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Hi,

It is wonderful that V7P2 has the rainfall-runoff model where we can add rainfall time series to model the discharge generated from rainfall. Thanks!

However, in the cas file (t2d_pluie_cn_geo_hyetograph.cas) I see:

RAIN OR EVAPORATION = YES
RAIN OR EVAPORATION IN MM PER DAY = 100.0

Are these 2 lines necessary?

I need to add a evaporation time series in my model without which I cannot get accurate scenarios. Because, my study area (inner Niger delta in West Africa) has huge loss from evaporation and I need to simulate with at least 4 months data.

Can anybody help me on how can I add evaporation time series? Best regards..

Hello,

As far as I can see there is no way of inserting a time-series of rain/evaporation in the cas file.

Then, digging the code of TELEMAC2D, I found the location where the rain is taken into account. It is in the subroutine PROSOU:RAIN_MMPD is the value of the rain/evaporaion in mm/day that you provide in the cas file.

The easiest way I can think of is to change this block to read from an external file.
The simplest way of doing that is adding a modified version of prosou.f to your fortran file and inserting an OPEN and READ statements to the code aboveThis should work, but keep in mind that your input file must be in a time interval equal to that of TELEMAC2D.

To have your file with a different time step you would need do add a few lines to interpolate along the time.

Hope it helps,

Best regards,

Phelype

Hi

If I understand correctly and if I follow the "pluie" example, Telemac2d (v7p2) reads the rainfall from an external file. The rainfall text file has the following format:

#T (s) RAINFALL (mm)
0 0
86400 4
172800 15
259200 6
345600 0
..
..

It is fine for me because I can also add distributed CN with it for the runoff.

But I would like to add following (for example) for my evaporation data:

#T (s) EVAPORATION (mm)
0 6
86400 7
172800 8
259200 6
345600 8
..
..

How can I add above evaporation data with new rainfall- runoff model?
I have also seen in the user manual that "evaporation is not supported".
Do you recommend that I use separate code e.i. prosou.f for evaporation?

Thanks,

Momin

Hello,

Sorry, I've mistakenly looked at the code of v7p1.

Indeed, in v7p2 the time series of rainfall is already implemented. The modification I suggested is useless.

Well, then. Looking at the subroutine runoff_scs_cn.f, that reads the formatted rainfall file, indeed, evaporation is not supported. There is a verification that if the value of the rainfall is negative, telemac2d is aborted.But as soon as that is implemented, in principle what you would need to do is indicate a negative value of rainfall.

What you could try is to use v7p1 to simulate the evaporation by providing a negative value of rainfall since it didn't have this limitation. If it would work I don't know, but you can try.

Hope it helps,

Best Regards,

Phelype

Hello

Sorry for this late reply.

In your case if I understant well, you want to introduce a time varying evaporation.
In this case, the easiest way to do is to adapt the case waq2d_thermic that you can find in folder examples/waqtel.
In this case, exchange with atmosphere, including rain, is taken into account. In your case you need only to put all the other columns of file "meteo_thermic_case1.txt" (T_air, Pvap,...) to zero and make variation only on the colomn corresponding to rain by adding negative rain values (evaporation).

I hope that this helps

with my best regards

Riadh

Ps: new features added for v7p2 dealing with CN methods are mostly recommanded to handle rainfall-runoff aspects and thus are not suitable for your case.

Thank you very much Dr. Riadh Ata,

You are right that it is time varying evaporation. I would also like to add time varying rainfall.

I looked on the "meteo_thermic_case1.txt" where I found that there is one column for rainfall.

I am thinking of making a combined time series for rainfall and evaporation by subtracting these two and put the values in that column. In that case, time series will contain positive and negative values like following:

#time T_air Pvap Vit_Vent wind dir Nebulo Ray3 atm rain
s degC hPa m/s degree octa W/m2 mbar mm
0 0 0 0 0 0 0 0 -5
86400 0 0 0 0 0 0 0 -6
172800 0 0 0 0 0 0 0 -5
259200 0 0 0 0 0 0 0 10
345600 0 0 0 0 0 0 0 13
432000 0 0 0 0 0 0 0 0
518400 0 0 0 0 0 0 0 -3
604800 0 0 0 0 0 0 0 0

Could you please tell either simulation will be fine with +/- values at the rain column.

I would also like to inform you that the boundary inputs i.e Q, WL are also time varying.

Thanking you,

Momin

hello Momin

yes this will be fine. just take care about the order of magnitude of rainfall and evaporation which could be very different.

with my best regards

riadh

Hello Dr Riadh,

Thank you very much.

Eagerly waiting to meet you at the short course in Montreal.

With best of my regards,

Momin

Hello Dr Riadh,

I am trying to do an actual simulation with rain and evaporation along with Q and WL. When I couple telemac2d with waqtel, I get the following massage:

GRACJG (BIEF) : EXCEEDING MAXIMUM ITERATIONS: 60 RELATIVE PRECISION: NaN

A number of such lines are generated. However, at the end of each step, I get the result.

May be the problem comes from temperature simulation which I do not need and I put zero data at the input file.

Is it possible to remove the lines "GRACJG (BIEF) : EXCEEDING ......" ?

best regards,

Momin

Hello Momin

If you do not need temperature in your model you do not need to use Waqtel coupled with Telemac. But this is less real scenario since evaporation is tighly linked to temperature.
Anyway, if you need only rainfall and evaporation, you can only adapt the case "pluie" as said earlier.

You can have a look on the subroutine meteo.f (in folder sources/telemac2d) if you need any additional adaptation.

with my best regards

Riadh