Subject: consumption WEAP = efficiency irrigation Posted: 4/8/2025 Viewed: 233 times
I compare the efficiency of 28% and 65%. it should be according to the formula then debit/efficiency. but WEAP analyzes with debitxefficiency.
so I get the value of increasing efficiency to 65% to be more deficit even though the deficit should actually be reduced because there is an improvement in the irrigation network. can you explain about consumption=irrigation efficiency in WEAP?
In modeling irrigation in WEAP using a demand node, the "Consumption" parameter would indeed represent the irrigation efficiency. If you are modeling irrigation using an irrigated catchment node, it would use a parameter called "Irrigation Efficiency" instead.
More on irrigation efficiency parameter:
For irrigation efficiency, are you referring to an irrigated catchment using the MABIA method? If so, then the irrigation efficiency represents the percentage of supplied water (from any source) that is available for evapotranspiration for that catchment(representing the water that is actually used and consumed by the crops). I believe a lower irrigation efficiency would result in a higher supply requirement and higher return flows.
More on consumption parameter:
Consumption on the other hand is used for demand sites. It changes the % of the inflow that is consumed, used to determine the inflow. For agriculture, it would indeed represent irrigation efficiency. Consumption does not affect demand or supply requirement.
Hope this helps!
-Doug
Ms. Belia Tatika
Subject: Re: consumption WEAP = efficiency irrigation Posted: 4/8/2025 Viewed: 217 times
In conducting my simulation using the WEAP model, I encountered some conceptual inconsistencies related to the input parameters and theoretical expectations. I would like to ask two key questions:
1. Should the parameter Annual Water Use Rate in WEAP be based on the Delivery Requirement (DR) or the Net Field Requirement (NFR)?
This distinction is crucial, as it affects the validity of input data in reflecting the actual water needs, especially when irrigation efficiency is being compared across scenarios."*
2. I found a discrepancy between the theoretical expectations and the simulation results. Theoretically, an improvement in irrigation efficiency (e.g., from 28% to 65%) should reduce the water deficit. However, in the simulation, increasing the efficiency led to a greater deficit.
Upon further review, I discovered that WEAP defines 'Consumption' as the proportion of water that is not returned to the system (non-recoverable losses), thereby applying the formula:
Water Use
Water Use=Delivery Requirement (DR)×Consumption
This contrasts with the theoretical (KP) approach, where:
Delivery Requirement
= Net Field Requirement (NFR)
Efficiency
Delivery Requirement= Net Field Requirement (NFR) / efficiency
Given this difference, the model outcomes appear inconsistent with theoretical expectations. I would appreciate your advice on whether it is appropriate to recalibrate the model based on manual calculations (using KP), or if I may include a comparison between the theoretical and simulated results as a form of cross-validation. How should such differences in formula interpretation between WEAP and theoretical literature?
Could you please clarify- are you looking at demand node objects (red circle) or irrigated catchment objects (green circle)?
Ms. Belia Tatika
Subject: Re: consumption WEAP = efficiency irrigation Posted: 4/8/2025 Viewed: 202 times
i'm looking at demand node (red circle)
could you help me to solve my problem?
Mr. Doug Chalmers
Subject: Re: consumption WEAP = efficiency irrigation Posted: 4/8/2025 Viewed: 194 times
I can provide an example-
Let's say your irrigation efficiency is 75%. In this case, if you deliver 4 units of water to your field, 3 units would be consumed by the crops and 1 unit would exit the field as return flow without being consumed by the crops. This would be modeled by setting the demand to 4 units (where demand = the amount of water needed to be delivered to the site NOT the amount of water actually used by the crops). Then, set the consumption to 25% (100%-irrigation efficiency %).
Alternatively, if you want to input the water demand instead as the water actually used by the crops, you could enter a loss rate on the demand node or the loss to groundwater or loss from system on the transmission link as 100%-irrigation efficiency %.
