Flood Height

[lauralozano1]

Hello everyone,

I would like to ask if someone has an idea of how to calculate the flood height using Arc-gis if the only data I could get is:

-2m resolution DEM

-A shapefile with the extension of the flood (for a return period given)

-the daily, monthly, and water year flow mean data for a period of 30 years.

The ideal thing would be to do it using the shapefile and the DEM so if someone can shed light about that I'd be infinitely grateful.

Many thanks in advance

Laura Lozano

[XanderBakker]

Could you elaborate a little more on what exactly you mean with flood height? Are you trying to get a raster with for each pixel the water height (based on the difference of the shapefile and DEM)? I suppose you could use a median value for the border of the extension of the flood to get the water level...

[lauralozano1]

Hi Xander,

Many thanks for your email.

I need to estime the flood height for a 50 year return period as a part of an input of a model. The thing is, I need something to compare with that shapefile. So I got now 30 year series of anual mean flow.  Do you think I could use it in Hec-ras to generate different return period and compare them with that shapefile?

[XanderBakker]

If you want to use Hec-ras you may want to move the thread to Arc Hydro

If it is the floodplain you are after and you know the flood level you could use the method described here:

Re: Determine Floodplain: Based on known flood level

[lauralozano1]

Many thanks Xander, I'll give it a really throughout look to see if I can do a combination of both. Apologies in advance if once I start doing it I need your pice of advice again!

Regards

Laura