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All Topics | Topic "Flood, Diversion, and Spill"
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Author Message
Bereket Tesfatsion

Subject: Flood, Diversion, and Spill   
Posted: 12/9/2010 Viewed: 19996 times
Hello everyone,
Here is the real system: there is a river and at some point-O there is a canal-A that diverts part of the river to a reservoir off the river course. At the same point, there is another canal-B which carries water to a service area. The river continues its course and carries supply for more down stream demands. Canal-A has zero slope so water can flow in both directions or none at all depending on the circumstances. If the water in the river could satisfy all demands at point-O and it still has more water left, water flows to the reservoir through canal-A. If the water in the river could not satisfy all demands at the same point, water is called from the reservoir via canal-A. However, during times of excess runoff, if the flow in the river below point-O reaches 740 cfs , then water is sent to the reservoir via canal-A and if the reservoir has no space, water is released through a spill in the reservoir.
My questions are: How do you represent such a dynamic system? The diversion with two flow directions, the spill from the reservoir, and the flood protection requirement?

Thanks,
Bereket.

Jack Sieber

Subject: Re: Flood, Diversion, and Spill   
Posted: 12/9/2010 Viewed: 19995 times
The two-way flow in Canal A could be handled with another diversion just below the reservoir which takes water released from the reservoir back to the river just below point O, in times when there is insufficient river flow to satisfy downstream demands.

However, I don't think you can implement your flood control constraint--there is no way in WEAP to implement a maximum flow constraint. One way to approximate it, if you knew how much needed to be diverted to keep the river flow below 740 cfs, would be to put a minimum flow requirement on Canal A above the reservoir with the amount that should be diverted. If this was too much for the reservoir to hold, it would automatically spill the excess.

Jack
Bereket Tesfatsion

Subject: Re: Flood, Diversion, and Spill   
Posted: 12/9/2010 Viewed: 19992 times
Thanks Jack.
What do you mean by "automatically spill the excess"? How can I view the spill? Should I attach a transmission link but then I don't have a service area to be attached to it? I was not able to attach a river to the reservoir to carry the spill away.
Jack Sieber

Subject: Re: Flood, Diversion, and Spill   
Posted: 12/10/2010 Viewed: 19977 times
Any water in a reservoir above the top of conservation pool will be released. WEAP does not differentiate between releases for downstream demand and spill above the top of conservation. You cannot attach a river directly to a reservoir, but you can put a diversion just below the reservoir. Where do you want the spill to go?
Bereket Tesfatsion

Subject: Re: Flood, Diversion, and Spill   
Posted: 12/10/2010 Viewed: 19967 times
Thanks Jack,
I want to route the spill through a river course (probably artificially made) downstream the reservoir and it would end up into a lake. I wanted to know how much water is being spilled and view it some how.
Jack Sieber

Subject: Re: Flood, Diversion, and Spill   
Posted: 12/14/2010 Viewed: 19953 times
You could put a second reservoir node below the first to represent the lake that would receive the overflow from the first.
Bereket Tesfatsion

Subject: Re: Flood, Diversion, and Spill   
Posted: 1/11/2011 Viewed: 19636 times
I was not able to put " another diversion just below the reservoir " for there was no element on the schematic to attach it to. I tried to attach the diversion directly to the reservoir and then connect it to the main river but it did not work. I used a transmission in stead and the model runs with that but I am still getting some discrepancies when I compare End of Month Storage, for each reservoir in the system, from WEAP and Observed Storage. I am trying to figure out the problem...
Jack Sieber

Subject: Re: Flood, Diversion, and Spill   
Posted: 2/6/2011 Viewed: 19629 times
Have you gotten it working? To put a diversion on the river below the reservoir, drag the orange diversion symbol from the Schematic legend and drop it on any empty reach on the river, then drag and double click on the to mark the end of the diversion. WEAP will ask you "Do you want Diversion to flow out of River ?" If you answer yes, a diversion node will be created on the main river with the diversion flowing out of it.
Topic "Flood, Diversion, and Spill"