open TELEMAC-MASCARET The mathematically superior suite of solvers

Hello everyone,
I have a little question about Gaia. I work on a sedimentary model with 3 sedimentary classes. I use the version 8 of telemac and i have no entry of sediment at the upstream limit condition.
My simulation works well but when I process my results, I observe a difference in sediment volumes at my downstream boundary condition. If i take the "CUMUL BED EVOL" parameter, i found that 10364 m3 came out of my model (difference between erosion and sedimentation with the "Compute volume" tool)(Figure 1).
But if I take the weight of sediment out of my model, I find 6270 m3 (the weight is in kilogram but I divided by the density of the sediment. 16614830/2650 = 6270)(Figure 2). I have not been able to find an explanation for this difference.
Can someone help me please ?

Thanks
Best regards,
Gael

Is your bed porosity 0.6?

no, my bed porosity is 0.4

Sorry, of course I should have said 0.4. But what I meant to imply is that the volume going out of the domain is 60% of the bed volume change, so it is what it should be.

I understand, thank you very much for these explanations