Waterfall charts are useful tools in design when there is a very wide range of possibilities and that something needs to be done. A good example of this is cable selection. A waterfall chart for cable selection makes the life of an electrical designer in creating cables schedules.
I have almost always used waterfall charts for cable selection in my previous projects.Some people who are not familiar with this tool are adamant in its usage but for those who use them regularly got a different perspective. Motor starting, earth fault, voltage drops are just some parameters that could be integrated into waterfall charts to make them even more useful.
The current project that I am involve with now is just on its concept stage. I was assigned to do in-field distribution reticulation for CSG upstream facilities. The underground distribution will be much easier to do in a waterfall chart but overhead distribution will be a different story.
For overhead, GMD and GMR are needed to be able to get the line parameters. Likewise, several voltages are being considered, in my case, I am considering 11kV, 22kV and 33kV. If required later on, 66kV and 132kV will be considered.
The usage of a waterfall chart in design is limitless. All is needed is your imagination.