Hi All,

My general question is - can direct rainfall to landscaped areas that soaks in through the soil contribute to the irrigation demand in the WEc1?

Our project is in Australia and using the bureau of meteorology (BOM) data for ETo - our site is showing a total water applied (TWA) of 29.5 kGal for Jan (month with highest ETo rate). Looking at rainfall data for the month, we can expect around 6 kGal of direct rainfall over the landscaped area that would be soaked into the soil. My interpretation is that the supplied irrigation demand would then be 23.5 kGal.. However looking at the LEED worked example in the reference manual they don't seem to consider the rainfall contribution (only potable / recycled water contribution)??

I think my confusion revolves around how ETo is calculated. The LEED referenced ETo is the amount of water required in a region to grow a reference plant (not clear if this is water in addition to natural rainfall?) - whereas in Australia it is the amount of water that is expected to be evaporated from moist soil - so in our case; total water applied (TWA) minus rainfall = irrigation demand.

I think I can explain this clearly enough to the assessors, just wondering if anybody has done something similar before?

Note that i'm only including rainfall directly to the irrigated areas that is soaked in through the soil.. I'm no including rainfall to rooftops etc. which is diverted to the storage tanks (not double counting).

Thanks.