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Global River Discharge Analyses: Impact of Variable Precipitation in the Context of Different Climate Zones

Abstract

Models for fluvial architecture are important for predicting reservoir presence, distribution, quality, and connectivity in continental basins. However, most fluvial models are based on perennial precipitation zone rivers and do not take discharge variability into account; this oversight means many systems preserved in the sedimentary record are modeled inaccurately. Multiple authors (Leier et al., 2005; Fielding et al., 2009; Plink-Bjorklund, 2015) have described a link between seasonal precipitation and variable river discharge in monsoon domain and subtropical rivers, which results in distinct morphodynamic processes and a noticeably different sedimentary record from perennial precipitation zone rivers in tropical rainforest zone and mid-latitudes. These seasonal effects on surface water supply affects river morphodynamics and sedimentation on a wide timeframe, ranging from large single events to an inter-annual or even decadal timeframe. This study further develops our understanding of discharge variability using a global river database created with data from the Global Runoff Data Centre (GRDC) and the University of Wisconsin's Center for Sustainability and Global Environment (SAGE). This research examines the influence of variable discharge on river systems. We compare river discharge patterns in a variety of climate zones (rainforest, monsoonal, sub-humid subtropics, arid to semi-arid subtropics, mid-latitude and arctic) to establish the similarities and differences in discharge patterns as well as sediment distribution. A key difference between this study and previous studies is the inclusion of arctic rivers in the dataset. We analyze the data to test the effects of hydrological connectivity and variability within rivers. We review river discharge data to assess hysteresis and any potential buffering that occurs as large precipitation events propagate through a river system. The ultimate objective of this research is to develop differentiated fluvial facies and reservoir models for each of these climate zones.