×
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

SWMM vs TR-55 for Runoff

SWMM vs TR-55 for Runoff

SWMM vs TR-55 for Runoff

(OP)
Using the same rainfall events and identical subcatchments, the peak flow rate (at the outlet) is much smaller in SWMM than TR-55.  Does anyone have any experience comparing the output of these two programs/methods?

Basically, it appears to me that SWMM uses one of three methods to determine how much rainfall infiltrates the ground.  Then it uses one of three theoretical methods to route the runoff to the outlet and develop a hydrograph.

The infiltration methods offered by SWMM are:  Horton, Green Ampt, and Curve Number

The routing methods offered by SWMM are: Steady Flow, Kinematic Wave, and Dynamic Wave

No matter which combination of these option I select, the peak flow generated is much less than what TR-55 generates using the "unit hydrograph" method to estimate peak flow rate.

Is TR-55 really that conservative? Or am I likely not setting up the model correctly?

Thanks in advance for the feedback.

RE: SWMM vs TR-55 for Runoff

You are running two distinct models with probably different runoff and hyetograph selections.  Depending on your assumptions for each I like a about 10% agreement.

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!


Resources