SuDS through streetworks project (SSM)

Project highlights

We're using planned roadworks to create greener streets, reduce flooding, and improve neighbourhoods at lower cost. 

Challenge: Accelerating sustainable drainage delivery to reduce flood risk

Flooding from heavy rainfall is a real and present threat. In 2021, two extreme summer storms flooded more than 2,000 homes and businesses in London, and severely affected a number of hospitals, schools, tubes and rail lines.  

In London alone, more than 320,000 properties are at high risk of flooding from rainwater that cannot drain away quickly enough. Climate change, growth and ‘urban creep’ (the loss of permeable, ‘soft’ spaces like front gardens to ‘hard’ impermeable land cover like off-street parking) are expected to make this problem worse. 

There is no silver bullet to managing this risk. There is a wide-ranging consensus on the need to reduce the rate and volume of rainwater reaching our sewers by re-greening the capital, using Sustainable Drainage Systems (SuDS), such as raingardens, street trees and permeable paving.  

Our own Drainage and Wastewater Management Plan proposes that over 7,000Ha – an area equivalent to 10,500 football pitches – of currently impermeable land needs to be drained to SuDS in London by 2050. However, these projects can be expensive and are often delivered too slowly. 

What is therefore urgently needed is a way to deliver SuDS at an unprecedented rate and at lower cost.  

Every year, utility companies carry out tens of thousands of works to repair or upgrade water, gas, electricity and telecommunications services. In addition, highways agencies (the Boroughs and Transport for London) resurface their roads or install traffic control measures. Once the work is finished, the pavement or road is usually put back exactly as it was before. 

This creates a missed opportunity to utilise these excavations to install SuDS and reduce flood risk at lower cost and disruption.  

Solution: Delivering SuDS through routine streetworks

The SuDS through Streetworks Market (SSM) project will create a new way for organisations to work together to reduce flooding. 

Instead of carrying out separate flood prevention projects, the SSM will help install sustainable drainage features when planned roadworks are already taking place. 

This means one piece of work can deliver multiple benefits such as: 

• Reduced flood risk  
• Greener streets and neighbourhoods  
• Better habitats for wildlife  
• Improved water quality  
• Less disruption for residents and road users  
• Better value for money  

The project will create the tools, processes and partnerships needed to make this happen at a much larger scale. 

We will test the approach in London, learn from the results, and create a model that can be used by other towns and cities across the UK. 

Project timeline and collaboration

The £7.6 million project funded by Ofwat is expected to take 4.7 years. 

The aim is to develop, test and demonstrate a new approach for delivering sustainable drainage through planned streetworks and create a model that can be used across the UK by April 2031. 

As part of this project, we'll be working with Greater London Authority (GLA).