Subject: irrigation demand Posted: 4/18/2017 Viewed: 82 times
what do the water demand and supply requirement in the result tab actually represent. it is a bit confusing. Hoping for your guidence
Subject: Re: irrigation demand Posted: 4/18/2017 Viewed: 49 times
When looking at the two results, you'll see that the text begins to clarify the difference:
Water Demand (not including loss, reuse and DSM)
Supply Requirement (including loss, reuse and DSM).
So the different between the two has to do with these three factors: loss, reuse and DSM.
To learn what these are, go into your demand site. You've probably been entering data under your "Water Use" button, but to the right of it are two buttons called "Loss and Reuse" and "Demand Management."
Start with "Loss and Reuse", which has tabs for rates for both of those. You can imagine that your city citizens, for example, might demand 300 m3/person/year, but if the city transmission link has a loss rate of 10%, the *demand* doesn't change, but there is a higher *supply requirement* that incorporates the loss in the system, that specifies the amount of water that would need to be transferred (330 m3/person/year).
Similarly, if you have reuse in the system, the total demand stays the same, but the reuse means that less water needs to be transferred (less supply requirement).
The next data entry button in your demand site, to the right of "Loss and Reuse", is "Demand Management". This assumes that there is a percentage reduction in demand due to demand side management programs. You could of course enter this information directly into WEAP under the "Water Use" button as well, but this is another way to do it. See the "Refining the Demand Analysis" module in the WEAP tutorial. This would be another example where the "supply requirement" would be less than the demand.