There is an issue in such approach: people do not see them except during a drought so... Not very useful. The real issue is that domestically we can store wate

There is an issue in such approach: people do not see them except during a drought so... Not very useful. The real issue is that domestically we can store water if we live at a not that high density. We can collect even 50-100m³ underground per home, out of rain water on the roof, make it drinkable with sand filters + Cl, potentially a not so cheap home can store enough water for its residents on yearly basis. Agriculture can't. Industry can't. We actually need to eat, so we need agriculture (also to farm animals, since they also eat), and since we do not build anything forever and ever and we evolve we need industry.