Hi all,

I have some months in my dataset where the return flow volume exceeds the diversion volume. This occurs because the return flow data are reported with a one-month lag (i.e., part of the previous month’s return is recorded in the following month).

I’d like to correct for this timing issue directly in WEAP. Under the Demand → Consumption tab, I currently use an expression to consume 100% of the diverted water when the return flow volume is greater than the diversion, and otherwise consume the calculated amount:

If( Return Flow > Monthly Demand[AF],100,
100 – (Return Flow/Monthly Demand[AF]*100))

In addition, I’d like to add the remaining amount of water back to the previous time step when the return flow volume is larger than the diversion volume, to account for the lag effect.

I’d appreciate any guidance on how to write this type of time-lag adjustment using WEAP’s expression syntax.

Thank you,
Burcu