a global review of sediment source fingerprinting research incorporating fallout radiocesium 137cs abstract information on the main sources supplying deleterious sediment loads to river systems is needed to improve our understanding of soil erosion processes to better target erosion control measures in particular it is important to quantify the respective contributions of surface and subsurface sources to material degrading waterbodies radiocesium 137cs emitted during thermonuclear bomb testing 1950 1980 and nuclear accidents provides significant discrimination between surface material exposed to atmospheric fallout and subsurface material sheltered from it a systematic worldwide review of research articles n 123 that used 137cs to trace sediment sources showed that the united kingdom n 24 australia n 23 and the united states n 20 had the highest number of publications utilizing 137cs in a sediment tracing framework in contrast few studies were published for catchments in africa n 9 or south america n 2 in the northern hemisphere positive relationships were evident between 137cs activities in surface and subsurface sources and the proportion of thermonuclear bomb fallout however given the low proportions of fallout received in regions between 0 and 20 n and 0 20 s the potential application of 137cs tracing techniques may be limited in this area of the world as well as in agricultural regions with severe soil erosion i e chinese loess plateau and south africa in total 94 of the studies researching surface and subsurface sources that analysed 137cs as a potential tracing property included this parameter in end member mixing models the main challenges for the future of this technique are related to the access to ultra low background gamma spectrometry facilities and the development of surrogate tracers future research should ensure that basic catchment information and details on the sampling design are properly documented to ensure studies are reproducible moreover researchers should provide raw measurement data to help improve our global understanding of 137cs dynamics in soil erosion research

a multivariate mixing model for identifying sediment source from magnetic measurements a sequential method for quantitative identification of sediment source components based on magnetic measurements has been developed and tested for sediments from the rhode river maryland simulated mixing tests and multiple regression were employed to establish numerical relationships between source component proportions and the magnetic measurements of mixtures on the basis of these multivariate mixing models source components of three estuarine sediment cores were estimated by linear programming the results strongly support the previous studies on this catchment which indicated a dramatic change in sediment source some 150 to 200 yr ago quantitative calculations are more useful and informative than purely qualitative descriptions

the characteristics of overbank deposits associated with a major flood event in the catchment of the river ouse yorkshire uk overbank floodplain deposits associated with a major flood which occurred in 1995 were collected shortly after the event from transects at 14 locations within the catchment of the river ouse yorkshire uk at most sites the sediment deposited nearest to the channel consisted primarily of sand sized material and the absolute particle size composition of the mineral fraction of the deposits evidenced fining with increasing distance from the channel most of the sand sized material was deposited within 20 to 40 m of the channel although at some sites sand was present at distances 100 m from the channels there was no obvious downstream trend in the texture of the sediment deposited on the floodplains in most places the overbank sediment was considerably coarser than the suspended sediment transported in the study rivers although at several sites thed50 of the latter was similar to that of overbank sediment deposited furthest from the channel although the c n ratio of the organic fraction of the overbank sediment was approximately constant across the width of the floodplain the organic carbon and137cs content of the deposited sediment increased with distance from the channel and both properties were positively related to the magnitude of the 63 m fraction the texture of sediment in cores collected from two of the sites in 1994 was generally finer than that of the overbank deposits from the 1995 flood at the same locations confirming the extreme nature of the 1995 flood event

sediment sources and transport pathways in a rural catchment herefordshire uk the relative significance of primary and secondary suspended sediment sources has been identified in a small 15 km2 agricultural catchment through the application of a linear unmixing model using mineral magnetic geochemical and radionuclide signatures of fine sediments roads appear to be important as a secondary source of suspended sediment and in the conveyance of topsoils to the river channel roads also alter the source signatures of sediment in transport especially that derived from agricultural topsoils modelling suggests that c 30 of the suspended sediment collected from suspended sediment traps in the river leadon were derived from or transported via roads relative contributions from primary sources of c 43 and c 27 were estimated from a combined subsoil and channel bank subsurface source and a combined arable and grassland topsoil source respectively

targeted control of sand hazards for a railway in extremely arid regions using fingerprinting approaches abstract reliable quantitative information on sediment sources is key for the reasonable arrangement of targeted measures that effectively control hazards of wind erosion along railways in extremely arid regions in northwest china the newly built golmud korla railway suffers from serious wind blown sand hazards which severely affect its future safe operation this study applied two frequently used fingerprinting methods optimum composite fingerprint and multiple composite fingerprint to quantitatively examine the contributions of different sediment sources to the railway in two typical areas research areas r1 and r2 the results revealed that nebkha was the main sediment source for the railway 46 5 in r1 followed by a dry playa 37 7 and sand dunes dune 1 15 8 in contrast sand dunes dune 2 were the main sediment source for the railway 75 2 in r2 followed by gobi 12 9 and a low lying coarse sand sheet lcss 11 9 according to the comprehensive assessment the sand fixing measure of spraying salt lake brine to form a crust for nebkha was recommended and the sand fixing measure of large vertical grids 15 m 15 m 1 5 m made of reed rod was suggested to control wind erosion of the dry playa near the railway and to trap the eroded sand from the upwind direction in r1 in r2 a small reed rod checkerboard barrier 1 m 1 m 0 2 m was suggested for dune 2 to effectively prohibit drifting sand from endangering the railway in addition this study also indicated that when two or more sediment sources have relatively similar properties the pairwise test to select tracers with significant differences between the two sediment sources would help reduce uncertainty which was recommended for similar studies in the future

dynamics of a tidally forced stratified shear flow on the continental slope 1 the near seabed mean and turbulent processes on the continental slope were measured for a three week period using an array of acoustic doppler velocimeters and thermistors over the bottom 30 m at the 400 m isobath baroclinic motions with characteristics similar to internal bores or boluses propagated onshore during the flood phase of both spring and neap tides the arrival time of these internal bores at our measurement site varied amongst tidal cycles and their characteristics were not highly correlated with the amplitude of the barotropic tidal forcing the passage of the internal bores was associated with large turbulent overturns enhanced turbulent kinetic energy dissipation e 10 6 w kg 1 and intensified currents 6 times the barotropic forcing within meters of the seabed during the deployment stratification and shear competed to govern our observed overturning length scale 4 m that were characterized by the ellison length scale le only measurements closest to the seabed 1 7 m were described by the log law of the wall generally both buoyancy and the presence of the bottom boundary influenced le while sometimes flow induced shear determined le as the distance of our measurements from the seabed increased the influence of buoyancy became more pronounced these results highlight that a more general descriptor of the overturning length scale is necessary for complex stratified shear flows

magnetic resonance sounding evidence shows that shallow groundwater discharge maintains the lake landscape in the hunshandake sandy land north china the hunshandake sandy land hsl is a well known water rich sandy region in china that is home to many lakes most of these lakes are sustained by groundwater inflow however due to the limited hydrogeological survey data the mechanism by which the lakes interact with groundwater is not well understood magnetic resonance sounding mrs is a geophysical method that has emerged in recent years that can directly detect the distribution of groundwater and determine the lithology of the aquifer medium compared with drilling this method is convenient rapid and inexpensive in this study to determine how the lakes are recharged by groundwater a field experiment using mrs was conducted on haoletuyin lake which is located in the central hsl the results showed that compared with borehole data the mrs derived aquifer depth has an uncertainty of 6 88 additionally the lithology of the media derived from the mrs is consistent with that derived from the borehole data this finding suggests that the mrs derived results are highly accurate based on the mrs derived results two hydrogeological profiles were plotted and they show that the lake in the experimental area is recharged primarily by shallow groundwater and not by deep groundwater this study is significant because it not only reveals the mechanism by which haoletuyin lake is maintained but also proves that mrs is an excellent tool for studying lake groundwater relations in desert sandy land regions with limited hydrogeological survey data

changes in the physical and geochemical properties of suspended sediment delivered to the headwaters of lois river basins over the last 100 years a preliminary analysis of lake and reservoir bottom sediments bottom sediments from a single core retrieved from nine lakes and or reservoir sites have been analysed for particle size loss on ignition and the total concentration of ca mg na k fe al mn and p site differences reflect the relative significance of autochthonous and allochthonous contributions to the sedimentary record and are related to changes in sedimentation rate through time as determined from a 210 pb and 137 cs chronology determined for each core whilst changing sedimentation rates reflect both sediment influx from the contributing catchment and focusing within the lake basin the patterns generally reveal changes associated with catchment disturbance over the last century calcium rich sediments are found in two lakes draining catchments underlain by oolitic limestones organic matter contents as determined by low temperature loss on ignition range from 13 to 25 high organic matter levels are found in bottom sediments either where the contributing catchment has extensive blanket peat accumulations or in lakes with low sediment accumulation rates where the organic matter content is more likely to be controlled by lake productivity in general organic matter content is inversely related to sedimentation rate and to sediment yield greatest down core variations in sediment physical and geochemical signatures are found in lake sediment records where catchments have experienced significant increases in sediment influx from the catchment the average sediment yield determined for each of the nine lake catchments is inversely related to average organic matter and p content of the sediments but an increase in sediment yield is associated with better sorting and a decrease in the proportion of coarse and medium silt sized particles six of the nine sites show evidence for significant increases in the total p load in their near surface sediments either resulting from higher than average sediment yields or as a result of significant increases in sediment p concentrations

fingerprinting suspended sediment sources in the catchment of the river ouse yorkshire uk statistically verified composite fingerprints and a multivariate mixing model have been employed to establish the main sources of the suspended sediment transported through the lower non tidal reaches of the river ouse and one of its main tributaries the river wharfe during the period 1994 1997 in the case of the suspended sediment samples collected from the river ouse the load weighted mean contributions from uncultivated topsoil cultivated topsoil and channel bank sources were estimated to be c 25 38 and 37 respectively while for the river wharfe these sources contributed c 70 4 and 23 respectively c 4 was derived from woodland topsoil suspended sediment samples collected during higher flows evidenced a greater contribution from channel banks than samples collected during lower flows source materials were also differentiated according to the three main geological source areas carboniferous permian and triassic and jurassic and their load weighted mean contributions were estimated to be c 24 41 and 35 for the river ouse and c 91 9 and 0 there are no jurassic rocks in this catchment for the river wharfe respectively when suspended sediment samples from tributary streams were used to characterize each geological source area the equivalent results for the river ouse were c 30 46 and 24 considering the three main tributaries that contribute to the river ouse the load weighted mean contributions from the rivers swale ure and nidd were estimated to be 82 15 and 3 respectively these values have been compared with estimates of the relative magnitude of the annual suspended sediment loads of these three rivers for the years 1995 and 1996 derived from continuous monitoring of discharge and turbidity differences between the two sets of results are ascribed to the different periods of record involved and to the timing of suspended sediment sampling relative to the overall storm hydrograph and thus the degree to which the available samples are representative of the overall suspended sediment flux although a number of limitations must be recognized the fingerprinting approach to source ascription is seen as providing valuable information regarding suspended sediment sources in the study catchments copyright 1999 john wiley sons ltd

sources of fine sediment recovered from the channel bed of lowland groundwater fed catchments in the uk abstract groundwater fed lowland permeable catchments in the uk are particularly susceptible to fine sediment accumulation on the bed of their main channel systems appropriate catchment management solutions are therefore required accurate targeting of sediment abatement strategies is however hampered by the dearth of reliable information on the principal sediment sources involved in view of this a composite fingerprinting technique incorporating uncertainty analysis has been used to investigate the primary sources of fine sediment samples recovered from a total of 18 individual sampling sites on the channel bed of the rivers frome 437 km 2 and piddle 183 km 2 dorset uk in the frome study catchment mean relative contributions from areas of woodland pasture and cultivation and from channel banks subsurface sources ranged between 1 1 6 2 10 2 42 2 44 4 81 2 and 7 2 19 4 respectively the corresponding mean relative contributions in the piddle study area were 1 1 11 4 woodland 10 2 28 4 pasture 44 2 80 2 cultivated and 7 2 21 2 channel banks and subsurface sources these findings have important implications for establishing a scientific basis for assisting the targeting of sediment management and control policies

fingerprinting and tracing the sources of soils and sediments earth and ocean science geoarchaeological forensic and human health applications abstract fine grained sediment is perhaps the most widespread and pervasive contaminant in aquatic systems reflecting its role in influencing the quality of the water e g turbidity vector of chemicals and other pollutants and its detrimental effect on infrastructure e g dams turbines and aquatic habitats e g salmonid spawning grounds through sedimentation determining the sources of fine grained sediment thus represents an important requirement for watershed and coastal management as well as for understanding the evolution of landscapes and ocean basins sediment source fingerprinting utilizes the diagnostic physical chemical and biological properties i e tracers of source materials to enable samples of collected sediment to be apportioned to these sources this review examines the development of the technique within the earth and ocean sciences focusing mainly on agricultural landscapes however the development of new tracers such as compound specific stable isotopes has allowed the technique to be applied in a growing number of environmental settings including forested including wildfire impacted forests urban and estuarine coastal settings this review also describes other applications of the fingerprinting approach such as geoarchaeological e g archaeological site formation forensic e g identifying the sources of soil sediment particles in criminal investigations and human health e g identifying the sources of airborne particulate matter pm 2 5 applications identifying commonalities in methods and approaches between environments and disciplines should foster collaboration and the exchange of ideas furthermore refinement of the sediment source fingerprinting technique requires that several methodological issues be addressed these methodological issues range from the initial sampling design to the interpretation of the final apportionment results this review also identifies and assesses these methodological concerns

use of floodplain sediment cores to investigate recent historical changes in overbank sedimentation rates and sediment sources in the catchment of the river ouse yorkshire uk abstract floodplain sediment cores collected from seven sites in the catchment of the river ouse in yorkshire uk have been used to provide information on recent historical changes in both rates of overbank sedimentation and sediment sources the environmental radionuclides 137 cs and unsupported 210 pb have been used to establish chronologies for each core and to estimate average sediment accumulation rates for the last ca 30 and 100 years respectively average sedimentation rates for the individual cores ranged from 0 11 to 1 04 g cm 2 yr 1 in all but one case the estimates of average sedimentation rate during the last ca 30 years for the individual cores are broadly similar to those for the last ca 100 years suggesting that overbank sedimentation rates have been essentially uniform over the longer time period composite fingerprints based on a combination of geochemical and mineral magnetic properties and a numerical mixing model have been used to investigate downcore changes in sediment source in the case of source type most of the cores reflect a primarily topsoil source although there have been periods with increased contributions from subsoil channel bank sources within the ouse basin in general the period commencing in the late 19th and early 20th century and extending through to the 1960s was characterised by increased contributions from topsoil sources however contributions from subsoil channel bank sources have increased over the last few decades the source tracing results relating to sediment contributions from the three main geological topographic zones are in broad agreement with the proportion of the area of the catchment underlain by each rock type temporal variations in the contributions from the three geological topographic zones vary from site to site but for the lower reaches of the river ouse contributions from areas underlain by permian and triassic rocks which mainly outcrop in the vale of york have increased since the turn of the century the changes in sediment source identified are probably a reflection of changes in land use and management and possibly changes in climate these results enable estimates of contemporary suspended sediment fluxes and sources to be placed into a historical context and provide a means of considering the likely impact of potential future changes in land use and climate in the study basin

establishing fine grained sediment budgets for the pang and lambourn locar catchments uk summary an integrated approach to data collection combining the use of 137cs measurements sediment source fingerprinting bed sediment surveys and conventional river monitoring has been successfully employed to establish the fine grained sediment budgets of two lowland groundwater fed catchments in the uk gross surface erosion is higher on cultivated land pang 55 263 t yr 1 or 507 t km 2 yr 1 lambourn 79 997 t yr 1 or 437 t km 2 yr 1 than on pasture pang 1960 t yr 1 or 140 t km 2 yr 1 lambourn 1425 t yr 1 or 95 t km 2 yr 1 in both study areas and a substantial proportion of the mobilized sediment is sequestered within the fields pang 28 058 t yr 1 or 228 t km 2 yr 1 lambourn 55 575 t yr 1 or 281 t km 2 yr 1 and between the individual fields and the river channel network pang 28 672 t yr 1 or 233 t km 2 yr 1 lambourn 24 782 t yr 1 or 125 t km 2 yr 1 the sediment contribution from banks and subsurface sources is relatively low and typically ca 5 t yr 1 in the pang and ca 11 t yr 1 in the lambourn representing only about 1 of the suspended sediment output from each study catchment the mean level of fine grained sediment storage in the main channel system is equivalent to 38 pang and 21 lambourn of the respective mean annual suspended sediment yields of the two catchments the estimated sediment delivery ratio for both study catchments is ca 1

joint inversion of aquifer test mrs and tem data this paper presents two methods for joint inversion of aquifer test data magnetic resonance sounding mrs data and transient electromagnetic data acquired from a multilayer hydrogeological system the link between the mrs model and the groundwater model is created by tying hydraulic conductivities k derived from mrs parameters to those of the groundwater model method 1 applies k estimated from mrs directly in the groundwater model during the inversion method 2 on the other hand uses the petrophysical relation as a regularization constraint that only enforces k estimated for the groundwater model to be equal to mrs derived k to the extent that data can be fitted both methodologies can jointly calibrate parameters pertaining to the individual models as well as a parameter pertaining to the petrophysical relation this allows the petrophysical relation to adapt to the local conditions during the inversion the methods are tested using a synthetic data set as well as a field data set in combination the two case studies show that the joint methods can constrain the inversion to achieve estimates of k decay times and water contents for a leaky confined aquifer system we show that the geophysical data can assist in determining otherwise insensitive k and vice versa based on our experiments and results we mainly advocate the future application of method 2 since this seems to produce the most reliable results has a faster inversion runtime and is applicable also for linking k of 3 d groundwater flow models to multiple mrs soundings

quantitative sediment source ascription using magnetic measurements in a reservoir catchment system near nijar s e spain the magnetic properties of sediments from a dried out reservoir and its inflowing streams were measured to provide a basis for sediment source determination quantitative estimates of source component proportions in the reservoir sediments were made using linear programming procedures the study confirms that this type of research must be based on a detailed knowledge of the relationship between magnetic properties and particle size in both the sediments and the potential sources in the case of the site studied the isabel ii reservoir near nijar s e spain the sediments generated by contemporary surface processes within the reservoir catchment fail to reflect fully the 19th century material largely responsible for the rapid infill of the reservoir an additional source type namely unweathered schist derived material not represented in the fine sediments sampled within channels upstream from the reservoir has to be included in the model before calculations of source component contributions can be made it is inferred that one or more high magnitude low frequency event outside the amplitude of the most recently operating processes was largely responsible for the infilling of the reservoir

sedimentation in arctic proglacial lakes mittivakkat glacier south east greenland several sediment cores were collected from two proglacial lakes in the vicinity of mittivakkat glacier southeast greenland in order to determine sedimentation rates estimate sediment yields and identify the dominant sources of the lacustrine sediment the presence of varves in the ice dammed icefall lake enabled sedimentation rates to be estimated using a combination of x ray photography and down core variations in 137 cs activity sedimentation rates for individual cores ranged between 0 52 and 1 06 g cm 2 year 1 and the average sedimentation rate was estimated to be 0 79 g cm 2 year 1 despite considerable down core variability in annual sedimentation rates there is no significant trend over the period 1970 to 1994 after correcting for autochthonous organic matter content and trap eaciency the mean fine grained minerogenic sediment yield from the 3 8k m 2 basin contributing to the lake was estimated to be 327 t km 2 year 1 cores were also collected from the topset beds of two small deltas in icefall lake the deposition of coarse grained sediment on the delta surface was estimated to total in excess of 15 cm over the last c 40 years in the larger lake kuutuaq which is located about 5 km from the glacier front and for which the glacier represents a smaller proportion of the contributing catchment sedimentation rates determined for six cores collected from the centre of the lake based on their 137 cs depth profiles were estimated to range between 0 05 and 0 11 g cm 2 year 1 and the average was 0 08 g cm 2 year 1 the longer term c 100 150 years average sedimentation rate for one of the cores estimated from its unsupported 210 pb profile was 0 10 0 13 g cm 2 year 1 suggesting that sedimentation rates in this lake have been essentially constant over the last c 100 150 years the average fine grained sediment yield from the 32 4k m 2 catchment contributing to the lake was estimated to be 13 t km 2 year 1 the 137 cs depth profiles for cores collected from the topset beds of the delta of lake kuutuaq indicate that in excess of 27 cm of coarse grained sediment had accumulated on the delta surface over the last approximately 40 years caesium 137 concentrations associated with the most recently deposited uppermost fine grained sediment in both icefall lake and lake kuutuaq were similar to those measured in fine grained sediment collected from steep slopes in the immediate proglacial zone suggesting that this material rather than contemporary glacial debris is the most likely source of the sediment deposited in the lakes this finding is confirmed by the 137 cs concentrations associated with suspended sediment collected from the mittivakkat stream which are very similar to those for proglacial material copyright 2000 john wiley sons ltd

identifying subsoil sediment sources with carbon and nitrogen stable isotope ratios increased sediment loads from accelerated catchment erosion significantly degrade waterways worldwide in the south east queensland region of australia sediment loads are degrading moreton bay a ramsar listed wetland of international significance in this region like most parts of coastal australia sediment is predominantly derived from gully and channel bank erosion processes a novel approach is presented that uses carbon and nitrogen stable isotope ratios and elemental composition to discriminate between these often indistinguishable subsoil sediment sources the conservativeness of these sediment properties is first tested by examining the effect of particle size separation testing for consistency during transport and the effect of sampling at different times testing for temporal source consistency the discrimination potential of these sediment properties is then assessed with the conservative properties based on the particle size and temporal analyses modelled to determine sediment provenance in three catchments nitrogen sediment properties were found to have significant particle size enrichment and high temporal variance indicative of non conservative behaviour conversely carbon stable isotopes had very limited particle size and temporal variability highlighting their suitability for sediment tracing channel erosion was modelled to be a significant source of sediment 51 9 contrasting desktop modelling research that estimated gully erosion is the predominant sediment source to limit the supply of sediment to moreton bay channel bank and gully erosion must both be targeted by sediment management programs by distinguishing between subsoil sediment sources this approach has the potential to enhance the management of sediment loads degrading waterways worldwide copyright 2014 john wiley sons ltd

improvement in mrs parameter estimation by joint and laterally constrained inversion of mrs and tem data we developed a new scheme for joint and laterally constrained inversion lci of magnetic resonance sounding mrs data and transient electromagnetic tem data which greatly improves the estimation of the mrs model parameters during the last few decades electrical and electromagnetic methods have been widely used for groundwater investigation but they suffer from some inherent limitations for example equivalent layer sequences furthermore the water content information is only empirically correlated to resistivity of the formation mrs is a noninvasive geophysical technique that directly quantifies the water content distribution from surface measurements the resistivity information of the subsurface is obtained from a complementary geophysical method such as tem or dc resistivity methods the conventional inversion of mrs data assumes the resulting resistivity structure to be correct and considers a constant mrs kernel through the inversion we found that this assumption may introduce an error to the forward modeling and consequently could result in erroneous parameter estimations in the inversion process we investigated the advantage of tem for the joint inversion compared to dc resistivity a fast and numerically efficient mrs forward routine made it possible to invert the mrs and tem data sets simultaneously along profiles furthermore by application of lateral constraints on the model parameters lateral smooth 2d model sections could be be obtained the simultaneous inversion for resistivity and mrs parameters led to a more reliable and robust estimation of all parameters and the mrs data diminished the range of equivalent resistivity models we examined the approach through synthetic data and a field example in denmark where good agreement with borehole data was demonstrated with clear correlation between the relaxation time

assessing the sources of sediment transported in gully systems using a fingerprinting approach an example from south east china abstract eroded sediment is an important feature of permanent gully s development however obtaining the specific characteristics of the sediment transport in the gully can be difficult thus a composite fingerprinting technique incorporating uncertainty analysis has been employed to investigate the mean relative contribution of sediment sources in permanent gullies in this study 31 tracers were measured at 62 different sampling sites from three layers of a gully wall surface layer sl sandy soil layer ssl and semi weathering rock layer swl and 36 sediment samples from the slumping deposit and alluvial fan of the gullies the sediment source tracing procedure was therefore used to assess the relative contribution of each source the mean relative contribution from the sl to the sediment of the slumping deposit is higher in the active gully g1 and is relatively lower in the potentially stable g2 and stable gullies g3 thus there was no obvious gully bank retreat in g2 and g3 in different places of the g1 alluvial fan the mean relative contribution of the sl ssl and swl ranged from 9 11 36 43 and 46 55 respectively however the sediment contribution of the sl increased in g2 and g3 due to the changes in the erosion type the mean relative contributions of the sl were 33 5 g2 and 30 3 g3 these findings have important implications for the establishment of a scientific basis for permanent gully sediment transport management and control policies

buried and open tunnel valleys in denmark erosion beneath multiple ice sheets abstract tunnel valleys are large elongate and irregular depressions cut beneath the margin of former ice sheets they are generally believed to play a substantial role for the entire hydraulic system beneath ice sheets and thus also for ice sheet behaviour their origin however remains poorly understood examination of newly collected danish hydrogeophysical and lithological data has revealed numerous systems of buried valleys 50 350 m deep and 0 5 4 km wide these valleys are similar to the open tunnel valleys found in the present day landscape infills comprise a variety of sediments often with subglacial clay till and meltwater deposits the incised substratum consists of limestone heavy paleogene clay sand and silt the tunnel valleys have preferred orientations and can be divided into several generations each ascribed individual ice advances or ice sheets occurring during multiple glaciations the processes forming the valleys appear to prefer pre existing open and buried valleys for the renewed erosion thus old subglacial erosion pathways have been re used several times and some of the present tunnel valleys may have been established in the middle or early quaternary or even earlier this valley re use effect causes apparently anastomosed valley systems to emerge in the data images the valleys were mainly eroded by meltwater supposed to have drained from subglacially stored reservoirs probably behind a frozen margin the water was most likely released in repeated jokulhlaups and flowed in relatively small channels on the floors of the tunnel valleys which gradually became ice filled with the lowering of the bed selective linear glacial erosion is also believed to have contributed to the erosion this however was most pronounced for the widest valleys and is supposed to have played a secondary role

pumping tests in non uniform aquifers the linear strip case abstract many pumping tests are performed in geologic settings that can be conceptualized as a linear infinite strip of one material embedded in a matrix of differing flow properties a semi analytical solution is presented to aid the analysis of drawdown data obtained from pumping tests performed in settings that can be represented by such a conceptual model integral transform techniques are employed to obtain a solution in transform space that can be numerically inverted to real space examination of the numerically transformed solution reveals several interesting features of flow in this configuration if the transmissivity of the strip is much higher than that of the matrix linear and bilinear flow are the primary flow regimes during a pumping test if the contrast between matrix and strip properties is not as extreme then radial flow should be the primary flow mechanism sensitivity analysis is employed to develop insight into the controls on drawdown in this conceptual model and to demonstrate the importance of temporal and spatial placement of observations changes in drawdown are sensitive to the transmissivity of the strip for a limited time duration after that time only the total drawdown remains a function of strip transmissivity in the case of storativity both the total drawdown and changes in drawdown are sensitive to the storativity of the strip for a time of quite limited duration after that time essentially no information can be gained about the storage properties of the strip from drawdown data an example analysis is performed using data previously presented in the literature to demonstrate the viability of the semi analytical solution and to illustrate a general procedure for analysis of drawdown data in complex geologic settings this example reinforces the importance of observation well placement and the time of data collection in constraining parameter correlation a major source of the uncertainty that arises in the parameter estimation procedure

the uncertainties associated with sediment fingerprinting suspended and recently deposited fluvial sediment in the nene river basin the use of tracers within a sediment fingerprinting framework has become a commonly used technique for investigating the sources of fine sediment however uncertainties associated with tracer behaviour have been cited as major potential limitations to sediment fingerprinting methodologies this paper aims to determine the differences between fingerprinting results derived using different groups of tracer properties and to determine the role of organic matter content particle size and within source variability in tracer concentrations on the observed differences a mean difference of 24 1 between the predicted contributions of sediment originating from channel banks was found when using different tracer groups mean differences between tracer group predictions were lower at between 8 and 11 when fingerprinting contributions from urban street dusts organic matter content and or particle size showed little indication that they caused differences between tracer group predictions the within source variability in tracer concentrations and small contrasts between the tracer concentrations of different source groups were identified as probable causes of inherent uncertainty in the fingerprinting predictions we determined that the ratio of the percentage difference between median tracer concentrations in the source groups and the average within source tracer concentration coefficient of variation could indicate the likely uncertainty in model predictions prior to tracer use

heavy metal release by peat erosion in the peak district southern pennines uk upper north grain ung is a heavily eroding blanket peat catchment in the peak district southern pennines uk concentrations of lead in the near surface peat layer at ung are in excess of 1000 mg kg 1 for peatland environments these lead concentrations are some of the highest globally high concentrations of industrially derived atmospherically transported magnetic spherules are also stored in the near surface peat layer samples of suspended sediment taken during a storm event that occurred on 1 november 2002 at ung and of the potential catchment sources for suspended sediments were analysed for lead content and the environmental magnetic properties of anhysteretic remanent magnetization arm and saturation isothermal remanent magnetization sirm at the beginning of the storm event there is a peak in both suspended sediment and associated lead concentration sirm arm values for suspended sediment samples throughout the storm reveal that the initial lead flush is associated with a specific sediment source namely that of organic sediment eroded from the upper peat layer using the magnetic fingerprinting approach to discrimination of sediment sources this study reveals that erosion of the upper peat layer at ung is releasing high concentrations of industrially derived lead and by inference other toxic heavy metals associated with industrial particulates into the fluvial systems of the southern pennines climate change scenarios for the uk involving higher summer temperatures and stormier winters may result in an increased flux both of sediment associated and dissolved heavy metals from eroding peatland catchments in the southern pennines adversely affecting the quality of sediment and water entering reservoirs of the region copyright 2005 john wiley sons ltd

the application of fallout radionuclides to determine the dominant erosion process in water supply catchments of subtropical south east queensland australia previous studies using fallout radionuclides 137cs and 210pbex to determine the relative contributions of surface soil and channel erosion including gullies and channel banks to stream sediments have used a relatively small number of composite samples 25 to characterize the source end members and concentrations in each of the source end members have through the use of means and standard errors been assumed to be normally distributed here we examine 137cs activity concentrations to determine the erosion processes supplying sediment in seven water supply catchments in south east queensland first we test some of the underlying assumptions in the method using concentrations of 137cs and 210pbex in composite samples collected from 109 surface soil sites and 39 channel bank sites paired composite samples each consisting of 20 subsamples from five sites are used to demonstrate that this sampling approach was sufficient to average out any local variations in surface soil 210pbex and 137cs concentrations across the 300 m2 sampled we derive probability distributions for 137cs and 210pbex concentrations in the group of samples from each of the end members and show that only the distribution of 210pbex in samples from surface soils is normally distributed we use the probability distributions for 137cs which provides the greatest discrimination between sources to show that the 137cs concentrations on the river sediment samples are consistent with channel erosion being the dominant source conservation works aimed at reducing the supply of sediments in these catchments should therefore focus on rehabilitation of the channel network and decreasing the runoff to the channel network these findings are consistent with other similar studies on tropical australian rivers copyright 2012 john wiley sons ltd

on determining uncertainties of magnetic resonance sounding estimated transmissivities for groundwater modeling abstract the nuclear magnetic resonance sounding mrs method is used increasingly as a tool for hydrological investigations compared to other geophysical methods the advantage of mrs is that it is directly sensitive to the presence of water in the subsurface data interpretations can also be used to get information about the subsurface pore structures which under special conditions can be related to hydraulic properties such as aquifer transmissivity however to broaden the usage of this information in hydrological modeling the uncertainties related to these transmissivity estimates must be determined otherwise properly balanced weights cannot be given to the prior information obtained from mrs transmissivity estimates as compared to the hydrological data sets when used for groundwater model calibration we have developed a methodology to estimate the uncertainties of mrs based transmissivity estimates compared to previous studies the methodology is well defined and it takes into account import

sources of fine sediment stored in agricultural lowland streams midwest usa abstract agricultural activities can accelerate the offsite transport of productive soil from fields leading to stream water quality degradation identification of the nature and relative contribution of different sources to fine grained sediment e g silts clays in streams is important to effectively focus agricultural best management practices in watersheds sediment fingerprinting techniques through the use of geochemical tracers are commonly used to differentiate relative contribution from various sources research was conducted in lowland streams in the pleasant valley watershed in south central wisconsin usa to identify provenance of fine grained sediment deposits and evaluate the impact of land use on relative contributions from the following potential sources cropland pasture woodland and eroding stream banks results show that both agriculture croplands and pastures and eroding stream banks are primary sources to fine sediment deposits on the stream bed with contributions ranging from 19 to 100 and 0 to 81 respectively the increase in area under agricultural land use within a subwatershed results in greater contribution from agriculture r2 0 846 p 0 0034 relative contributions from eroding stream banks increased with increasing area under grasslands and woodlands within a subwatershed r2 0 814 p 0 0055 subwatersheds with greater mass of fine sediment deposited on the stream bed per unit area should be prioritized for best management practices the conservation practices should be targeted to stream banks or croplands depending on the dominant source of fine sediment within a subwatershed site specific changes in relative contributions from different sources to fine grained sediment in this watershed highlights the complexities involved in sediment transport dynamics the nested sampling sites helped determine that sediment dynamics at the subwatershed scale need to be considered for application of targeted conservation techniques

the suspended sediment dynamics in the inner mongolia reaches of the upper yellow river article i nfo suspended sediment dynamics are still imperfectly understood especially in the upper yellow river where few studies on this issue have been conducted this study analyzed the variability in suspended sediment concentration at different temporal scales within flood monthly seasonal and annual using a dataset up to 49 years long 1954 2002 at toudaoguai station this paper provided insight into the characteristics of suspended sediment transport in the ningxia inner mongolia reaches of the upper yellow river the results show that in a single flood event changes in ssc are not simultaneous with changes in discharge resulting in counterclockwise hysteretic loops clockwise loops or figure eight loops the c q loops and sediment rating curves for different seasons had different characters the diversiform c q loops in the inner mongolia reaches of the upper yellow river may be mainly caused by the sediment inputs from tributaries the differ ent propagation velocity of sediment and water discharge spatial and temporal storage depletion processes of available sediment at annual scale the variations of annual mean discharge and ssc displayed a similar gradually deceasing trend and the relation between water discharge and ssc during 1954 2002 could be de scribed by a cubic polynomial function since the joint operation of liujiaxia and longyangxia reservoirs after 1986 the transport capacity of the upper yellow river has been much reduced

use of the geochemical record preserved in floodplain deposits to reconstruct recent changes in river basin sediment sources abstract the geochemical record preserved in overbank floodplain deposits is used in combination with a composite fingerprinting technique and the chronology provided by 137 cs dateable horizons to reconstruct recent changes in sediment sources in the exe and severn basins uk composite fingerprints for discriminating potential source materials are identified from a suite of properties including heavy metals trace metals and cation bases these fingerprints are then compared with those of historical floodplain deposits using a numerical sediment mixing model relative contributions from distinct spatial sources characterised in terms of the devonian carboniferous and permian geological sub areas of the exe and the ordovician silurian devonian carboniferous permian and triassic jurassic sub areas of the severn are shown to fluctuate over the recent past in response to intrinsic e g the occurrence of extreme hydrologic events and extrinsic e g anthropogenic disturbance associated with land use change controls the potential for fingerprint property transformation in association with floodplain storage is assessed and the scope for further research using fingerprinting to reconstruct longer term sediment sources is discussed