Thank you for your suggestion. From the research that I have found, vetiver plant technology is good for many countries in South East Asia, such as Thailand, Malaysia, and The Philippines. Moreover, the deep root system technology also work profitably in Queensland, Australia as the attachment research.
However, this will be the innovative idea to introduce new vetiver grass species, to adapt in particular region to get the best result. As I mention, the deep root system helps soil moisture to absorb water underneath the ground. Therefore, it support an agriculture that farmers can cultivate even in the dry season.
Hi Sarah, Sorry for being late reply, as I am unwell and had to meet doctor. Yes, I agree with you about the limited of land in urban area. My thought is about how can we handle with the rainwater that can have a flood in city. Therefore, if we can stop rainwater from a circle area before it get into urban slum, that would be good. However, thank you for your suggestion, that's very thoughtful.