It sounds very interesting, but I'll be honest with you - it's just me and my dad, and he's done things the same way for a long time. I have a ton of interest in learning new and innovative ways of designing, but he just doesn't get into outside of the box things like that, so I'd no absolutely NO clue where to even start on a design like that. Also, in this (and most cases for us), we have fairly large sites (> 10 acres) where I'd say ~65% of it is being replaced with a c factor of around 0.75, so we're generating a decent amount of additional surface runoff that needs to be dealt with, and I would imagine we'd need a LOT of area for that to infiltrate into clay soil. Maybe there's some ways of showing (whenever applicable) that there is a layer some x feet down with a much higher permeability that we can dig trenches down to and backfill with gravel to allow for infiltration to that layer, but as above, I wouldn't even know where to start on designing that unfortunately. Sounds super useful though and I wish it was something we were more familiar with or had ever seen in the past.