Active heat pulse sensing of 3-D-flow fields in streambeds

Abstract. Profiles of temperature time series are commonly used to determine hyporheic flow patterns and hydraulic dynamics in the streambed sediments. Although hyporheic flows are 3-D, past research has focused on determining the magnitude of the vertical flow component and how this varies spatially. This study used a portable 56-sensor, 3-D temperature array with three heat pulse sources to measure the flow direction and magnitude up to 200 mm below the water–sediment interface. Short, 1 min heat pulses were injected at one of the three heat sources and the temperature response was monitored over a period of 30 min. Breakthrough curves from each of the sensors were analysed using a heat transport equation. Parameter estimation and uncertainty analysis was undertaken using the differential evolution adaptive metropolis (DREAM) algorithm, an adaption of the Markov chain Monte Carlo method, to estimate the flux and its orientation. Measurements were conducted in the field and in a sand tank under an extensive range of controlled hydraulic conditions to validate the method. The use of short-duration heat pulses provided a rapid, accurate assessment technique for determining dynamic and multi-directional flow patterns in the hyporheic zone and is a basis for improved understanding of biogeochemical processes at the water–streambed interface.

Download Full-text

Active heat pulse sensing of 3D-flow fields in streambeds

10.5194/hess-2017-582 ◽

2017 ◽

Author(s):

Eddie W. Banks ◽

Margaret A. Shanafield ◽

Saskia Noorduijn ◽

James McCallum ◽

Jörg Lewandowski ◽

...

Keyword(s):

Hyporheic Zone ◽

Flow Direction ◽

Temperature Response ◽

Past Research ◽

Flow Patterns ◽

Heat Pulse ◽

Breakthrough Curves ◽

Hyporheic Flow ◽

Heat Pulses ◽

Streambed Sediments

Abstract. Profiles of temperature time series are commonly used to determine hyporheic flow patterns and hydraulic dynamics in the streambed sediments. Although hyporheic flows are 3D, past research has focused on determining the magnitude of the vertical flow component and how this varies spatially. This study used a portable 56 sensor, 3D temperature array with 3 heat pulse sources to measure the flow direction and magnitude up to 200 mm below the water-sediment interface. Short, one-minute heat pulses were injected at one of the three heat sources and the temperature response was monitored over a period of 30 minutes. Breakthrough curves from each of the sensors were analyzed using a heat transport equation. Parameter estimation and uncertainty analysis was undertaken using the DREAM algorithm, an adaption of the Markov chain Monte Carlo method, to estimate the flux and its orientation. Measurements were conducted in the field and in a sand tank under an extensive range of controlled hydraulic conditions to validate the method. The use of short duration heat pulses provided a rapid, accurate assessment technique for determining dynamic and multi-directional flow patterns in the hyporheic zone and is a basis for improved understanding of biogeochemical processes at the water-streambed interface.

Download Full-text

The Effect of Stream Discharge on Hyporheic Exchange

Water ◽

10.3390/w11071436 ◽

2019 ◽

Vol 11 (7) ◽

pp. 1436 ◽

Cited By ~ 4

Author(s):

Brian Babak Mojarrad ◽

Andrea Betterle ◽

Tanu Singh ◽

Carolina Olid ◽

Anders Wörman

Keyword(s):

Hyporheic Zone ◽

Hyporheic Exchange ◽

Subsurface Water ◽

Stream Discharge ◽

Hyporheic Flow ◽

Sediment Permeability ◽

Natural Tracer ◽

Streambed Sediments ◽

The Impact ◽

Numerical Approaches

Streambed morphology, streamflow dynamics, and the heterogeneity of streambed sediments critically controls the interaction between surface water and groundwater. The present study investigated the impact of different flow regimes on hyporheic exchange in a boreal stream in northern Sweden using experimental and numerical approaches. Low-, base-, and high-flow discharges were simulated by regulating the streamflow upstream in the study area, and temperature was used as the natural tracer to monitor the impact of the different flow discharges on hyporheic exchange fluxes in stretches of stream featuring gaining and losing conditions. A numerical model was developed using geomorphological and hydrological properties of the stream and was then used to perform a detailed analysis of the subsurface water flow. Additionally, the impact of heterogeneity in sediment permeability on hyporheic exchange fluxes was investigated. Both the experimental and modelling results show that temporally increasing flow resulted in a larger (deeper) extent of the hyporheic zone as well as longer hyporheic flow residence times. However, the result of the numerical analysis is strongly controlled by heterogeneity in sediment permeability. In particular, for homogeneous sediments, the fragmentation of upwelling length substantially varies with streamflow dynamics due to the contribution of deeper fluxes.

Download Full-text

Quantifying microplastic particle transport and retention in an experimental flume environment

10.5194/egusphere-egu21-14789 ◽

2021 ◽

Author(s):

Jan-Pascal Boos ◽

Benjamin Gilfedder ◽

Sven Frei

Keyword(s):

Particle Transport ◽

Solid Phase ◽

River Sediments ◽

Time Resolved ◽

Fluvial Systems ◽

Particle Mobility ◽

Hyporheic Flow ◽

Scale Experiment ◽

Streambed Sediments ◽

Experimental Flume

Rivers and streams are the dominant transport vectors for microplastic (MP) input into marine environments. During transport, complex physicochemical interactions between particles, water and river sediments influence particle mobility and retention. The specific transport mechanisms of MP in fluvial systems are not yet fully understood, and the main reason lies in the limitation in reliable data derived from experimental analysis.In our subproject of the &#8216;CRC 1357 Microplastics&#8217;, we investigate the hydrodynamic mechanisms that control the transport and retention behavior of MP in open channel flows and streambed sediments. In an experimental flume environment, we create realistic hydrodynamic and hyporheic flow conditions by using various porous media (e.g. glass beads or sand) and bedform structures (e.g. riffle-pool sequences, ripples and dunes), modelled from real stream systems.The method developed here can quantitatively analyze the transport of pore-scale particles (1-40 &#181;m) based on fluorometric techniques. Particle velocity distributions and particle transport are measured using Particle-Image-Velocimetry and Laser-Doppler-Velocimetry. With our setup, we can quantitatively investigate time-resolved MP transport and retention through the aqueous and solid phase in a flume scale experiment.

Download Full-text

Insight into the influence of local streambed heterogeneity on hyporheic-zone flow characteristics

Hydrogeology Journal ◽

10.1007/s10040-020-02244-5 ◽

2020 ◽

Vol 28 (8) ◽

pp. 2697-2712

Author(s):

Robert Earon ◽

Joakim Riml ◽

Liwen Wu ◽

Bo Olofsson

Keyword(s):

Surface Water ◽

Hydraulic Conductivity ◽

Penetration Depth ◽

Hyporheic Zone ◽

Flow Characteristics ◽

Time Lapse ◽

Hyporheic Exchange ◽

Tracer Injection ◽

Hyporheic Flow ◽

Exchange Processes

AbstractInteraction between surface water and groundwater plays a fundamental role in influencing aquatic chemistry, where hyporheic exchange processes, distribution of flow paths and residence times within the hyporheic zone will influence the transport of mass and energy in the surface-water/groundwater system. Geomorphological conditions greatly influence hyporheic exchange, and heterogeneities such as rocks and clay lenses will be a key factor for delineating the hyporheic zone. Electrical resistivity tomography (ERT) and ground-penetrating radar (GPR) were used to investigate the streambed along a 6.3-m-long reach in order to characterise geological layering and distinct features which may influence parameters such as hydraulic conductivity. Time-lapse ERT measurements taken during a tracer injection demonstrated that geological features at the meter-scale played a determining role for the hyporheic flow field. The penetration depth of the tracer into the streambed sediment displayed a variable spatial pattern in areas where the presence of highly resistive anomalies was detected. In areas with more homogeneous sediments, the penetration depth was much more uniformly distributed than observed in more heterogeneous sections, demonstrating that ERT can play a vital role in identifying critical hydraulic features that may influence hyporheic exchange processes. Reciprocal ERT measurements linked variability and thus uncertainty in the modelled resistivity to the spatial locations, which also demonstrated larger variability in the tracer penetration depth, likely due to local heterogeneity in the hydraulic conductivity field.

Download Full-text

Trait-specific dispersal of bacteria in heterogeneous porous environments: from pore to porous medium scale

Journal of The Royal Society Interface ◽

10.1098/rsif.2020.0046 ◽

2020 ◽

Vol 17 (164) ◽

pp. 20200046 ◽

Cited By ~ 1

Author(s):

David Scheidweiler ◽

Filippo Miele ◽

Hannes Peter ◽

Tom J. Battin ◽

Pietro de Anna

Keyword(s):

Preferential Flow ◽

Cell Attachment ◽

Flow Direction ◽

Time Lapse ◽

Breakthrough Curves ◽

Porous System ◽

Dispersal Patterns ◽

Multi Scale ◽

Motile Cells ◽

Hydrodynamic Shear

The dispersal of organisms controls the structure and dynamics of populations and communities, and can regulate ecosystem functioning. Predicting dispersal patterns across scales is important to understand microbial life in heterogeneous porous environments such as soils and sediments. We developed a multi-scale approach, combining experiments with microfluidic devices and time-lapse microscopy to track individual bacterial trajectories and measure the overall breakthrough curves and bacterial deposition profiles: we, then, linked the two scales with a novel stochastic model. We show that motile cells of Pseudomonas putida disperse more efficiently than non-motile mutants through a designed heterogeneous porous system. Motile cells can evade flow-imposed trajectories, enabling them to explore larger pore areas than non-motile cells. While transported cells exhibited a rotation in response to hydrodynamic shear, motile cells were less susceptible to the torque, maintaining their body oriented towards the flow direction and thus changing the population velocity distribution with a significant impact on the overall transport properties. We also found, in a separate set of experiments, that if the suspension flows through a porous system already colonized by a biofilm, P. putida cells are channelled into preferential flow paths and the cell attachment rate is increased. These two effects were more pronounced for non-motile than for motile cells. Our findings suggest that motility coupled with heterogeneous flows can be beneficial to motile bacteria in confined environments as it enables them to actively explore the space for resources or evade regions with unfavourable conditions. Our study also underlines the benefit of a multi-scale approach to the study of bacterial dispersal in porous systems.

Download Full-text

Transient hyporheic exchange during rainfall events in a gaining stream: Field investigation, conceptual model, and numerical interpretation

10.5194/egusphere-egu2020-4386 ◽

2020 ◽

Author(s):

Chengpeng Lu ◽

Keyan Ji ◽

Yong Zhang ◽

Jan Fleckenstein ◽

Chunmiao Zheng ◽

...

Keyword(s):

Numerical Modeling ◽

Conceptual Model ◽

Hyporheic Zone ◽

Flow Model ◽

Surface Flow ◽

Hyporheic Exchange ◽

Biogeochemical Processes ◽

Cross Sectional ◽

Rainfall Events ◽

Hyporheic Flow

Hyporheic exchange is transient in nature, considering the temporal fluctuations in hydrological and/or biogeochemical conditions in surface water and groundwater (SW/GW).&#160; Efforts are needed to further identify the patterns and driving mechanisms of transient hyporheic exchange.&#160; This study combined a reach-scale field survey and numerical modeling analysis to reveal the pattern of transient hyporheic exchange during rainfall events in the Zhongtian River, southeast of China. Field observations revealed hydrodynamic properties and temperature variations in SW/GW, suggesting that the regional groundwater recharged the study reach.&#160; A one-dimensional heat transport solution was built and used to generate the planar and cross-sectional hyporheic flow fields. A two-step numerical modeling procedure, including a hydraulic surface flow model and a groundwater flow model, was then used to simulate the observed flow system. The hyporheic exchange exhibited strong temporal evolution, as indicated by the rainfall event-driven hyporheic exchange, the depth-dependent hysteretic response to rainfall, and the area of local downwelling flow increasing with rainfall. Dynamics of the hyporheic exchange in the study reach, therefore, significantly changed in space and time due to rainfall. The reversal of hydraulic gradient and transient hyporheic exchange were observed and validated using the numerical simulation. Anisotropic hydraulic conductivity is the key to generate transient hyporheic exchange. A revised conceptual model was used to interpret the observed temporal patterns in hyporheic exchange &#160;The pattern of transient hyporheic exchange indicates that transient hyporheic exchange only appears after an increased phase of river stage but does not last for a long time. The temporal pattern of hyporheic exchange can significantly affect the evolution of biogeochemical processes in the hyporheic zone for a gaining stream by, for example, temporally facilitating special biogeochemical processes.

Download Full-text

Heat-pulse propagation along nonequilibrium nanowires in thermomass theory

Communications in Applied and Industrial Mathematics ◽

10.1515/caim-2016-0005 ◽

2016 ◽

Vol 7 (2) ◽

pp. 39-55

Author(s):

Antonio Sellitto ◽

Patrizia Rogolino ◽

Isabella Carlomagno

Keyword(s):

Temperature Gradient ◽

Transport Equation ◽

Heat Transport ◽

Pulse Propagation ◽

Heat Pulse ◽

Average Temperature ◽

Temperature Ranges ◽

Heat Transport Equation ◽

Heat Pulses ◽

Theoretical Proposal

AbstractWe analyze the consequences of the nonlinear terms in the heat-transport equation of the thermomass theory on heat pulses propagating in a nanowire in nonequilibrium situations. As a consequence of the temperature dependence of the speeds of propagation, in temperature ranges wherein the specific heat shows negligible variations, heat pulses will shrink (or extend) spatially, and will increase (or decrease) their average temperature when propagating along a temperature gradient. A comparison with the results predicted by a different theoretical proposal on the shape of a propagating heat pulse is made, too.

Download Full-text

Indocyanine green videoangiography for recipient vessel stratification in superficial temporal artery–middle cerebral artery bypass surgery

Journal of Neurosurgery ◽

10.3171/2020.5.jns20642 ◽

2020 ◽

pp. 1-9

Author(s):

Johannes Goldberg ◽

Peter Vajkoczy ◽

Nils Hecht

Keyword(s):

Blood Flow ◽

White Light ◽

Bypass Surgery ◽

Flow Direction ◽

Superficial Temporal Artery ◽

Flow Patterns ◽

Low Flow ◽

Indocyanine Green Videoangiography ◽

Recipient Vessel ◽

Potential Recipient

OBJECTIVEIn superficial temporal artery–middle cerebral artery (STA-MCA) bypass surgery, recipient vessel properties are likely one of the main reasons for bypass failure. In daily practice, most surgeons select the recipient with the largest diameter. However, selection of the ideal recipient remains debatable because there are no objective selection criteria if multiple potential recipients exist. Here, the authors assessed the benefit of using indocyanine green videoangiography (ICG-VA) to optimize recipient vessel selection in patients undergoing STA-MCA bypass surgery for hemodynamic compromise.METHODSAll patients who had undergone STA-MCA bypass procedures with pre- and postanastomosis ICG-VA between 2010 and 2019 were eligible for inclusion in this study. The primary bypass surgeon was blinded to the preanastomosis ICG-VA. Preanastomosis white-light and ICG-VA images were compared to determine the identifiability of potential recipient vessels and pathological flow patterns. After completion of the anastomosis, a second (postanastomosis) ICG-VA image was used to analyze the flow increase within the chosen recipient based on the vessel diameter, initial recipient blood flow, initial sequence of appearance on ICG-VA, initial blood flow direction within the recipient, and orientation of the bypass graft. ICG-VA, FLOW 800, and intraoperative white-light images, as well as demographic, clinical, and radiographic patient data, were retrospectively analyzed by a clinician who was not directly involved in the patients’ care.RESULTSSixty patients underwent 65 STA-MCA bypass procedures with pre- and postanastomosis ICG-VA. The ICG-VA permitted identification of a significantly higher number of potential recipient vessels (median 4, range 1–9) than the white-light images (median 2, range 1–5; p < 0.001), with detection of pathological flow patterns in 20% of all procedures. No association was found between the diameter and blood flow within potential recipients (Spearman r = 0.07, p = 0.69). After bypass grafting, the highest flow increase was noted in recipients with an initially low flow (p < 0.01), a late appearance (p < 0.01), and an initially retrograde flow direction (p = 0.02). Interestingly, flow increase was not significantly influenced by the recipient diameter (p = 0.09) or graft orientation (p = 0.44).CONCLUSIONSICG-VA facilitates identification of potential recipient vessels and detection of pathological flow patterns. Recipients with an initially low flow, a late appearance, and a retrograde flow seem to bear the highest potential for flow increase, possibly due to a higher hemodynamic need for revascularization.

Download Full-text

Influence of Streambed Heterogeneity on Hyporheic Flow and Sorptive Solute Transport

Water ◽

10.3390/w12061547 ◽

2020 ◽

Vol 12 (6) ◽

pp. 1547 ◽

Cited By ~ 1

Author(s):

Yuanhong Liu ◽

Corey D. Wallace ◽

Yaoquan Zhou ◽

Reza Ershadnia ◽

Faranak Behzadi ◽

...

Keyword(s):

Solute Transport ◽

Hyporheic Zone ◽

Preferential Flow ◽

Hyporheic Exchange ◽

Sorptive Capacity ◽

Hyporheic Flow ◽

Sedimentary Architecture ◽

Mixing Dynamics ◽

Facies Types ◽

Sediment Heterogeneity

The subsurface region where river water and groundwater actively mix (the hyporheic zone) plays an important role in conservative and reactive solute transport along rivers. Deposits of high-conductivity (K) sediments along rivers can strongly control hyporheic processes by channeling flow along preferential flow paths wherever they intersect the channel boundary. Our goal is to understand how sediment heterogeneity influences conservative and sorptive solute transport within hyporheic zones containing high- and low-K sediment facies types. The sedimentary architecture of high-K facies is modeled using commonly observed characteristics (e.g., volume proportion and mean length), and their spatial connectivity is quantified to evaluate its effect on hyporheic mixing dynamics. Numerical simulations incorporate physical and chemical heterogeneity by representing spatial variability in both K and in the sediment sorption distribution coefficient ( K d ). Sediment heterogeneity significantly enhances hyporheic exchange and skews solute breakthrough behavior, while in homogeneous sediments, interfacial flux and solute transport are instead controlled by geomorphology and local-scale riverbed topographies. The hyporheic zone is compressed in sediments with high sorptive capacity, which limits solute interactions to only a small portion of the sedimentary architecture and thus increases retention. Our results have practical implications for groundwater quality, including remediation strategies for contaminants of emerging concern.

Download Full-text

About the Dependence of Breakthrough Curves on Flow Direction in Column Experiments of Transport across a Sharp Interface Separating Different Porous Materials

Geofluids ◽

10.1155/2019/8348175 ◽

2019 ◽

Vol 2019 ◽

pp. 1-8

Author(s):

Francesca Giacobbo ◽

Mauro Giudici ◽

Mirko Da Ros

Keyword(s):

Porous Materials ◽

Flow Direction ◽

Breakthrough Curves ◽

Coarse Grained ◽

Low Flow ◽

Flow Rates ◽

Fine Grained ◽

The Past ◽

Asymmetric Behaviour ◽

Flow Through

Conservative transport experiments with layered porous materials (coarse-grained vs. fine-grained) were performed through experimental cylindrical columns to assess the possible occurrence of interface processes at the discontinuity between media with different hydrodynamic and hydrodispersive properties, as proposed by some authors in the past based on modelling and experimental results. The outcomes of the present work show that, under certain conditions, the breakthrough curves (BTCs) obtained for flow through the coarse-grained and then through the fine-grained media (CtF) or vice versa (FtC) can differ. More specifically, an asymmetric behaviour is observed for cases when the ratio between the column and grain diameters is small. Moreover, the discrepancies between CtF and FtC BTCs are enhanced for low flow rates and low quantity of injected solute.

Download Full-text