Coupling Climate Conditions, Sediment Sources and Sediment Transport in an Alpine Basin

Abstract

In a fluvial system, mountain basins control sediment export to the lowland rivers. Hence, analysis of erosion processes and sediment delivery patterns in mountain basins is a key factor for many applications such as land‐use management, hazard assessment and infrastructure design. Several studies have investigated the alterations triggered by recent climatic change on the hydrological regime, while only a few works have explored the consequences on fluvial sediment dynamics. Here, we combined and analyzed the quasi‐unique dataset of climatic conditions, landform response and sediment export produced, since 1986 in the Rio Cordon basin (5 km2, Eastern Italian Alps) to examine the sediment delivery processes occurring in the last 3 decades. The temperature, precipitation and fluvial sediment fluxes in the basin were analyzed using continuous measurement executed by a permanent monitoring station, while the evolution of sediment source areas was investigated using three sediment source inventories. The results showed that during the period 1986–1993 the sediment fluxes (339 Mg yr−1) reflected the stable trend of the climatic conditions. The period between the first and second source inventory (i.e. 1994–2006) was characterized by climatic fluctuations and by the occurrence of high magnitude floods. Nevertheless, a limited increase in the extent of sediment source areas was detected, suggesting that the increased sediment export (759 Mg yr−1) was mainly driven by in‐channel sediment supply. Notwithstanding the marked climate warming and the increased precipitation, a weak source area evolution and a reduction in sediment export (237 Mg yr−1) were observed during the period 2007–2015. In particular, the higher rainfall did not result in an intensification of flood events, stressing the absence of hillslope‐channel connectivity. Copyright © 2017 John Wiley & Sons, Ltd.

Connectivity in hydrology and sediment dynamics

“…Some studies focus on catchment scale (e.g., van der Waal and Rowntree, 2018; Yang, & Lu, 2018), while others look at smaller scale soil processes (e.g., Thomaz, 2018; Bagarello et al, 2018). There are studies looking at land‐use effects, such as grazing (Martínez‐Murillo, Hueso‐González, & Ruiz‐Sinoga, 2018), revegetation (Lizaga, Quijano, Palazón, Gaspar, & Navas, 2018), land abandonment (Calsamiglia et al, 2018), urbanization (Ferreira, Walsh, Steenhuis, ∓ Ferreira, 2018), and effects of wild fire (Martínez‐Murillo, & López‐Vicente, 2018), and others focus on characterization of specific landscape types, including alpine (Rainato et al, 2018), badlands (Moreno‐de las Herras et al, 2019; Caraballo‐Arias, Di Stefano, & Ferro, 2018), and gullies (Conoscenti, Agnesi, Cama, Caraballo‐Arias, & Rotigliano, 2018; Zegeye et al, 2018). Also, some studies address only hydrological connectivity (e.g., Laine‐Kaulio and Koivusalo, 2018) or sediment connectivity (e.g., Porto, Walling, & Callegari, 2018), while others look at both types of connectivity (Ricci, Girolamo, Abdelwahab, & Gentile, 2018).…”

“…Within this COST Action, five working groups were established: (a) theory: advancement of the theory of connectivity, including sound and unambiguous definitions of connectivity and related parameters (see coonecteur.info/wiki/connectivity-wiki); (b) measuring: methodology development for measuring connectivity in field and laboratory settings; (c) modelling: numerical model development for successful predictions of connectivity in diverse environments; (d) indices: development of suitable indices of connectivity; and (e) society: determining how the concept can be used to enable sustainable land and water management. The studies presented in this Special Issue reveal a wide variety of connectivity applications which can be classified in various ways.Some studies focus on catchment scale (e.g., van der Waal and Rowntree, 2018;Yang, & Lu, 2018), while others look at smaller scale soil processes (e.g.,Thomaz, 2018;Bagarello et al, 2018).There are studies looking at land-use effects, such as grazing (Martínez-Murillo, Hueso-González, & Ruiz-Sinoga, 2018), revegetation(Lizaga, Quijano, Palazón, Gaspar, & Navas, 2018), land abandonment(Calsamiglia et al, 2018), urbanization(Ferreira, Walsh, Steenhuis, ∓ Ferreira, 2018), and effects of wild fire (Martínez-Murillo, & López-Vicente, 2018), and others focus on characterization of specific landscape types, including alpine(Rainato et al, 2018), badlands (Moreno-de las Herras et al, 2019; Caraballo-Arias,, and gullies…”

Bedload transport in a steep alpine stream: Assessment of sediment mobility and virtual velocity using the bedload tracking

“…The catchment exhibits alpine climatic conditions with mean annual rainfall equal to 1150 mm. Overall, the basin area is principally covered by Alpine grassland with a wide presence of sediment source areas [20]. The Rio Cordon stream flows on a rough channel-bed, which exhibits a prevalent boulder-cascade and step-pool configuration.…”

Hydro‐meteorological drivers influencing suspended sediment transport and yield in a semi‐arid mountainous basin

“…However, few studies delve into the relationship of transport processes with hydro-meteorological drivers, which are especially relevant in mountainous environments (e.g. Micheletti and Lane, 2016;Lane et al, 2017;Kumar et al, 2018;Rainato et al, 2018;Vercruysse and Grabowski, 2019). In these areas, the dynamics of suspended sediment are greatly influenced by the torrential nature of rainfall, snow cycles and high local atmospheric and topographic gradients.…”

“…Nevertheless, the dynamics of hydro-meteorological drivers, although very active and diverse in mountainous areas, only allow a partial description of the sediment delivered. The continuity of sediment flows downstream is also essential to understanding sediment yield (Lana-Renault et al, 2007;Cavalli et al, 2013;Messenzehl et al, 2014;Micheletti and Lane, 2016;Lane et al, 2017;Rainato et al, 2018). From headwaters to floodplains, sediment transport and connectivity between hillslopes and rivers can be understood from measurements of suspended sediment concentration (SSC) and water discharge (Q).…”