Characterizing spatial and temporal patterns of stream network dynamics

Abstract:

Temporary streams (streams that cease to flow after rainfall events or during certain seasons of the year) are observed in a wide range of climatic settings, and likely represent a major fraction of the global river network; however, empirical datasets about event-based and/or seasonal active network dynamics bacame popular only in the last few years. These datasets require extensive fieldwork, often involving the use of high-tech sensors, but offer a unique opportunity to decipher the physical mechanisms that undelie runoff generation processes in river basins. In this contribution, we use observational data gathered in a set of representative case studies to investigate the main physical drivers of spatial and temporal variations of the active stream length of rivers. Particular emphasis is given to the impact of climatic and physiographyc features on stream network dynamics. We also introduce and formalize the concept of Stream Length Duration Curve (SLDC), a robust statistical tool that summarizes the catchment-scale effect of network expansions and contractions in response to individual events and seasonality. SLDCs allow the quantification of the magnitude of active stream dynamics across diverse settings providing an objective basis for the classification of temporary streams.