[Scfdglkn]

I think we should use solar energy to vapourise sea water, then use existing landforms and wind patterns to condense the water vapour, and collect it in large natural tanks by placing artificial barriers at the end of existing valleys.

I seem to remember being involved in the construction of one of those some years back. Only difference, we placed the artificial barrier just downstream of a lake discharge, raising the river level to that of the lake.