<p>For my thesis, I model flash floods in urban areas. A book with recommended practices says to use events with a recurrence interval of 30 and 50 years. Regarding the duration of the precipitation event, it says to use a "relevant duration".</p>

<p>Now I'm wondering what "relevant" means, and can't find information so far. What rainfall duration should be used in urban areas, and why? In papers many use 1h events, but there is no explanation for the chosen duration. Sometimes I read 15min, sometimes 6h.</p>

<p>Perhaps someone can give me ideas in what situations what rainfall duration is "relevant".</p>

CC BY-SA 4.0
2020-03-06T16:19:49.500Z
It is the one hundred year and 500 year events that are the problems.
blacksmith37
CC BY-SA 4.0
2020-03-06T17:44:02.687Z
what rainfall duration would you use for 100 or 500 year events?
DGIS
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2020-03-06T18:49:32.790Z
The relevant precipitation is the one that gives a larger flow. From the available precipitation record you should be able to tell which one.
Pere
CC BY-SA 4.0
2020-03-07T15:32:56.163Z
When it recently rained 40 in. in Houston area , I think it was over 3 days.
blacksmith37
<hydrology><models><rainfall>
How to choose "relevant" precipitation durations for flash flood modelling?
DGIS
# How to choose "relevant" precipitation durations for flash flood modelling?

(Asked by: username_0 on 2020-03-06)

For my thesis, I model flash floods in urban areas. A book with recommended practices says to use events with a recurrence interval of 30 and 50 years. Regarding the duration of the precipitation event, it says to use a "relevant duration".

Now I'm wondering what "relevant" means, and can't find information so far. What rainfall duration should be used in urban areas, and why? In papers many use 1h events, but there is no explanation for the chosen duration. Sometimes I read 15min, sometimes 6h.

Perhaps someone can give me ideas in what situations what rainfall duration is "relevant".

**Tags:** hydrology, models, rainfall

> **Comments:**
> **username_1**: It is the one hundred year and 500 year events that are the problems.  
> **username_0**: what rainfall duration would you use for 100 or 500 year events?  
> **username_2**: The relevant precipitation is the one that gives a larger flow. From the available precipitation record you should be able to tell which one.  
> **username_1**: When it recently rained 40 in. in Houston area , I think it was over 3 days.  

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## 0 answers

