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All Topics | Topic "Error in result calculation - Loop in the schematic"
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Author Message
Ms. Rebeca Doctors

Subject: Error in result calculation - Loop in the schematic   
Posted: 6/1/2016 Viewed: 10515 times

My name is Rebeca and I'm running a WEAP simulation for a river basin in Brazil. I've added the supply nodes and rivers and demand sites. Also I've added the river headflows, storage capacities of reservoirs and the annual water use rate. I've tried to run an initial result, but I get the following error: "There is a loop in the schematic, involving the following river nodes and reaches: Rio Paraiba: Rio Pirai inflow
Rio Pirai: S.Cecilia inflow [....] ".

Do you know what this means and how I could solve it?

Thank you in advance,


An image of the erro is available in this link: http://psr.me/4u6me5
Ms. Stephanie Galaitsi

Subject: Re: Error in result calculation - Loop in the schematic   
Posted: 6/6/2016 Viewed: 10467 times
Dear Rebecca,

I'm guess from the description that you must have a loop somewhere in your schematic - for example, as the river is flowing downstream, part of it is diverted and returned to the flow upstream. This can be problematic for WEAP because it could count this water twice in the same time step, so it impedes the system calculations.

Ms. Rebeca Doctors

Subject: Re: Error in result calculation - Loop in the schematic   
Posted: 6/6/2016 Viewed: 10461 times
Hello Stephanie,

Thank you for your reply! That's exactly what I have. I've taken this part out of my model, just to see a first run of the model. However, this part is extremely important if I want to model realistically what is happening. The following link shows a schematic of the system http://psr.me/m2ha23
As you can see, part of the water is diverted, creating a loop. Is there any way I could keep this schematic but manage it to run? Do you think that if I load rules, such as the amount of water to be diverted, WEAP will run?

Thank you!


Ms. Stephanie Galaitsi

Subject: Re: Error in result calculation - Loop in the schematic   
Posted: 6/6/2016 Viewed: 10452 times
Dear Rebecca,

Because you don't have any demands in your system within the loops, it's fine in this case to force WEAP to allow loops (it's not supplying the demand sites with duplicated water). I'll send you an email with the instructions.

Topic "Error in result calculation - Loop in the schematic"