Ketaki Agrawal Junior Research Fellow

Is there a weay to batch export .dfs1 files to ASCII?

Hi,

I am working on a MIKE 21 FM coupled model (ST-SW) to compute the annual bed level change along the Beach and feeding the model with annual wave data as input .

The direction of wave driven currents are making sense to me, however, the sediment transport pattern is simulated to be governed by accretion, though the observed sediment drift is erosive.

I have tried multiple trials with varying Bed friction and directional spreading index but couldn't get the bed level change to perform as required. The beach line continues to show accretion.

Any help or advice on this would be highly appreciated .

Hi,

If you have the data for Peak wave period, Tp, then Directional spreading index would be the whole number of it. For Example if Peak wave period is 10.44sec then Spreading index is 10.

Also, you can refer to MIKE 21 SW user manual to know the directional standard deviation. There is a table provided from which you can correlate the standard deviation using spreading index values.

Thanks for the reply Paul, but am guessing that, being a first time user, am unable to understand the setup procedure.

Steps Followed are-

1. Convert Dem to .dfs2 format.
2. Open the file in grid viewer, edit items, change the type to Bathymetry.
Doubt -1 : What should be land value?? the elevation values vary from 700 to 12m
3. Anyhow, I gave a value of 30, as per my understanding, all the values above 30 will be considered as land values.
4. In the MIKE21 set up file, at the boundary conditions options, the coordinates of boundary box is detected. , Now I have point source discharge values at upstream, downstream and at the tributary, if you can follow the figure in post 1.
5. The setup runs without error, but the result is empty :(

Hi Christian,

Wetted initial boundary condition means??

I have been able to create a proper flood inundation map now! :)

Thanks.

Hi,

PFA the bathymetry and the MIKE 21 result file.

I have created this bathymetry using DEM data.

I have time varying .dfs0 files of discharge and water level at all open boundaries.

I am using the program detected boundary points. I have also attached the .m21 log file, to follow the simulation settings.

The final result that I get is with depth value as 0 at all points. I guess its the boundary editor setup where i have messed up, and need an advice on that.

Thank you for the reply Mr. Torben. Its been quite some time since this post. I Could figure out the Q/h auto calculation.

I have still been trying to get a proper inundation, will work on the cross section distances as you have mentioned.

And, regarding digitization of rivers, as you can see in the flood area, there are many interconnecting rivers, so I was trying to digitize them all , and draw smaller cross sections, so that the inundation comes along all the rivers.

Would like to have your comments on this. Your guidance on this would be highly appreciated.

Hi All,

While adding the .xns11 file, am getting a warning call " Identical chainages in the same section, such sections are NOT inserted" what does this mean?

Hi,

I am a new user to MIKE software and am using it for creating flood inundation maps. As a beginner, I have started with MIKE 11 and have been partially successful so far.

Please refer the attachment for better understanding of my query.

There is an image file of my area of interest, Digitized river network and cross sections, flood inundation image.

Branch 1 is the main river channel, which bifurcates to Branch 5 in the downstream side which is the flood plain area. Branch 2 and Branch 3 are the joining rivers.

1. I need to confirm the rules for digitization of river network , i.e, in my case, I have digitized the Branch 1 till the end,  then joined the tributaries and the Branch 5. So wanted to know if this way of digitization is appropriate or there can be a other alternative?

2. the cross section spacing? Since, the study area is very big around 300 km, I have taken 2000 m as spacing.

3. I don't understand the concept of alignment markers. Like, is digitization of these make any difference? In my case , there aren't any kind of structures in the study area.

***4. Boundary conditions- This is where am stuck. I have time varying discharge and water level data at the U/S end,i.e Branch 1 , 2 and 3 ,hence using open ,inflow boundary conditions at these places.
But, I don't have any data at the D/S end. so I have assumed constant water level based on the cross sections, since the dem I use is very precise.

I was advised to opt for Q-H boundary condition but I dont know why, the "auto calculation of q-h" tab does not pop up when clicked. kindly help me figure that out.

5. The Manning's n value. We give n value in the cross section editior and also in the HD parameters dialog. Since, changing n value  at one place doesnt effect the other, Please help me understand which one effects the simulation.

6. Last question is , the flood map does not match the requirements near the flood plain area, as in the water spread is very bizzare. I have tried a number of times, by changing the cross section spacing, but no positive results. Also the water depth is very less in the flood plain area.