Hi,

we're pursuing credit compliance following option 2. According to reference guide (page 184), to achieve compliance, annual increase in runoff volume has to be managed (post development against natural land cover conditions). Our doubt is related with the way rainfall shall be treated in these calculations. 

Taking into account that we need annual runoff calculations for both scenarios, in order do calculate the difference between them and determine the amount of runoff to manage, I can't understand why in reference guide (page 187), the percentile 95 is referred.

How are you treating these calculations? Any specific software, excel datasheets?

Regards,