Channel and cut-bluff failure connectivity in a river system: Case study of the braided-wandering Belá River, Western Carpathians, Slovakia.

Straightforward sediment transport is not common in nature and material is storage during transport and reworked by the same processed that lead to initial mass erosion. Despite the development of quantitative assessment by application high accuracy topography measurement, lack of conceptualisation and combination with precise elevation model changes is still missing. This paper presents a field-based channel-bluff connectivity study based on a sediment cascade approach. A TLS (terrestrial laser scanning) time-series database was generated by systematic monitoring of cut-bluff slope surface of the braided-wandering Belá River. The database was used to estimate volume changes and allowed to develop the conceptualisation model of coupling of cut-bluff slope based on spatial and temporal analyses of channel hydrology, gravity conditioned transformation of matter and a detailed of sediment budget calculations. Historical analyses have shown that a flow direction perpendicular to the slope is crucial to activate cut-bluff slope material movement and initiate a sediment cascade, as significant contributors of sediment into the river. Sediment supply to the channels correlates with the magnitude of flood events (maximum discharge, cumulative discharge, cumulative discharge higher than RI1.5, and duration of discharges higher than RI1.5) and lateral migration as a main factor controlling the behaviour of the cut-bluff slope-channel system. During the survey from March 2016 to November 2018, were transported 10,103 m3 (25,964 t) of fine-grained sediment into the river channel.