MIKE21 FM rain on grid

Can anyone share or direct me to references related to MIKE21FM application with rainfall and culverts for overland flow computation?
What is the ideal meshing pattern around multiple culverts (say, 1m apart) in MIKE 21FM?

I dont find any example for MIKE21FM showing the meshing pattern around culverts? We experiences lot blow out around the culvert when using with rainfall option.
Thanks for any respose.

Regards

Hi,

do you use the "Advanced Flood and Dry (Floodplain)" - Option ?
If not that could stabilize your problem.

Bests
Christian