scholarly journals The Effect of Stream Discharge on Hyporheic Exchange

Water ◽  
2019 ◽  
Vol 11 (7) ◽  
pp. 1436 ◽  
Author(s):  
Brian Babak Mojarrad ◽  
Andrea Betterle ◽  
Tanu Singh ◽  
Carolina Olid ◽  
Anders Wörman

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.

2020 ◽  
Vol 28 (8) ◽  
pp. 2697-2712
Author(s):  
Robert Earon ◽  
Joakim Riml ◽  
Liwen Wu ◽  
Bo Olofsson

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.


2020 ◽  
Author(s):  
Chengpeng Lu ◽  
Keyan Ji ◽  
Yong Zhang ◽  
Jan Fleckenstein ◽  
Chunmiao Zheng ◽  
...  

<p>Hyporheic exchange is transient in nature, considering the temporal fluctuations in hydrological and/or biogeochemical conditions in surface water and groundwater (SW/GW).  Efforts are needed to further identify the patterns and driving mechanisms of transient hyporheic exchange.  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.  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  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.</p>


Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1547 ◽  
Author(s):  
Yuanhong Liu ◽  
Corey D. Wallace ◽  
Yaoquan Zhou ◽  
Reza Ershadnia ◽  
Faranak Behzadi ◽  
...  

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.


2018 ◽  
Vol 22 (3) ◽  
pp. 1917-1929 ◽  
Author(s):  
Eddie W. Banks ◽  
Margaret A. Shanafield ◽  
Saskia Noorduijn ◽  
James McCallum ◽  
Jörg Lewandowski ◽  
...  

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.


2017 ◽  
Author(s):  
Eddie W. Banks ◽  
Margaret A. Shanafield ◽  
Saskia Noorduijn ◽  
James McCallum ◽  
Jörg Lewandowski ◽  
...  

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.


2021 ◽  
Vol 80 (6) ◽  
Author(s):  
Andrea Betterle ◽  
Anna Jaeger ◽  
Malte Posselt ◽  
Claudia Coll ◽  
Jonathan P. Benskin ◽  
...  

AbstractHyporheic exchange (HE) contributes to the biogeochemical turnover of macro- and micro-pollutants in rivers. However, the spatiotemporal complexity and variability of HE hinder understanding of its role in the overall functioning of riverine ecosystems. The present study focuses on investigating the role of bacterial diversity and sediment morphology on HE using a multi-flume experiment. A fully coupled surface–subsurface numerical model was used to highlight complex exchange patterns between surface water and the underlying flow field in the sediments. Under the experimental conditions, the surface water flow induced by bedforms has a prominent effect on both local trajectories and residence time distributions of hyporheic flow paths, whereas mean hyporheic retention times are mainly modulated by average surface flowrates. In case of complex bedform morphologies, the numerical model successfully reproduces the HE estimated by means of salt dilution tests. However, the 2D numerical representation of the system falls short in predicting HE in absence of bedforms, highlighting the intrinsic complexity of water circulation patterns in real scenarios. Finally, results show that higher bacterial diversities in the stream sediments can significantly reduce hyporheic fluxes. This work provides a framework to interpret micropollutants turnover in light of the underlying physical transport processes in the hyporheic zone. The study emphasizes the importance of better understanding the tradeoff between physically driven transport processes and bacterial dynamics in the hyporheic zone to quantify the fate of pollutants in streams and rivers.


Water ◽  
2019 ◽  
Vol 11 (4) ◽  
pp. 665 ◽  
Author(s):  
Jie Ren ◽  
Xiuping Wang ◽  
Yinjun Zhou ◽  
Bo Chen ◽  
Lili Men

The hyporheic zone is a transition zone for the exchange of matter and energy between surface water and subsurface water. The study of trends and sensitivities of bed hyporheic exchanges to the various influencing factors is of great significance. The surface−groundwater flow process was simulated using a multiphysics computational fluid dynamics (CFD) method and compared to previous flume experiments. Based on that, the single-factor effects of flow velocity (u), water depth (H), dune wave height (h), and bed substrate permeability (κ) on hyporheic exchange in the bed hyporheic zone were investigated. The sensitivity analysis of various factors (H, u, dune wavelength (L), h, bed substrate porosity (θ), κ, and the diffusion coefficient of solute molecules (Dm)) in the surface−subsurface water coupling model was done using orthogonal tests. The results indicated that u, h, and κ were positively related, whereas H was negatively related to hyporheic exchange. H and u showed large effects, whereas κ, Dm, and θ had moderate effects, and L and h showed small effects on hyporheic exchange. This study provides valuable references for the protection and recovery of river ecology.


2018 ◽  
Author(s):  
Wenqing Shi ◽  
Qiuwen Chen ◽  
Jianyun Zhang ◽  
Cheng Chen ◽  
Yuchen Chen ◽  
...  

Abstract. In dammed rivers, sediment accumulation creates potential methane emission hotspots, which have been extensively studied in forebays. However, methane emissions from sidebays remain poorly understood. We investigated methane emissions from a sediment-deposited island situated in the sidebay of the Manwan Reservoir, Lancang-Mekong River. High methane emissions (maximum 10.4 mg h−1 m−2) were observed at the island center, while a ring-like zone of low-to-negative methane emission was discovered around the island edge, whose flux varied between −0.2–1.6 mg h−1 m−2. The ring-like zone accounted for 89.1 % of the island area, of which 9.1 % was a methane sink zone. Microbial processes in the hyporheic zone, regulated by hydrological variations, were responsible for the low methane flux in this area. Under reservoir operation, frequent water level fluctuations enhanced hyporheic exchange and created redox gradients along the hyporheic flow path. Dissolved oxygen in hyporheic water decreased from 4.80 mg L−1 at the island bank edge to 0.43 mg L−1 at the center, which in turn decreased methanogen abundance for methane production and increased methanotroph abundance for methane oxidation at the ring-like zone. This study adds to our understanding of methane emissions from dammed rivers and helps to screen efficient strategies for future mitigation of the global warming effects of hydropower systems.


2006 ◽  
Vol 63 (1) ◽  
pp. 120-133 ◽  
Author(s):  
Tamao Kasahara ◽  
Alan R Hill

Stream restoration projects that aim to rehabilitate ecosystem health have not considered surface–subsurface linkages, although stream water and groundwater interaction has an important role in sustaining stream ecosystem functions. The present study examined the effect of constructed riffles and a step on hyporheic exchange flow and chemistry in restored reaches of several N-rich agricultural and urban streams in southern Ontario. Hydrometric data collected from a network of piezometers and conservative tracer releases indicated that the constructed riffles and steps were effective in inducing hyporheic exchange. However, despite the use of cobbles and boulders in the riffle construction, high stream dissolved oxygen (DO) concentrations were depleted rapidly with depth into the hyporheic zones. Differences between observed and predicted nitrate concentrations based on conservative ion concentration patterns indicated that these hyporheic zones were also nitrate sinks. Zones of low hydraulic conductivity and the occurrence of interstitial fines in the restored cobble-boulder layers suggest that siltation and clogging of the streambed may reduce the downwelling of oxygen- and nitrate-rich stream water. Increases in streambed DO levels and enhancement of habitat for hyporheic fauna that result from riffle–step construction projects may only be temporary in streams that receive increased sediment and nutrient inputs from urban areas and croplands.


2021 ◽  
Author(s):  
Océane Gilibert ◽  
Dan Tam Costa ◽  
Sabine Sauvage ◽  
Didier Orange ◽  
Yvan Capowiez ◽  
...  

<p>Wetlands are known for their natural service of water quality regulation. The hyporheic zones of the rivers filter and purify the surface water from the stream and infiltrated waters in soil nearby through the riparian zone. This purification service occurs because of a synergy between the substrate and its biodiversity (including plants, bacteria and other invertebrates). Our study deals with constructed wetlands (CW) as a nature-based solution mimicking wetlands water purification process, to purify wastewaters. The REUSE technology of CW is based on the use of specific layers of gravels and sands inside a close concrete structure, planted with specific sub-aquatic plants, where wastewaters or runoff of stormwaters are introduced to be filtered. The technology of Vertical Flow Constructed Wetlands (VFCW) reproduces the water flux observed in the riparian zone with a gravity flow of water. It is composed of reeds planted on a sandy layer (Ø 0-4 mm) and succession of gravel layers. This substrate can be saturated or unsaturated to reproduce the functioning of the hyporheic zone or the riparian zone respectively. By the time, the substrate is colonized by a community of bacteria producing biofilms which capture the residual organic matter from wastewaters to mineralize them. However, the VFCW substrates tend to clog over time due to the accumulation of organic matter and biofilms. Many studies consider earthworms as one of the solutions to alleviate this clogging, thanks to their burrows recreating macropores and preferential channels which help to improve the dispersion of water into the deep soil. The main goal of this study is to assess the impact of earthworm activities on the hydraulic conductivity of columns composed with the same substrate used in the VFCW. Different densities of earthworms (Eisenia fetida) were introduced (0, 100, 500, 1000 g of earthworms/m²) in these columns to be monitored for 37 days. The hydraulic conductivity was measured every 7 days, aside from day 23 with the addition of 40 g of peat bedding on column surfaces to simulate a high organic matter input. Columns with earthworm density superior to 500 g/m² shows an amelioration of their hydraulic conductivity after 21 days. These densities are also able to restore the hydraulic conductivity of the column in less than 7 days after the setting of clogged condition due to the organic matter input (peat bedding) at the sediment surface. This study showed that the burrowing activity of E. fetida improves the hydraulic flux of a sandy substrate and this impact is dependent on the earthworm density introduced. So, the addition of earthworms in the VFCW could serve as a prevention against clogging.</p>


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