Contact US

Log In

Come Join Us!

Are you an
Engineering professional?
Join Eng-Tips Forums!
  • Talk With Other Members
  • Be Notified Of Responses
    To Your Posts
  • Keyword Search
  • One-Click Access To Your
    Favorite Forums
  • Automated Signatures
    On Your Posts
  • Best Of All, It's Free!

*Eng-Tips's functionality depends on members receiving e-mail. By joining you are opting in to receive e-mail.

Posting Guidelines

Promoting, selling, recruiting, coursework and thesis posting is forbidden.

Students Click Here

Stormwater Drainage design for Cloud Bursts

Stormwater Drainage design for Cloud Bursts

Stormwater Drainage design for Cloud Bursts

I need to evaluate a drainage system for the capacity to capture and convey stormwater runoff from cloud bursts.
Is there any guidance available on what storm frequency and duration we should use to capture intensity and volume from a typical cloud burst.


RE: Stormwater Drainage design for Cloud Bursts

By "cloud burst", I assume you're referring to the rainfall from a short duration event. The shortest duration that is commonly tabulated is 5 minutes. You can get this information from a local IDF curve, or you can use an online source such as the NOAA Precipitation Frequency Data Server: https://hdsc.nws.noaa.gov/hdsc/pfds/

Peter Smart
HydroCAD Software

RE: Stormwater Drainage design for Cloud Bursts

5 minute storm seems a bit crazy and for what recurrence?

suggest that it is a relatively common event such as a 2-, 5- or 10-year, 1-hour storm
a 1-hour storm will easily contain the "5-minute cloudburst".

RE: Stormwater Drainage design for Cloud Bursts

I suspect a lot of the climate data may change in the not too distant future to reflect climate change. We'll have to wait and find out. ponder

So strange to see the singularity approaching while the entire planet is rapidly turning into a hellscape. -John Coates


RE: Stormwater Drainage design for Cloud Bursts

I was assuming a very simple Rational method calculation. I suggested 5 minutes since it will produce the highest peak runoff from the roof. Unless the Tc for the roof is more than 5 minutes, you would commonly use a 5 minute duration.

For a more rigorous analysis you could generate a full runoff hydrograph using a complete rainfall distribution, but I'm not sure what the OP is looking for.

Peter Smart
HydroCAD Software

RE: Stormwater Drainage design for Cloud Bursts

Thank you Peter and Cvg for you input
I need to develop a rainfall distribution for this evaluation.
Here is some information on the problem
This is landfill site with stormwater swales along the slopes that collect water along slopes and carry to a downchute.
The swales were designed for 25 year storm event using rational method, many years ago.
The swales have some settlements and erosion from the time they were built.
A recent storm of 2.31" in three hours has overtopped the swale bank on top of landfill, and resulted in a cascading failure of swales downslope and some damage to landfill slopes.
We are trying to evaluate how far we should go with repair and/or rehab of these channels.
We have done new topographic survey. The swales in their present state do not have clean geometrical cross sections or constants slopes.
We are thinking about building a 2d model with either HECRAS or PCSWMM and one of the scenarios we want to test is a short duration intense storm like a cloud burst.

RE: Stormwater Drainage design for Cloud Bursts

pay particular attention to low spots in the swales. thats where you will lose capacity and overtop. assume you will have a lot more settlement in the future. assume the cover is nearly impervious. 2D model is a good idea.

a 1 hour storm is probably adequate. the rainfall distribution is up to you.

Red Flag This Post

Please let us know here why this post is inappropriate. Reasons such as off-topic, duplicates, flames, illegal, vulgar, or students posting their homework.

Red Flag Submitted

Thank you for helping keep Eng-Tips Forums free from inappropriate posts.
The Eng-Tips staff will check this out and take appropriate action.

Reply To This Thread

Posting in the Eng-Tips forums is a member-only feature.

Click Here to join Eng-Tips and talk with other members! Already a Member? Login


Low-Volume Rapid Injection Molding With 3D Printed Molds
Learn methods and guidelines for using stereolithography (SLA) 3D printed molds in the injection molding process to lower costs and lead time. Discover how this hybrid manufacturing process enables on-demand mold fabrication to quickly produce small batches of thermoplastic parts. Download Now
Design for Additive Manufacturing (DfAM)
Examine how the principles of DfAM upend many of the long-standing rules around manufacturability - allowing engineers and designers to place a part’s function at the center of their design considerations. Download Now
Taking Control of Engineering Documents
This ebook covers tips for creating and managing workflows, security best practices and protection of intellectual property, Cloud vs. on-premise software solutions, CAD file management, compliance, and more. Download Now

Close Box

Join Eng-Tips® Today!

Join your peers on the Internet's largest technical engineering professional community.
It's easy to join and it's free.

Here's Why Members Love Eng-Tips Forums:

Register now while it's still free!

Already a member? Close this window and log in.

Join Us             Close