nyuuzyou/wikis huggingface dataset:
CSDMS 2016 annual meeting poster AlbertKettner

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=The impact of climate change on riverine flooding=
Albert Kettner, CSDMS-IF, INSTAAR, Univ. of Colorado boulder Colorado, United States. albert.kettner@gmail.comSagy Cohen, University of Alabama Tuscaloosa Alabama, United States. sagy.cohen@ua.eduIrina Overeem, University of Colorado Boulder Colorado, United States. irina.overeem@colorado.eduBalazs Fekete, The City University of New York New York New York, United States. bfekete@ccny.cuny.eduRobert Brakenridge, University of Colorado Boulder Colorado, United States. Robert.Brakenridge@colorado.eduJames Syvitski, University of Colorado Boulder Colorado, United States. james.syvitski@colorado.edu
Abstract:
Flooding is the most common natural hazard worldwide, affecting 21 million people every year. River induced flooding typically occurs when streamflow exceeds bankfull stage at a certain stretch along a river at a given point in time. While some, mostly large-scale, flooding events are relatively perennial most are highly transient. This makes flooding difficult to predict. Although hydrological models can quite accurately estimate streamflow conditions, overbanking is dependent upon localized river morphology and hydraulics, both difficult to ascertain. Recent advances in characterization and modeling of river-floodplain interactions now allows us to provide a spatially and temporally explicit first order estimates of the location, magnitude, frequency, and duration of floods of global rivers.
Here we apply the global Water Balance Model (WBM) to quantify a) location, frequency and magnitude of flooding and b) the impact of future predicted climate change on this quantification. Among others, WBM simulates daily riverine streamflow at 6 arcminutes spatial resolution. The bankfull water discharge is estimated for each river location by determining the 2year flood frequency return interval based on the Log-Pearson Type III Distribution. Similarly, globally discharges that mimic the 10, 25, 50 and 100 year flood event were established. Flood magnitude and frequencies of the last 30 years (1975-2004) are determined and compared to future simulated floods (2070-2099).
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CSDMS 2016 annual meeting poster AlejandroTejedor

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Quantifying delta complexity toward inference and classification=
Alejandro Tejedor, St. Anthony Falls Laboratory Minneapolis Minnesota, United States. alej.tejedor@gmail.comAnthony Longjas, St. Anthony Falls Laboratory Minneapolis Minnesota, United States. alongjas@umn.eduEfi Foufoula-Georgiou, St. Anthony Falls Laboratory Minneapolis Minnesota, United States. efi@umn.edu
Abstract:
Delta channel networks self-organize to a variety of stunning and complex patterns in response to different forcings (e.g., river, tides and waves), sediment composition, incoming flow variability, sea level rise, etc. Recently, we presented a rigorous framework based on spectral graph theory to study delta channel networks from a topologic (channel connectivity) and dynamic (flux exchange) perspective for advancing our understanding of deltas as complex systems [Tejedor et al., 2015a,b]. The question that we aim to answer in this work is how the complexity of delta channel networks evolves as the delta grows and how it depends on a specific physical parameter namely the incoming sediment size. To explore the dependence of complexity with sediment composition, we have used numerical modeling (Delft3D) where the different geomorphic parameters can be controlled and/or isolated. We have analyzed the channel networks of river-dominated deltas that arise from using different size distributions of the incoming sediment. The results of our analysis show how complexity metrics (topologic and dynamic) are able not only to capture the variability in the delta structure, but also quantify the increase of complexity when the sediment composition transitions to coarser grains. Furthermore, from a joint analysis of ﬁeld and simulated deltas within this quantitative framework, we showed encouraging results and provided preliminary evidence toward a path for quantitative delta classiﬁcation by exploring similarities and discrepancies in the underlying processes and the resulting network complexity.
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CSDMS 2016 annual meeting poster AnastasiaPiliouras

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Discharge controls on plant distribution and channel network formation in vegetated delta experiments=
Anastasia Piliouras, University of Texas at Austin Austin Texas, United States. anastasia.piliouras@gmail.com
Abstract:
Increasing rates of relative sea level rise are depleting coastal land, causing scientists and engineers to propose solutions, such as river diversions, for coastal restoration. Success in delta restoration projects largely depends on the understanding of interactions between physical and biological processes that can drastically change delta morphology. However, the effects of vegetation on delta dynamics and morphology are still poorly understood. Here we show that there are clear differences in delta morphology between experiments conducted with high and low discharges but that vegetation has the same effects on large-scale delta morphology regardless of discharge. Lower discharge experiments had more, narrower channels that created more small, sparse patches of vegetation that aided in increased channel bifurcation. Deltas created with higher water and sediment discharges had fewer, wider channels that created fewer large, dense patches of vegetation that instead steered channels. Vegetation in both experiments made wider deltas and smoother shorelines, regardless of the differences in patch distribution, compared to experiments without plants. These results are important for coastal restoration as engineers decide whether to implement few large diversions of many small diversions: the discharge controls the morphology and the distribution of vegetation relative to the flow, and vegetation can change the channel processes and feedbacks to make a more or less distributive network of channels to build new land.
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CSDMS 2016 annual meeting poster AndressaViannaMansur

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=A Composite Vulnerability Index for Urban Areas in Deltaic Regions: An Application in the Amazon Delta=
Andressa Vianna Mansur, Indiana University Bloomington Indiana, United States. andressavmansur@gmail.com
Abstract:
Deltas are complex socio-ecological systems subject to a wide range of human pressures and hazards, where population density is many-folds that of other regions. Urban development patterns, urban growth, river damming & sediment control coupled with climate change are increasing flood risks and the degree of vulnerability in many deltas of the world. The need for integrated vulnerability assessments that capture both socio-economic and geophysical elements in deltas is emergent. This study presents a composite index for the vulnerability assessment of the urban Amazon Delta (AD) based in three dimensions of vulnerability: flood exposure, socio-economic sensitivity and infrastructure. The vulnerability index was developed using the Analytical Hierarchy process (AHP), which helps to gage level of interdependence and the role of different dimensions of vulnerability. The index combines data from public databases at the most disaggregated level of analysis of census data (n = 2938 census sectors) and uses a methodology based on data from Shuttle Radar Topography Mission (SRTM) to assess and characterize sectors based on their flood risks. Results indicate that over 60% of the urban sectors within the AD present high degree of vulnerability, reaching a population of over one million inhabitants. This degree of urban vulnerability defines and reiterates the impacts of future climate changes across society and as it extends beyond the urban areas of the AD. The methodology proposed in this study contributes to a multi-dimensional assessment of urban vulnerability and it can be applied to other urban areas, allowing for cross-site comparison of vulnerabilities across urban spaces within deltaic systems. Depending on particular case study of an urban area, a more context specific sub set of model indicators can be selected to assess vulnerability. Some indicators can be adapted to individual urban systems thereby providing a useful tool to assess vulnerability in a particular case study while developing a broader model. Future work will involve additional emphasis on time dependent land cover changes and their effects on urban vulnerability based on compositional and configurational changes to the landscape.
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CSDMS 2016 annual meeting poster AndrewWickert

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Evolution of river valleys and terraces: a geometric approach=
Andrew Wickert, University of Minnesota Minneapolis Minnesota, United States. awickert@umn.edu
Abstract:
River terraces are prominent flat surfaces formed at old persistent river bed elevations. They correlate with changes related to past sediment supply and base-level and therefore climate and tectonics. The goal here is to create a reduced-complexity model that obeys the physics of geomorphic processes while generating terrace surfaces for direct comparison and interpretation of river systems in the field. A simple set of rules that includes aggradation, incision, lateral migration, and angle of repose, can, when applied in sequence, reproduce many of the most salient observables of the fluvial landscape.
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CSDMS 2016 annual meeting poster AngangLi

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Effects of In-stream Mixing on Carbon Photo-mineralization in Arctic Rivers=
Angang Li, Northwestern University Evanston Illinois, United States. angang-li@u.northwestern.edu
Abstract:
Photo-mineralization, the oxidation of dissolved organic carbon (DOC) to CO2 by light, is an important mechanism of CO2 production in arctic inland waters. Current estimates of arctic CO2 production assume that DOC is well-mixed in the water column, which overlooks circumstances when vertical mixing is not strong enough to replenish DOC in the photo-active near-surface region. To determine conditions for which the well-mixed assumption is valid, we used a physically based model that numerically computes whole-stream effective reaction rates as an integrated effect of spatial patterns of photo-chemical reaction and mixing limitations, and quantified the difference in these rates with and without mixing limitations. The well-mixed assumption holds when the mixing timescale is sufficiently smaller than photo-mineralization timescale. However, mixing limits effective whole-stream photo-mineralization rates when total light attenuation over depth is strong and when the reaction rate is faster than the mixing rate. We applied this analysis to estimate whole-system photo-mineralization of DOC in the Kuparuk River, Alaska. We found that the well-mixed assumption is valid for photo-mineralization of DOC in the main stem of the Kuparuk River, and upscaling of available observations with this assumption yields a total DOC photo-mineralization rate of 1.26×105 mol CO2 day-1. Scaling analysis indicates that photo-mineralization rates in other arctic systems with similar photon attenuation over depth but longer mixing timescales will be limited by hydrodynamic mixing rates.
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CSDMS 2016 annual meeting poster AnjaliFernandes

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=A Simple Land-building Model for Suspended Sediment in Coastal Diversions=
Anjali Fernandes, The University of Connecticut Storrs Connecticut, United States. anjali.fernandes@uconn.edu
Abstract:
We use sediment cores, grain-size data and time-lapse bathymetry maps from Cubit’s Gap and the West Bay Diversion on the lowermost Mississippi River, to inform a simple advection settling model to investigate patterns of land construction at diversions. In this model, sediment used for land-building is suspended sediment sourced from the upper fraction of the river’s water column. We couple the record of deposition in Cubit’s Gap, which opened in 1862, with the shorter record available from the West Bay Diversion, which was opened in 2003. Bathymetry and grain-size data from sediment cores show that mud-rich riverine sediment was distributed as a blanketing deposit over a low-sloping subaqueous clinoform.
Using flow hydraulics and channel geometries at these sites, and neglecting the effects of waves and tides, computed advection lengths of well-suspended sediment range from just under 1 km for 100µm sand to more than 8km for 44µm silt. This is in good agreement with grain-size patterns and deposition rates at both sites. The settling velocity of the median particle size in deposits is used in a 2-D advection settling model to compute deposition rates. We use published values and field observations to constrain suspended sediment concentrations, outlet depth and current velocity, the other variables required in this model. Sediment concentration near the bed is taken to be twice the average sediment concentration for a turbulent, well-mixed water column in the Mississippi River. We use the pre-existing bathymetry at these two sites as the basal surface upon which we build deposition. 
Contrary to the traditional prograding delta model, blanketing deposition and net shallowing of the basin is dictated by the hydrodynamics of well-suspended sediment at the diversion outlet. This lengthens the time-scale associated with land emergence, but once the basin is sufficiently shallow emergent deposits can “pop up” over a very short span of time.
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CSDMS 2016 annual meeting poster AnnieBoucher

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Implications Of Fault Damaged Bedrock To Tectonic and Landscape Evolution In Coastal Alaska=
Annie Boucher, University of Maine Orono Maine, United States. anne.l.boucher@maine.edu
Abstract:
Bedrock material strength properties heavily impact erosion rates in temperate glacial environments. We focus on the influence of localized tectonic crustal weakening in southeast Alaska on modern glacial erosion rates, thereby quantifying a primary feedback in tectonic/climatic coupling. Southeast Alaska, with its coincident high strain rates, vigorous glacial erosion and rapid sedimentation rates, provides an excellent setting in which to evaluate this interaction. 
To characterize the relationship between fault damage and glacial incision, we collected data in transects across the strike-slip Fairweather Fault in Yakutat and Disenchantment Bays, in deglaciated valleys below the Mendenhall, Herbert, Ptarmigan, and Lemon Creek Glaciers on the perimeter of the Juneau Icefield, and on deglaciated nunataks on the Echo and Vaughan Lewis Glaciers in the interior of the Juneau Icefield. The mechanical properties of the bedrock are characterized by estimates of fault spacing and material cohesion. In structurally-controlled bedrock valleys exploited by glaciers, fracture spacing may vary by several orders of magnitude across fault damage zones, from more than 10 m to less than 0.1 m. Analysis of active and quiescent fault zones indicate that this variation approximates a power law relationship and correlates with a gradient in cohesive strength varying from greater than 50 MPa to less than 50 kPa between intact bedrock and the core of fault damage zones. The width and orientation of the damage zones is highly variable and we have chosen our field sites to sample zones of very large total displacement, up to kilometers along the Fairweather Fault, and substantially smaller displacements, down to centimeters for the Juneau Icefield locales. We further use elevation variance analysis (EVA) to extrapolate these field observations to an orogeny-scale estimate of variation of cohesion strength.
Using a Cordilleran Ice sheet model to extend our modern observations into last glacial maximum conditions, we predict both erosion rates and sediment provenance for a material strength pattern influenced by tectonically induced fault damage. Compared to an earth model of homogeneous strength properties, our fault damage model predicts high spatial heterogeneity of erosion rates and sediment yield that changes as Cordilleran ice sheet thickness decreases from last glacial maximum to modern conditions. Understanding erosion dynamics through a changing climate helps us to better define the tectonic/climatic coupling.
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CSDMS 2016 annual meeting poster AnthonyLongjas

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=An entropy based quantification of delta channel network complexity=
Anthony Longjas, St. Anthony Falls Laboratory, University of Minnesota Minneapolis Minnesota, United States. alongjas@umn.eduAlejandro Tejedor, St. Anthony Falls Laboratory, University of Minnesota Minneapolis Minnesota, United States. alej.tejedor@gmail.comEfi Foufoula-Georgiou, St. Anthony Falls Laboratory, University of Minnesota Minneapolis Minnesota, United States. efi@umn.edu
Abstract:
River deltas across the world exhibit an astonishing variety of morphologies in response to different forcings (e.g., river, tides and waves), sediment composition, incoming flow variability, sea level rise, etc. Understanding and quantifying the patterns imprinted on the landform would enable us to infer processes from observed imagery. Galloway [1975] introduced a qualitative diagram to classify deltas, showing how the balance of upstream (fluvial) and downstream (waves and tides) forcings dictates the delta form, depicted most distinctively in the coastline morphology. Recently, we presented a rigorous framework [Tejedor et al., 2015a,b] based on spectral graph theory to study delta channel networks, enabling us to extract important structural and dynamics-related information of river deltas. Using that information, we are able to introduce a suite of metrics to quantify channel network complexity, including entropic-based metrics measuring the complexity in terms of the uncertainty in the splitting and rejoining paths and fluxes, enhancing the comparison of deltas and process from form inference. Finally using the above mentioned framework, we are able to construct vulnerability maps that depict the relative change of sediment and water delivery to the shoreline outlets in response to possible perturbations in hundreds of upstream links. We show that an inverse relationship exists between entropy and vulnerability, reinforcing the idea that entropy is a surrogate of the capacity of the system to undergo changes.
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CSDMS 2016 annual meeting poster ArvindSingh

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<FONT style="FONT-SIZE:10pt" color="#ffffff">Presentation provided during SEN - CSDMS annual meeting 2016</font>
=Experimental investigation of the effect of climate change and tectonic anisotropy on landscape evolution=
Arvind Singh, University of Central Florida Orlando Florida, United States. </small>arvind.singh@ucf.edu</small>Alejandro Tejedor, University of Minnesota Minneapolis Minnesota, United States. alej.tejedor@gmail.comGrimaud Jean-Louis, University of Minnesota Minneapolis Florida, United States. jeanlouis.grimaud@gmail.comEfi Foufoula-Georgiou, University of Minnesota Minneapolis Minnesota, United States. efi@umn.edu
Abstract:
Based on a series of controlled laboratory experiments conducted at the St. Anthony Falls laboratory, University of Minnesota, we study the effect of changing external forcing such as the temporal pattern (i.e. increase/decrease) of precipitations as well as spatial distribution of uplift rates on landscape evolution at the short and long-time scales. These experiments were designed to create an evolving and self-organized complete drainage network by the growth and propagation of erosional instabilities (e.g. fluvial knickpoint retreat, hillslope erosion) in response to such external forcing. High resolution digital elevation (DEM) recorded every 5 min allowed following this evolution in both space and time. First, we focus on the investigation of how changes in the frequency and magnitude of large precipitation events affect the geomorphic and topologic re-organization of landscape across a range of scales. Our results show distinct signatures of extreme climatic fluctuations on the statistics and geometry of topographical features which are evident in widening and deepening of channels and valleys, change in drainage patterns within a basin and change in the probabilistic structure of “hot-spots” of change contributing to mass-wasting events, such as, landslides and debris flows. These results suggest a regime shift during the onset of the transient state in the transport processes on the fluvial regime of the landscape, i.e., from supply-limited to transport-limited. Finally, we investigate drainage reorganization in response to an asymmetric relative uplift rate with emphasis on the main drainage divide dynamics. This is achieved through the lowering of base levels at different rates on each side of the experiment. In response to such base level fall, the main drainage divide migrates towards the side of low base level fall rate. Such example provide experimental constraint on the evolution of a landscape under large-scale increase/decrease in drainage area on the sides of an orogen.
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