Extreme droughts do more than just precede floods—they actually ruin the soil so the next flood is way more dangerous.
April 2, 2026
Original Paper
Response Characteristics and Graded Control Thresholds of Urban Stormwater Systems to Drought-Flood Abrupt Alternation
SSRN · 6508231
The Takeaway
Common sense suggests a parched landscape would act like a dry sponge and soak up more rain. This study of urban stormwater systems reveals that 'exceptional' drought actually damages the soil's ability to absorb water so severely that it triggers a 'risk reversal,' amplifying the speed and volume of runoff compared to normal conditions.
From the abstract
Drought-flood abrupt alternation has become an important compound hydrological extreme, highlighting the need to understand urban runoff and inundation responses. This study develops a coupled 1D-2D urban inundation model that accounts for infiltration differences among underlying surfaces. Multiple drought and rainfall scenarios are designed to investigate runoff generation and inundation dynamics during the transition from drought to heavy rainfall. A threshold identification method for draina