What a Surface Water Drainage Strategy in Scotland Needs Before Submission

1. A clear understanding of site conditions

This covers everything from topography and natural drainage paths to ground conditions, infiltration potential, and any existing drainage infrastructure. A solid baseline is essential before any strategy can be developed.

2. Flood risk considerations

Identify existing overland flow routes and exceedance pathways, then assess how the proposed development may alter them. The strategy must show how surface water will be managed safely during both everyday rainfall and extreme events.

3. Assessment of the drainage hierarchy, with Scottish Water and SEPA engagement

Where you want to discharge and where you can discharge are not always the same. Early engagement with Scottish Water and alignment with SEPA guidance helps confirm what is feasible before progressing.

4. SuDS proposals appropriate to the site, in collaboration with the wider team

Consider which SuDS features are suitable for the site and how they interact with the proposed infrastructure and landscape. On many sites, drainage requirements will influence or even dictate elements of the layout, so early collaboration with the wider team is essential. The strategy must demonstrate that the chosen SuDS provide appropriate levels of treatment and manage runoff effectively.

5. Design criteria and runoff calculations

Establish pre‑ and post‑development runoff rates and explain how flows will be controlled. Note that discharge expectations vary between Scottish local authorities, so local guidance must be checked early.

6. Clarity on maintenance and adoption requirements

Long‑term maintenance is critical for SuDS performance. The strategy must identify who will be responsible for maintaining each component. If adoption is proposed, the system must meet the relevant standards and obtain the necessary approvals.

7. Prepare drawings and the technical report

Only once all assessments, decisions, and coordination steps are complete should the drawings and technical report be prepared.