Data sections may be unequally distributed along the canal. In fact, the model user should select sections which best represent the canal dimensions, the changes of slopes and so on. Depending on the regularity of the canal, the spacing of the data sections may then be small or large.

For the hydraulic calculation, the spacing between computational sections should be such that a reliable estimation of the water surface profile is possible. This spacing is chosen by the model user depending on his knowledge of the canal hydraulic behavior (when the data sections are too far away, the model interpolates supplementary computational sections in order to allow a better simulation of the water surface profile).

All the entered data sections are retained as computational sections. Irrespective of the manner in which a data section was defined, the program transforms it into width-elevation data for storage and interpolation. Only groups of 4 characteristic values: elevation, width, wetted perimeter (if a section had been entered in terms of abscissa-elevation, the wetted perimeter would take into account the section asymmetry) and area are finally retained.