How Can Urban Areas Improve Drainage?

Improve Drainage

How Can Urban Areas Improve Drainage?

Flood risk in the U.K is being exacerbated due to climate change; however, the risk is often overlooked by the public. Currently, the Environment Agency advise that 1 in 4 homes in the U.K. are at risk of flooding, with 2.8 million properties being vulnerable to surface water flooding, especially in urban areas.

Climate change, land management practices and increased urbanisation are the main driving forces behind the increasing flood risk vulnerability within the U.K. Land use management and urbanisation has resulted in more impermeable surfaces in areas that were once natural green open spaces, and subsequently the existing drainage systems are unable to cope with the additional rainfall and surface water discharge.

This has led many built up cities and urban environments around the world to adopt a ‘greener’ approach to their design, and develop innovative solutions to manage rainwater effectively.

These solutions are often known as SuDS- Sustainable Urban Drainage Systems.

What are Sustainable Urban Drainage Systems (SuDS)?

SuDS are natural approaches designed to manage drainage and surface water around properties and urban developments. SuDS are intended to imitate nature, and the natural catchment of an area by managing rainfall and water close to where it falls. SuDS are designed to:

  • Provide areas to store and absorb excess amounts of water
  • Transfer surface water safely, without it affecting neighbouring areas
  • Attenuate the water before it returns back into watercourses
  • Allow water to soak into the ground as naturally as possible or evaporate from surface water.

Traditional Drainage Systems versus SuDS.

Traditional urban drainage systems are designed to transport water away from built up and populated areas in order to prevent flooding. For traditional drainage systems to work, rainfall runoff needs to be transferred as quickly as possible. This means that there is very limited opportunity for the water to be reused and does not reflect the natural catchment and infiltration of the area.

Traditional systems have not been designed to consider the long-term sustainability. Instead, they are just transferring water elsewhere, which can often cause problems for these areas, along with the areas where the rainwater initially fell.

Traditional systems are heavily limited by their volume capacity.

Outdated drainage infrastructure is unable to cope with channelling the increased precipitation levels brought on by climate change, meaning that flooding from artificial sources such as drains, and sewage systems is on the rise.

Traditional systems are also susceptible to blockages caused from storm debris, which impedes their ability to manage water efficiently.

In comparison, by intercepting and managing precipitation at the source through making good use of permeable layers and surfaces, such as soil and vegetation; SuDS help ensure that precipitation is managed effectively by mimicking the natural groundwater recharge of the area.

This method causes a reduction in surface water runoff, ensures better water quality, and is much more effective at reducing surface water flooding in built up areas.

When can SuDS be used?

It is a legal requirement that any new commercial or residential developments take into account where their excess surface water run-off will go. It is essential that water is either reintroduced back into the natural water cycle or disposed of accordingly.

SuDS can be used at a range of scales and can often be incorporated into the development design and architecture itself. In many incidences SuDS can be a focal point and provide attractive spaces, or alternatively be designed so they aren’t even noticeable.

There are many opportunities and ways in which SuDS can be incorporated into designs, such as green roofs, permeable surfaces, detention basins, infiltration trenches, filter strips and purpose-built ponds.

Environmental Benefits of SuDS:

SuDS are much more sustainable and effective at minimizing the risk of surface water flooding when compared with traditional drainage systems as they:

  • Reduce the risk of sewer flooding following heavy rain
  • Protect water quality and reduce pollution from runoff
  • Create habitats for wildlife in built up urban areas
  • Manage runoff volumes and flow rates in a controlled way, reducing potential flooding
  • Help prevent drought by recharging the local groundwater
  • Reduce pressure on existing infrastructure by enabling evapotranspiration from vegetation and surface water areas.


How can we Help?

At FPS Environmental we have extensive background and experience developing SuDS and drainage designs for surface water. We look at each site holistically and ensure our SuDS recommendations and designs try to reflect that of the local catchment, as well as being visually appealing to work alongside the specific occupation of the site.

Our highly qualified engineers and consultants use the most up to date and high-tech data available to understand the risk of flooding at your development, and we work work closely with our clients to develop SuDS solutions to mitigate flood risk for your development.

If you’re unsure and need advice, then get in touch with our team of specialists who can help and advice at or call 020 8050 3194.

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