hierarchies and spatial scale in process geomorphology a review abstract the form and functioning of a geomorphic system is the end product of a set of interacting processes which operate at a large variety of spatial and temporal scales an appreciation of the nested hierarchical structure of geomorphic systems offers insight into the effect of scale in process geomorphology a literature review led to the formulation of a series of propositions concerning the spatial scale problem in process geomorphology these propositions are presented in a theoretical framework indicating their association central to the spatial scale problem in process geomorphology is that a geomorphic system must be viewed in its complex hierarchicl context every geomorphic system consists of an array of ever smaller lower level systems and is at the same time part of a sequence of ever larger higher level system in a geomorphic system there exists a similarity between the scales of process and form furthermore within a geomorphic system there is a similarity between spatial and temporal scales so that the timespan to present system behaviour and morphology increases with system size in a geomorphic system differences occur in the sensitivity of morphology to changing process conditions depending on the time elapsed since a change in process conditions morphology in a geomorphic system may be either polygenetic when only partial adjustment of the morphology i e only at smaller scales has occurred or characteristic of the process domain when all aspects of morphology i e at all scales are adjusted to present process conditions in the latter case dominance of landscape evolution by high frequency low magnitude process results in a smooth landscape having small scale irregularities whereas dominance by low frequency high magnitude processes produces an irregular landscape having large scale irregularities when spatial scale is held constant the model of evolution of a geomorphic system varies with the timescale of interest conversely when temporal scale is held constant the model of evolution varies with the spatial scale of interest in both cases the canon fixed rules and options of a geomorphic system vary with the scale temporal or spatial of interest the linkages between spatial and temporal scale and between the scales of form and process of geomorphic systems lead to four additional points first whether or not an event is catastrophic depends on the hierarchical level of the geomorphic system second because of increased travel time and a larger variety of possible pathways differences between the temporal patterns and material properties of input and output increase with the hiirarchical level and scale of a geomorphic system third frequent small scale processes may cause infrequent large scale events when viewed at the same hierarchical level fourth and last differences between geomorphic systems at the same level are controlled by variables varying over distances equal to or smaller than the distance between the system but equal to or larger than the spatial dimensions of the systems

short term geomorphological evolution of proglacial systems proglacial systems are amongst the most rapidly changing landscapes on earth as glacier mass loss permafrost degradation and more episodes of intense rainfall progress with climate change this review addresses the urgent need to quantitatively define proglacial systems not only in terms of spatial extent but also in terms of functional processes it firstly provides a critical appraisal of prevailing conceptual models of proglacial systems and uses this to justify compiling data on rates of landform change in terms of planform horizontal motion elevation changes and sediment budgets these data permit us to produce novel summary conceptual diagrams that consider proglacial landscape evolution in terms of a balance of longitudinal and lateral water and sediment fluxes throughout we give examples of newly emerging datasets and data processing methods because these have the potential to assist with the issues of i a lack of knowledge of proglacial systems within high mountain arctic and polar regions ii considerable inter and intra catchment variability in the geomorphology and functioning of proglacial systems iii problems with the magnitude of short term geomorphological changes being at the threshold of detection iv separating short term variability from longer term trends and v of the representativeness of plot scale field measurements for regionalisation and for upscaling we consider that understanding of future climate change effects on proglacial systems requires holistic process based modelling to explicitly consider feedbacks and linkages especially between hillslope and valley floor components such modelling must be informed by a new generation of repeated distributed topographic surveys to detect and quantify short term geomorphological changes

spatial and temporal variation of sediment yield in the landscape example of huanghe yellow river regional scale relations between specific sediment yield and drainage basin area in the huanghe basin reveal varying landscape sedimentary dynamics declining specific sediment yield with area is typical of disturbed agricultural areas while increasing yields indicate the remobilization of stored sediment by bank and floodplain erosion along major tributaries using the developed relations areally adjusted sediment yield maps are created over the entire huanghe basin maps of the loess plateau for periods before and after 1970 reveal major changes in sediment yield indicating that land management may have a major effect on sediment dynamics within a short period of time copyright 2008 by the american geophysical union

slope distributions threshold hillslopes and steady state topography digital elevation models of two steady state mountain ranges the olympic mountains om and oregon coast range ocr are used to examine relationships between slope distributions the development of threshold hillslopes and steady state topography plots of drainage area versus slope for these mountain ranges exhibit substantial scatter that complicates comparison of range form to analytical theories and landscape evolution models contour plots of the density of such data reveal an attractor at the scale of the transition from hillslope processes to channel processes and log bin averaging reveals trends that parallel predictions of steady state erosion laws but with different rate laws for five distinct process domains hillslopes valley heads and colluvial bedrock and alluvial valley segments slope histograms computed for 100 km2 areas defined by a 10 10 km grid throughout the om exhibit approximately normal or exponential distributions in areas of active rock uplift and depositional topography respectively local slope distributions in the ocr also tend to be normally distributed but some are left skewed in areas with gentler slopes mean slopes determined both over the above referenced grid and a 10 km diam moving window are relatively invariant in the core of the om in spite of strong contrasts in bedrock erodibility and gradients in long term rock uplift rates in contrast the mean slopes in the ocr parallel latitudinal gradients in rock uplift rates and bedrock erodibility hence the slope distributions in the om and ocr reflect distinct relationships between development of threshold bedrock and soil mantled hillslopes and steady state topography

fluvial clastic sediment yield in canada scaled analysis this report presents a set of maps of regional fluvial sediment yield in canada based mainly on the water survey of canada archive of riverine suspended sediment observations regional scaling rel

geomorphic coupling and sediment connectivity in an alpine catchment exploring sediment cascades using graph theory through their relevance for sediment budgets and the sensitivity of geomorphic systems geomorphic coupling and sediment connectivity represent important topics in geomorphology since the introduction of the systems perspective to physical geography by chorley and kennedy 1971 a catchment has been perceived as consisting of landscape elements e g landforms subcatchments that are coupled by geomorphic processes through sediment transport in this study we present a novel application of mathematical graph theory to explore the network structure of coarse sediment pathways in a central alpine catchment numerical simulation models for rockfall debris flows and hillslope and channel fluvial processes are used to establish a spatially explicit graph model of sediment sources pathways and sinks the raster cells of a digital elevation model form the nodes of this graph and simulated sediment trajectories represent the corresponding edges model results are validated by visual comparison with the field situation and aerial photos the interaction of sediment pathways i e where the deposits of a geomorphic process form the sources of another process forms sediment cascades represented by paths a succession of edges in the graph model we show how this graph can be used to explore upslope contributing area and downslope source to sink functional connectivity by analysing its nodes edges and paths the analysis of the spatial distribution composition and frequency of sediment cascades yields information on the relative importance of geomorphic processes and their interaction however regardless of their transport capacity in the study area the analysis stresses the importance of mass movements and their interaction e g the linkage of large rockfall source areas to debris flows that potentially enter the channel network moreover it is shown that only a small percentage of the study area is coupled to the channel network which itself is longitudinally disconnected by natural and anthropogenic barriers besides the case study we discuss the methodological framework and alternatives for node and edge representations of graph models in geomorphology we conclude that graph theory provides an excellent methodological framework for the analysis of geomorphic systems especially for the exploration of quantitative approaches towards sediment connectivity

from gullies to mountain belts a review of sediment budgets at various scales this paper reviews the state of the art in the concept as well as in the application of sediment budgets in sedimentary research sediments are a product of mass dispersal at the earth surface and take part in global cycles sediment budgets aim at quantifying this mass transfer based on the principle of mass conservation and are the key to determine ancient fluxes of solid matter at the earth surface this involves fundamental questions about the interplay of uplift climate and denudation in mountain belts and transfer of sediments from the continents to the oceans as well as applied issues such as soil and gully erosion reservoir siltation and coastal protection first after introducing basic concepts relevant scales and methodologies the different components of quaternary routing systems from erosion in headwaters river systems glacial and paraglacial systems lakes deltas estuaries coasts shelves epicontinental seas and deep sea fans are discussed in terms of their sediment budget most suitable are sedimentologically closed or semi closed depositional environments e g alluvial fans lakes deltas and deep sea fans in a second step the dynamics of passive active and collisional tectonic settings and sediment budgets in related sedimentary basins are explored and new concepts of sediment portioning at large geodynamic scales are introduced ancient routing systems are more or less incomplete and may be intensively fragmented or destroyed in active tectonic settings in terms of sedimentary basin types rifts intracontinental and epicontinental settings are preferred objects of sediment budgets because of their persistence and relatively simple overall sedimentary architecture however closing basins such as foreland forearc retroarc piggy back and wedge top basins may provide excellent snapshots of orogenic sediment fluxes in a third step the large long lived routing systems of the amazon the ganges brahmaputra and the rhine are reviewed for each system estimates of either sediment volumes mass or sediment fluxes of continental and marine subsystems have been compiled in order to receive a complete routing in terms of mass conservation for specific time periods since the late glacial maximum as well as the cenozoic following lessons can be taken from these case studies i depositional centers and fluxes show strong shifts in space and time and call for caution when simply looking at subsystems ii the response times of these large systems are within the milankovich time interval thus lower than predicted from diffusion models iii cyclic routing of sediments in continental basins is much more dominated by climate human control than by eustacy and iv at long time scales ultimate sinks win over intermittent storage it is concluded from this review that the quantitative understanding of global sediment cycling over historic and geologic time and its response to allogenic forcing is still in its infancy and further research is needed towards a holistic view of sediment routing systems at various temporal and spatial scales and their coupling with global biogeochemical cycles this includes i to better determine response times of large routing systems by linking quaternary with cenozoic sediment budgets and continental with marine sub systems ii to combine advanced provenance techniques with sediment budgets in order to reconstruct ancient systems iii to study sediment partitioning at the basin scale iv to reconcile continental supply dominated sequence stratigraphy with the eustatic dominated marine concept and iv to account for non actualism of ancient systems with respect to their erosion and transport mode in particular during glaciations and pronounced arid intervals glacial and eolian sediment routing may cross over hydrologic boundaries of drainage basins thus challenging the principle of mass conservation

channel initiation and the problem of landscape scale since the 1940s it has been proposed that landscape dissection into distinct valleys is limited by a threshold of channelization that sets a finite scale to the landscape this threshold is equal to the hillslope length that is just shorter than that necessary to support a channel head a field study supports this hypothesis by showing that an empirically defined topographic threshold associated with channel head locations also defines the border between essentially smooth undissected hillslopes and the valley bottoms to which they drain this finding contradicts assertions that landscapes are scale independent and suggests that landscape response to changes in climate or land use depends on the corresponding changes in the threshold of channelization

geoarchaeology the four dimensional 4d fluvial matrix and climatic causality abstract geoarchaeology is the application of geological and geomorphological techniques to archaeology and the study of the interactions of hominins with the natural environment at a variety of temporal and spatial scales geoarchaeology in the uk over the last twenty years has flourished largely because it has gone beyond technological and scientific applications over the same period our ability to reconstruct the 3 dimensional stratigraphy of fluvial deposits and the matrix of fluvial sites has increased dramatically because of a number of technological advances these have included the use of lidar laser imaging and radar to produce high resolution digital surface models the use of geophysics particularly ground penetrating radar and electrical resistivity to produce sediment depth models and the use of gis and data visualisation techniques to manipulate and display the data these techniques along with more systematic and detailed sedimentological recording of exposed sections have allowed the construction of more precise 3 dimensional volumetric models of the matrix of artefacts within fluvial deposits additionally a revolution in dating techniques particularly direct sediment dating by luminescence methods has enabled the creation of 4 dimensional models of the creation and preservation of these sites these 4 dimensional models have the ability to provide far more information about the processes of site creation preservation and even destruction and also allow the integration of these processes with independent data sources concerning cultural evolution and climatic change all improvements in the precision of dating fluvial deposits have archaeological importance in our need to translate events from a sequential or geological timeframe to human timescales this allows geoarchaeology to make a more direct contribution to cultural history through the recognition of agency at the individual or group level this data can then form a component of biocomplexity or agent based modelling which is becoming increasingly used in the natural sciences particularly ecology and geomorphology and which can be used to test scenarios including the impact on and response of hominins to abrupt or catastrophic environmental change whilst catastrophic events clearly represent the atypical they can be illuminating in revealing cognitive processes resulting in abandonment coping mitigation and innovation these points are exemplified using two in depth case studies one from the holocene geoarchaeological record of the river trent in central england and the other from the palaeolithic record from rivers in south west britain in the former the interaction between climate change and human activity is illustrated at the year to century timescale whilst in the other the timescale is millennial these case studies have deliberately been chosen to be as different as possible in temporal and spatial scale with the aim of examining the applicability of methodological and theoretical aspects of geoarchaeology lastly the paper considers the problem of scale in geoarchaeology and concludes it is process dependency which ultimately affects the questions we can ask and that questions of human response to climate change are fundamentally a product of materiality and cognitive processes this demands an in depth contextual approach to such questions rather than database driven assertions of causality

multivariate geostatistical modeling of the spatial sediment distribution in a large scale drainage basin upper rhone switzerland abstract there is a notable discrepancy between detailed sediment budget studies in small headwater catchments 103 km2 in higher order catchments applying modeling and or remote sensing based approaches for major sediment storage delineation to bridge the gap between these scales we compiled an inventory of sediment and bedrock coverage from field mapping remote sensing analysis and published data for five key sites in the upper rhone basin val d illiez val de la liene turtmanntal lotschental goms 360 3 km2 equivalent to 6 7 of the upper rhone basin this inventory was used as training and testing data for the classification of sediment and bedrock cover from a digital elevation model 2 2 m ground resolution and landsat imagery we derived 22 parameters characterizing local morphometry topography and position contributing area and climatic and biotic factors on different spatial scales which were used as inputs for different statistical models logistic regression principal component logistic regression generalized additive model best prediction results with an excellent performance mean auroc 0 8721 0 0012 and both a high spatial and non spatial transferability were achieved applying a generalized additive model since the model has a high thematic consistency the independent input variables chosen based on their geomorphic relevance are suitable to model the spatial distribution of sediment our high resolution classification shows that 53 5 21 7 of the upper rhone basin are covered with sediment these are by no means evenly distributed small headwaters

holocene sediment fluxes in a fragile loess landscape saxony germany abstract the loess region of the central saxon hill country is characterized by a relief of gently rolling hills whose most distinctive landscape elements are well defined shallow valleys called dells the aim of this research is to gather morphodynamic information on the dells in a qualitative and quantitative way by means of high resolution field mapping and laboratory based analyses the intensity of sediment shifting has been modelled via sediment budgeting on a small catchment scale research objectives are to determine the character and magnitude of geomorphic processes for a holocene time frame concerning the absence of currently obtainable dating this study represents a reflection which summarises all sediment shifting related to anthropogenic land use during the holocene as a specific parameter in terms of landscape development the relief is considered to be strongly associated with varying process intensities agrarian land use of the loess region since the late neolithic has resulted in severe soil erosion lower middle slope positions are the apparent spots were soil erosion processes take place in terms of rill erosion a detailed survey of three dells provided a very heterogeneous pattern of the relocation of soil material dell 1 zehren shows medial holocene soil profile truncation of 1090 mm in contrast dell 3 lobschutz shows soil loss of around 660 mm all systems have similarly high slope gradients up to 12 actually the deepening of the dell s depth contours and therewith the extent of erosive slope lengths is varying thus a higher longitudinal decline of the valley floors and a more intensive incision lead to enlarged erosive slope lengths which causes increasing sediment transport hence land use patterns trigger the process of material displacement whereas relief modifies the intensity of geomorphic processes

stochastic forcing of sediment supply to channel networks from landsliding and debris flow sediment influx to channel networks is stochastically driven by rainstorms and other perturbations which are discrete in time and space and which occur on a landscape with its own spatial variability in topography colluvium properties and state of recovery from previous disturbances the resulting stochastic field of sediment supply interacts with the topology of the channel network and with transport processes to generate spatial and temporal patterns of flux and storage that characterize the sedimentation regime of a drainage basin the regime varies systematically with basin area we describe how the stochastic sediment supply is generated by climatic topographic geotechnical and biotic controls that vary between regions the general principle is illustrated through application to a landscape where sediment is supplied by mass wasting and the forcing variables are deterministic thickening of colluvium random sequences of root destroying wildfires and random sequences of rainstorms that trigger failure in a population of landslide source areas with spatial variance in topography and colluvium strength landslides stop in channels or convert to scouring debris flows depending on the nature of the low order channel network sediment accumulates within these channels for centuries before being transferred downstream by debris flows time series of sediment supply transport and storage vary with basin scale for any combination of climatic topographic and geotechnical controls in a companion paper benda and dunne this issue we use simulations of timing volumes and locations of mass wasting to study the interaction between a stochastically forced sediment supply and systematic changes of storage and flux through channel networks

synchronization and scale in geomorphic systems abstract geomorphic systems consist of coupled subsystems with traits of small world networks swn characterized by tightly connected clusters of components with fewer connections between the clusters geomorphic systems based on scale hierarchies often exhibit a connected caveman small world network ccswn structure swns are efficient for linking a large number of components with a relatively small number of links but effects of ccswn structure on synchronization and scale linkage have not been examined synchronization is analyzed via graph theory and applied to 1 relationships among three levels of form process interaction in stream channels 2 hierarchical relationships of weathering systems at scales from weathering profiles to landscapes and 3 interactions in fluviokarst systems at the scale of flow processes and of landscape evolution relationships among system components are represented as simple unweighted graphs the largest eigenvalue of the adjacency matrix spectral radius reflects the critical coupling strength required to synchronize the system the second smallest eigenvalue of the laplacian of the adjacency matrix algebraic connectivity is a measure of the synchronizability in all examples both are much less than the maximum for networks of the same number of nodes the sparseness of the networks is the major contributor to the low synchronization but the specific pattern of connections wiring is also significant where ccswn structures arise naturally they help explain how geomorphic effects are transmitted between disparate scales in the absence of obvious scale linkage where ccswns are an option for representation of geomorphic systems in models and data structures they will not improve scale linkage despite the efficiency of swns in other respects methods developed here can be applied to evaluating alternative spatial data structures or mapping strategies which either increase synchronization supporting a lumping or aggregation approach or decrease synchronization indicating disaggregation or splitting into scale hierarchies

sediment flux from a mountain belt derived by landslide mapping in humid uplands landsliding is the dominant mass wasting process in the western southern alps of new zealand landslides are scale invariant and have a power law magnitude frequency distribution independent studies from other regions suggest that this is a general property of landsliding this observation is of critical importance to the evaluation of the impact of events of different length scales over different time intervals on landscape evolution it is particularly useful when estimating regional geomorphic rates because it constrains the frequency and overall significance of extreme events which cannot otherwise be evaluated by integrating the complete response of the system we estimate the regional denudation rate due to landsliding to be 9 4 mm yr 1 sediment discharge from the western southern alps is dominated by landslide derived material

extraction of the m2 ocean tide from seasat altimeter data summary three complementary methods for the extraction of the m2 ocean tide using seasat altimetry are presented and compared the first method that developed by cartwright alcock which provides point measurements of the tide at the crossovers of the seasa t repeat orbit ground track has been applied to a study of the tide in tropical ocean areas the other two methods involve spatial expansions of m2 in terms of either surface spherical harmonics in the case of the method developed by mazzega or platzman normal modes of the world ocean the results obtained by each method from only one month of seasat data reproduce many features of the tide represented in recent tidal models and promise well for satellite altimetry as a future source of tidal knowledge

contemporary suspended sediment dynamics within two partly glacierized mountain drainage basins in western norway erdalen and bodalen inner nordfjord abstract this paper focuses on environmental controls spatiotemporal variability and rates of contemporary fluvial suspended sediment transport in the neighboring partly glacierized and steep erdalen 79 5 km 2 and bodalen 60 1 km 2 drainage basins in the fjord landscape of the inner nordfjord in western norway field work including extended samplings and measurements was conducted since 2004 in erdalen and since 2008 in bodalen the distinct intra and inter annual temporal variability of suspended sediment transport found is mostly controlled by meteorological events with most suspended sediment transport occurring during pluvial events in autumn september november followed by mostly thermally determined glacier melt in summer july august and by mostly thermally determined snowmelt in spring april june extreme rainfall events 70 mm d 1 in autumn can trigger significant debris flow activity that can cause significant transfers of suspended sediments from ice free surface areas with sedimentary covers into main stream channels and is particularly important for fluvial suspended sediment transport in years with occurring relevant debris flow activity the total annual drainage basin wide suspended sediment yields are strongly determined by these single extreme events the proportion of glacier coverage followed by steepness of slopes and degree of vegetation cover in ice free surface areas with sedimentary covers are the main controls for the detected spatial variability of suspended sediment yields the contemporary sediment supply from glacierized surface areas and the jostedalsbreen ice cap through different defined outlet glaciers shows a high spatial variability the fact that the mean annual suspended sediment yield of bodalen is with 31 3 t km 2 yr 1 almost twice as high as the mean annual suspended sediment yield of erdalen 16 4 t km 2 yr 1 is to a large extent explained by the higher proportion of glacier coverage in bodalen 38 of the drainage basin surface area as compared to erdalen 18 of the drainage basin surface area and by a significantly higher sediment yield from the glacierized area of the bodalen drainage basin compared to the glacierized surface area in erdalen when looking at the total annual mass of suspended sediments being fluvially exported from both entire drainage basin systems the total amount of suspended sediments coming from the ice free drainage basin surface areas altogether dominates over the total amount of suspended sediments coming from the glacierized surface area of both drainage basins drainage basin wide annual suspended sediment yields are rather low when compared with yields of other partly glacierized drainage basin systems in norway and in other cold climate environments worldwide which is mainly due to the high resistance of the predominant gneisses towards glacial erosion and weathering the altogether only small amounts of sediments being available within the entire drainage basin systems the stable and nearly closed vegetation cover in the ice free surface areas with sedimentary covers and the efficiency of proglacial lakes in trapping sediments supplied by defined outlet glaciers both contemporary and long term suspended sediment yields are altogether supply limited contemporary suspended sediment transport accounts for nearly two thirds of the total fluvial transport and accordingly plays an important role within the sedimentary budgets of the entire erdalen and bodalen drainage basins

towards the identification of scaling relations in drainage basin sediment budgets abstract drainage basin sediment budgets concern inputs storages and outputs of sediments and solutes through monitored cross sections at the mouth of basins or at the base of individual slopes the question under consideration is whether and to what extent it is possible to transfer knowledge from one spatial scale to another the answer hinges on the question of scale invariance of a individual processes of sediment and solute transfer and b aggregate sediment budgets scale invariance of a number of hydrologic parameters has been established but in general with a few exceptions geomorphic parameters are subject to scale distortion by inference but not yet established by experimental or field evidence scale invariance of sediment budgets is improbable there is therefore a priority to explore scaling relations in sediment budgets so as to determine the precise extent of scale distortion that is present in this paper five ways of identifying scaling relations in drainage basin sediment budgets are identified 1 a fractal approach 2 a theory hierarchy approach 3 a non linear dynamic systems approach 4 a panarchy approach and 5 a hybrid approach there are no a priori bases for selection of any one of these approaches until further field research and modeling of sediment and solute fluxes has been completed

understanding the impacts of late quaternary climate change in tropical and sub tropical regions abstract the understanding of climate impacts on tropical rivers and catchments has developed in part from models developed for temperate landscapes and a common rhythm is often apparent when millennial scale studies are compared at this level issues arising from the complex response of rivers to internal and external factors appear less important than the climate driven signal understanding the fluvial record however depends on the availability and interpretation of other sources of proxy data such as pollen spectra lake levels and ocean cores in many rainforest areas few pollen records exist and many of these reveal a hiatus at the time of the last glacial maximum examples of fluvial archives from africa indonesia and tropical queensland australia are discussed in relation to independent records of vegetation change and inferences are made concerning critical episodes in fluvial history focusing on the transitions from oxygen isotope stage ois 3 towards glacial conditions in ois2 and the pleistocene holocene transition to modern climates links between climate vegetation change and fluvial activity are presented as descriptive models

gypsum karst features as evidence of diapiric processes in the betic cordillera southern spain in the triassic evaporite deposits of the betic cordillera halokinesis has played a fundamental role in the morphodynamic evolution of gypsum karst as evidenced by the morphology and distribution of dolines and poljes by data obtained from caves and from the types of water associated with evaporite domes distribution patterns of major exokarstic forms display a subcircular array with collapse sinkholes located in the centre of the domes and solution drawdown dolines on the outer limits of the diapiric forms in addition the least mineralized waters are situated in association with the caprock gypsum hypersaline waters which are also hotter drain deeper flow systems that flow out at the edges of the halokinetic structures the morphodynamic and hydrogeological information constitute a valuable tool for the correct interpretation of the tectonic structure of such complex areas

stochastic forcing of sediment routing and storage in channel networks the stochastic field of sediment supply to the channel network of a drainage basin depends on the large scale interactions among climatically driven processes such as forest fire and rainstorms topography channel network topology and basin scale during infrequent periods of intense erosion large volumes of colluvium are concentrated in parts of a channel network particularly near tributary junctions the rivers carry bed material and wash load downstream from these storage sites at different rates the bed material travels slowly creating transient patterns of sediment transport sediment storage and channel morphology along the channel network as the concentrations of bed material migrate along the network their waveforms can undergo changes by diffusion interference at tributary junctions and loss of mass through temporary sediment storage in fans and terraces and through particle abrasion which converts bed material to wash load we investigated how these processes might influence the sediment mass balance in channels of third and higher order in a 215 km 2 drainage basin within the oregon coast range over a simulated 3000 year period with a climate typical of the late holocene we used field measurements and a simulation model to illustrate interactions between the major controls on large scale processes functioning over long periods of time in complex drainage basins

sediment sources spatiotemporal variability and rates of fluvial bedload transport in glacier connected steep mountain valleys in western norway erdalen and bodalen drainage basins abstract contemporary fluvial bedload transport rates are still very difficult to measure and as a result of this in many sites only quantitative data on suspended and solute transport are included in sediment budget studies carried out for defined drainage basin systems the presented analysis of fluvial bedload dynamics in different defined subsystems of the glacier connected erdalen 79 5 km 2 and bodalen 60 1 km 2 drainage basins in the steep fjord landscape of western norway provides insights into i detectable relevant sediment sources ii instream channel storage of bedload material iii spatiotemporal variability and controls of bedload transport rates and bedload yields and iv the absolute and relative importance of fluvial bedload transport within the sedimentary budgets of these steep cold climate mountain valleys rockfalls snow avalanches stream channel bank erosion and fluvial transfers through small tributaries draining slope systems are relevant sediment sources for fluvial bedload transport in the main stream channels whereas the main outlet glaciers in both drainage basins are not of importance as all bedload material delivered directly from these outlet glaciers is trapped within proglacial lakes narrow valleys within both drainage basin systems are characterized by a higher intensity of slope channel coupling and display higher rates of sediment supply from slopes into the main stream channels than wider valleys snow avalanches are the most important sediment source in erdalen whereas fluvial transfers through small tributaries followed by snow avalanches are most important in bodalen longer term instream channel storage is not of great importance in the steep bodalen drainage basin but currently plays an important role within the erdalen drainage basin which is characterized by a stepped longitudinal main valley bottom profile favoring deposition of bedload material within less steep main channel reaches the mean annual bedload yields 2010 2013 are 2 4 t km 2 y 1 for the entire erdalen and 13 3 t km 2 y 1 for the entire bodalen drainage basin which are comparably low values for steep and partly glacierized drainage basin systems because of supply limited conditions the intensity of fluvial bedload transport is generally much more related to the availability of sediments than to channel discharge fluvial bedload transport accounts for about one third of the total fluvial transport and accordingly plays an important role within the sedimentary budgets of both drainage basin systems

disequilibrium of holocene sediment yield in glaciated british columbia it is generally supposed that specific sediment yield the quantity of sediment passing a monitored river cross section per unit area drained upstream of that section declines as the area drained increases1 3 part of the sediment mobilized from the land surface is supposed to go back into storage at field edges and on footslopes and floodplains in contrast we show here that data from british columbian rivers reveal a pattern of increasing specific sediment yield at all spatial scales up to 3 104 km2 this results from the dominance of secondary remobilization of quaternary sediments along river valleys over primary denudation of the land surface the result controverts the conventional model which has been derived from studies of small highly disturbed agricultural catch ments the rivers are still responding to the last glaciation giving a landscape relaxation time greater than 10 kyr this holds pro found implications for geomorphological theory and for studies of erosion