Can I estimate greenfield and post development runoff?

ReFH 2 can be used to estimate greenfield, brownfield and post development runoff rates and volumes.

Latest research has shown that FEH methods that are implemented within ReFH 2 are more accurate than methods such as IH124 for conducting greenfield, brownfield and (simple) post development runoff calculations. ReFH 2 is the recommended method within the current CIRIA SuDS guidance for estimating peak runoff rates and volumes for greenfield, brownfield and (simple) post development scenarios.

Section 9 of the ReFH 2 technical guidance provides detailed instructions on how to estimate peak runoff rates and volumes for all three scenarios, available here.