Can you recommend a method for development of a small highly sinuous channel surrounded by a large floodplain. I am having difficulty with domain resolution over such variable scales.
I would suggest to start with the channel first and then create grid for the flood plains. You can try the inbuilt grid generation feature in the EFDC Explorer but RGFgrid from DELFT would give you more capability and then create a grid. First create a grid for the channel with enough resolution and make the grid sizes coarser for the floodplain than the channel. Do not vary the grid sizes by more than 3-4 times than the adjacent cells. I hope this helps.