Spatial scaling of floods during hurricane events in Mexico

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Jose Agustin Breña-Naranjo, Adrian Pedrozo-Acuña

Tuesday 30 june 2015

9:00 - 9:15h at North America (level 0)

Themes: (T) Extreme events, natural variability and climate change, (ST) Hydrological extremes: floods and droughts

Parallel session: 4I. Extreme events – Flood Drought

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The spatial scaling of flood events can be assessed through a power-law relationship between the maximum observed discharge (Qp) and the upstream drainage area (A). This envelope of data points is of great usefulness for predicting peak flows in ungauged basins. Previous works have demonstrated the scale invariance of flood peaks with respect to a drainage area. Such patterns are usually represented by a cloud of flood peak values limited by an upper and lower envelope suggesting a maximum and minimum possible discharge values during precipitation events. While the scaling behavior of floods has been primarily linked to the intrinsic hydro-climatic and geomorphological characteristics of watersheds in temperate regions, little is known about the spatial scaling of floods in tropical watersheds. This work analyzes the Qp-A scaling relationship in several Mexican watersheds that are occasionally impacted by tropical storms and hurricanes. The findings of this study show exceptional peak flows generated by cyclonic events. These values are comparable to maximum discharge values found in other regions of the world, even when they are not generated by cyclonic precipitation systems. This study highlights the contribution of cyclonic precipitation to flooding through the magnitude found in the scaling exponents.