You're forgetting to take into account transport costs. Want to pump that cubic meter of water 100 km inland and the energy cost alone will be over $1/m^3. Ign

You're forgetting to take into account transport costs. Want to pump that cubic meter of water 100 km inland and the energy cost alone will be over $1/m^3. Ignoring pumps, piping, maintenence, land purchasing, cabling, planning permission, etc etc.