Time series dataset of precipitation and friction maps

[Sindre Eikenes]

Hi,

I am currently trying to establish and create the rainfall and friction data needed to perform the flooding analysis which has lead me to two questions:

Question 1.

I've seen in the article "Itzï (version 17.1): an open-source, distributed GIS model for dynamic flood simulation" (seeing that there are not any more updated versions?) that a uniform rainfall recording was used in the whole area of Hull, recorded every hour for 24 hours. This is similar to what I'd like to do in my analysis. I have a rain gauge with recordings every hours (statistical data), but these need to be transformed to a strds as I've understood. In the tutorial of the North Carolina dataset the rainfall was set with a uniform value which did not have any temporal changes. My question is, where do I proceed from having data from rain-gauges to adding a strds into the analysis?

Question 2.

Also in the article, a landcover dataset was used in combination with Manning's n to calculate the friction of the different areas. In the tutorial there is again a uniform value stated for the friction coefficient. So the question here is how do I firstly use the landcover dataset in combination with the manning's n coefficient, and should this also be a strds (as proposed in the configuration file), if so, how should I create this in order to implement it into the model?

I am not that familiar (as of yet) to Grass and Itzï, so I'm grateful for all help.

Best regards,

Sindre

[Laurent C.]

Hi Sindre,

The last version of itzi is 18.2. Unfortunately available time has been a limiting factor to continue updating the software. Programmers are welcome!

Now for your questions:

Q1: If you wish to use a uniform rainfall that varies in time, you can create a series of uniform maps with r.mapcalc. Then "assemble" the maps into a STRDS with the GRASS tools (https://grasswiki.osgeo.org/wiki/Temporal_data_processing/GRASS_R_raster_time_series_processing)

Q2: You should decide which type of Manning values you wish to use. Uniform values are perhaps easier to calibrate the model with. It does not need to be a STRDS, although this is accepted.

Best regards,

Laurent

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[Sindre Eikenes]

Hi Laurent, thank you so much for your reply. I am currently using itzi 18.2, but the article you wrote was performed in version 17.1 so I wondered if there existed any supplementary articles. 

But anyhow, I will try to follow your suggestions:)

Another question for you if you've encountered this. In the tutorial, a single outlet location was used. My AOI (Bergen) is much similar to the one in Hull where it borders to a lake/ocean. How did you locate all of the outlet-points to the AOI when modeling Hull? It wouldn't be sufficient to use only a single one. Is there a method to calculate all the outlet-points of an area?

Thanks in advance!

Best regards,

Sindre

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[Sindre Eikenes]

Here's a map of Bergen included (most of) the catchment area where I want to do my analysis, if it makes it somewhat more clear.

Best regards,

Sindre

[Laurent C.]

Sindre,

When the boundary condition is continuous, like a coast, you can just put more values in the map, in the form of lines, for example.

Additionally, you can simulate the changing tide levels by setting the water depth boundary condition as a STRDS.

Best regards,

Laurent

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