and empower people. But policymakers need evidence about which solutions are more effective before taking action.
