USE mode is designed for the actual simulation of all the phases of water use in irrigation systems, particularly suited for areas where water conveyance takes place through open channels and water distribution to the individual farms is on rotation or continuous.
Multiple sources with different characteristics can be considered (see § 4.1.1 of the Technical manual and Installation and use manual ) and a great deal of flexibility is provided in defining different irrigation methods (see § 4 of the Technical manual ).
The USE mode requires further steps, in addition to those of the NEED mode:
- identification of the study area,
- selection of the meteorological stations,
- collection of the daily meteorological input series of each station over the selected simulation horizon,
- selection of the irrigation water sources,
- collection of the daily hydrometric input series of each station over the selected simulation horizon,
- discretization of the area with a regular spatial mesh,
- setting land use and soil hydraulic parameters of each cell,
- setting irrigation method and management criterion for each cell,
- subdividing the study area into irrigation units,
- defining conveyance efficiencies from each water source to the served areas (individual cells or irrigation units),
- running the simulation of the water conveyance, distribution, application and of the daily water balance for each cell of the mesh over the simulation horizon.
The USE mode computes the space-variable values of all terms of the soil water balance of each cell on a daily basis and provides an estimate of the potential and actual crop yields.
Finally, the USE mode also allows for the computation of tailwater amounts generated in the study area and can account for their reuse within the area itself (see § 4.1.1.3 of the Technical manual ).
In both modes the size of the cells of the regular discretization mesh is defined by the user.