Units of SWAT outputs

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cyrilgarneau@gmail.com
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Units of SWAT outputs

Postby cyrilgarneau@gmail.com » Tue Jul 02, 2013 09:38

Dear all,

I'm using the SWAT-MOHID coupling to provide inputs to my river model. However, I cannot find the units used to define the different quantities that SWAT generates.

Specifically, what are the units of the Sediment_concentration?

And at a larger scope: How are the units defined within MOHID? I keep searching for definition, but without success.

Thank you for everything,

Cyril Garneau

cyrilgarneau@gmail.com
MOHID Beginner
Posts: 19
Joined: Tue Oct 18, 2011 12:28

Re: Units of SWAT outputs

Postby cyrilgarneau@gmail.com » Tue Jul 02, 2013 10:03

Sorry, I must already make a comment: The units are clearly indicated in the *.rch outputs. However, they are not indicated in the *.dis outputs.

Furthermore, I generate outputs for an upstream subwatershed. I would then assume that the sediment concentration is the same in both ouputs (*.rch and *.dis), but they are not. What is the difference between these two outputs?

And finally, how can one transform the sediments from tons (the specified unit) to tons/seconds or kg/m3? In other words, which time step is used by SWAT?

Thank you

chambelpc@ist.utl.pt
MOHID Beginner
Posts: 2
Joined: Fri Mar 15, 2013 15:04

Re: Units of SWAT outputs

Postby chambelpc@ist.utl.pt » Tue Jul 02, 2013 13:57

Hello Cyrill,

The DIS files have all units in mg/l (mg/dm3) - http://www.mohid.com/wiki/index.php?tit ... _sub-basin

The RCH file have sediments in tons/day and are the sediments going out of reach - http://www.mohid.com/wiki/index.php?tit ... _sub-basin

The sediments in DIS files are the sediments going in to the channel. That is why they are different from the RCH files.

In MOHID the sediments are specified as concentration. I do not see a way of specifying in flux...

Pedro Chambel Leitão

cyrilgarneau@gmail.com
MOHID Beginner
Posts: 19
Joined: Tue Oct 18, 2011 12:28

Re: Units of SWAT outputs

Postby cyrilgarneau@gmail.com » Tue Jul 02, 2013 15:05

Thank you Pedro,

It answer all of my questions. And concerning the flux, it means that I
cannot use the RCH files directly in my river network. I will have to
transform the units to concentrations, but that's not too much work.

Thanks again!

Cyril

chambelpc@ist.utl.pt
MOHID Beginner
Posts: 2
Joined: Fri Mar 15, 2013 15:04

Re: Units of SWAT outputs

Postby chambelpc@ist.utl.pt » Tue Jul 02, 2013 15:21

Dear Cyril,
DIS files is the input of flows and concentration from each sub-basin in to its river.
The RCH files integrate all the flows and concentrations that come from the sub-basin where the reach is located but also what is coming from all the reaches upstream to it.
The RCH files are to see SWAT results in the river and to compare with measurements in the river and to compare with results in the river of other models (like Mohid Land or Mohid River Network).
So RCH should never be used as input to Mohid River Network.
Best regards
Pedro Chambel Leitão


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