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Welcome to the distributed hydrologic model WATFLOODÔ, developed by

Nicholas Kouwen, PhD., P. Eng., F.ASCE.

Distinguished Professor Emeritus

Department of Civil & Environmental Engineering

University of Waterloo , Waterloo, Ontario, Canada

You are visitor # Hit Counter  Since Jan. 6, 1996

WATFLOOD manual16.pdf  with WORKSHOP chapter   (4Mb) (updated June 2, 2016)

WATFLOOD & WATROUTE Executables can be downloaded free at:  Watflood Downloads

Green Kenue (ENSIM/HYDROLOGIC) can be downloaded (free) at:

Green Kenue (ENSIM/HYDROLOGIC) Reference Manual    EnSimHydrologic.pdf  (Aug. 2007)


WATFLOOD**    Features

** WATFLOOD is a registered trademark

WATFLOOD     Publications   &   Presentations

Note  for prospective graduate students

Introduction to WATFLOOD  
Find out about how WATFLOOD works, the data requirements of the program, and see a list of publications involving WATFLOOD. You can try the software with the demo data

History of WATFLOOD

WATFLOOD is modelling system including all the pre & post processing programs.

WATFLOOD  studies
WATFLOOD is constantly evolving, this page describes the current modifications which are under development as well as viewing some of the results of recent WATFLOOD studies.

WATFLOOD FOR WINDOWS is no longer available or supported. Due to the ever changing coding requirements of MS Visual Basic™ it is no longer possible to continually upgrade the program to meet the changing file structure for WATFLOOD™ .

Download Page
Get a copy of the WATFLOOD users manual which goes into more detail about the workings of the model or obtain copies of reports from studies using WATFLOOD™ .

Comment Form
Leave a comment about the WATFLOOD homepage.

About the developer of WATFLOOD

Dr. Kouwen is a Distinguished Professor Emeritus and Adjunct Professor at the University of Waterloo, a registered Professional Engineer in Ontario and a Fellow of the American Society of Civil Engineers.

He currently provides support to the WATFLOOD user community which currently includes Manitoba Hydro, Ontario Ministry of Natural Resources, Lake of the Woods Control Board, Manitoba Ministry of Inrastructure and Technology, 4DM Consulting (Toronto), Conestoga Rovers (Waterloo) and the University of Manitoba.

Dr. Kouwen acknowledges the work of Ric Soulis, Todd Neff, Frank Seglenieks, Luis Leon, John Donald, Wayne Jenkinson and Trish Stadnyk who have contributed substantially to to the development of WATFLOOD.

Dr. Kouwen is known for the development of the WATFLOOD hydrological model and for the development of flow resistance relationships for vegetation in channels and on flood plains. WATFLOOD was the first non-urban hydrological model to use the Grouped Response Unit (GRU). Dr. Kouwen’s unique experience in dealing with vegetated channels and other hydraulic problems, as well as several years working on highway construction projects, conducting hydrological field work and life on a farm, has resulted in a hydrological model that robustly represents the hydrological processes of watersheds from a few km2 to watersheds as large as the Great Lakes and the Mackenzie River.

WATFLOOD is the first hydrological model to compare isotope flow separation measurements to computed flows from source areas in a watershed. This feature is of the utmost importance for water quality modelling by ensuring that contributions to streamflow are properly assigned to their sources.

Key words: Grouped Response Units GRU's; Hydrologically Similar Units HSU's; Aggregated Simulation Areas ASA's; Hydrotops; Pixel Grouping; Tiles. These are some of the names used by other modellers for the GRU method. The GRU method originates(!!!!)  with WATFLOOD - first published by Tao & Kouwen in 1989.


Click on picture for full size.

For more information about Dr. Kouwen's work on resistance in vegetated channels, please click here.

For Dr. Kouwen's full resume, please click here


If you have any questions about WATFLOOD that haven't been answered at this site or would like to know how to order WATFLOOD, please do not hesitate to contact:

Dr. Nick Kouwen by e-mail at

Please note that we do not look at any mail unless the mail is a text file AND

  1. We know the sender     OR

  2. the subject line is marked with "WATFLOOD QUESTION"

** WATFLOOD is a registered trademark: Enter WATFLOOD at

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