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WATFLOOD is a registered trademark

Since 1972


  • Manitoba Hydro - Nelson River System (Red, Winnipeg, Saskatchewan, Interlake and Churchill Rivers) Climate Change and Flow Forecasting
  • Environment Canada - Great Lakes 
  • Mackenzie River Basin Board - Mackenzie River Basin
  • Lake of the Woods Control Board - Winnipeg River Flow Forecasting
  • Ontario Power Generation - Mattagami and Madawaska River Systems
  • Manitoba Infrastructure - Flow forecasting


WATFLOOD is a set of computer programs for hydrological modelling:

  • BSN.exe - converting measures watershed data (DEM & Landcover) to hydrologically relevant watershed data for modelling

  • RAGMET.exe - point to gridded precipitation

  • TMP.exe - point to gridded temperatures

  • SNW.exe - snow course data to gridded Snow Water Equivalent

  • MOIST.exe - point to gridded soil moisture

  • CHARM - Canadian Hydrological And Routing Model

Modelling Objectives for WATFLOOD™

  • Flood forecasting and flood studies
  • Climate change impact studies
  • Environmental impact studies
  • Continuous modelling
  • Ability to model very large as well as small areas
  • Ability to optimally use gridded data sources e.g.. Land cover, DEM’s, NWP model output, Radar data
  • Universally applicable parameter set
  • Quick turn around
  • Ability to model a wide variety of landscapes


  • Green Kenue (ENSIM) pre & post processor
  • Grouped response units (GRU’s): leads to universal parameter set because parameters are associated with land cover and NOT watersheds
  • Gridded model:
    1. Optimal use of remotely sensed data
    2. Optimal use of numerical weather data
    3. Optimal use of RADAR precipitation data
    4. Optimal use of 1,2 and 3D display facilities (e.g. GREEN_KENUE)
  • The combination of GRU’s and grids make the effective resolution much greater than the grid size used.
  • Source tracing
  • Grids < 1 km
  • Meta-data on all files

For more details, please check out the Features page.

Over 37000 visitors since Jan. 6, 1996  (counter out of order)

WATFLOOD™   manual_v16-1.pdf  with WORKSHOP chapter   (4Mb) (updated Oct. 13, 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     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.

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.

WATFLOOD was developed by

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

Distinguished Professor Emeritus

Department of Civil & Environmental Engineering

University of Waterloo , Waterloo, Ontario, Canada

About the developer:

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 Infrastructure and Technology, 4DM Consulting (Toronto), Conestoga Rovers (Waterloo), NRC 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: CHARM (Canadian Hydrological And Routing Model); 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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© copyright 1999-2016 N. Kouwen.