Dr Somnath Jha,
Thank you very much for your important question.
In Algerian arid surface water resources are very scarce. The irrigation of oases is through groundwater.
It is not possible to use the waters of extreme precipitation in arid regions because the nature of most soil is sandy (it promotes permeability).
The only appropriate solution is to build small dams to get the following benefits:
1- Supply groundwater
2- protect flood areas
3- fertilize farmland
For more information, I invite you to visit the following links: