Learning the basics of designing the gradation of sand and gravel filters is Soil Mechanics 1 (think 2nd year university). The massive reports are because of ma

Learning the basics of designing the gradation of sand and gravel filters is Soil Mechanics 1 (think 2nd year university). The massive reports are because of massive problems caused by poorly functioning or failed filters, but the basic premise of much of these videos is "give the first lesson in some subject without any math and actually try to explain things instead of typical engineering prof standards". If you google "Gradation Design of Sand and Gravel Filters" you'll find Chapter 26 of the USDA's national engineering handbook, which will give the basics of how its done with some simple examples. This is baby engineer type stuff, for the most part. If you're designing for big structures or complicated situations it becomes a much more complicated exercise.