In its simplest form XPRafts can be used with design storm bursts as per ARR with appropriate loss rates to estimate runoff with a similar frequency of occurrence to the rainfall itself.

This procedure is by far the most commonly applied with runoff routing techniques in a design mode to estimate frequency based design hydrographs.

Runoff frequency is, however, a function of a number of input parameters including rainfall, soil antecedent moisture and infiltration characteristics, amongst others.