Hydrologic Modelling Made Easy

VO5 is the fifth version of the INTERHYMO-OTTHYMO hydrologic model simulation software package. OTTHYMO is a successful hydrologic management model that has been used for various simulation analyses such as: Watershed Studies, Sub-watershed Studies, Master Drainage Plans, Functional Stormwater Management Plans, Site Plans, and Stormwater Management Pond Designs.

visual otthymo

Visual OTTHYMO offers single-event and NEW continuous hydrologic modelling to simulate runoff from statistical storm events. The hydrographs generated are based on unit hydrograph theory and can be used for uncalibrated or calibrated modelling studies.

Low Impact Development Tools Coming Soon...

VO with LID commands (Beta version) is now available. Try it out now! (Only for users with a valid VO license)

Yes, Visual OTTHYMO is introducing LID Toolkit for a single event. The Toolkit will include eight new LID commands - Bio-Retention, Permeable Pavement, Rain Gardens, Soakaway Pits, Underground Storage Chambers, Enhanced Swale, Green Roofs, and Filter commands built right into the program.

Download VO with LID Commands (Beta version) today! We'd love to know your feedback.

Why Visual OTTHYMO?

Easy To Use

Visual OTTHYMO has been created to provide you with a reliable and dependable model that is straightforward and user-friendly.

Saves you time

Visual OTTHYMO gives users reliable results without a large number of input parameters, giving the model an edge over other “parameter intensive” models. This translates into reduced staff time on your projects.

Reliable & Dependable

Visual OTTHYMO can simulate runoff from statistical storm events. The hydrographs generated are based on unit hydrograph theory and can be used for calibrated or uncalibrated modeling studies.

Efficient Interface

Visual OTTHYMO has an improved interface that makes the model creation and interpretation of results easier and more efficient than ever.

Widely Accepted

Visual OTTHYMO is the standard model of choice with many regulatory agencies in Canada, from conservation authorities and municipalities to top consulting firms.

Expert Support

Integrated with an online help system and efficient tech support, the new Visual OTTHYMO Help System will provide invaluable assistance to all levels of user.


**Continuous modelling is now available!**

Experience Visual OTTHYMO

Build: VO 5.1.2006

Visual OTTHYMO Brochure


Get Started

Our User's Manual helps you get started.

Technical Questions?

Have a look at the Guide.

License Agreement

Read the complete End User License Agreement here.

Wait no more. Get your 30-day FREE trial now!

Follow the steps below to start using your VO Demo:

  1. Click on VO 5.1 Download to begin the download.
  2. Install VO. Refer the Guide and Manual - they are useful.
  3. Email us at to get your Demo License key.
  4. We will send you the license. Add it onto the VO License Manager and everything is set!

Get immersed in Visual OTTHYMO.

Do you have more questions? Fill out your information and we will get back to you quickly!

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