Living with flood risk in Cambridgeshire

Cambridgeshire County Council’s participation in a European Union flood management project led to the creation of Lamb Drove, a residential development featuring best practice sustainable urban drainage techniques.

We talked to Mark Vigor, the director of strategic planning at Cambridgeshire County Council and the Lamb Drove project manager.

“The Cambridgeshire sub-region is experiencing major housing growth, with 73,300 new homes due to be built by 2021,” explains Vigor. “Alongside this, our county is one of the lowest-lying and driest parts of England - which puts us at increased risk of flooding.” These were the two key drivers for the project.

Developing a showcase scheme

The Lamb Drove development was part of Cambridgeshire’s ‘floodplain land use optimising workable sustainability’, or FLOWS, project, which ran for three years from 2004 to 2007. The aim of the project was to develop a practical scheme showing people how to adapt to cope with increased levels of street water and the threat of flooding.

‘When the project got under way in 2004, the lessons from the floods of 2000/01 were high on our agenda – we knew that we had to take steps to prepare for major storms and other severe weather events,’ explains Vigor. ‘It was natural for us to be involved in projects which dealt with managing flood risk and we were also keen to exchange best practice approaches with European partners.’

Selecting the site

Lamb Drove is a residential development of 35 affordable homes, built by registered social landlord Cambridge Housing Society. Cambridgeshire selected Lamb Drove for the FLOWS exemplar project for its suitability in demonstrating a range of sustainable water measures. The site size of one hectare meant that the development would be manageable. The site also had a mixture of building densities and came with planning permission.

Public and private sector partners were keen to be involved in the project, creating a group of stakeholders with a broad range of interests. ‘Registered social landlords were particularly keen to be involved, for the chance to demonstrate their sustainability credentials to the then Housing Corporation,’ says Vigor.

Designing the drainage system

SUDS involve management practices and control structures that drain surface water in a more sustainable way than conventional techniques. From the project outset, the local authority worked with drainage consultant Royal Haskoning to ensure that sustainable drainage was incorporated into the masterplan for the development.

Although the design for the drainage system was revised several times, the overall aim was to establish a natural flow pattern that would retain water within the site and control the flow and release of water into the wider catchment area. The final design incorporated permeable paving, green rooftops, swales and detention basins.

Monitoring performance

Following the completion of Lamb Drove in 2006, Cambridgeshire County Council continued to work with Royal Haskoning to monitor the long-term impact of the SUDS. A two-year monitoring project started in late 2008, with funding coming from organisations including DEFRA, the Environment Agency and Cambridgeshire Horizons, the local delivery vehicle responsible for delivering growth in the sub-region. ‘The site is working well and we’ll continue to monitor the performance of the SUDS closely over the coming months and years,’ explains Vigor. ‘We published the first monitoring newsletter in 2008 and will be producing an interim report in autumn 2009.’

Learning from the project

Vigor says that a central lesson from the project is that SUDS must be an integral part of the development process from the start. ‘Practice follows policy, so SUDS need to be enabled through local planning policy,’ says Vigor. Local authorities that are still working their way towards adopting their core strategies have a particularly good opportunity to incorporate SUDS into local development policy.

Vigor also emphasises the importance of having a sound arrangement for the long-term maintenance of SUDSs. Lamb Drove is well placed in this respect, as Cambridge Housing Society has an ongoing interest in the upkeep of the 35 homes and the site.

The FLOWS project produced a number of reports outlining the lessons learnt from the development and success of Lamb Drove. Cambridgeshire County Council has also published a best practice guide and web content based on the project.

Further information

Floodplain land use optimising workable sustainability (FLOWS)