Sustainable Drainage

Information about the impact of new development on flood risk and resilience to flooding

Introduction

Sustainable Drainage Systems offer an approach to drainage that mitigates the impact of new development on flood risk and builds our resilience to flooding. It also provides opportunities to remove pollutants from urban run-off at source, and combines water management with green space, with benefits for amenity, recreation and wildlife.

Local planning policy and decisions on major developments – 10 dwellings or more, or equivalent non-residential or mixed development – are expected to make sure that sustainable drainage systems for the management of run-off are put in place, unless demonstrated to be inappropriate.

The current national policy requirement that all new developments in areas at risk of flooding should give priority to the use of sustainable drainage systems will continue to apply.

Lead Local Flood Authority as a statutory Consultee

As a Lead Local Flood Authority, we are now a Statutory Consultee on the drainage aspect of Major Planning Applications. Please contact us to find out more LLFA@somerset.gov.uk.

We welcome enquiries before applications and encourage developers to look at the West of England Sustainable Drainage Systems Developer Guidance for more information.

West of England Sustainable Drainage Systems Developer Guidance

To develop a Sustainable Drainage Systems guidance document, we have collaborated with:

  • Bristol City Council
  • Bath and North East Somerset Council
  • North Somerset and South Gloucestershire Council

The guide is primarily intended to be used by developers, planners, designers and consultants. It is for those who are looking for guidance on the requirements for the design and approval of Sustainable Drainage Systems in the sub-region of the West of England and Somerset.

It provides information on the planning, design and delivery of attractive, high quality and well-integrated sustainable drainage schemes. These schemes should offer multiple benefits to the environment and community alike. The aim is to show that meeting these requirements need not be an onerous task and can greatly help add to the appeal of your development. The guide aims to support developers in their understanding of how the current development management process supports the delivery of high quality Sustainable Drainage Systems.

Other Sustainable Drainage Systems activities involving Somerset Council

In addition to our statutory duties, we are involved in a number of projects on urban water management with the aim of improving Sustainable Drainage Systems provision in Somerset. Following the serious flood events in the county that led to the 20 Year Somerset Flood Action Plan, a number of common questions were posed:

  • How can we better manage urban run-off?
  • Are we achieving all we can for sustainable drainage through the planning process?
  • How can we encourage developers and residents and businesses to consider Sustainable Drainage Systems when developing and redeveloping sites?
  • Are Sustainable Drainage Systems delivered by developers being constructed in accordance with the approved drawings?
  • Are Sustainable Drainage Systems in Somerset functioning as they should and are they delivering the anticipated benefits?
  • Are Sustainable Drainage Systems being maintained appropriately once constructed?

One of the workstreams delivering the actions contained in the Somerset Flood Action Plan is ‘Urban Water Management’. This workstream was created to reduce run-off and its impact from both existing and proposed developments, principally for flood risk management benefits. The Somerset Rivers Authority provides funding for a number of enhanced activities seeking to improve and promote Sustainable Drainage Systems in Somerset.

We are working with other risk management and local planning authorities to build evidence to prove or disprove these concerns and to implement measures to address known shortcomings. This is supported by the additional funding available through the Somerset Rivers Authority.

Last updated: June 19, 2024

Next review due: December 19, 2024

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