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setting up an irregular 1D culvert

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I’m trying to set up an irregular culvert and am getting a bit lost in the manual with the various tables, parameters, commands, and database files I need to do.

Does anyone have a small model where an irregular structure is setup? My application involves a closed 3.6m diameter culvert with a flat bottom. (see the P.S. for the XY pairs).

If not, if someone could provide the easiest steps in setting this up, I’d be happy to make a v.simple test model, then zip and post this for other users in future.

I can see the Read MI Table Links command should also be used.



X (m) Y (m)

0.00 1.80

0.04 1.44

0.14 1.08

0.36 0.72

0.50 0.60

0.72 0.60

1.08 0.60

1.44 0.60

1.80 0.60

2.16 0.60

2.52 0.60

2.88 0.60

3.10 0.60

3.24 0.72

3.46 1.08

3.56 1.44

3.60 1.80

3.56 2.16

3.46 2.52

3.24 2.88

2.88 3.24

2.52 3.46

2.16 3.56

1.80 3.60

1.44 3.56

1.08 3.46

0.72 3.24

0.36 2.88

0.14 2.52

0.04 2.16

0.00 1.80

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Hi Paul,

Off the top of my head here are the steps required for setting up an irregular culvert:

1) Digitise the culvert in your 1d_nwk layer.

2) Edit the 1d_nwk attributes as per any other culvert, with Type attribute set to I (type I culverts use thte height contraction coefficient - not entirely sure how to work this in your case, as circular culverts don't use this coefficient)

2) Import the 1d_tab_empty layer, I normally save it in \mi\cu\1d_cu_xxx (i.e. the same filing structure as 1d_xs files)

3) Digitise a line in the 1d_cu layer perpendicular to your 1d_nwk layer (as you would with a 1d_xs mid-section, i.e. 2-point line just needs to cross the 1d_nwk layer, a 3-point line will need to snap to a node)

4) In the Source attribute type the name of your table to link to (eg. cu_10.csv)

5) Type should be HW, all other attributes can be ignored

6) Edit your .csv file (i.e. cu_10.csv), which must be in the same folder as your 1d_cu file. There should be two columns: H (elevation) and W (width) - making sure that you never have a width of 0, use something like 0.01. You will need to convert your XZ pairs to this format.

7) In your .ecf file, add the following lines: Read MI Network == ..mi\1d_nwk_xxxxxx.mif ; Read MI Table Links == ..\mi\cu\1d_cu_xxx.mif

Essentially it is the same principle as reading a cross section. Hope this makes sense! See the attached jpeg which shows the MI setup (*the use channel storage at nodes looks like an I but it's actually a T*.

e.g. of .csv file:

CU100510.csv (Arch Culvert beneath railway - Silted)


3.505 0.01

3.553 0.64

3.6 0.89

3.642 1.4

3.98 1.4

4.19 1.33

4.385 1.135

4.543 0.824

4.638 0.435

4.672 0.01

If you want I can send you through some MI layers and .csv files I've used in past models - just let me know.




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