Coastal fog harvesting with mesh collectors where advection fog is reliable

Mechanism

Many arid coasts (driven by cold offshore currents) are dry on the ground but bathed in thick advection fog for months of the year. Fog harvesting hangs large vertical mesh panels perpendicular to the prevailing wind; fog droplets impact the mesh, coalesce, run down, and collect in a trough and reservoir, gravity-fed to villages. It needs no power, no membranes, no high-salinity intake, and no brine handling — making it intrinsically low-maintenance at the hardware level.

Where it fits

For communities on fog-rich coasts, this can be cheaper and simpler than any desalination. It applies only where the fog resource exists and is seasonal, so it typically supplements rather than fully replaces other supply. It pairs naturally with a professionalized maintenance model; its most famous failure is a textbook ownership/maintenance collapse.

Operating profile

• Dar Si Hmad's system: ~600 m² of nets, 7 reservoirs (~539 m³ storage), 6 solar panels, and 10+ km of piping deliver potable water to 400+ people across 5 villages via prepaid SMS-linked meters; later expanded with next-generation