Policy information sourced from Brentwood Local Plan
BE05: Sustainable Drainage
All developments should incorporate appropriate Sustainable Drainage Systems (SuDS) for the disposal of surface water, in order to avoid any increase in surface water flood risk or adverse impact on water quality.
Development within areas identified as a Critical Drainage Area (CDA) on the policies map, should optimise the use of Sustainable Drainage Systems by providing an individually designed mitigation scheme to address the sitespecific issues and risk, as informed by a site specific Flood Risk Assessment. This could be provided as part of the Drainage Strategy and must address any issues highlighted in the Surface Water Management Plan, where relevant.
Greenfield developments, major development and all development within a Critical Drainage Area must achieve a greenfield runoff rate. Where it is demonstrated that this is not possible on brownfield developments then a runoff reduction of 50% minimum should be achieved. The technical approach should be justified in the Drainage Strategy.
Applicants are required to submit a surface water Drainage Strategy and a Flood Risk Assessment for all major development as well as for all development within a Critical Drainage Area. The Drainage Strategy must include a SuDs Management Plan setting out the long-term management and maintenance arrangements.
SuDs will be required to meet the following design criteria:
- the design must follow an index-based approach when managing water quality. Implementation in line with the updated CIRIA SuDS Manual is required. Source control techniques such as green roofs, permeable paving and swales should be used so that rainfall runoff in events up to 5mm does not leave the site;
- SuDS should be sensitively designed and integrated into the Green and Blue infrastructure to create high quality public open space and landscaped public realm, in line with Strategic Policy NE02: Green and Blue Infrastructure;
- maximise opportunities to enhance biodiversity net-gain;
- improve the quality of water discharges and be used in conjunction with water use efficiency measures;
- function effectively over the lifetime of the development;
- the preferred hierarchy of managing surface water drainage from any development is through infiltration measures, secondly attenuation and discharge to watercourses, and if these cannot be met, through discharge to surface water only sewers;
- have regard to Essex County Council SuDS Design Guide 2020, or as amended.
When discharging surface water to a public sewer, developers will be required to provide evidence that capacity exists in the public sewerage network to serve their development, in line with policy requirements in BE02 Water Efficiency and Management.
Development proposals should be designed to include permeable surfaces wherever possible. Proposals for impermeable paving, including on small surfaces such as front gardens and driveways, will be strongly resisted unless it can be suitably demonstrated that this is not technically feasible or appropriate.
For more information please see the Local Plan