Some studies are telling us this may not be the solution. The water would go under the rock and go deeper. Research are focusing on sand retention instead. Mai 2, 2017 à 2:10 Réponse
Francois Trahan 
Hey, that’s a clever way of thkniing about it.
Some studies are telling us this may not be the solution. The water would go under the rock and go deeper. Research are focusing on sand retention instead.