Our Vetiver in Action :Video

I think that what Andy has  done  here is an important fix-it exercise for so many Brisbane suburban properties that are built on rolling hills. Not only do so many blocks suffer from  cascades during heavy rain, but the run off through the local catchment creates flood conditions further downstream.
What used to be natural flow and seepage is now blocked by  brick houses, paths and roadways with less native vegetation dealing with any water in situ.
You can also see how from the video the V-grass engineering encourages the seepage of water  -- a feature relevant to any garden designed for water saving.
Also planting Vetiver won't bust a gut like earth moving/digging can. And it is certainly cheaper than a lot of other options.