intro story Coast / Estuary

Coast / Estuary

Coastal systems are among the most dynamic physical systems on earth and are subject to a large variety of forces. The morphodynamic changes occurring to coastlines worldwide are of great interest and importance. These changes occur as a result of the erosion of sediments, its subsequent transport as bed load or suspended load, and eventual deposition. 
 
Estuaries are partly enclosed water bodies that have an open connection to the coast. Estuaries generally have one or more branching channels, intertidal mudflats and/or salt marshes. Intertidal areas are of high ecological importance and trap sediments (sands, silts, clays and organic matter).
Within the Delft3D modelling package a large variation of coastal and estuarine physical and chemical processes can be simulated. These include waves, tidal propagation, wind- or wave-induced water level setup, flow induced by salinity or temperature gradients, sand and mud transport, water quality and changing bathymetry (morphology). Delft3D can also be used operationally e.g. storm, surge and algal bloom forecasting. 
 
On this discussion page you can post questions, research discussions or just share your experience about modelling coastal and/or estuarine systems with Delft3D FM. 
 

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Sub groups
D-Flow Flexible Mesh
DELWAQ
Cohesive sediments & muddy systems

 

 

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swan diag warning - length of segment short

KS
Kit Stokes, modified 2 Years ago.

swan diag warning - length of segment short

Youngling Posts: 5 Join Date: 11/8/16 Recent Posts
Hi all,

I'm getting a warning from a coupled wave-flow simulation in the swn-diag file for one of my four boundaries. The warning says:

"** Warning : Length of segment short, boundary values ignored".

I'm running condspecatdist using 2D spectra files as input at each location specified by condspecatdist. As you can see from an extract of the swn-diag file below, I'm not getting the warning at any of the other three boundaries. Oddly, the results seem to be ok, and I can see waves propagating in from all segments of all boundaries, so it would seem that it is not ignoring the boundary values, as the warning below indicates. But the warning is worrying, as I'm not sure why it is there, or what effect it is having in the model. Does anyone have any experience with this issue?

It looks like this:

BOUN SEGM IJ 0 240 153 240 &
VAR FILE 3.18 'North_2DSpec_1.bnd' 1 &
2.98 'North_2DSpec_2.bnd' 1 &
** Warning : Length of segment short, boundary values ignored
segment length= 2.13; [len]= 2.98
2.73 'North_2DSpec_3.bnd' 1 &
** Warning : Length of segment short, boundary values ignored
segment length= 2.13; [len]= 2.73
2.39 'North_2DSpec_4.bnd' 1 &
** Warning : Length of segment short, boundary values ignored
segment length= 2.13; [len]= 2.39
2.06 'North_2DSpec_5.bnd' 1 &
** Warning : Length of segment short, boundary values ignored
segment length= 2.13; [len]= 2.06
1.81 'North_2DSpec_6.bnd' 1
** Warning : Length of segment short, boundary values ignored
segment length= 2.13; [len]= 1.81

BOUN SHAPE JONSWAP 3.30 PEAK DSPR POWER

BOUN SEGM IJ 355 0 355 29 &
VAR FILE 0.00 'East_2DSpec_1.bnd' 1 &
0.19 'East_2DSpec_2.bnd' 1 &
0.26 'East_2DSpec_3.bnd' 1

BOUN SHAPE JONSWAP 3.30 PEAK DSPR POWER

BOUN SEGM IJ 4 0 355 0 &
VAR FILE 0.04 'South_2DSpec_1.bnd' 1 &
0.21 'South_2DSpec_2.bnd' 1 &
0.46 'South_2DSpec_3.bnd' 1 &
0.78 'South_2DSpec_4.bnd' 1 &
1.11 'South_2DSpec_5.bnd' 1 &
1.36 'South_2DSpec_6.bnd' 1 &
1.69 'South_2DSpec_7.bnd' 1 &
2.03 'South_2DSpec_8.bnd' 1 &
2.28 'South_2DSpec_9.bnd' 1 &
2.61 'South_2DSpec_10.bnd' 1 &
2.86 'South_2DSpec_11.bnd' 1 &
3.18 'South_2DSpec_12.bnd' 1

BOUN SHAPE JONSWAP 3.30 PEAK DSPR POWER

BOUN SEGM IJ 0 0 0 240 &
VAR FILE 2.15 'West_2DSpec_1.bnd' 1 &
2.02 'West_2DSpec_2.bnd' 1 &
1.69 'West_2DSpec_3.bnd' 1 &
1.36 'West_2DSpec_4.bnd' 1 &
1.10 'West_2DSpec_5.bnd' 1 &
0.78 'West_2DSpec_6.bnd' 1 &
0.45 'West_2DSpec_7.bnd' 1 &
0.20 'West_2DSpec_8.bnd' 1 &
0.00 'West_2DSpec_9.bnd' 1

$


Thanks in advance!
KS
Kit Stokes, modified 2 Years ago.

RE: swan diag warning - length of segment short

Youngling Posts: 5 Join Date: 11/8/16 Recent Posts
I eventually resolved this issue. I had mistakenly entered condspecatdist as the distance from the corner of the grid to each forcing location, rather than the distance from the start of the boundary segment to each forcing location. As the north boundary segment started half way along the side of the grid, this meant that the distances were actually off the edge of the grid, hence the warning. Now that I've resolved that issue, the warnings in the swan diag file have dissapeared.
JB
Jason Boozer, modified 1 Month ago.

RE: swan diag warning - length of segment short

Youngling Posts: 2 Join Date: 10/23/20 Recent Posts
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