This topic may be a little O/T so I apologise.
I have seen from time to time on here where it has been referenced by architects or other industry types that bunkers can be lined with turf in an effort to prevent subsoil contamination. This is done in place of a more formal liner of cloth or the newer porous type concretes and gravel systems.
I am keen to hear a bit more about the process and get a feel for how effective it is and the impact on drainage. Also, what is a reasonable lifespan before it needs to be readdressed.