How landscape memory, hysteresis shape the way Indian cities flood Premium

Explore how hydrological hysteresis shapes flooding patterns in Indian cities, revealing landscapes' memory of past rainfall.

Rain comes down steadily, painting the skies a dull grey and sending a chill breeze wafting through the windows of high-rise buildings. On the street below, water creeps out of cracks and pores.

Next to the highway lies a lake but the boundary between water and land has blurred. What was once contained spreads across the wetland, dampening the mud path joggers run on, seeping into the road beneath the churning wheels of buses, cars, and motorcycles.

It is water that seems out of place, yet it moves with familiarity, following paths the land remembers long after they have been paved over.

What does it mean for a landscape to remember rain? 

In cities across India, streets remain waterlogged long after the downpour has passed.

These familiar scenes are often dismissed as failures of human-made drainage systems or excess rainfall. But hydrology offers an additional insight: landscapes don’t respond to rain instantly or forget it quickly. Instead they retain a memory of past rainfall, shaping how water moves through soils, wetlands, rivers, and cities.