Sustainable Drainage Systems Major Design Guidance

Sustainable Drainage Systems (SuDS) are mandatory on all planning applications which could affect drainage on or around a development site in England.

The Town and Country Planning (Development Management Procedure) (England) Order 2015, makes The Royal Borough of Windsor and Maidenhead Council (RBWM) as Lead Local Flood Authority (LLFA), the statutory consultee for surface water drainage for all major planning applications in the Borough.

The LLFA is required to provide consultation responses on the surface water drainage strategies associated with major development to the Local Planning Authority (LPA).

It should be noted that RBWM as LLFA is not a statutory consultee in respect of groundwater, as this falls outside of our role in planning that is defined above. However, applicants should consider and mitigate against any potential impacts of groundwater on the management of surface water.

We encourage applicants to seek pre-application advice and especially where a site is hydrologically complex or where a proposed approach goes against our advice in this guidance or the National standards for sustainable drainage. Pre-application advice can be requested through the LPA who will link up with the relevant consultees including the LLFA.

This guidance sets out the LLFA’s surface water management requirements for major development in line with the National standards for sustainable drainage.

It provides a summary of the information and a checklist of the evidence needed to show that SuDS have been satisfactorily considered within the application, in accordance with:

•National Planning Policy Framework (NPPF)
•Planning practice guidance (PPG)
•Royal Borough of Windsor and Maidenhead Borough Local Plan (BLP)

Meeting the requirements set out in this guidance will assist the LLFA in assessing the application, enabling a more streamlined assessment process.

This advice does not cover in detail other considerations the LLFA may take into account such as works affecting Ordinary Watercourses or specific requirements of Flood Risk Assessments (FRAs).

The Environment Agency have created guidance for Flood Risk Assessments in relation to flood zones 1, 2, 3, and 3b.

Ordinary Watercourse Consent  is required for any works impacting a watercourse. The Council guidance for these applications and the application form can be found on the website.