Flooded duration output

[peteraylett 0]

Hi,

There are many times when it is useful to know the duration of flooding to a property or area. Could a new map output be introduced to show this please? It would only need a single layer showing the number of hours each cell was wet during the simulation. This would possibly benefit from having the option to set a threshold level.

A further extension of this would be having a few of these (output Fd1, Fd2, Fd3, etc...) for which thresholds can be independantly set.

This information is sufficiently extractable from POs, but it would be nice to have it as a map output.

Probably all a bit late for the '08 release though!

[par 0]

Hi PHA,

Failing Bill getting this into the 08 release, it can be currently be post processed using the Dat_to_Dat.exe utility. Obviously this only works on outputted data, so you would need reasonably frequent output. Be careful in areas with tidal inundation.

I think the command would look something like:

dat_to_dat.exe -dur<cutoff_value>

The .dat file created should contain durations (hours) in which cutoff value is exceeded. You should then be able to view it in SMS or use tuflow_to_GIS to convert it to a GIS format for mapping .

Phillip

[peteraylett 0]

Thanks Phillip.

I wasn't aware that it could be post-processed with quite such ease as that! Dat_to_Dat.exe is not a tool I use very often. I think perhaps I need to investigate more of it's other features sometime...

I still think it'd be useful to be able to have the data with the higher 'resolution' than whatever save interval was appropriate (for some of my larger models, obtaining flooded duration to the nearest 10 minutes would make the results files somewhat large!), but this makes life easier for now.

[Bill Syme 0]

From memory, I'm pretty sure the dat_to_dat.exe interpolates between output time intervals, so provided your rate of change is fairly linear between outputs, there isn't a great need to output on a short interval. Usually, the output interval you would normally adopt should be fine with the -dur option.

You may also be interested in the -ddur option, which gives the change in duration between two simulations. Can by very useful for establishing the increased (or decreased) period of inundation due to proposed works. Just noticed a small typo in the manual: "specify d0.1" should read "specify ddur0.1" in Table 11.2 of the TUFLOW manual (2007 or 2008) for the -ddur option.