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

middle to late holocene decreased fluvial aggradation and widespread peat initiation in the ishikari lowland northern japan this study investigated the influence of sea level and climate changes on the decreased fluvial aggradation and subsequent widespread peat initiation in the middle to late holocene in the ishikari lowland which is a coastal floodplain formed in response to the postglacial sea level change by introducing a new approach to separately evaluate the rates of organic and clastic sediment input we demonstrated that the peat began to form when the fluvial sedimentation rate was significantly decreased less than 0 6 mm yr while plant macrofossil analysis suggested that lowering of water level is also important to the peat initiation such changes in sedimentary environment may be associated with the abrupt abandonment of crevasse splays the concentrated ages of the peat initiation around 5600 5000 4600 4300 and 4100 3600 cal bp suggest that an allogenic control promoted the abandonment of crevasse splays and different onset ages can be explained by different fluvial responses of the ishikari river and i

multirate flowing fluid electric conductivity logging method the flowing wellbore electric conductivity logging method involves the replacement of wellbore water by de ionized or constant salinity water followed by constant pumping with rate q during which a series of fluid electric conductivity logs are taken the logs can be analyzed to identify depth locations of inflow and evaluate the transmissivity and electric conductivity salinity of the fluid at each inflow point the present paper proposes the use of the method with two or more pumping rates in particular it is recommended that the method be applied three times with pumping rates q q 2 and 2q then a combined analysis of the multi rate data allows an efficient means of determining transmissivity and salinity values of all inflow points along a well with a confidence measure as well as their inherent or far field pressure heads the method is illustrated by a practical example

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

formation and infilling of oxbow lakes in the ishikari lowland northern japan abstract oxbow lakes are common landforms in meandering river floodplains despite the possible importance of oxbow lakes in floodplain evolution little is known about sedimentary facies and sedimentation rates of oxbow fills their formation ages and their persistence in the landscape we analyzed infilling records by interpretation of borehole cores from four oxbow lakes in the ishikari lowland northern japan the borehole sediments were interpreted as basal coarse grained streambed sediments unit 1 succeeded by channel fills before complete disconnection unit 2 and overbank deposits after complete disconnection unit 3 unit 2 is thick in one core but very thin or absent in the other cores this difference may result from the diversion angles of the incipient oxbow at the time of cutoff rather than the cutoff mechanism meander cutoff or local avulsion detailed chronology based on the 14c ages tephra analysis and 137cs suggests that the oxbow lakes formed during the last centuries and the sedimentation rates are approximately 45 90 mm y in unit 2 and 3 9 22 0 mm y in unit 3 oxbow lakes in the ishikari lowland may persist in the landscape during 600 1300 years since the initiation of cutoff the relationship between the production rate of oxbow lakes and their persistence suggests that the production rate of oxbow lakes was high during 1899 1959 the number of oxbow lakes in the landscape may be variable in time scales of several decades or a century depending on the production rate of oxbow lakes

recovering tracer test input functions from fluid electrical conductivity logging in fractured porous rocks a radially convergent tracer test was carried out in an unconfined chalk aquifer of berkshire united kingdom fluorescent tracers were injected into two boreholes lying 32 m pl10a and 54 m pl10b from the abstraction hole the tracers were also mixed with an nacl solution so that vertical distributions of tracer within the injection wells could be monitored using fluid electrical conductivity fec logging the breakthrough curve btc from pl10a was unimodal and had a first arrival time of 14 min the btc from pl10b exhibited two distinct peaks and a first arrival time of just 4 min the tracer test input functions were derived by numerically modeling the observed fec logs of the injection wells these were then convoluted with a conventional fickian matrix diffusion dual porosity model the results suggested that the multiple peaks were due to the way in which the tracers left the injection wells and migrated into the aquifer fec log inversion proved to be an effective method for predicting borehole flow data obtained by flowmeters and recovering tracer test input functions for radially convergent tracer tests

signatures in flowing fluid electric conductivity logs flowing fluid electric conductivity logging provides a means to determine hydrologic properties of fractures fracture zones or other permeable layers intersecting a borehole in saturated rock the method involves analyzing the time evolution of fluid electric conductivity fec logs obtained while the well is being pumped and yields information on the location hydraulic transmissivity and salinity of permeable layers the original analysis method was restricted to the case in which flows from the permeable layers or fractures were directed into the borehole inflow recently the method was adapted to permit treatment of both inflow and outflow including analysis of natural regional flow in the permeable layer a numerical model simulates flow and transport in the wellbore during flowing fec logging and fracture properties are determined by optimizing the match between simulation results and observed fec logs this can be a laborious trial and error procedure especially when both inflow and outflow points are present improved analyses methods are needed one possible tactic would be to develop an automated inverse method but this paper takes a more elementary approach and focuses on identifying the signatures that various inflow and outflow features create in flowing fec logs the physical insight obtained provides a basis for more efficient analysis of these logs both for the present trial and error approach and for a potential future automated inverse approach inflow points produce distinctive signatures in the fec logs themselves enabling the determination of location inflow rate and ion concentration identifying outflow locations and flow rates typically requires a more complicated integral method which is also presented in this paper

using dendrogeomorphology and 137cs and 210pb radiochronology to estimate recent changes in sedimentation rates in kushiro mire northern japan resulting from land use change and river channelization abstract the purpose of this study is to describe the history of sediment deposition that has been occurring for several decades along the margins of the kushiro mire into which the kuchoro river drains the dendrogeomorphic technique was used to examine an even aged forest and adventitious roots to assess short term 20 years deposition rates and the frequency of heavy rainfall events for medium 40 years and long term 100 years deposition rates radiochronological analyses using 137 cs and 210 pb were also conducted several instances of high deposition rates caused by flooding events during the last 20 years were identified from the analysis of adventitious roots the average sedimentation rate from 1963 to the present estimated from the 137 cs study is over 1 3 cm year using the 210 pb dating method based on a cfcs model which considered the organic matter content appropriate to wetland sediment three deposition rates in the last 60 years were estimated 2 0 cm year from 1981 to 2000 8 9 cm year from 1975 to 1981 and 0 14 cm year from 1939 to 1975 the analysis of environmental radionuclides indicated that the greatest sedimentation rates occurred in the years 1975 to 1981 when the kuchoro river was extensively channelized and flood and or precipitation events occurred this suggests that land use development and channelization introduced a large amount of sediment into the marginal areas of wetland through the drainage system and this was deposited on top of the peat soil

flowing fluid electric conductivity logging for a deep artesian well in fractured rock with regional flow the flowing fluid electric conductivity ffec logging method is a well logging technique that may be used to estimate flow rate salinity transmissivity and hydraulic head of individual fractures or high permeability zones intersected by a wellbore wellbore fluid is first replaced with fluid of a contrasting electric conductivity then repeated fec logging is done while the well is pumped zones where fluid flows into the wellbore show peaks in the fec logs which may be analyzed to infer inflow rate and salinity of the individual fractures conducting the procedure with two or more pumping rates multi rate ffec logging enables individual fracture transmissivity and hydraulic head to be determined here we describe the first application of the multi rate ffec logging method to an artesian well using a 500 m well in fractured rock at horonobe japan an additional new factor at the site is the presence of regional groundwater flow which heretofore has only been studied with synthetic data ffec logging was conducted for two different pumping rates several analysis techniques had to be adapted to account for the artesian nature of the well the results were subsequently compared with independent salinity measurements and transmissivity and hydraulic head values obtained from packer tests in the same well despite non ideal operating conditions multi rate ffec logging successfully determined flow rate salinity and transmissivity of 17 conducting fractures intercepted by the logged section of the borehole including two fractures with regional groundwater flow predictions of hydraulic head were less accurate a not unexpected result in light of operational problems and the form of the equation for hydraulic head which involves the difference between two uncertain quantities this study illustrates the strengths and weaknesses of the multi rate ffec logging method applied to artesian wells in conjunction with previous studies it demonstrates the usefulness of the method for a broad range of conditions encountered in subsurface fractured rock

integrated borehole logging methods for wellhead protection applications modeling of ground water infiltration and movement in the wellhead area is a critical part of an effective wellhead protection program such models depend on an accurate description of the aquifer in the wellhead area so that reliable estimates of contaminant travel times can be used in defining a protection area geophysical and hydraulic measurements in boreholes provide one of the most important methods for obtaining the data needed to specify wellhead protection measures most effective characterization of aquifers in the wellhead vicinity results when a variety of geophysical and hydraulic measurements are made where geophysical measurements can be calibrated in terms of hydraulic variables and where measurements are made at somewhat different scales of investigation the application of multiple geophysical measurements to ground water flow in the wellhead area is illustrated by examples in alluvial fractured sedimentary and fractured crystalline rock aquifers data obtained from a single test well are useful but cannot indicate how conductive elements in the aquifer are connected to form large scale flow paths geophysical and hydraulic measurements made in arrays of observation boreholes can provide information about such large scale flow paths and are especially useful in specifying aquifer properties in wellhead protection studies

characterisation of fractured carbonate aquifers using ambient borehole dilution tests abstract fractured carbonate aquifers derive their transmissivity essentially from a well developed network of solutionally enhanced fractures and conduits that can lead to high groundwater velocities and high vulnerability to contamination of water quality characterisation of the variation of hydraulic properties with depth is important for delineating source protection areas characterising contaminant fate and transport determination of the effectiveness of aquifer remediation and parameter estimation for models in this work ambient open borehole uniform and point injection dilution tests were conducted on observation boreholes in the unconfined cretaceous chalk aquifer of east yorkshire uk and interpreted in conjunction with other data via the implementation of a new work flow this resulted in the characterisation of flow in these boreholes and the inference of properties such as groundwater flow patterns and velocities in the surrounding aquifer formation our workflow allowed sections of open boreholes showing horizontal versus vertical flow to be distinguished and the magnitude of such flows and exchanges with the aquifer to be determined flow within boreholes were then used to characterise i presence and direction of vertical hydraulic gradients ii nature and depth distribution of flowing features iii depth interval porosity and permeability estimation of the flowing features from overall borehole transmissivity and geophysical image or caliper logs iv groundwater velocity estimation in the surrounding aquifer discrete flowing features were distributed across the range of depths sampled by the observation boreholes typically up to 45 60 mbgl but the majority were located in the zone of water table fluctuation marked by solutionally enlarged flow features quantitative interpretation of both uniform injection tracer distributed throughout the open borehole section and point injection slug of tracer introduced at targeted depth yielded vertical velocities within the borehole water column in broad agreement with those measured by flow logging depth specific fracture kinematic porosities inferred from the ambient dilution data combined with long interval pump test and geophysical log data ranged between 3 7 10 4 4 1 10 3 with an average of 2 1 10 3 these values were in excellent agreement with those from other methods applied to the same aquifer such as larger scale pumping tests a new approach to estimation of groundwater velocities from the dilution test data using externally measured hydraulic gradients gave inferred horizontal groundwater velocities ranging between 60 and 850 m day in full agreement with those from previously conducted borehole to borehole tracer tests these results confirm that the studied aquifer is karstic with rapid preferential pathways which have implication for flow and transport modelling and pollution vulnerability our study results indicate that ambient single borehole dilution approaches can provide an inexpensive and reliable approach for the characterisation of fractured and karstic aquifers

a multidisciplinary fractured rock characterization study at raymond field site raymond ca abstract a dedicated field site was developed and a suite of experiments were conducted in the sierra nevada foothills near the town of raymond ca to develop and test a multi disciplinary approach to the characterization of groundwater flow and transport in fractured rocks a wealth of geologic hydrologic and geophysical data was collected at the site using a variety of unique tools a cluster of nine approximately 90 m deep boreholes were drilled at the site in a v shaped pattern with an angle of 60 the boreholes are spaced 7 5 15 30 and 60 m from the central borehole various geophysical and hydrologic tests were conducted in and between these boreholes integration of cross hole radar and seismic tomography borehole flow surveys and images from a new digital borehole scanner indicated that groundwater flow is mainly confined to a few sub horizontal fracture zones a unique suite of hydraulic tests were conducted in which three to four intervals in each of the nine boreholes were isolated using pneumatic packers some 130 injection tests were conducted and more than 4100 cross hole transient pressure measurements were obtained a computer algorithm was developed to analyze such massive interference data systematically as a result of the analysis an image of the fracture connections emerged which is consistent with the geophysical data high precision tiltmeters were effective in remotely characterizing the preferential flow path several radial convergent tracer tests were conducted by injecting a mixture of several conservative tracers and one sorbing tracer deuterium fluorescein lithium bromide and polystyrene micro spheres some differences between the breakthrough curves are observed which may be due to possible differences among so called conservative tracers some characterization tools were found to be more effective than others in locating flowing fractures however no single tool was almighty characterization of fractured rock is extremely challenging and requires a stepwise and well thought approach which is basically a good old scientific approach prediction of transport based on the characterization results is even more challenging and one should always bear in mind that it is virtually impossible to uniquely characterize a fractured rock

use of composite fingerprints to determine the provenance of the contemporary suspended sediment load transported by rivers sediment fingerprinting appears to offer a valuable alternative to direct monitoring for elucidating the provenance of suspended sediment and the relative importance of spatial zones or subcatchments comprising larger 500 km 2 drainage basins against this background a quantitative composite fingerprinting technique incorporating both statistically verified multicomponent signatures and a multivariate sediment mixing model has been employed to determine the spatial origin of contemporary suspended sediment transported from the upper and middle reaches of the river exe 601km 2 and river severn 4325 km 2 basins uk spatial origin is addressed in terms of the relative contribution from three distinct geological subareas constituting each study basin the consistency of the composite fingerprinting approach is examined using the estimates for mean and seasonal variations in source area contributions and also a comparison between the results obtained for individual flood events and alternative lines of evidence provided by flood travel times and the spatial distribution of precipitation it is argued that fingerprinting estimates for sediment provenance are consistent with existing information on suspended sediment yields from different subcatchments within the study basins although in the severn the role of storage and remobilization in producing signature averaging may complicate comparison of the fingerprinting data with typical floodwater routing times validation represents the greatest problem for the cost benefit of fingerprinting and scope still exists for further refinement of the procedures involved 1998 john wiley sons ltd

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

application of multirate flowing fluid electric conductivity logging method to well dh 2 tono site japan 1 in the flowing fluid electric conductivity fec logging method well bore fluid is replaced with deionized water following which fec profiles in the well bore are measured at a series of times while the well is pumped at a constant rate locations where fluid enters the well bore show peaks in the fec logs which are analyzed to infer inflow strengths and salinities of permeable features intersected by the borehole in multirate flowing fec logging the flowing fec logging method is repeated using two or more pumping rates the results coupled with those of a conventional well test over the entire borehole enable the transmissivities and inherent pressure heads of permeable features to be determined multirate fec logging is carried out on a deep borehole in fractured granitic rock using three different pumping rates results identify 19 hydraulically conducting fractures and indicate that transmissivity pressure head and salinity vary significantly among them using three pumping rates rather than the minimum number of two permits an internal consistency check on the analysis that provides a measure of the uncertainty of the results good comparisons against static fec profiles and against independent chemical geological and hydrogeological data have further enhanced confidence in the results of the multirate flowing fec logging method

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

tectonic and climatic control of triassic sedimentation in the beryl basin northern north sea the beryl basin embayment occupies a central position along the viking graben of the northern north sea and has been a hydrocarbon play since the early 1970s detailed analysis reveals a complex half graben that was established during a rift phase of development that occurred in the early triassic teist formation after which a long period of thermal subsidence lomvi and lunde formations provided accommodation for in excess of 1000 m of sediment the teist formation sediments are complex they include shales sands and conglomerates and their superimposition on zechstein salts is indicative of both uplift and the development of a moderate relief they give way to the comparatively clean and occasionally pebbly sands of the lomvi formation for which an analysis of both bedding and texture suggests deposition by a westerly directed river system draining the hanging wall ramp the lunde formation records the spreading influence of a bajada playa complex and its eventual conversion to a more persistent lake the growing importance and eventual dominance of the succession by lacustrine sediments gives clear indication of a change in climate and this has been attributed to the rapid northward drift of pangea during the triassic period

changes in the fine sediment dynamics of the ouse and tweed basins in the uk over the last 100 150 years sediment cores collected from nine headwater lakes and reservoirs in their catchments and adjacent areas and from ten floodplain sites in the middle and lower reaches of the two river systems have been used to reconstruct changes in suspended sediment yields rates of sedimentation and suspended sediment sources for the ouse and tweed catchments in the uk over the last ca 100 150 years in response to recent environmental change for the small lake reservoir catchments in or adjacent to the ouse basin average sediment yields for the recent period 1963 95 were generally found to exceed those for the period prior to 1963 by up to 94 suggesting that sediment yields have increased over time for the equivalent lake reservoir catchments in and adjacent to the tweed basin sediment yields were generally lower in the period since 1963 in both basins sediment yields over the past 100 150 years were characterized by considerable temporal variability which was seen to reflect at least in part the significant changes in land use and land management that occurred within their catchments no clear links between the variability of sediment yields and changes in climate were apparent changes in sediment source reconstructed for one of the lakes appeared primarily to reflect catchment disturbance during afforestation in the 1940s average rates of overbank sedimentation for the ten floodplain sites varied considerably between sites for those cores collected from the ouse basin there was no consistent temporal trend and average sedimentation rates for the period extending from ca 1895 to 1963 were broadly similar to those for the period since 1963 for the tweed basin sedimentation rates for all three cores were higher prior to 1963 reflecting the increased soil erosion and sediment yields associated with the conversion of pasture to arable land in the immediate post world war ii period and the ditching and planting operations associated with afforestation in the 1940s substantial downcore variability in the source of the overbank sediment considered in terms of both source type and spatial location was found in both river basins this was seen to reflect land use change including land drainage the conversion of pasture to arable land afforestation and increased cereal production the evidence provided by the floodplain cores again showed little indication of any influence linked to climate change although the detailed patterns of temporal variation of sediment yield overbank sedimentation rate and sediment source reconstructed from the sediment cores collected from the lake reservoirs and floodplain locations are site specific there is a general consistency between the changes in sediment dynamics reconstructed for the headwater catchments based on the cores collected from the lakes and reservoirs and the equivalent evidence for the middle and lowland reaches of the catchments provided by overbank floodplain deposits despite significant changes in climate and more particularly land use over this time period the general lack of evidence of substantial changes in downstream sediment yield and rates of overbank sedimentation over the last ca 100 150 years in the ouse and tweed basins suggests that their sediment dynamics have been generally insensitive to recent environmental change this finding has important implications when considering the likely response of these and similar uk river basins to future environmental change

evidence for 17th century tsunamis generated on the kuril kamchatka subduction zone lake tokotan hokkaido japan abstract in the seventeenth century two tsunamis that were generated by earthquakes on the kuril kamchatka subduction zone inundated the eastern coast of hokkaido northern japan stratigraphic evidence for these two tsunamis and related land level change in coastal hokkaido consists of two landward thinning sand layers in the sediments of lake tokotan a coastal lagoon on the hokkaido coast the marine origin of these sand layers is indicated by the presence of brackish marine diatoms the rarity and high degree of fragmentation of diatom valves suggests that the sands were transported in a short time over a considerable distance tsunamis at this site were probably generated by great earthquakes along the kuril kamchatka trench volcanic ash deposits lying just above the sands suggest that tsunamis occurred in the late 17th century tsunamis during the historic period are not recorded in lake tokotan which suggests that the sand layers were deposited by tsunamis substantially larger than historic tsunamis

hydration and refractive indices of holocene tephra glass in hokkaido northern japan abstract refractive indices of incompletely hydrated tephra glasses vary widely thus glass refractive index is not a practical indicator for identifying holocene tephras hydration near the surface of tephra glass shards can be removed by either hydrofluoric acid treatment or annealing for 12 h at 400 c the annealing procedure is a particularly reliable and simple way to dehydrate tephra glasses standard deviations s of refractive indices for glasses after 12 h annealing are small s 0 0014 0 0018 in contrast with untreated glasses s 0 0034 0 0405 the refractive indices of dehydrated tephra glasses are 0 006 0 014 lower than those of the untreated hydrated glasses using the 400 c 12 h annealing procedure values for the refractive indices of eight holocene tephras in hokkaido were obtained these refractive indices are useful indicators for identification and correlation of holocene tephras

triassic sediments of the inner moray firth scotland early rift deposits patterns of triassic sedimentation in the inner moray firth are examined in the light of a new model of continental rift sedimentation that has been developed in the tertiary to recent rifts of east africa the major tectonic control during the trias was the great glen fault to the northwest which can be shown to have been moving in dip slip fashion at this time the structure of the firth appears to have resembled the simple half graben that makes up the great east african rift system deposits both thicken and get finer towards the fault sediments found in off shore wells are dominated by laminated fine sand and silty clay with sporadic evaporites similar sequences are characteristic of or associated with ephemeral lakes in modern semi arid continental rift settings no alluvial fans have been detected close to the faulted margin again this is consistent with general patterns of sedimentation against boundary faults in the kenyan rift the coarsest sedimentary sequences in the moray firth are on the unfaulted margin to the south around burghead they consist of fluviatile lake shore and aeolian deposits the fluvial sediments show evidence of tectonically induced cycles of sedimentation which are interpreted in terms of waves of detritus working down the drainage system beds dominated by pebbly horizontal laminae and reminiscent of steep straight and shallow ephemeral streams alternate with troughed sands of deeper more sinuous but equally ephemeral rivers these are the coarsest sediments of the unfaulted margin of the basin however the lack of thick conglomerate sheets which are a feature of east african sequences at equivalent positions within the rift basin suggests only small scale fault activity and a relatively subdued topography during triassic times this is supported by evidence of extensive calichification during the rhaetic which produced a top trias marker horizon found throughout the inner moray firth

inflow and outflow signatures in flowing wellbore electrical conductivity logs flowing wellbore electrical conductivity logging provides a means to determine hydrologic properties of fractures fracture zones or other permeable layers intersecting a borehole in saturated rock the method involves analyzing the time evolution of fluid electrical conductivity logs obtained while the well is being pumped and yields information on the location hydraulic transmissivity and salinity of permeable layers as well as their initial or ambient pressure head earlier analysis methods were restricted to the case in which flows from the permeable layers or fractures were directed into the borehole more recently a numerical model for simulating flowing conductivity logging was adapted to permit treatment of both inflow and outflow including analysis of natural regional flow in the permeable layer however determining the fracture properties with the numerical model by optimizing the match to the conductivity logs is a laborious trial and error procedure in this paper we identify the signatures of various inflow and outflow features in the conductivity logs to expedite this procedure and to provide physical insight for the analysis of these logs generally inflow points are found to produce a distinctive signature on the conductivity logs themselves enabling the determination of location inflow rate and ion concentration in a straightforward manner identifying outflow locations and flow rates on the other hand can be done with a more complicated integral method running a set of several conductivity logs with different pumping rates e g half and double the original pumping rate provides further information on the nature of the feed points in addition to enabling the estimation of flow parameters from conductivity logs an understanding of the conductivity log signatures can aid in the design of follow up logging activities

a simple inverse method for the interpretation of pumped flowing fluid electrical conductivity logs pumped flowing fluid electrical conductivity ffec logs also known as pumped borehole dilution testing is an experimentally easy to perform approach to evaluating vertical variations in the hydraulic conductivity of an aquifer in contrast to the simplicity of the logging equipment analysis of the data is complex and laborious current methods typically require repeated solution of the advection dispersion equation ade for describing the flow in the borehole and comparison with the experimental results in this paper we describe a direct solution for determining borehole fluid velocity that bypasses the need for complex numerical computation and repetitive optimization the method rests on the observation that while solving the ade for concentration profile in the borehole as required for modeling and combined methods is computationally challenging the solution for flow distribution along the length of the borehole given concentration data is straightforward the method can accommodate varying borehole diameters and uses the fact that multiple profiles are taken in the standard logging approach to reduce the impact of noise data from both a simulated borehole and from a field test are successfully analyzed the method is implemented in a spreadsheet which is available as supporting information material to this paper

comparison of hydrogeochemical logging of drilling fluid during coring with the results from geophysical logging and hydraulic testing example of the morte merie scientific borehole ardeche france deep geology of france programme abstract a 980 m deep well was cored on the ardeche border of the southeastern basin of france as part of the deep geology of france gpf programme hydrogeochemical logging was carried out during drilling which involved the monitoring of physico chemical parameters ph eh temperature and conductivity and chemical parameters concentrations of he rn co 2 ch 4 o 2 ca cl and sio 2 of the drilling fluid permanently circulating in the well this logging programme was complemented by geophysical logging and two hydraulic tests the combination of these measurements enabled identification of a transmissive interval due to fractures in the jurassic carbonates and of fluid inflow both at the base of the porous and slightly permeable triassic sandstones and from an open fracture in the permian conglomerates these intervals are marked by changes in the drilling fluid chemistry such as an increase in chemical species content or a drop in ph the degree of modification depends on the natural permeability of the fractures and the salinity of the fluids the porous and permeable intervals are also marked by he anomalies which act as a tracer for these zones comparison between the geophysical and hydrogeochemical logs reveals that the latter provide information on the liquid phase whether the fractures are productive or not whereas the geophysical logs are more directly related to the solid phase

inverting fluid conductivity logs for fracture inflow parameters fluid electrical conductivity logging experiments introduced by tsang et al 1990 represent a new technology for studying the hydraulic properties of discrete fractures in open boreholes these experiments consist of replacing water in the well bore with deionized water and then pumping the well to induce formation water to return to the well bore during and after the fluid exchange the entire well is logged to measure fluid electrical conductivity fec at locations where formation water enters the well there are abrupt increases in the borehole fec thereby revealing the location of hydraulically conductive fractures as pumping continues high fec water moves up the well bore at a rate proportional to the total inflow rate below the observation point inflow rates and fecs of formation water associated with each fracture can be inferred by modeling the fec profiles with the one dimensional advective dispersion equation in this paper i present an inverse model which estimates the inflow rates and formation fec values that optimally fit observed fec logs acquired during fluid exchange experiments described by tsang et al 1990 with this inverse model inflow rates are constrained by the rate at which the well is pumped during the experiment the forward model is solved numerically using a control volume finite difference scheme with power law upstream weighting and source term linearization the inverse problem is solved using the gauss newton iterative method the rows of the jacobian matrix or the sensitivity coefficients are calculated numerically with the same algorithm that solves the forward problem both constrained and unconstrained inverse models are used to interpret fluid logging experiments performed in research wells penetrating piedmont rocks of north carolina

fluctuations in relative sea level during the past 3000 yr in the onnetoh estuary hokkaido northern japan this paper presents the results of a litho bio and chronostratigraphical study of the evidence for late holocene sea level change palaeoseismicity and coastal evolution at the onnetoh estuary northwest japan alternating peat and mud couplets record evidence for four falls in relative sea level since ca 2500 cal yr bp in the latest instance intertidal mud with a salt tolerant diatom and plant macrofossil flora is abruptly overlain by a freshwater peat containing abundant macrofossil remains of the conifer picea glehnii these stratigraphical changes record an abrupt change from tidal flat to upland with no intermediate transition through saltmarsh in the other three instances the stratigraphy records a more gradual fall in relative sea level as shown by gradational stratigraphical contacts and transitional diatom and plant macrofossil assemblages once established these freshwater peat communities are gradually submerged and become overlain by saltmarsh and then intertidal muds radiocarbon ages and tephra date the emergence events to 2700 1750 gradual 1350 950 gradual 650 300 gradual and ca 400 cal yr bp abrupt these ages are similar to a sequence of emergence events recorded at the akkeshi estuary 70 km to the west of the present study site the three falls in relative sea level may record coseismic or swift post seismic uplift caused by plate boundary subduction earthquakes on the kurile subduction zone the oldest relative sea level fall is correlated with the so called yayoi regression dated to 1500 3000 cal yr bp in other parts of japan copyright 2002 john wiley sons ltd

the nature and distribution of flowing features in a weakly karstified porous limestone aquifer the nature and distribution of flowing features in boreholes in an area of approximately 400 km2 in a weakly karstic porous limestone aquifer the chalk was investigated using single borehole dilution tests sbdts and borehole imaging one hundred and twenty flowing features identified from sbdts in 24 boreholes have densities which decrease from 0 3 m 1 near the water table to 0 07 m 1 at depths of more than 40 m below the water table the average density is 0 20 m 1 there is some evidence of regional lithological control and borehole imaging of three boreholes indicated that most flowing features are associated with marls hardgrounds and flints that may be developed at a more local scale borehole imaging also demonstrated that many flowing features are solutionally enlarged fractures suggesting that even in carbonate aquifers where surface karst is developed on only a small scale groundwater flow is still strongly influenced by dissolution fully connected solutional pathways can occur over 100s sometimes 1000s of metres however conduits tubules and fissures may not always be individually persistent along a flowpath instead being connected together and also connected to unmodified fractures to create a relatively dense network of voids with variable apertures 15 cm groundwater therefore moves along flowpaths made up of voids with varying shape and character local solutional development of fractures at significant depths below the surface suggests that mixing corrosion and in situ sources of acidity may contribute to solutional enhancement of fractures the study demonstrates that single borehole dilution testing is a useful method of obtaining a large dataset of flowing features at catchment regional scales the chalk is a carbonate aquifer with small scale surface karst development and this study raises the question of whether other carbonate aquifers with small scale surface karst have similar characteristics and what hydrological role small scale dissolutional features play in highly karstic aquifers

determination of fracture inflow parameters with a borehole fluid conductivity logging method there is much current interest in determining the flow characteristics of fractures intersecting a well bore in order to provide data for use in estimating the hydrologic behavior of fractured rocks inflow rates from these fractures into the well bore are usually very low moreover in most cases only a few percent of the fractures identified by core inspection and geophysical logging actually conduct water the rest being closed clogged or isolated from the water flow system a new procedure is proposed and a corresponding method of analysis developed to locate water conducting fractures and obtain fracture inflow rates by means of a time sequence of electric conductivity logs of the borehole fluid the physical basis of the analysis method is discussed and the procedure is applied to an existing set of data which shows initiation and growth of nine conductivity peaks in a 900 m section of a 1690 m borehole corresponding to nine water conducting fractures intersecting the borehole by applying our analysis to these nine peaks the flow rates and the salinity of the water from these fractures are determined these results are used with other information to obtain transmissivities of the nine fractures which are validated against independent hydraulic measurements by packer tests the salinities measured in fluids from the fractures are also validated against salinity values obtained by chemical sampling of fluids from different depths of the borehole the applicability of this technique is discussed in the context of a borehole testing program

elevated sedimentation in lake records linked to agricultural activities in the ishikari river floodplain northern japan the purpose of this study was to examine the historical change in sedimentation rates in lakes that have been impacted by river regulation and agricultural activities in the ishikari river floodplain we dated sediment cores using caesium 137 137cs dating and tephrochronology and we estimated sediment sources from 137cs concentrations in the topsoil of representative land covers we found that between 1739 and 1963 the distance between the lake and the main river channel and whether or not the lake was connected to the river affected the sedimentation rates after 1963 agricultural drainage systems were established in the ishikari river floodplain the average sedimentation rate before and after the construction of drainage ditches varied between 1 66 and 87 301 mg cm 2 a 1 respectively the increase in the sedimentation rate after 1963 was caused by the construction of a number of drainage networks as well as extensive cultivation activity and or fragmentation of the swamp buffers surrounding the lakes the 137cs activities at the surfaces of the lake as well as the catchment derived 137cs contributions and 137cs inventory in the lake profiles were used to examine the sediment influx from the various drainage areas after the establishment of the drainage system our results indicate that the majority of the lake sediments were derived from cultivated areas and therefore the catchment derived 137cs contribution in the lakes was strongly correlated with the sedimentation rate the 137cs inventory across all of the lake profiles was also significantly greater than the atmospheric fallout we identified a negative correlation between the 137cs lake profile inventory and the sedimentation rate this is because the sediment originating from the drainage areas contained low 137cs concentrations which diluted the overall concentration of 137cs in the lake sediment copyright 2009 john wiley sons ltd

analysis of 6 year fluid electric conductivity logs to evaluate the hydraulic structure of the deep drill hole at outokumpu finland over the last two decades the flowing fluid electric conductivity ffec logging method has been applied in boreholes in the well testing mode to evaluate the transmissivity hydraulic head and formation water electrical conductivity as a function of depth with a resolution of about 10 20 cm ffec profiles along the borehole are obtained under both shut in and pumping conditions in a logging procedure that lasts only 3 or 4 days a method for analyzing these ffec logs has been developed and successfully employed to obtain formation parameters in a number of field studies the present paper concerns the analysis of a unique set of ffec logs that were taken from a deep borehole reaching down to 2 5 km at outokumpu finland over a 6 year time period the borehole intersects paleoproterozoic metasedimentary granitoid and ophiolite derived rocks after the well was drilled completed and cleaned up ffec logs were obtained after 7 433 597 948 and 2036 days in analyzing these five profiles we discovered the need to account for salinity diffusion from water in the formation to the borehole analysis results include the identification of 15 hydraulically conducting zones along the borehole the calculation of flow rates associated with these 15 zones as well as the estimation of the variation of formation water electrical conductivity as a function of depth the calculated flow rates were used to obtain the tentative hydraulic conductivity values at these 15 depth levels

application of direct fitting mass integral and multirate methods to analysis of flowing fluid electric conductivity logs from horonobe japan 1 the flowing fluid electric conductivity ffec logging method is an efficient way to provide information on the depths salinities and inflow strengths of individual conductive features intercepted by a borehole without the use of specialized probes using it in a multiple flow rate mode allows in addition an estimate of the transmissivities and inherent far field hydraulic heads in each of the conductive features the multirate method was successfully applied to a 500 m borehole in a granitic formation and reported recently the present paper describes the application of the method to two zones within a 1000 m borehole in sedimentary rock which produced for each zone three sets of logs at different pumping rates each set measured over a period of about 1 day the data sets involve several complications such as variable well diameter gradual water level decline in the well during logging possible fluid flow through the unfractured rock matrix and effects of drilling mud various techniques were applied to analyze the ffec logs direct fitting mass integral and the multirate method mentioned above in spite of complications associated with the tests analysis was able to identify 44 hydraulically conducting fractures distributed over the depth interval 150 775 m below ground surface the salinities in fec and transmissivities and hydraulic heads in dimensionless form of these 44 features were obtained and found to vary significantly among one another these results were compared with transmissivity and head values inferred from eight packer tests that were conducted in this borehole over the same depth interval ffec results were found to be consistent with packer test results thus demonstrating the robustness of the ffec logging method under nonideal conditions

historical change in lake sedimentation in lake takkobu kushiro mire northern japan over the last 300 years abstract environmental degradation including shallowing deterioration of aquatic habitat and water pollution has arisen from the inflow of fine sediment to lake takkobu in northern japan the lake has experienced gradual environmental degradation due to agricultural development which has introduced both fine sediment and sediment associated nutrients into the lake we have reconstructed the history of sediment yield to lake takkobu in kushiro mire over the last 300 years and have examined trends with reference to land use development fifteen lake sediment core samples were obtained and various physical variables of lake sediments were analyzed and dated using 137cs and tephrochronology the physical variables showed that all points contained mainly silt except for two points close to the river mouths where the mean diameter was

interpreting the 137cs profiles observed in several small lakes and reservoirs in southern england abstract the depth distribution of bomb derived 137cs has been studied in cores collected from five small lakes and reservoirs with high sediment accumulation rates in southern england an empirical approach was employed to demonstrate the influence of the catchment derived 137cs input and the post depositional redistribution of 137cs on the 131cs profiles of the sediment cores by incorporating the remobilisation of 137cs and deposited sediment a catchment related 137cs lake deposition model has been used to interpret the 137cs inventories and concentrations in the lake and reservoir sediments in terms of sediment sources a clear linkage between the 137cs concentration in the lake sediment and that in catchment source soils has been established for the five water bodies estimates of the proportion of the total 137cs inventory of individual sediment cores derived from the catchments ranged between 57 and 97 these values emphasise the importance of the catchment derived contribution to the overall 137cs inventory of sediments in small lakes and reservoirs receiving significant sediment inputs from their catchments the estimates of sedimentation rates for the water bodies provided by the cores were also used to estimate the sediment yields from their respective catchments