How might sediment connectivity change in space and time?

Abstract

Many authors focus on the concept of sediment connectivity to predict the sedimentary signal delivered at catchment outlets. In this framework, the sedimentary signal is seen as an emergent aggregation of local links and interactions. The challenge is then to open black boxes that remain within a sediment cascade, which requires both accurate geomorphic investigations in the field (reconstruction of sequences of geomorphic evolution and description of sediment routes) and the development of tools dedicated to the modeling of sediment cascades. On the basis of study cases in various environmental regimes (high‐energy mountainous environment and agricultural lowland catchments), in this paper, we (a) exhibit some spatial and temporal paradoxes in terms of sediment delivery and (b) develop various modeling procedures to test some hypothesis of interpretations. These modeling approaches explore different components of sediment connectivity at the catchment scale, including graph theory, agent‐based modeling, and differential equations. Each protocol is chosen according to the scientific objective and how the geomorphological system is simplified. Collectively, the results show that connectivity is an efficient conceptual framework with which to predict how a sediment cascade may transmit (or not) a perturbation throughout the system, including local perturbations (local sediment input, removal of a reservoir, etc.) and perturbations due to external‐boundary forces.

Perspectives and ambitions of interdisciplinary connectivity researchers

“…Previous studies demonstrated that different or even diverging perspectives do not negatively influence the knowledge creation processes when interactions between the actors are repeated, positively perceived and sufficiently adjusted to encourage relationship building (e.g. Dewulf et al, 2007). The approaches and results of our study have been presented to connectivity scientists in EU COST Action ES1306 and closely discussed with the leaders of the action's working groups in order to facilitate effective communication within the working groups and the network.…”

“…Second, constructive conflicts may help to improve group communication, e.g. by unravelling different points of view (De Dreu and Weingart, 2003;Krueger et al, 2016) that affect how interdisciplinary group approaches open questions in connectivity science. Although the colour contours Figure 3.…”

“…We claim that if the concepts of connectivity methodsboth theoretical aspects (e.g. Bracken et al, 2015;Cossart et al, 2018;Keesstra et al, 2018) and practical aspects regarding monitoring the design, model and index implementation adapted to planning applications (e.g. Clauzel et al, 2013;Foltête et al, 2015;Tannier et al, 2016;Ahlmer et al, 2018) -have not yet fully entered the mindset of water and land managers, they cannot understand how to monitor, model and subsequently manage environmental problems.…”

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“…Second, constructive conflicts may help to improve group communication, e.g. by unravelling different points of view (De Dreu and Weingart, 2003;Krueger et al, 2016) that affect how interdisciplinary group approaches open questions in connectivity science. Although the colour contours Öberg (2011).…”

Effects of Roughness Coefficients and Complex Hillslope Morphology on Runoff Variables under Laboratory Conditions

“…Divergent hillslopes have a decreasing rate of change due to parallel and direct movements of runoff toward the outlet and the effect of the lower part of plot on the outlet runoff volume, while parallel hillslopes have a constant rate of head change due to the constant up and down widths of the plot [49]. However, in convergent hillslopes due to a greater area of upward of plot over time, the rate of increase of runoff peak increases [50,51]. The study of the CHs also shows that the start time of runoff and time to concentration increases with increasing soil RCs (Figure 4).…”