Vetiver Grass is used as a land stablilisation tool due to its downward root growth and thick roots with high tensile strength. Pictured here is an example of how it might work when planted in the soil.

This is growing in greywater in a biochar medium and is the initial treatment subsurface stage which then flows through more rows of Vetiver to absorb any excess missed nutrients.

What's Vetiver? https://piped.kavin.rocks/watch?v=i5cORxJ6N-o

https://postimg.cc/HJ042kvv - original resolution here (click zoom).