×
INTELLIGENT WORK FORUMS
FOR ENGINEERING PROFESSIONALS

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!
  • Students Click Here

*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

Jobs

Rational Method and Time of Concentration

Rational Method and Time of Concentration

Rational Method and Time of Concentration

(OP)
I am evaluating an existing roadside ditch capacity for approx.2,100 ft length. The drainage area contributing to the ditch is a narrow section of roadside ditch area, and half of the pavement, so there is not much flow added. With the rational method, as the Time of Concentration increases, the rainfall intensity decreases, which is resulting very small flow increase, in some sections constant, and in some sections decrease. Although, it doesn't sound realistic in the practical world that the flow is not increasing downstream, the less increase in the flow or decrease is due to the time it takes for the upstream flow to outfall. What is your thoughts on appropriateness of the rational method for capacity evaluation of the ditch in may case.
Ditch Length 2,100 ft approx., Tc= 23 minutes, Total Contributing Drainage Area upto Outfall (along 2,100 ft of ditch) = 7.13 acres (310,830 sft)

RE: Rational Method and Time of Concentration

drainage area bigger, the ToC will be greater and the Intensity will be smaller. The assumption here is a larger area is hard to get a uniformly distributed rainfall at a higher intensity.

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


Resources

eBook - 10 Reasons to Choose CATIA on the Cloud
To compete in today’s fast-paced and competitive market, smaller and newer firms need a powerful platform that will enable them to compete with bigger players, without the heavy investments needed in computer hardware, software and personnel. Download Now
White Paper - Smart Manufacturing for Electronics
This white paper describes a transformative approach to electronics manufacturing made possible by the addition of Mentor Graphics to the Siemens family. It describes a completely digitalized strategy that supports both printed circuit board (PCB) and mechanical design and manufacturing, uniting the entire product lifecycle – from idea and production to customers and back. 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