Hello Stephy,

The warnings you are seeing are fairly well explained, but if you are uncertain,
it's always a good idea to contact DHI Technical Support for assistance on these
issues. Without seeing your actual model, it is difficult to offer up anything
more than anecdotal suggestions, but here goes:

1/ It is difficult to determine what the problem is without knowledge of the
river cross-section geometry and topography of the adjacent land surface, but
judging from the error, it seems to be a numerical instability issue and I would
try reducing the MIKE 11 time step.

2/ no idea

3/ This one is pretty self-explanatory and can likely be addressed by reducing
your overland flow time step.

4/ Again, reduce the MIKE 11 time step.

5/ This one might be helped by reducing time steps as well, but I am not as
confident about this one.

In general, the MIKE 11 1D river flow model should have time steps ranging from
1-15 minutes depending on a wide range of factors. If it's a deep slow moving
river, then you can probably get away with larger time steps, but that doesn't
seem to be the case with your model.

Hope this helps.

Patrick Delaney



To: hydrologymodel@...
From: stephychanym@...
Date: Sat, 8 Aug 2009 08:06:52 +0000
Subject: [hydrologymodel] Warnings related to MIKESHE coupling with MIKE11

Dear friends,

I got warnings as follows when using MIKESHE coupling with MIKE 11 to simulate
stream discharge of a small catchment. How I could find out the problems and
solve them? Thanks a lot.

1/ Warning no 42: The lateral outflow in BRANCH173 at chainage 613.646 was
greater than the amount of water available.
The lateral outflow has been modified to avoid the local water
level falling below the bed level. This modification has occured 9506 times.
First time at time step 145.

2/ Warning No 53: The total corrected volume is 0.000 m3.

3/ WARNING: Evaporation from ponded water on ground surface has been reduced
in UZ class(es) with less ponded water in transfer point(s)
than in the corresponding computational point(s).
Total apriori : 171.4545 [ catchment mm ]
Total used : 23.13893 [ - - ] ( 13.50 % of apriori ).
Please check the applied UZ classification.

4/ WARNING: Exchange flows FROM RIVER TO SZ reduced to avoid drying river.
No. of time steps: 63510
Total outflow before reduction: 19147.67 m3
Total reduced outflow : 7581.811 m3 ( 39.59652 %)

5/ WARNING: Retention curve too steep. Processed water contents
and/or capacities have been adjusted.
- average reduction of Theta = -2.4895095E-03
Max = -4.3501346E-03 from 1.0971338E-02 to 6.6212039E-03 at pF =6.950000
- average rel. change of capacity = 9.9819386E-04
Max = 3.3869114E-02 from 4.8696500E-09 to 5.0345808E-09 at pF =6.950000

(The soil I use in my study is decomposed grantie soil with the hydraulic
conductivity of 1.1E-005 m/s. no specific value for other parameters )

Thanks very much for your kind help!