Why the Sediment transport rate is different for total simulation time and the accumulated monthly sediment drift rate?

This is more a discussion item than a question...

Receiving yet another global study in my feed, claiming the importance of looking at the big picture, my eyes rolled back and I felt like shutting down the PC.

The approach of taking a solid data set, hopefully in a regional setting, and using it to validate processes to be modelled AND calibrate model parameters, to the best level possible seems to be increasingly 'unnecessary'. Almost by definition, global studies must necessarily ignore secondary or tertiary processes, even if they are locally primary, and therefore we end up with poor validation. This generally means they are unusable at a local scale, which is the main level of application for science and management.

In a simple sense, if geographic (or temporal) biases of a model are bigger than than the signal, then the model is no good. This is one of the main questions I ask, when I start a journal article review. I have stopped accepting reviews that are global in scale, thanks to repeated disappointment.

Can someone please point me towards a global study (waves, water levels, streamflow, sediment transport) that has provided truly valuable academic insights, that is also meaningful at a local scale? I would like to direct would-be authors towards a rare beast.

Dear All,

I have an issue regarding a sediment transportation simulation. I have computed the sediment transport rate based on a 20 years wave climate, and simulated the sediment drift for the total time span and either by monthly filtering of the data, the monthly sediment transport is also computed. However there is a problem that the summation of monthly sediment transport is much more than what I have calculated for the total time span. Is it possible this happening? Is there any reason behind this?

I appreciate it if you could share your Idea with me.

Best

Saeideh

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How does reservoir sedimentation affect downstream environments and how does the sediment size and shape change downstream?

Typical bed load: What you find in the rubble on the beach or in the North German Plain is usually difficult to interpret - if the fossil has not been known for a long time. The sediment fossils are no longer in the existing layer, but have been pushed up by the glaciers of the last ice age and distributed everywhere. So I thought this enigmatic fossil to be Lower Cambrian. Now a scientist thinks that it is more likely to be Ceratopygekalk: Origin Oslo region/Norway, Scania, Öland or Vestergötland/Sweden; Age 495 million years, Lower Ordovician, Tremadoc. I tested the stone and found that it is chalk, not sandstone. So here I am again asking if anyone has any idea what it is - body fossil or trace fossil?

I'm finding a 3D hydrodynamic model that considers the processes of water & sediment quality and sediment transport at the same time.

Delft3d seems to be a good one, as Delft3d-WAQ couples the deposition of organic matters and sediment transport and wave can be computed as well.

SCHISM seems to be another good model system as it contains all needed module, however, I'm not sure if it can work as Delft3d-WAQ.

Therefore, I want to ask:

1. Is SCHISM okay for the above requirements (considering the processes of water & sediment and sediment transport at the same time)?

2. Is there any other models that meet these requirements?

Your help will be the most grateful.

Is it possible to model a sediment transport model in a channel with gated structure? When I try to do it, it gives me HDF error. But when i remove the gate, it seems to be working fine.

Hi,

I am learning MIKE 21 model and I would like to create input bathymetry file from GEBCO 30 Arc Second data for north coastal Bay of Bengal. Which one do I need to follow? Bathymetry or mesh generator? I have generated the coast line (land / water boundary) from the shape file and converted to .xyz format and stuckup for further steps.

I'm doing a mike 21 flow model for hydrodynamic simulation in a coastal area and my simulation runs for 3 days with the time step interval of every 5 minutes. However my data input for wind is recorded at 4 times daily (every 6 hours). Can anyone tell me what the limitations of mike 21 are when it comes to a short time step interval and the effect on the simulation from input data of wind with only 4 pieces of recorded data daily?