Sur1 - Mandatory - Assessment Criteria (1)

Mandatory at all levels to ensure peak rate of run-off into watercourses is no greater for the developed site than it was for the pre-development site (brownfield or greenfield).

Should comply with Interim Code of Practice for SUDS or for at least the 1 year and 100 year return period event.

• Sites less than 200 ha use IH 124 – Flood estimation for small catchments.
• Sites 200 ha and more use FEH - Flood Estimation Handbook.

An allowance for climate change should be made in accordance with current best practice (PPS25, 2006).

The Source Control Rural Runoff calculator allows you to calculate Greenfield runoff rates for IH 124 and FEH and is covered in training courses G and H. Compare the developed and pre-developed run-off rates using the ICP SUDS test in the Design Audit Wizard in Simulation APT covered in training courses C, G and H.