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arrowright.jpg (541 bytes) Introduction to Watflood
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arrowright.jpg (541 bytes) About Watflood 5.x
arrowright.jpg (541 bytes) Downloads
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arrowright.jpg (541 bytes) FAQ
arrowright.jpg (541 bytes) Event Edit
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Online Manual

arrowright.jpg (541 bytes) File Menu
arrowright.jpg (541 bytes) Edit Menu
arrowright.jpg (541 bytes) Edit - Rain
arrowright.jpg (541 bytes) Edit - Snow
arrowright.jpg (541 bytes) Edit - Climate
arrowright.jpg (541 bytes) Edit - Streamflow
arrowright.jpg (541 bytes) Edit - Reservoirs
arrowright.jpg (541 bytes) Run Utilities
arrowright.jpg (541 bytes) Run SPL
arrowright.jpg (541 bytes) Tools Menu
arrowright.jpg (541 bytes) Flow Hydrographs
arrowright.jpg (541 bytes) Stage Hydrographs
arrowright.jpg (541 bytes) Flow Animation


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


  • 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.
  • GREEN_KENUE (ENSIM) pre & post processor
  • Source tracing
  • Grids < 1 km
  • Meta-data on all files


  • Shell program for modelling sub-units
  • Separate programming units for transport processes model, snow melt water quality, wetland coupling and sediment production and routing.
  • Domain configuration for modelling.
  • Event generation
  • Point data to distributed data conversion for meteorological inputs (these can be replaced by users).
  • Output visualization (e.g. Ensim, Grapher™, Surfer™, Excel™, etc.)
  • Statistical analysis of output.
  • Interfacing with other models
  • Gridded model allows 1 to 1 matching of runoff units to meteorological driving data from NWM
  • Gridded surface model allows 1 to 1 matching of recharge to groundwater model such as MODFLOW
  • Computed river inflows can be accumulated on a reach by reach basis for input to an internal Lake routing module or be written to a file in a format compatible with routing models such as DWOPER or FLOW-1D
  • Grid outflow (runoff) computed with any model can be routed with WATROUTE (a subset of WATFLOOD Code)

Scaling/Domain Size

  • WATFLOOD has been used with grid sizes from 1 to 25 km and for watershed areas from 15 to 1,700,000 km^2
  • WATFLOOD is not sensitive to grid size as long as there are a sufficient number of grids to maintain the integrity of the drainage system and preserve the variability in the meteorological data
    Regional model: models multiple watersheds (cannot properly calibrate model with one or two flow stations)

Hydrological Features

  • 4 zone model:
    1. surface
    2. upper zone (saturated, varying depth) (UZS)
    3. unsaturated zone (API dependent soil moisture – not part of the water balance) 
    4. saturated lower zone (LZS)
  • Hargreaves, Priestley-Taylor or climatic evaporation
  • Green-Ampt infiltration, Hortonian runoff model
  • Anderson’s snow model with cover based snow cover depletion curves
  • Hartly sediment model
  • Glacier melt (crude)

Routing Features

  • Storage routing (center difference KW solution with variable time steps to satisfy Courant criteria everywhere)
  • Coupled lower zone-wetland-stream routing model
  • Coupled lower zone-prairie coulee-stream routing model
  • Lake routing, reservoir operating rules (diversions)
  • Overbank flow (with different resistance coefficients)
  • River, Lake and groundwater initialization based on recession curve of observed hydrographs. 
  • Nudging: computed flows at flow stations can be replaced by observed flows.
  • Tracer model - ground water flow contribution in the hydrograph

Water Quality Modelling

  • Upland sediment production model: supply or transport limiting
  • Nitrate and Phosphate production models (based on AGNEPS but done hourly)
  • Mixing cell sediment and nutrient routing
  • For details: downloads/


  • On the fly updating of snow pack
  • On the fly updating of land cover (coming soon)
  • Precip. smearing (convert 24 hr. precip. to a shorter flat distribution)
  • Precipitation Adjustment Factors (PAF) (to correct for bias in precip. Data)
  • Unsaturated zone updating using API

Special Features

  • Interfaced with ENSIM-HYDROLOGIC
  • Chaining events – a continuous run of individual events
  • Automatic soil moisture initialization for flood forecasting
  • Grid shifting for ensemble forecasting
  • Forecast mode for training purposes
  • Hooke & Jeeves pattern search optimization
  • Stage output for flood warning

Future Additions

  • Automatic generation of all ‘required’ files for a new watershed including sample .rag, .snw, .str, & .rel files
  • Source tracing
  • Grids < 1 km
  • Meta-data on all files
  • Autoclose windows 
  • Additional outputs for .wfo file
  • Prairie slough model
  • Lake evaporation model
  • Frozen soil model
  • Rainforest model

Watflood Highlights

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