local scale variability of seepage and hydraulic conductivity in a shallow gravel bed river seepage rate and direction measured with a seepage metre modified for use in flowing water were greatly variable along a 300 m reach of a shallow gravel bed river and depended primarily on the local scale bed topography the median value of seepage measured at 24 locations was 24 cm day but seepage measured at specific sites ranged from 340 to 237 cm day seepage also varied substantially over periods of hours to days and occasionally reversed direction in response to evolution of the sediment bed vertical hydraulic conductivity was related to seepage direction and was larger during upward seepage than during downward seepage with differences ranging from 4 to 40 in areas of active sediment transport to more than an order of magnitude in areas where current was too slow to mobilize bed sediment seepage was poorly related to hydraulic gradient measured over vertical distances of 0 3 m and appeared to be opposite the hydraulic gradient at 18 of the locations where both parameters were measured results demonstrate the scale dependence of these measurements in coarse grained hyporheic settings and indicate that hydraulic gradients should be determined over a much shorter vertical increment if used to indicate exchange across the sediment water interface published in 2009 by john wiley sons ltd

evaluating the reliability of the stream tracer approach to characterize stream subsurface water exchange stream water was locally recharged into shallow groundwater flow paths that returned to the stream hyporheic exchange in st kevin gulch a rocky mountain stream in colorado contaminated by acid mine drainage two approaches were used to characterize hyporheic exchange sub reach scale measurement of hydraulic heads and hydraulic conductivity to compute streambed fluxes hydrometric approach and reachscale modeling of in stream solute tracer injections to determine characteristic length and timescales of exchange with storage zones stream tracer approach subsurface data were the standard of comparison used to evaluate the reliability of the stream tracer approach to characterize hyporheic exchange the reach averaged hyporheic exchange flux 1 5 ml s 1 m 1 determined by hydrometric methods was largest when stream base flow was low 10 l s 1 hyporheic exchange persisted when base flow was 10 fold higher decreasing by approximately 30 reliability of the stream tracer approach to detect hyporheic exchange was assessed using first order uncertainty analysis that considered model parameter sensitivity the stream tracer approach did not reliably characterize hyporheic exchange at high base flow the model was apparently more sensitive to exchange with surface water storage zones than with the hyporheic zone at low base flow the stream tracer approach reliably characterized exchange between the stream and gravel streambed timescale of hours but was relatively insensitive to slower exchange with deeper alluvium timescale of tens of hours that was detected by subsurface measurements the stream tracer approach was therefore not equally sensitive to all timescales of hyporheic exchange we conclude that while the stream tracer approach is an efficient means to characterize surface subsurface exchange future studies will need to more routinely consider decreasing sensitivities of tracer methods at higher base flow and a potential bias toward characterizing only a fast component of hyporheic exchange stream tracer models with multiple rate constants to consider both fast exchange with streambed gravel and slower exchange with deeper alluvium appear to be warranted

geomorphology perspectives on observation history and the field tradition abstract other than a common interest in form and process current geomorphologists have little in common with those who established the foundations of this science educated people who had an interest in earth processes during the nineteenth century cannot be compared to the scholars who study geomorphology in the twenty first century whereas earth has undergone natural change from the beginning of time the human record of observing and recording processes and changes in the surface is but a recent phenomena observation is the only thread however that connects all practitioners of geomorphology through time as people acquired knowledge related to all aspects of life technological revolutions such as the iron age bronze age agricultural revolution the atomic age and the digital age shaped human existence and thought technology has greatly changed the power of human observation including inward to the atomic scale and outward into the realm of space books and articles describe how to collect and analyze data but few references document the field experience each of us however has experienced unique circumstances during field work and we learned from various mentors how to observe the surface of earth on which we practice the vocation of geomorphology may not be much different from a hundred years ago but many things about how we collect data analyze it and disseminate the results have changed how we function in the field including what we wear what we eat how we get there and where we choose to collect data clearly reflects the complexity of the human system on earth and the processes and forms that arouse our interest computers miniaturization of electronics satellite communications and observation platforms in space provide access to data to aid in our quest to understand earth surface processes once people lived closer to nature in primitive shelters in contrast with life in urban environments but as urban life continues to expand and people need to know how earth operates geomorphologists therefore serve humanity today as the primary observers and reporters in the realm of earth surface processes

estimating streambed parameters for a disconnected river evaluation of stream aquifer interaction and water balance for a catchment often requires specific information on streambed parameters such as streambed hydraulic conductivity seepage flux across the streambed and so on this paper describes a simple inexpensive instrument that is used to measure these streambed parameters under the condition of a stream disconnected from groundwater our method includes a seepage cylinder for simulation of river water depth the proposed method was applied to estimate the vertical hydraulic conductivity of a streambed and the changes in vertical seepage rate from stream to groundwater with varied stream water depth in the manasi river of xinjiang uygur autonomous region china the vertical hydraulic conductivities of the streambed determined from 12 sites along the manasi river vary from 1 01 to 29 m day where the stream disconnects from the groundwater the experimental results suggest that there are two kinds of relations between the vertical seepage rate and the simulated stream water depth one is a linear relation between the two variables with low reynolds numbers less than 10 the other is a nonlinear relation exponential relation between the two variables with larger reynolds numbers greater than 10 this second relationship is quite different from the traditional model that usually calculates the vertical seepage rate from stream to groundwater under the condition of disconnection using a linear relation darcy s law our results suggest that a linear relation can only be used for a limited range of river water depth this method gives a convenient tool for rapidly estimating the streambed hydraulic conductivity and the changes in the vertical seepage rate across streambed with varied stream water depths for the case of a stream disconnected from groundwater copyright 2013 john wiley sons ltd

comparison of darcian flux calculations and seepage meter measurements in a sandy streambed in north carolina united states 1 we compared two methods for estimating groundwater flux into a stream reach seepage meters and darcian flux calculations both methods were applied at the same 53 points on the streambed of a 62 5 m long reach of west bear creek in the coastal plain of north carolina at each point a seepage meter was used to measure groundwater flux vmeter and several minutes later the streambed hydraulic conductivity k and hydraulic head gradient j were measured we compared the 53 paired point values of groundwater flux from each method vmeter and vdarcy kj the integrated volumetric groundwater flux to the stream reach from each method qdarcy and qmeter and the spatial distributions of vdarcy and vmeter on the streambed values of qmeter 268 m3 d and mean vmeter 0 66 m d were each about 0 70 the corresponding darcian flux quantities qdarcy 375 m3 d and mean vdarcy 0 92 m d despite their differences the two methods gave the same direction of groundwater flow into the stream at all 53 points a result not found in all previous comparison studies and thus not to be taken for granted also vdarcy and vmeter had similar spatial distributions on the streambed the ratio vmeter vdarcy 0 70 is within the range of 0 3 7 from previous studies and is closer to 1 than in previous studies the differences between the two methods are probably in part due to random measurement error and to the spatial scales for the darcy and seepage meter measurements being of a slightly different size and offset several centimeters from each other on the heterogeneous streambed but these effects are unlikely to produce the observed consistent bias the mean bias between the methods ratio of 0 70 may be related to gas bubbles in the streambed pore spaces e g collection of gas bubbles in the seepage meters lowering vmeter and loss of gas from the streambed upon seepage meter removal or permeameter insertion increasing the subsequent vdarcy measurement

intercomparison of submarine groundwater discharge estimates from a sandy unconfined aquifer summary recent studies suggest that chemical loading from submarine groundwater discharge sgd may rival other major sources such as rivers in many coastal areas sgd can occur as terrestrially derived typically fresh groundwater discharge or by seawater circulation through aquifer sediments because both terrestrial and recirculated seawater sgd can be significant sources of chemical loading to coastal waters appropriate methods are needed to properly assess and quantify the rates and distribution of these different inputs although many techniques exist to quantify sgd each method samples different components of sgd e g fresh versus saline discharge over different temporal and spatial scales the result is that confusion exists about how to use the different methods in this study we investigate the applicability of a variety of techniques for estimating sgd from an unconfined sandy coastal aquifer physical methods are first used to understand the spatial variability of discharge this information is then used with physical and geochemical data to estimate sgd investigative methods include direct measurement via seepage meters hydrogeologic estimation using darcy s law and tracer based estimates using radon and radium isotopes at our field site on cape cod massachusetts nearshore landward topography appears to exert a significant control on the spatial variability of fresh groundwater discharge presumably through its effects on evapotranspiration and hence recharge rates the darcy estimate of fresh sgd 4 0 m 3 m 1 d 1 is similar to a previous estimate made using a seepage meter transect that spans the seepage face radon serves as a valuable estimator of total sgd fresh plus saline 5 6 m 3 m 1 d 1 the difference between the total and fresh sgd estimates is in good agreement with the radium based sgd estimate 0 56 m 3 m 1 d 1 which primarily measures saline circulation through coastal sediments thus we conclude that the hydrogeologic estimate and radon and radium techniques are complimentary for estimating different components of total sgd at our field site

dynamic temporal patterns of nearshore seepage flux in a headwater adirondack lake abstract although seepage in lakes is known to vary as a function of precipitation and watershed characteristics temporal patterns of seepage flux over daily and weekly time scales have not been extensively studied with a concentrated effort of direct measurement of seepage in nearshore areas in this study seepage was intensively measured with seepage meters over two summers and during snowmelt in lower sylvan pond a small lake in the adirondack mountains region of new york state usa a consistent pattern of slight discharge never exceeding 105 ml m 2 h 1 was observed at three stations along a segment of the shoreline near the inlet stream a distinct temporal pattern of seepage was observed at three stations along another portion of the shoreline seepage discharged 400 ml m 2 h 1 for a portion of the summer in 1998 and then shifted to recharge 2 h 1 for the remainder of the summer a similar temporal pattern was observed again in 1999 but the transition to recharge occurred earlier and higher rates of discharge 610 ml m 2 h 1 and recharge 608 ml m 2 h 1 were recorded additionally seepage at these three stations increased after large rainfall events and a pronounced episodic increase of seepage was measured during snowmelt distinct seepage patterns along portions of the shoreline show that seepage can vary considerably within seasons and suggests a need to consider changes of seepage over time periods of days to weeks as well as among seasons and years this study demonstrates that the resolution of temporal seepage data can be important to the understanding of water fluxes to aquatic ecosystems

geomorphology the research frontier and beyond introduction there appears to be something inherent in the thought processes of modern day humans that as the calendar turns whether it be from one year to the next one decade to the next or one century to the next it is appropriate to examine what has happened in the past and contemplate what is likely to happen in the future although the circumstances of the calendar may trigger these actions there must be more justification to engaging seriously in such an exercise than just the calendar itself is such the case for geomorphology were the editors of this volume john vitek and john giardino wise in their picking our approach to the 21 st century as an appropriate point in time to consider geomorphology s research frontiers as pointed out by j b thornes 1978 geomorphology and associated scientific disciplines are undergoing rapid and accelerated development throughout the world interestingly this comment appears in the introduction of a book entitled geomorphology present problems and future prospects embleton et al 1978 certainly developments during the intervening 15 years have continued to accelerate vast changes have occurred in 1 the specific geomorphic topics studied 2 the number of scientists practicing geomorphology 3 the techniques used in geomorphic research 4 areal coverage including that of extraterrestrial bodies 5 the amount of interdisciplinary collaboration 6 the extent of international involvement 7 the number of scientific articles published 8 the number of geomorphology organizations that have been formed around the world and 9 the number of conferences devoted to geomorphologic topics indeed the conference the third international conference on geomorphology hamilton canada august 1993 at which the papers in this volume were presented represents a turning point in geomorphology following a successful regional conference in ankara turkey in 1991 it became the first international conference to be held under the auspices of the international association of geomorphologists iag iga an association that was officially founded in 1989 its founding followed many years of preparation including the holding of the first manchester england and second frankfurt germany international conferences on geomorphology at both conferences each attended by over 600 delegates from over 50 countries a cornucopia of research papers gave testimony to both the breadth and depth of geomorphologic research further they demonstrated the rapidity at which geomorphology is evolving and provided hints at what the future holds wanting to formalize such hints vitek and giardino assembled a set of papers that illustrate 1 the potentials for further development in some of geomorphology s well established subdisciplines 2 the dynamism of

denitrification in the recharge area and discharge area of a transient agricultural nitrate plume in a glacial outwash sand aquifer minnesota 1 recharge rates of nitrate no3 to groundwater beneath agricultural land commonly are greater than discharge rates of no3 in nearby streams but local controls of no3 distribution in the subsurface generally are poorly known groundwater dating cfc 3h was combined with chemical ions and gases and stable isotope n s and c analyses to resolve the effects of land use changes flow patterns and water aquifer reactions on the distributions of o2 no3 so4 and other constituents in a two dimensional vertical section leading from upland cultivated fields to a riparian wetland and stream in a glacial outwash sand aquifer near princeton minnesota within this section a plume of oxic no3 rich groundwater was present at shallow depths beneath the fields and part of the wetland but terminated before reaching the stream or the wetland surface groundwater dating and hydraulic measurements indicate travel times in the local flow system of 0 to 40 years with stratified recharge beneath the fields downward diversion of the shallow no3 bearing plume by semiconfining organic rich valley filling sediments under the wetland and upward discharge across the valley and stream bottom the concentrations and 15n values of no3 and n2 indicate that the no3 plume section was bounded in three directions by a curvilinear zone of active denitrification that limited its progress however when recalculated to remove the effects of denitrification the data also indicate changes in both the concentrations and 15n values of no3 that was recharged in the past isotope data and mass balance calculations indicate that fes2 and other ferrous fe phases were the major electron donors for denitrification in at least two settings 1 within the glacial fluvial aquifer sediments beneath the recharge and discharge areas and 2 along the bottom of the valley filling sediments in the discharge area combined results indicate that the shape and progress of the oxic no3 plume termination were controlled by a combination of 1 historical and spatial variations in land use practices 2 contrast in groundwater flow patterns between the agricultural recharge area and riparian wetland discharge area and 3 distribution and abundance of electron donors in both the sand aquifer and valley filling sediments the data are consistent with slow migration of redox zones through the aquifer in response to recharging oxic groundwater during holocene time then an order of magnitude increase in the flux of electron acceptors as a result of agricultural no3 contamination in the late twentieth century to which the redox zone configuration still may be adjusting the importance of denitrification for no3 movement through formerly glaciated terrains should depend on the source areas and depositional environments of the glacial sediments as well as geomorphology and recent stream valley sediment history

canons revisited and reviewed lester king s views of landscape evolution considered 50 years later fifty years after its publication lester king9s canons of landscape evolution is reviewed and is considered in light of subsequent trends and actual developments some of his ideas such as the role of scarp recession and the antiquity of some surfaces remain current his broad view of the world and his interest in major relief anticipated trends that are now fashionable some of his interpretations however and in particular his downgrading of the importance of structural factors and his linking of scarp retreat and pedimentation have not stood the test of time other concepts such as the etch or two stage origin of forms which were mooted but not fully appreciated in king9s day have come to the forefront and technological advances in dating and survey particularly of the ocean floors have signaled new perspectives in landscape interpretation nevertheless king9s was a courageous attempt to provide guidelines for landscape study

spatial and depth variability of streambed vertical hydraulic conductivity under the regional flow regimes this study investigated the influence of the regional flow on the streambed vertical hydraulic conductivity k v within the hyporheic zone in three stream reaches of the weihe river in july 2016 the streambed k v with two connected depths was investigated at each test reach based on the sediment characteristics the three test reaches could be divided into three categories a sandy streambed without continuous silt and clay layer a sandy streambed with continuous silt and clay layer and a silt clay streambed the results demonstrate that the streambed k v mainly decreases with the depth at the sandy streambed without continuous silt and clay layer and increases with the depth at the other two test reaches at the sandy streambed with continuous silt and clay layer where streambed k v mainly decreases with the depth the regional upward flux can suspend fine particles and enhance the pore spacing resulting in the elevated k v in the upper sediment layers at another sandy streambed the continuous silt and clay layer is the main factor that influences the vertical distribution of fine particles and streambed k v an increase in streambed k v with the depth at the silt clay streambed is attributed to the regional downward movement of water within the sediments that may lead to more fine particles deposited in the pores in the upper sediment layers the streambed k v is very close to the bank in the sandy streambed without continuous silt and clay layer and the channel centre in the other two test reaches differences in grain size distribution of the sediments at each test reach exercise a strong controlling influence on the streambed k v this study promotes the understanding of dynamics influencing the interactions between groundwater and surface water and provides guidelines to scientific water resources management for rivers

an historical look at the binghamton geomorphology symposium abstract the binghamton geomorphology symposium bgs is an annual meeting held since 1970 usually in the u s a on timely topics in the field of geomorphology a special issue of this journal presents the papers from each meeting and provides an opportunity to disseminate to the international community research relevant to that year s theme written by key people in that field in this paper we review the history of the bgs examine the academic disciplines of each year s organizers compile a list of the researchers who have made multiple contributions to bgs note the citation impact of papers published in the annual proceedings map the spatial distribution of the meeting locations and categorize the gender distribution of the contributors to the symposium contributions from female authors to the bgs have steadily increased since the 1970s however from 2003 to 2013 females still only accounted for 23 6 of the proceeding s papers an increase of 16 4 from the 1970s these numbers are not surprising when compared to the gender distribution of the top positions in specialty groups in the u s between 1989 and 2010 over 7000 citations were from articles published in bgs special issues indicating their contributions to the geomorphology field when normalized by the number of years the articles have been available papers from bgs whose themes combined geomorphology with other fields i e natural hazards and geomorphology rated higher numbers of citations the dispersion of the location of bgs meetings illustrates how the series is maturing by moving away from its origin in the u s northeast

applying fluvial geomorphology to river channel management background for progress towards a palaeohydrology protocol significant developments have been achieved in applicable and applied fluvial geomorphology as shown in publications of the last three decades analyzed as the basis for using results of studies of environmental change as a basis for management the range of types of publications and of activities are more pertinent to river channel management as a result of concern with sustainability global climate change environmental ethics ecosystem health concepts and public participation possible applications with particular reference to river channel changes include those concerned with form and process assessment of channel change urbanization channelization extractive industries impact of engineering works historical changes in land use and restoration with specific examples illustrated in table 1 in order to achieve general significance for fluvial geomorphology more theory and extension by modelling methods is needed and examples related to morphology and process characteristics integrated approaches and changes of the fluvial system are collected in table 2 the ways in which potential applications are communicated to decision makers range from applicable outputs including publications ranging from review papers book chapters and books to applied outputs which include interdisciplinary problem solving educational outreach and direct involvement with examples summarized in table 3 on the basis of results gained from investigations covering periods longer than continuous records a protocol embracing palaeohydrological inputs for application to river channel management is illustrated and developed as a synopsis version table 4 demonstrating how conclusions from geomorphological research can be expressed in a format which can be considered by managers

alpine subglacial hydrology abstract the size and shape of subglacial flow pathways exert a strong influence over the pressure and speed at which meltwaters are routed through glaciers these characteristics in turn influence glacier sliding velocity and the quantity and quality of bulk meltwaters discharging from glaciers in this paper we summarise four empirical research approaches that have been developed to improve our understanding of the subglacial hydrology of predominantly temperate based alpine glaciers investigations of bulk meltwater discharge and chemistry tracer studies proglacial bedrock investigations and borehole investigations as a result of linking these studies to conceptual or numerical models three arborescent and four non arborescent or distributed subglacial drainage configurations are described these drainage networks may be neither spatially nor temporally persistent but may compete with and replace each other on a seasonal basis a qualitative model of the temporal and spatial evolution of a typical alpine subglacial drainage system is advanced on the basis of research conducted at haut glacier d arolla switzerland

groundwater transit time distribution and mean from streambed sampling in an agricultural coastal plain watershed north carolina usa we measured groundwater apparent age and seepage rate v in a sandy streambed using point scale sampling and seepage blankets a novel seepage meter we found very similar mtt estimates from streambed point sampling in a 58 m reach 29 years and a 2 5 km reach 31 years the ttd for groundwater discharging to the stream was best fit by a gamma distribution model and was very similar for streambed point sampling in both reaches between adjacent point scale and seepage blanket samples water from the seepage blankets was generally younger largely because blanket samples contained a fraction of young stream water correcting blanket data for the stream water fraction brought estimates for most blanket samples closer to those for adjacent point samples the mtt estimates from corrected blanket data were in good agreement with those from sampling streambed points adjacent to the blankets collectively agreement among age dating tracers general accord between tracer data and piston flow model curves and large groundwater age gradients in the streambed suggested that the piston flow apparent ages were reasonable estimates of the groundwater transit times for most samples overall our results from two field campaigns suggest that groundwater collected in the streambed can provide reasonable estimates of apparent age of groundwater discharge and that mtt can be determined from different age dating tracers and by sampling with different groundwater collection devices coupled streambed point measurements of groundwater age and groundwater seepage rate represent a novel reproducible and effective approach to estimating aquifer ttd and mtt

the effect of streambed topography on surface subsurface water exchange in mountain catchments a numerical hydrological simulation suggested that water exchange between stream channels and adjacent aquifers is enhanced by convexities and concavities in streambed topography at st kevin gulch an effluent stream in the rocky mountains of colorado subsurface hydraulic gradients and movement of ionic tracers indicated that stream water was locally recharged into well defined flow paths through the alluvium stream water filled flow paths in the alluvium referred to as substream flow paths returned to the stream a short distance downstream 1 to 10 m recharge to the substream flow paths occurred where stream water slope increased at the transition from pools 1 to steeper channel units 5 20 return of substream flow paths to the stream occurred where stream water slope decreased at the transition from steeper channel units to pools a net water flux calculation is typically used to characterize water and solute fluxes between surface and subsurface zones of catchments along our study reach at st kevin gulch the net inflow of water from subsurface to stream 1 6 ml s 1 m 1 underestimated the gross inflow 2 7 ml s 1 m 1 by 40 the influence of streambed topography is to enhance hydrological fluxes between stream water and subsurface zones and to prolong water sediment contact times these effects could have important consequences for solute transport retention and transformation in catchments

air compression as a mechanism for the underdamped slug test response in fractured glacier ice 1 artificial perturbations of borehole water levels known as slug tests are a useful means of characterizing the glacier hydrologic system slug tests were performed on bench glacier alaska in 21 boreholes over three field seasons during the transition from a winter to a summer drainage mode fifty four slug tests were conducted with water level monitoring in up to five boreholes adjacent to the slugged borehole seven of the slug tests were performed in conjunction with dye dispersion tests to identify water pathways within the slugged borehole following perturbation nearly 60 of monitored adjacent boreholes showed a hydraulic connection to the slugged borehole via the glacier bed the nature and degree of connectivity was temporally variable suggesting that the drainage network at the bed was highly dynamic on a daily timescale and spatial scale of tens of meters the variability of slug test responses over time and space limit the feasibility of six alternative explanations for the oscillatory water level behavior characteristic of the underdamped response we propose a seventh that is that coherent air packages are a reasonable means of producing the compliance needed to generate the underdamped slug test responses on bench glacier and that these air packages may exist within the glacier at the tips of subglacially propagated fractures

a field investigation of groundwater surface water interaction in a fractured bedrock environment abstract to facilitate a better understanding of the exchange processes between a fractured rock aquifer and a bedrock stream a study of groundwater surface water interaction between twenty mile creek and the local aquifer in smithville ont was completed the points of interaction between the creek and the local aquifer were identified and quantified through the use of air photo interpretation detailed stream surveys electrical conductivity and temperature surveys isotopic analysis mixing calculations and point measurements of hydraulic head and discharge obtained using mini piezometers seepage meters and weirs the results indicate that the interaction between twenty mile creek and the local aquifer is extremely limited with greater than 95 of the groundwater within the study area underflowing the creek completely during baseflow conditions in addition it was observed that groundwater discharge in a bedrock stream environment occurs primarily through discrete point sources associated with open fractures as compared to more diffuse or continuous seepage zones often observed in a porous media environment the small quantity of groundwater discharging into twenty mile creek through these features has an electrical conductivity and isotopic signature consistent with shallow groundwater and most likely originates in the upper 3 7 m of bedrock although previous investigations have identified potentially open vertical fractures within the study area it is apparent that the fracture network has extremely poor vertical connections limiting groundwater exchange in the vicinity of the creek in addition the low velocity and discharge rate within the creek does not allow for incising into the bedrock as a result horizontal fractures do not play a significant role in the exchange process within the study area

estimating the groundwater contribution into florida bay via natural tracers 222rn and ch4 groundwater may represent a significant pathway for nutrients and other dissolved solutes into florida bay especially near the keys where wastewater disposal practices add large amounts of nitrogen and phosphorus to the subsurface each year previously we suggested that high water column inventories of the tracers 222rn and ch4 may be indicative of groundwater discharge in this study we employed mass balance calculations to determine that the total benthic fluxes required to maintain the measured water column tracer inventories were significantly larger than diffusive fluxes and varied between 4 2 5 6 dpm m 2 min 1 and 5 8 15 4 nmoles m 2 min 1 for 222rn and ch4 respectively independent estimates of the diffusive flux and porewater activities concentrations allowed us to calculate an advective groundwater velocity assuming that the difference between the total benthic flux given above and the diffusive flux is driven by seepage driven porewater advection these calculated velocities ranged from 0 2 to 4 3 cm d 1 for all sites tracers and sampling periods with a best estimate of approximately 1 7 cm d 1 these estimates of groundwater velocities compare very well with previous measurements of groundwater flux 1 3 cm d 1 at the same sites via seepage meters

design of a light oil piezomanometer for measurement of hydraulic head differences and collection of groundwater samples 1 this paper describes a device piezomanometer that combines three components an oil water manometer a pushable screened pvc probe and a system for groundwater sample collection into a single inexpensive 130 easily built reliable tool for rapid collection of shallow groundwater from a streambed or lake bed and accurate measurement of even very small head differences between this groundwater and overlying surface water the piezomanometer has been tested with excellent results both in the lab and in a stream shallow enough for wading in principle it could be adapted for use in deeper water where work is done from a dock boat or other platform the problem of gas bubbles collecting in the groundwater line a common drawback of field manometers was nearly eliminated by use of a three way valve at a local elevation maximum in the groundwater line gas bubbles in the groundwater line can be purged through this valve field application is illustrated here with data from a 2 day study using four piezomanometers in a north carolina stream

hydrogeological analysis of slug tests in glacier boreholes slug testing allows estimation of subglacial hydraulic properties by evaluating the response of a coupled borehole subglacial flow system to an artificial displacement of its steady state hydraulic head however existing models developed specifically for application to slug test data collected in glacier boreholes are challenging to apply in practice here we demonstrate that conventional linear methods which are relatively readily applicable and widely used in groundwater studies can also be used to estimate subglacial hydraulic properties overdamped underdamped and critically damped slug test data were recorded in fluctuating boreholes drilled to the bed of haut glacier d arolla valais switzerland we find that non linear effects in the data are negligible supporting the application of conventional hydrogeological methods results suggest that the hydraulic conductivity of the unconsolidated sediments within the area influenced by a major subglacial drainage channel is enhanced several 10 2 ms 1 typical of gravelly sand compared to areas outside the zone of influence 0 1 10 2 ms 1 typical of silty sand a distance to a flow boundary within the subglacial aquifer inferred on the basis of slug test analysis was found to coincide with the actual location of the subglacial channel sensitivity analyses reveal that uncertainties in borehole and filter radii as well as the storage coefficient of the subglacial aquifer are more likely to affect the accuracy of the hydraulic and distance estimates than uncertainties regarding the repeatability of the slug test responses and curve fitting procedures involved in the conventional hydrogeological methods

diurnal fluctuations in glacier ice deformation haut glacier d arolla switzerland mair d hubbard b nienow p willis i fischer u h 2008 diurnal fluctuations in glacier ice deformation haut glacier d arolla switzerland earth surface processes and landforms 33 8 1272 1284 sponsorship carnegie trust for the universities of scotland

borehole drainage and its implications for the investigation of glacier hydrology experiences from haut glacier d arolla switzerland studies of glacier hydrology rely increasingly on measurements made in boreholes as a basis for reconstructing the character and behaviour of subglacial drainage systems in temperate glaciers in which boreholes remain open to the atmosphere following drilling the interpretation of such data may be complicated by supraglacial or englacial water flows to and from boreholes we report on a suite of techniques used to identify borehole water sources and to reconstruct patterns of water circulation within boreholes at haut glacier d arolla switzerland results are used to define a number of borehole drainage types examples of each drainage type are presented along with the manner in which they influence interpretations of borehole water levels borehole water quality data and borehole dye traces the analysis indicates that a full understanding of possible borehole drainage modes is required for the correct interpretation of many borehole observations and that those observations provide an accurate indication of subglacial conditions only under relatively restricted circumstances copyright 2001 john wiley sons ltd

the binghamton geomorphology symposium bgs 50 years of enhancing geomorphology abstract the binghamton geomorphology symposium bgs celebrated its golden anniversary in 2019 fifty years have passed since donald r coates and marie e morisawa organized a symposium to bring geomorphologists together in a single venue as faculty members at the state university of new york they foresaw that such an event was needed to enhance the science from this small university and city in central new york ny a geomorphology event blossomed into an international event that influences geomorphic thought theory and has shaped the direction of the discipline this introductory paper sets the stage for the volume from the 50th binghamton geomorphology symposium by providing an historical perspective of the beginning growth and impact that this symposium has had and continues to have on the science of geomorphology given that a variety of topics have been covered over the years the organizers of the 50th bgs elected to have presenters address the status of the profession and to provide their perspectives on future advancements this introduction provides a brief synopsis of the presentations delivered at the 50th bgs symposium and concludes with a tribute to the two founders of the bgs donald r coates and marie e morisawa

landscape analysis and the search for geomorphic unity geomorphology has been an integral part of geological science since the inception of the geological society of america even though different investigative goals have existed continuously in the discipline the dichotomy of purpose began with the vastly different perception of landscape analysis embraced by william morris davis and g k gilbert historical and physical geomorphic studies have always been conducted simultaneously but one of these research activities has dominated the field at any given time during the first half of this century most geomorphic work was devoted to the interpretation of long term evolutionary history of regional landscapes in the past four decades however research has concentrated on the study of geomorphic processes this revised direction placed greater emphasis on the physical component of geomorphology and provided a more complete understanding of the time factor in landscape analysis historical geomorphology is now less concerned with theories of cyclic time landscape development and more involved in determining the time and sequence of shorter episodes of geomorphic disequilibrium caused by tectonism and or climate change the tenor of future research in surficial geology will require input from both physical and historical geomorphology and therefore a greater unity of purpose among geomorphologists can be expected geomorphologists will have the opportunity to provide geologists and engineers with useful data about major scientific and technical problems related to plate tectonic theory interpretation of the stratigraphic record and prediction of landform stability for environmental planning

seasonal variation in surface subsurface water exchange and lateral hyporheic area of two stream aquifer systems abstract we used two dimensional unconfined transient groundwater flow models to investigate the interface between stream and groundwater flow systems or hyporheic zone of two first order streams that drain catchments with distinctly different alluvial sediments and bedrock lithology particle tracking showed that lateral hyporheic area planimetric area of flow paths lateral to the stream that are recharged by and return to the stream with travel times of 10 days or less differed between the two study streams and varied with discharge within each system at the rio calaveras welded tuff lateral hyporheic area ranged from 1 7 to 4 m 2 over the annual cycle in the aspen creek system sandstone lateral hyporheic area 1 1 5 m 2 was restricted to roughly half of that observed at rio calaveras the size of the hyporheic zone lateral to the streams at both sites decreased by approximately 50 during high flows sensitivity analyses indicated that changes in the hydraulic conductivity of alluvial and streambed sediments and variation in recharge rates have greatest impact on the magnitude direction and spatial distribution of stream groundwater exchange

inter borehole electrical resistivity imaging of englacial drainage borchole based electrical resistivity surveys have the capacity to enhance our understanding of the structure of englacial drainage pathways in temperate ice we summarize inter borehole electrical resistivity tomography ert as currently used in hydrogeological investigations and as adapted for imaging englacial drainage ert connections were success for the first time in glacier ice following artificial mineralization of borehole waters haut glacier d arolla switzerland here two types of electrical connection were made between boreholes spaced up to 10 m apart and drilled to depths of between 20 and 60 m most tests indicated the presence of resistively homogencous ice with uniform bulk resistivities of 10 10 9 m however ert was also successfully used to identify and characterize a hydraulically conductive englacial fracture that intersected two boreholes at a depth of 13 m below the glacier surface the presence of this connecting void as suggested by drilling records and verified by dual borehole impulse testing the reconstructed tomogram for these boreholes is characterized by a background ice resistivity field of 10 9 m that is disrupted at a depth of 13 m by a sharp sub horizontal low resistivity zone 10 1 m inter borehole ert therefore has the capacity to image both uniform and fractured temperate glacier ice

seasonal variations in ice deformation and basal motion across the tongue of haut glacier d arolla switzerland records of surface motion englacial tilt and repeat inclinometry are used to determine patterns of surface internal and basal motion across the tongue of haut glacier d arolla switzerland over temporal scales ranging from days to months findings are interpreted with reference to contemporaneous measurements of subglacial water pressures and prior knowledge of the glacier s subglacial drainage system structure long term inclinometry results show pronounced extrusion flow over a subglacial drainage axis with basal velocities up to twice those measured at the glacier surface deformation profiles are more conventional away from the drainage axis with basal velocities 60 70 of surface velocities comparison of long term tilt rates from repeat inclinometry and englacial tilt meters shows close correspondence englacial tiltmeter data are used to reconstruct internal velocity profiles and to split surface velocities into internal deformation and basal motion contributions over spring summer and autumn winter periods although spatial patterns of surface movement are similar between periods patterns of internal and basal motion are not results are interpreted in terms of the location of sticky and slippery spots with temporally changing patterns of basal drag reflecting changing distributions of water pressure

effects of hyporheic processes on streambed vertical hydraulic conductivity in three rivers of nebraska 1 streambed hydraulic conductivity is of great importance in the analysis of stream aquifer interactions and stream ecosystems we investigated streambed vertical hydraulic conductivity kv with two connected depths in three rivers of nebraska our results demonstrated that streambed kv in the upper sediment layer was much higher than that in the sediment of the lower layer we speculate that hyporheic processes can result in larger streambed kv in the upper layer specifically water exchange through upwelling and downwelling zones can lead to bigger pore spaces and a more unconsolidated structure of sediments in the upper layer the upward movement of gas produced by redox processes can loosen the sediments and further enlarge pore spaces in the upper layers also permeability can increase as a result of expanded pore spaces caused by invertebrate activities in the upper part of streambed the higher kv will likely enhance exchange processes between stream and sediments

statistical and geostatistical features of streambed hydraulic conductivities in the platte river nebraska this paper presents streambed hydraulic conductivities of the platte river from south central to eastern nebraska the hydraulic conductivities were determined from river channels using permeameter tests the vertical hydraulic conductivities k v from seven test sites along this river in south central nebraska belong to one statistical population its mean value is 40 2 m d however the vertical hydraulic conductivities along four transects of the ashland test site in eastern nebraska have lower mean values are statistically different from the k v values in south central nebraska and belong to two different populations with mean values of 20 7 and 9 1 m d respectively finer sediments carried from the loup river and elkhorn river watersheds to the eastern reach of the platte river lowers the vertical hydraulic conductivity of the streambed correlation coefficients between water depth and k v values along a test transect indicates a positive correlation a larger k v usually occurs in the part of channel with deeper water experimental variograms derived from the vertical hydraulic conductivities for several transects across the channels of the platte river show periodicity of spatial correlation which likely result from periodic variation of water depth across the channels the sandy to gravelly streambed contains very local silt and clay layers spatially continuous low permeability streambed was not observed in the river channels the horizontal hydraulic conductivities were larger than the vertical hydraulic conductivities for the same test locations

in situ falling head test for hydraulic conductivity evaluation in layered sediments of an analysis derived for homogenous sediments summary the hydraulic conductivity k of streambeds is a critical variable controlling interaction of groundwater and surface water the hvorslev analysis for estimating k from falling head test data has been widely used since the 1950s but its performance in layered sandy sediments common in streams and lakes has not previously been examined our numerical simulations and laboratory experiments show that the hvorslev analysis yields accurate k values in both homogenous sediment for which the analysis was originally derived and layered deposits with low k sand over high k sand k from the hvorslev analysis deviated significantly from true k only when two conditions were present together 1 high k sand was present over low k sand and 2 the bottom of the permeameter in which k was measured was at or very near the interface between high k and low k when this combination of conditions exists simulation and laboratory sand tank results show that in situ hvorslev k underestimates the true k of the sediment within a permeameter because the falling head test is affected by low k sediment outside of below the bottom of the permeameter in simulation results the maximum underestimation occurring when the bottom of the permeameter was at the interface of high k over low k was by a factor of 0 91 0 59 and 0 12 when the high k to low k ratio was 2 10 and 100 respectively in laboratory sand tank experiments the underestimation was by a factor of about 0 83 when the high k to low k ratio was 2 3 also this underestimation of k by the hvorslev analysis was about the same whether the underlying low k layer was 2 cm or 174 cm thick 1 or 87 of the domain thickness numerical model simulations were useful in the interpretation of in situ field k profiles at streambed sites with layering specifically scaling the model results to the maximum measured k at the top of the field k profiles helped constrain the likely ratio of high k to low k at field locations with layered heterogeneity vertical k values are important in field studies of groundwater surface water interaction and the hvorslev analysis can be a useful tool even in layered media when applied carefully

the influence of local hydrogeologic forcings on near stream event water recharge and retention upper san pedro river arizona the rise in stream stage during high flow events floods can induce losing stream conditions even along stream reaches that are gaining during baseflow conditions the aquifer response to flood events can affect the geochemical composition of both near stream groundwater and post event streamflow but the amount and persistence of recharged floodwater may differ as a function of local hydrogeologic forcings as a result this study focuses on how vertical flood recharge varies under different hydrogeologic forcings and the significance that recharge processes can have on groundwater and streamflow composition after floods river and shallow groundwater samples were collected along three reaches of the upper san pedro river arizona usa before during and after the 2009 and 2010 summer monsoon seasons tracer data from these samples indicate that subsurface floodwater propagation and residence times are strongly controlled by the direction and magnitude of the dominant stream aquifer gradient a reach that is typically strongly gaining shows minimal floodwater retention shortly after large events whereas the moderately gaining and losing reaches can retain recharged floodwater from smaller events for longer periods the moderately gaining reach likely returned flood recharge to the river as flow declined these results indicate that reach scale differences in hydrogeologic forcing can control i the amount of local flood recharge during events and ii the duration of its subsurface retention and possible return to the stream during low flow periods our observations also suggest that the presence of floodwater in year round baseflow is not due to long term storage beneath the streambed along predominantly gaining reaches so three alternative mechanisms are suggested i repeated flooding that drives lateral redistribution of previously recharged floodwater ii vertical recharge on the floodplain during overbank flow events and iii temporal variability in the stream aquifer gradient due to seasonally varying water demands of riparian vegetation copyright 2011 john wiley sons ltd

hydrological controls on patterns of surface internal and basal motion during three spring events haut glacier d arolla switzerland three early melt season high velocity events or spring events occurred on haut glacier d arolla switzerland during the melt seasons of 1998 and 1999 the events involve enhanced glacier velocity during periods of rapidly increasing bulk discharge in the proglacial stream and high subglacial water pressures however differences in spatial patterns of surface velocity internal ice deformation rates the spatial extent of high subglacial water pressures and in rates of subglacial sediment deformation suggest different hydrological and mechanical controls the data from two of the events suggest widespread ice bed decoupling particularly along a subglacial drainage axis creating the highest rates of basal motion and plug flow in the overlying ice the other event showed evidence of less extensive ice bed decoupling and sliding along the drainage axis with more mechanical support for ice overburden transferred to areas adjacent to decoupled areas we suggest that 1 plug flow may be a common feature on glaciers experiencing locally induced reductions in basal drag 2 under certain circumstances enhanced surface motion may be due in part to non locally forced enhanced bed deformation and 3 subglacial sediment deformation is confined to a depth of the order of centimetres to decimetres

an integrated approach to quantify groundwater transport of phosphorus to narrow lake alberta an integrated approach was used to quantify groundwater phosphorus flux to narrow lake a smallglacial terrain lake in central alberta data from a drilling program major ion concentrations environmental isotopes and computer simulations indicated that the lake gains water through the nearshore region from a small shallow groundwater flow system at deep offshore regions water moves from the lake to the groundwater flow system seepage flux was quantified by water budget darcy s equation with data from wells near the lake darcy s equation with data from minipiezometers in the lake and seepage meters whole lake seepage flux determined from minipiezometer data 30 mm yr i was only lo 25 of the other estimates mean 221 mm yr i range 133 332 mm yr l from seepage meter and water budget data respectively groundwater contributed 30 of the annual water load to the lake the p concentration pi in pore water from lake sediments mean 175 mg m was 8 times higher than groundwater from wells near the lake mean 2 1 mg m 3 thus if well water was used to estimate the p of the seepage water the rate of groundwater p loading to the lake would be underestimated the rate of groundwater p loading to the lake computed from average seepage flux and average pore water p was 39 mg m 2 yr i and groundwater may be the largest single source of p to epilimnetic water in the lake