Physically-based modeling of network expansion and retraction in river basins

The wet channel length (L) of stream networks follows continuous expansion and retraction cycles, as driven by the unsteady hydroclimatic conditions of the surrounding landscape. A direct relation between L and the streamflow at the outlet (Q) has long been recognized in literature; however, a detailed understanding of the physical processes that drive the joint variability of Q and L is lacking. In this thesis, a spatially-distributed numerical model is applied to a number of synthetic catchments and hydroclimatic scenarios to provide insights on the emerging shape of the L(Q) relation. The analysis also aims to identify the main factors that generate hysteretic behaviours in the L vs Q space when network dynamics are observed at high frequency.