Vetiver System for Extreme Slope Stabilization - Part 1

There are situations where slopes are so steep, where rainfall is so intense, and where the soils are so fragile that applying the Vetiver System by itself will not work.  There are many such instances, and many occur in urban areas where very poor people reside.  This is the case in the DR Congo and Congo Brazzaville. Over the last few years Roley Noffke of Hydromulch, South Africa and his associate Alain Ndona of Kinsasha have been stabilizing massive urban gullys using earthfilled bags that are pinned together with Vetiver.  The bags provide protection and support for vetiver to establish, and after a while the bags disintegrate leaving vetiver to hold the slope together.  There are many other countries where similar problems occur, and this is probably the least costly and most effective way of doing so. Here follow some images. The top two show the before situation, the next two show the head of the gully at the time of earth-bagging and planting vetiver layout, then an image taken about a year later of the head of the gully stabilized with vetiver planted bags, then two close up images of the planted bags and the last a reminder of the "nail" that is used.

With Haiti in the spotlight, this method could be used for extreme situations in that country.  And by the way I remember when I worked in Eastern Nigeria in the 1970s urban gullies such as these.

I have put a couple of videos on YouTube that show the sort of urban gully problems in the two Congos - it is gullies like these that the earthbag/vetiver technology is being applied to


http://www.youtube.com/watch?v=zVuT3Rv7SUs and http://www.youtube.com/watch?v=TT1KmnxxT80

                                                                        

Photo credits: Roley Noffke, Alain Ndona, and Criss Juliard