aerial view of tidal channels and gullies, waddenzee, holland

travel river holwerd sand waddenzee wadden deposition branch fractal aerial mudflat shape westerschelde tidal land zeeland summer moddergat sea saltmarsh polder schelde mud marshland evolution background field water hedwigepolder holland netherlands gully marsh drowned tide channel nature natural landscape green drone delta coast tree saeftinghe swamp friesland groningen colorful