KCC emphasises that new development must integrate SuDS that manage rainfall naturally, deliver multiple benefits, and include clear long-term maintenance arrangements. In line with DEFRA’s National Standards, it is expected for SuDS to mimic natural drainage and manage surface runoff at or close to the surface and as close to its source as practicable – simple pipe to strategic large basins will not be acceptable, for example.
KCC advocates for SuDS integrated from the earliest planning stages of masterplanning by embedding SuDS as multi-use open spaces, aligning with key green routes and utilising retention basins and wetlands as community assets. Multi-functionality is an important consideration, and SuDS should improve amenity, support biodiversity and provide safe, functional public spaces.
There are five key success factors in delivering SuDS in Kent:
- Early LLFA engagement
- A clear design vision
- SuDS considered from onset of masterplanning
- Strong interdisciplinary teamwork
- Competent contractors and proper installation records
Please note that the Environment Agency remains a statutory consultee for all development at risk of flooding from rivers and the sea, defined as Flood Zones 2 and 3. They should be consulted as early in the development planning process as possible. Their formal consent will also be required for any works that might affect a main river or flood defence.
National requirements
The National Planning Policy Framework (NPPF)
The NPPF sets out the basis of how sustainable drainage systems should be approached within planning policies and decisions. All SuDS strategies must comply with NPPF requirements for sustainable development.
DEFRA National Standards
KCC explicitly bases its reviews on the latest DEFRA National standards for sustainable drainage systems (SuDS), including the runoff hierarchy, management of everyday rainfall, and minimum design criteria.
Mandatory Country-level requirements
The following technical information is provided by the relevant highways teams and forms mandatory County-level requirements for highways. Additional links to view this information are provided at the bottom of the page.
County-level Guidance
This guidance supports the mandatory County-level requirements listed above.
Industry Best Practice Guidance
The external links below provide industry best practice guidance, to support high-quality SuDS design in Kent, which reflects Kent’s Sustainable Design Principles.
All developments should engage in early joint discussions with the Local Planning Authority and KCC as the Lead Local Flood Authority to ensure the correct and appropriate surface water drainage solution is achieved. Please see Expert advise: who to speak to? for more information and the pre-application process.