from the WaterChannel:
Question: How can dusty roads provide water?
Answer: By harvesting and storing rainwater when it falls on them.
A 30 mm rainfall over a 1-kilometre stretch of road can produce up to 100,000 litres of water. This number points to a huge potential. And not one that has not been adequately tapped (around 7 billion USD are spent on road construction in sub-Saharan Africa alone).