We have 'sand dams' but it's not as effective as an Earth dam' a sub-surface dam so it captures all the rain in a 'storage' . Wells/Barkads are simply not 'best' solution for the large nomadic and livestock population. Wells/Barkads suit GM 45,000 SQ KM goof kkkkk or Isaaq, their simply isn't much ppl nor livestock in such a small 'goof' as they can't survive to grow if their 'land' is too small. This is going to serve our nomadic population but also our 'emerging farming communities.