Description: Establishing a sediment budget in the newly created “Kleine Noordwaard” wetland area in the Rhine–Meuse delta Eveline Christien van der Deijl, Marcel van der Perk, and Hans Middelkoop Earth Surf. Dynam., 6, 187-201, https://doi.org/10.5194/esurf-6-187-2018, 2018 To study the effectiveness of river delta restoration, we used field observations and elevation data to quantify the magnitude and spatial patterns of aggradation and erosion in a restored wetland in the Rhine-Meuse delta. Erosion and aggradation rates decrease over time, but aggradation compensates for sea-level rise and soil subsidence. Channels in the centre had aggraded, whereas the inlet and outlet eroded. Furthermore, sediment is in general uniformly distributed over the intertidal area.

Description: How concave are river channels? Simon M. Mudd, Fiona J. Clubb, Boris Gailleton, and Martin D. Hurst Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2018-7,2018 Manuscript under review for ESurf (discussion: open, 1 comment) Rivers can reveal information about erosion rates, tectonics, and climate. In order to make meaningful inferences about these influences one must be able to compare headwaters to downstream parts of the river network. We describe new methods for normalizing river steepness for drainage area to better understand how rivers record erosion rates in eroding landscapes.

Description: Numerical modelling of landscape and sediment flux response to precipitation rate change John J. Armitage, Alexander C. Whittaker, Mustapha Zakari, and Benjamin Campforts Earth Surf. Dynam., 6, 77-99, https://doi.org/10.5194/esurf-6-77-2018, 2018 We explore how two landscape evolution models respond to a change in climate. The two models are developed from a divergent assumption on the efficiency of sediment transport. Despite the different resulting mathematics, both numerical models display a similar functional response to a change in precipitation. However, if we model sediment transport rather than assume it is instantaneously removed, the model responds more rapidly, with a response time similar to that observed in nature.

Description: Scales of collective entrainment and intermittent transport in collision-driven bed load Dylan B. Lee and Doug Jerolmack Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2018-8,2018 Manuscript under review for ESurf (discussion: open, 3 comments) The transport of pebbles in a river is smooth and continuous under high flow conditions, but under typical flows becomes erratic and unpredictable. We perform experiments to learn more about the origins of this unpredictable, intermittent behavior. Our results show that this unpredictability is similar to how infrequent avalanches occur in a sandpile. Transport events are similar in size but become more infrequent and erratic as the river transports less and less sediment.

Description: Statistical modeling of the long-range dependent structure of barrier island framework geology and surface geomorphology Bradley A. Weymer, Phillipe Wernette, Mark E. Everett, and Chris Houser Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2018-5,2018 Manuscript under review for ESurf (discussion: open, 0 comments) This research presents a new method for quantifying the geologic controls on modern barrier island evolution. We used statistical time series analysis to evaluate the scale-dependent vs. scale-independent behavior of a barrier island in south Texas, USA. By integrating subsurface geophysical with surface geomorphological measurements we show that the island exhibits both free, and forced evolutionary behavior that has important implications for how the island may respond to rising sea levels.

Description: Temporal variability in detrital 10 Be concentrations in large Himalayan catchments Elizabeth H. Dingle, Hugh D. Sinclair, Mikael Attal, Ángel Rodés, and Vimal Singh Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2017-73,2018 Manuscript under review for ESurf (discussion: open, 3 comments) Accurately quantifying sediment fluxes in large rivers draining tectonically active landscapes is complicated by the stochastic nature of sediment inputs. Cosmogenic 10 Be concentrations measured in modern river sands have been used to estimate 10 2 –10 4 year sediment fluxes in these types of catchments, where upstream drainage areas are often in excess of 10,000 km 2 . It is commonly assumed that within large catchments, the effects of stochastic sediment inputs are buffered such that 10 Be concentrations at the catchment outlet are relatively stable in time. We present eighteen new 10 Be concentrations of modern river and dated Holocene terrace and floodplain deposits from the Ganga River near to the Himalayan mountain front. We demonstrate that 10 Be concentrations measured in modern Ganga River sediments display a notable degree of variability, with concentrations ranging between ~ 9,000–19,000 atoms g −1 . We propose that this observed variability is driven by two factors. Firstly, by the nature of stochastic inputs of sediment (e.g. the dominant erosional process, surface production rates, depth of landsliding, degree of mixing) and, secondly, by the evacuation timescale of individual sediment deposits which buffer their impact on catchment-averaged concentrations. Despite intensification of the Indian Summer Monsoon and subsequent doubling of sediment delivery to the Bay of Bengal at ~ 11–7 ka, we also find that Holocene sediment 10 Be concentrations documented at the Ganga outlet have remained within the error of modern river concentrations. We demonstrate that in these systems, sediment flux cannot be simply approximated by converting detrital concentration into mean erosion rates and multiplying by catchment area as it is possible to generate considerably larger volumetric sediment fluxes whilst maintaining comparable average 10 Be concentrations.

Description: How to explain variations in sea cliff erosion rates? Insights from a literature synthesis Mélody Prémaillon, Vincent Regard, Thomas J. B. Dewez, and Yves Auda Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2018-12,2018 Manuscript under review for ESurf (discussion: open, 0 comments) Coastal erosion is of major concern for society, our study focus on rocky coast whose evolution remains poorly understood. We use the increasing number of erosion-related data and compiled it for better understanding how and how much rocky coasts erode. We found that rock resistance explain in first order erosion rates whereas influence of climate and sea is secondary. Weak rock coasts loose in median 23 meters per century, about ten times more than hard rock coasts.

Description: Effect of changing vegetation on denudation (part 1): Predicted vegetation composition and cover over the last 21 thousand years along the Coastal Cordillera of Chile Christian Werner, Manuel Schmid, Todd A. Ehlers, Juan Pablo Fuentes-Espoz, Jörg Steinkamp, Matthew Forrest, Johan Liakka, Antonio Maldonado, and Thomas Hickler Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2018-14,2018 Manuscript under review for ESurf (discussion: open, 0 comments) Vegetation is crucial for modulating rates of denudation and landscape evolution, and is directly influenced by climate conditions and atmospheric CO 2 concentrations. Using transient climate data and a state-of-the-art dynamic vegetation model we simulate the vegetation composition and cover from the Last Glacial Maximum to present along the Coastal Cordillera of Chile. In part 2 we assess the landscape response to transient climate and vegetation cover using a landscape evolution model.

Description: Glacial Isostatic Adjustment modelling: historical perspectives, recent advances, and future directions Pippa L. Whitehouse Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2018-6,2018 Manuscript under review for ESurf (discussion: open, 2 comments) This article is a contribution to a special issue on “Two centuries of modelling across scales”. It describes the historical observations, evolving hypotheses, and early calculations that led to the development of the field known as Glacial Isostatic Adjustment (GIA) modelling, which seeks to understand feedbacks between ice-sheet change, sea-level change, and solid Earth deformation. Recent advances are discussed. Future research in the field is likely to involve an interdisciplinary approach.

Description: Tracking the 26 Al/ 10 Be source-area signal in sediment-routing systems of arid central Australia Martin Struck, John D. Jansen, Toshiyuki Fujioka, Alexandru T. Codilean, David Fink, Réka-Hajnalka Fülöp, Klaus M. Wilcken, David M. Price, Steven Kotevski, L. Keith Fifield, and John Chappell Earth Surf. Dynam. Discuss., https//doi.org/10.5194/esurf-2017-76,2018 Manuscript under review for ESurf (discussion: final response, 3 comments) Measurements of cosmogenic nuclides 10 Be and 26 Al in sediment along central Australian streams show that lithologically-controlled magnitudes of source-area erosion rates (0.2–11 m/m.y.) are preserved downstream despite sediment mixing. Conversely, downstream-increasing sediment burial signals (〉 400 k.y.) indicate sediment incorporation from adjacent, long-exposed storages, which, combined with low sediment supply and discontinuous flux, likely favours source-area 10 Be- 26 Al signal masking.