Changing Seasonality of Annual Maximum Floods over the Conterminous US: Potential Drivers and Regional Synthesis

Basu, B and Bhowmik, RD and Sankarasubramanian, A (2023) Changing Seasonality of Annual Maximum Floods over the Conterminous US: Potential Drivers and Regional Synthesis. In: Journal of Hydrologic Engineering, 28 (4).

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Abstract

Understanding the flood-generating mechanisms that influence flood seasonality in a region provides information on setting up relevant contingency measures. Although former studies estimated flood seasonality at regional/continental scale, limited/no studies have investigated the climate/basin drivers that influence the changes in flood seasonality. Considering this, the current study performed two analyses: (1) estimated the changes in the seasonality of annual maximum floods (AMF) between pre- and post-1970 across Hydroclimate Data Network basins over the conterminous US, and (2) identified the predictors that influence the change in the seasonality from a set of climate and geomorphic variables. Significant changes in the AMF seasonality were noted for approximately half of the basins in the eastern US, but low to no change was found in most basins in the central/western US. We found, except in the Northeast and mid-Atlantic basins, a decrease in the seasonality index, indicating floods arriving more uniformly is typically associated with an increase in the precipitation days in basins. On the other hand, increase in the seasonality index, indicating floods occurring more concentrated in time, is typically associated with an increase in the extreme precipitation in basins. Among the basin characteristics, elevation has a more dominant role than the drainage area in changing the flood seasonality. Elevation affects the form of precipitation, particularly in the western US, because floods arrive more distributed over the year (i.e., decrease in flood seasonality index), which potentially indicates increased warming resulting in early snowmelt. © 2023 American Society of Civil Engineers.

Item Type:	Journal Article
Publication:	Journal of Hydrologic Engineering
Publisher:	American Society of Civil Engineers (ASCE)
Additional Information:	The copyright of this article belongs to American Society of Civil Engineers (ASCE).
Keywords:	Catchments; Climate change; Precipitation (meteorology); Water resources; 'current; Annual maxima; Continental scale; Data network; Flood seasonality; Generating mechanism; Hydroclimates; North East Atlantic; Seasonality; Seasonality index; Floods
Department/Centre:	Division of Interdisciplinary Sciences > Interdisciplinary Centre for Water Research
Date Deposited:	09 Mar 2023 07:19
Last Modified:	09 Mar 2023 07:19
URI:	https://eprints.iisc.ac.in/id/eprint/80946

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