## Discharges

MOHID Land forum. Questions and discussion related to MOHID Land
epelde.ane@gmail.com
Posts: 172
Joined: Thu Jan 01, 1970 00:00

### Discharges

Hi,
I want to create a discgharge and I wonder if it is posible to simulate a discharge of which you know the maximum value. I´ve selected 3 nodes and I´d like to say that, as maximum, they output from my waterdhed Xm3/s. So, when it flows through the node more that it, the output is the value given, and, when it flows less, the output is all the quantity.
Can I do this by giving as a discharge of a constant value?

Thanks,
ane

Jauch
Posts: 98
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

Hello Ane

If I understood, you want to pump water off from the channel at some specific nodes, right?

In theory, this is possible with a discharge. All that you need is to set a negative value.
In practice, is not that simple.

The discharges were made to pump water into the channel, not to pump it off.
So, if you pump off more water than there is in the channel, you will have a negative value for the volume and probably this will have a very bad negative impact in the results (if not broking the simulation).

This is an important feature that we want to put into the model, but will take some time before we can realese a code with it.

So, right now, I think you can't do it, but I hope soon this will be possible.

epelde.ane@gmail.com
Posts: 172
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

I see.. It would be great if it was possible to make a maximum discharge because I think that it would best fit with my situation.
What I have is a channel that takes off water from the watershed. It takes as maximum 9m3/s and not from the same point but from different ones, because it is a channel that crosses the drainage network from 3 different channels. So I had thought to create 3 discharges of 3m3/s each one.
On the other hand, I have data of the water that is taken off but these measures are done from an outer point in the watershed. Would it be the same to simulate it as if the measures were done more downstream?

I attach an sketch I think will help my explanation
Attachments
arroa.png (94.87 KiB) Viewed 11870 times

Jauch
Posts: 98
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

Hello Ane

Well, first, I would like to tell you that soon will be possible to have discharges to pump water off a channel, with a maximum value. When I say soon, I say in a 2 or 3 weeks maximum.

For your idea of put a discharge (yellow marker) down the stream, it may work.

If you do not need to know exactly the amount of water that is been taken from each of the real discharge points (green), or if the behaviour in that part of the basin is not so important, and you are sure that the flow at the yellow point is alwys higher than 9m3/s, than you can use this aproach.

The only problem that I see here is this.
If the flow in the three river streams where you have the real discharges are different and can be lower than the discharges capacity, than maybe the amount of water that you will take off down the river can not be the same that is taken off on the three discharges...

Lets say that each discharge has a maximum input of 3m3/s, and that the flow that pass in each discharge position is as follow
D1 = 8m3/s
D2 = 1m3/s
D3 = 1m3/s

In the point where you have data you will see an output of 5m3/s, because the first discharge, despite the fact that the flow at that point is 8m3/s, has the hability to take in only 3m3/s.

But on the discharge dow the river, you will take the maximum 9m3/s, because in fact there are more than this flowing through it.
To this do not happen, the three rivers where the pump stations are located must have a flow always greater than 3m3/s. In that case, put the three discharges on the correct place will be better than put only one down the river.

You can try this aproach, but I think you will get better results when we launch the next version of MohidLand, where will be possible to do what you want without have to worry about input discharges being greater than the flow on its location...

epelde.ane@gmail.com
Posts: 172
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

Ok, so for now I will put a discharge on the yellow marker to see how the flow downstream change, and I´ll change it when the next version is launched.
Regards,
ane

epelde.ane@gmail.com
Posts: 172
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

Hello,
I think I´m missing something when I create the discharge, because in the model output I find:

"-----Discharges------
Numbre of discharges : 0" (And I guess that it is needed a 1 instead of a 0 if I want to compute a discharge).

I´ve done the following:

1. By querying th drainage network layer I´ve picked the node in which I want to create the discharge.
2. I have created a time series file (srm) with the information of the discharge. I havent written the coordenates X and Y because I thought that giving the node ID would be enough for mohid to know where the discharge has to be.
3.In the discharges module, I neither have written the I,J,K instead, I wrote the NODE_ID (these are alternatives to give a location, arent them?) and, I wrote the path to the *.srm in the keyword DATA_BASE_FILE.
4. In drainage network module I activated discharges with DISCHARGES:1.

I think that this would be the way, but when I run the model, it seems that it doesnt take it into account.

I know that I can activate discharges in the module runoff, but this would be to input water to the watershed surface or to take water from surface, isnt it?

Thanks again

Jauch
Posts: 98
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

Hello Ane

I use these steps:

Code: Select all

`1. In the DrainageNetwork input fileDISCHARGES : 12. In the Discharges input file<begindischarge>NAME                      : Laje's RiverDESCRIPTION               : testNODE_ID                   : 468DATA_BASE_FILE            : ..\General Data\Boundary Conditions\Discharges_3.srpFLOW_COLUMN               : 2<enddischarge>`

Have you set the FLOW_COLUMN keyword, to indicate the column where is the flow data inside the file? Usually the first column is the time and the second is the discharge
(NAME, DESCRIPTION and NODE_ID are for my project)

If you send me your project, I'll take a look
Also, sometimes a mispelled keyword can cause much trouble.

epelde.ane@gmail.com
Posts: 172
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

Hello Eduardo,
First of all thank you very much for all the replies
I´ve checked these two files and they seem ok, the only difference I found was that my discharge file was a *.srm and yours a *.srp. I thought that srp were files created by mohid, and the only time series files to input the information were srm..
Do you think that the error can come from this?
Regards,

Jauch
Posts: 98
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

Hi Ane

No, the file name will not be the error, because any file name is possible (and any extension too).

I assumed that you are using the Mohid Studio to Run the simulation.
Probably this will not be the reason for this behaviour, because I think it would raise an error, but you can see if in the nomfich.dat file in the exe folder there is a line with the DISCHARG keyword and if the file to where it is pointing is the correct one...

Besides this, for now, I can't see anything else that could cause this problem...

You can export your project (from mohid studio) and upload here as an attachment, and I'll take a look on it

epelde.ane@gmail.com
Posts: 172
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

There isnt any file related to discharges in nomfich.dat
Maybe it needs more time to create the discharge? cause I stopped the simulation when I saw the first log output saying that there werent discharges.. I thought that it should have appeared just from the beginning..

Jauch
Posts: 98
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

Hi Ane

If there isn't the keyword DISCHARG in the nomfich file, thi can be the problem.

You are running the simulations from Mohid Studio or from command line directly?
If you are using Mohid Studio, you need to click in the Simulation in the Tree view to select it and after than click with the right buttom of the mouse on it and chose "properties". In the properties you have to ADD the Dischargesa module and press OK.

This will ensure that Mohid Studio put the DISCHARG keyword in the nomfich file.

epelde.ane@gmail.com
Posts: 172
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

Hi eduardo!
yes, i did as you say. When I created the simulation I choose all the modules i needed including the discharges one.
So, all modules here should have a link in the nomfich file, right? but this one doenst..

frank.maretec@ist.utl.pt
MOHID Guru
Posts: 151
Joined: Thu Jan 01, 1970 00:00
Location: Technical University of Lisbon
Contact:

### Re: Discharges

Dear Ane,

in this case I assure that MOHID Studio does not have a bug I'm using this configuration since a lot of time and it works well.

Please be aware that the Nomfich Files are only created, right before you launch the simulation. So after adding the Discharge Module to the simulation, the nomfich file isn't changed. It only gets changed when you select "run" or "schedule" simulation. Please also notice that there are the nomfich_x.dat files in the "data" folder and the nomfich.dat file in the "exe" folder. The later is a temporary copy of the nomfich_x.dat files, only used during the startup of the runs.

Hope this helps.

Frank
In order to understand recursivity you must first understand recursivity.

epelde.ane@gmail.com
Posts: 172
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

I got finally the link to discharges file in Nomfich , although, I undestand with the logout message that it is not taking into account the discharge I created, because in the begining it appears something like:

------Discharges-----
Nº of discharges: 0
..
Is the "out volume channel.srb" the file where I should check it? What does this file represent? the water which has been taken out from all the discharge points, (as a sum of all of them)?
And similarly, out volume overland, will be the water taken out from discharges made on the runoff. Is it possible to make a discharge within the porous media? How can I represent for insatnce, a pumping procccess?

davidbrito
Posts: 187
Joined: Thu Jan 01, 1970 00:00

### Re: Discharges

Hi anne,
can you post here your discharge file?

David