How to assign different zones of different sediment to a one-layer uniform bed?

Dear EE support team, please look at this question first if you are busy to answer my previous questions (too many questions… but I truly cannot solve them after seeing the tutorial materials&videos ). Because my previous question is about mutiple bed layers, while this question has only one layer, which will be more clear.I want to use Cohesive 1 in the center of lake, and sand (Cohesive 2) in the littral zone. So I try to first generate a uniform bed(but spatially different with Cohesive 1&2. For example in lake center, Cohesive1 fraction = 1.0), and then edit the “Sed Frac” in ViewPlan by “Enable Edit”. Unfortunately, EE told me that “You cannot directly edit this data” [Bed_frac.png]. Must I define "sediment cores " and interpolate them to get a spatially different bed? I think this method is not appropriate, because I only want to divide the whole zone into two parts. If I use cores, it is too “precise” for the model at this stage.

My purpose is to make the bed have different shear properties (Tau) for silt/sand bed horizontally, like “bed_purpose.jpg”. My method is to define kinds of cohesives and then tried to find where is the “zone botton” to assign these cohesives to the bed, but failed.

I am sorry but you have a lot of questions about similar sediment issues on different threads and it is quite confusing. Can you summarize all your remained questions into one thread and we will delete the unanswered ones?

Sorry to confuse. About this question, the topic is that “to use Cohesive 1 in the center of lake, and sand (Cohesive 2) in the littoral zone”, like “Diff_zone_bed.jpg” here. I want to “make the bed have horizontally different shear properties (Tau) for silt/sand bed” to relise it. This question is about “one-layer sediment bed with horizontally different cohesive properties (e.g., Tau)”.Ways I tried(and failed) is described above(#5623, #5625).You can delete “The uppermost bed layer (thickness = 0.15m) disappear after the first snapshot” and “Why the lower bed lay’s thickness decrease when the top bed layer still exist” if necessary.