Policy information sourced from the Epping Forest District Local Plan 2011-2033

DM16 Sustainable Drainage Systems

  • All proposals for new development must seek to manage surface water as close to its source as possible using the most appropriate sustainable drainage systems solution, or combination of solutions, taking into account site specific circumstances and the Council’s preferred drainage hierarchy in the following order:
    1. store rainwater for later use;
    2. use infiltration techniques, such as porous surfaces in non-clay areas. Porous surfaces are suitable in areas of clay but must be adequately tanked with an outfall. The District is predominantly clay so any infiltration proposals must be subject to and pass the relevant percolation tests;
    3. attenuate rainwater in ponds or open water features for controlled release;
    4. attenuate rainwater by storing in tanks or sealed water features for controlled release.
  • The Council will encourage the use of green, brown and blue roofs.
  • The Council will require sustainable drainage systems to be sensitively incorporated into new development by way of site layout and design, having regard to the following requirements:
    1. all major development proposals will be required to submit a drainage strategy to identify the most appropriate drainage solutions;
    2. all major greenfield development proposals will be required to reduce surface water flows to the 1 in 1 greenfield run-off rate and provide storage for all events up to and including the 1 in 100 year critical storm event including an allowance for climate change, and include at least one source control sustainable drainage systems measure resulting in a net improvement in water quantity and quality discharging from the site to a sewer and/or a watercourse;
    3. all non-major greenfield development proposals should aim to achieve the 1 in 1 greenfield run-off rate where possible, including an allowance for climate change, or a rate as otherwise agreed with the Council;
    4. all major and non-major brownfield development proposals which involve a quantum of new-build should aim to achieve the 1 in 1 greenfield run-off rate and, at a minimum, achieve a 50% reduction in existing site run-off rates for all events, including an allowance for climate change, and include sustainable drainage systems measures resulting in a net improvement in water quantity and quality discharging from the site to a sewer and/or a watercourse; and
    5. for all development where the 1 in 1 greenfield run-off rate cannot be achieved, justification must be provided to demonstrate that the run-off rate has been reduced as much as possible.
  • Where sustainable drainage systems are implemented they will be expected to:
    1. meet the requirements set out in national standards, and meet the Council’s standards if they exceed national guidance;
    2. incorporate measures identified in Surface Water Management Plans;
    3. be designed to maximise biodiversity and local amenity benefits and where appropriate, ensure that sustainable drainage system techniques provide for clean and safe water at the surface;
    4. improve water quality; and
    5. full details of the means of achieving future management and maintenance of the sustainable drainage system scheme to ensure that it will function effectively over the lifespan of the development will be required, including responsibilities and funding.
  • The Council will give consideration to adopting sustainable drainage systems. Financial contributions will be sought for maintenance if adopted by the Council.
  • Where sustainable drainage systems cannot be implemented due to site constraints (such as land contamination) robust justification must be provided along with proposed alternative approaches to surface water management.
  • Where particular sites and the wider catchment have identified existing flood issues, the implementation of good practice on Natural Flood Management must be explored.

For more information please see the Epping Forest District Local Plan 2011-2033