New approach to sustainable drainage set to reduce flood risk and clean up rivers 

The Department for Environment, Food and Rural Affairs (Defra) published a report on 10 January 2023 of its review of sustainable drainage systems (SUDS) and announced plans to make SUDS mandatory for new developments in England. Defra will consult on the proposals later this year.

Environment Minister Rebecca Pow said:

• Our traditional drainage systems are under increasing pressure from the effects of climate change, urbanisation and a growing population.
• The benefits of sustainable drainage systems are many – from mitigating flood risk by catching and storing surplus water and reducing storm overflow discharges, to enhancing local nature in the heart of our developments and helping with harvesting valuable rain water.
• Taking a more consistent and effective approach to sustainable drainage systems will improve the resilience of our drainage and sewer infrastructure, while reaping these broader benefits.

SUDS collect surface water run-off and release it slowly, rather than discharging it all straight into the public sewer system or watercourse. They mimic the way surface water run-off occurs on undeveloped land, using soakaways, grassed areas, permeable surfaces and wetlands.

This reduces the impact of flooding and pollution. In England, the government has to date used the planning system to encourage the use of SUDS, whereas the Welsh Government dealt with this under the Flood and Water Management Act 2010.

Defra intends:

• To implement the relevant provisions of the Flood and Water Management Act 2010 in England. Implementation will guarantee that SUDS are designed, constructed, adopted and maintained to national standards throughout the development’s lifetime. The government will consult on a full regulatory impact assessment before making its final decisions on scope, threshold and process.
• That the SUDS Approving Body (SAB) will sit within the unitary authority or county council, if there is not one.
• That permitted development under 100 square metres, single buildings under 100 square metres and construction work carried out by an internal drainage board (under the Land Drainage Act 1991) will not require approval.

Defra will also conduct a full analysis of the costs and benefits, including the SAB running costs and the SUDS operation and maintenance costs. The net additional cost to local authorities will be assessed and funded.

There will be transitional arrangements for those developments at an advanced stage of planning at the point the new statutory provisions are commenced in England, to avoid incurring additional work and costs.

Defra will consult on the impact assessment, national standards for SUDS and statutory instruments in 2023. Defra expects the statutory provisions to be implemented in England during 2024.

Sources: Defra: Press release: New approach to sustainable drainage set to reduce flood risk and clean up rivers (10 January 2023), Defra: Policy paper: Sustainable drainage systems review (10 January 2023).