Spatial and temporal controls on historical channel responses – study of an atypical case: Someşu Mic River, Romania

摘要: In this paper the spatial and temporal responses of Somesu Mic River (Romania) to natural anthropogenic controls over past 150 years are analysed, based on a series morphometric parameters extracted from five successive sets topographic maps one set orthophotos. Prior intensive hydrotechnical interventions last four decades, river was characterized by complex alternation different channel types, resulting in mixture alluvial mixed sinuous – meandering anabranched reaches, each few hundred metres kilometres long. The main cause for behaviour local geology. Its effects were intensified larger scale slope, slightly higher than along longitudinal profile with normal concavity, as consequence presence 400 m elevation knick-point located catchment area. A generalized maintenance floodplain perimeter during entire interval study (centennial scale), planform adjustments lack median avulsion lateral tilting areas lengthening meander development hydrological stable periods shortening increasing cutoffs incidence floods (decadal incapacity morphologic changes resulted human completely counterbalance general trends supports idea decreasing amplitude frequency important floods, after end Little Ice Age. Channel metamorphosis canalization, diminishing/elimination overflows medium-scale avulsions flow regimes (dams) dykes perimeter, narrowing (43%) incision (at least 1945) downstream dams, probably because in-channel gravel mining anthropically induced River. Even if impact is important, both at drainage basin River, it has only impacts, subordinated climate. low level could be slope knick-point, which forces positioning its under an internal threshold fluvial system. This boundary condition defines atypical river. that climate more role post-Little Age (LIA) rivers' currently accepted. Copyright © 2011 John Wiley & Sons, Ltd.