Hydrological drought characteristics in basins with intermittent streamflow regimes in the conterminous United States

Keywords: drought, streamflow, precipitation, intermittent streamflow, threshold level
Session Type: Virtual Paper Abstract
Day: Friday
Session Start / End Time: 2/25/2022 09:40 AM (Eastern Time (US & Canada)) - 2/25/2022 11:00 AM (Eastern Time (US & Canada))
Room: Virtual 6

Abstract

Many basins in the conterminous US have intermittent streamflow regimes, and they are found in a range of climatic and ecological zones. This study investigates the characteristics of hydrological drought in basins with intermittent streamflow regimes. The specific research questions are (1) how their meteorological and hydrological drought characteristics vary over space and time and relate to each other, and (2) how hydrological drought characteristics are related to climate and catchment characteristics. We examined 189 basins known to have intermittent streamflow regimes, the majority of which are in the Great Plains. The hydrological and meteorological drought events were determined using the variable 15th percentile threshold of daily streamflow and precipitation for the period 1980-2018. Basin characteristics were obtained from the Catchment Attributes and Meteorology for Large-sample Studies dataset, and the principal component analysis was conducted to reduce the dimension. The results corresponding to each research question are summarized as follows: (1) The median durations of hydrological drought events are exceptionally long in the Southwest and the Great Plains. The spatial extent of hydrological droughts significantly increased during 1980-2018 (p < 0.001) whereas that of meteorological droughts did not. (2) The durations and deficits of hydrological drought are significantly correlated with principal components consisting of aridity, vegetation cover, zero flow frequency, and soil porosity. We find that the basins in the Great Plains and the Southwest are far more susceptible to hydrological than meteorological drought because of their arid climate and low vegetation cover.