The 0.6 Rule: Rivers Shape Fractal Waterways and Deltas

Hack's law: stream length scales roughly as drainage area to the 0.6 power, and it holds worldwide, now extending to river deltas. Through energy-efficient transport networks and landscape-evolution modeling, scientists explain why larger basins elongate rivers, how networks optimize drainage, and why this simple scaling persists even as sediments accumulate at deltas. The work links river bifurcation angles to fivefold symmetry and hints at connections to quasicrystals, revealing a universal geometry of Earth's waterways.