Mapping increases in hyporheic exchange from channel-spanning logjams

<p>Logjams increase hydraulic resistance and create hydraulic head gradients along the streambed that drive groundwater-surface water exchange. Here, we quantify changes in hyporheic exchange flow due to channel-spanning logjams using field measurements and numerical modeling in MODFLOW and MT3DMS. Electrical resistivity (ER) imaging was used to monitor the transport of solutes into the hyporheic zone during a series of in-stream tracer tests supplemented by in-stream monitoring. We conducted experiments in a variety of reaches in Little Beaver Creek, Colorado (USA) of varying complexity: a control reach with no logjams, a reach with a single, channel-spanning logjam, and additional jams with greater logjam complexity. Our results show that 1) higher hyporheic exchange flow occurs at reach with logjams, 2) logjams create complex hyporheic exchange flow pathways that can cause bimodal solute breakthrough behavior downstream, and 3) higher discharge rates associated with spring snowmelt increase the extent and magnitude of hyporheic exchange flow. The numerical modeling supports all three field findings, and also suggest that lower flows increase solute retention in streams, although this last conclusion is not strongly supported by field results. This study represents the first use of ER to explore hyporheic exchange flow around a naturally occurring logjam over different stream discharges and has implications for understanding how logjams influence the transport of solutes, the health of stream ecosystems, and stream restoration and conservation efforts.</p>

Download Full-text

Effects of rifflestep restoration on hyporheic zone chemistry in N-rich lowland streams

Canadian Journal of Fisheries and Aquatic Sciences ◽

10.1139/f05-199 ◽

2006 ◽

Vol 63 (1) ◽

pp. 120-133 ◽

Cited By ~ 86

Author(s):

Tamao Kasahara ◽

Alan R Hill

Keyword(s):

Urban Areas ◽

Hyporheic Zone ◽

Stream Water ◽

Ion Concentration ◽

Hyporheic Exchange ◽

Ecosystem Functions ◽

Exchange Flow ◽

Nutrient Inputs ◽

Lowland Streams ◽

Hyporheic Zones

Stream restoration projects that aim to rehabilitate ecosystem health have not considered surfacesubsurface 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 rifflestep construction projects may only be temporary in streams that receive increased sediment and nutrient inputs from urban areas and croplands.

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

<p>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.</p>

Download Full-text

The effect of unsteady streamflow and stream-groundwater interactions on oxygen consumption in a sandy streambed

Scientific Reports ◽

10.1038/s41598-019-56289-y ◽

2019 ◽

Vol 9 (1) ◽

Cited By ~ 2

Author(s):

Jason Galloway ◽

Aryeh Fox ◽

Jörg Lewandowski ◽

Shai Arnon

Keyword(s):

Oxygen Consumption ◽

Hyporheic Zone ◽

Drainage System ◽

Tracer Tests ◽

Interactive Effects ◽

Hyporheic Exchange ◽

Average Volume ◽

Planar Optode ◽

Consumption Rates ◽

Oxic Zone

AbstractStreamflow dynamics are often ignored when studying biogeochemical processes in the hyporheic zone. We explored the interactive effects of unsteady streamflow and groundwater fluxes on the delivery and consumption of oxygen within the hyporheic zone using a recirculating flume packed with natural sandy sediments. The flume was equipped with a programmable streamflow control and drainage system that was used to impose losing and gaining fluxes. Tracer tests were used to measure hyporheic exchange flux and a planar optode was used to measure subsurface oxygen concentration patterns. It was found that the volume of the oxic zone decreased when the losing flux declined, and was drastically decreased when gaining conditions were applied. It was also found that unsteady streamflow led to a slight increase in the average volume of the oxic zone, compared to the average volume of the oxic zone under steady streamflow. However, the average oxygen consumption rates were significantly higher under unsteady streamflow compared to steady streamflow under all groundwater conditions with the exception of the highest losing flux. The present study provides the first insight into the interactions between streamflow unsteadiness and losing/gaining fluxes and improve understanding of their impact on microbial metabolism in the hyporheic zone.

Download Full-text

Numerical Modeling of a Single Channel Polymer Electrolyte Fuel Cell

Journal of Fuel Cell Science and Technology ◽

10.1115/1.2756557 ◽

2007 ◽

Vol 4 (3) ◽

pp. 336 ◽

Cited By ~ 5

Author(s):

N. Vasileiadis ◽

D. J. L. Brett ◽

V. Vesovic ◽

A. R. Kucernak ◽

E. Fontes ◽

...

Keyword(s):

Numerical Modeling ◽

Fuel Cell ◽

Polymer Electrolyte ◽

Single Channel ◽

Polymer Electrolyte Fuel Cell

Download Full-text

Assessment of Hydrologic Transient Storage of Three Streams

The UW National Parks Service Research Station Annual Reports ◽

10.13001/uwnpsrc.2003.3545 ◽

2003 ◽

Vol 27 ◽

pp. 79-80

Author(s):

Michael Gooseff

Keyword(s):

Porous Media ◽

Hyporheic Zone ◽

Stream Water ◽

Stream Sediments ◽

Hyporheic Exchange ◽

Ecosystem Functions ◽

Main Stream ◽

Stream Channel ◽

Ample Opportunity ◽

Biogeochemical Transformations

Stream sediments are important locations of biogeochemical transformations upon which many stream ecosystem functions depend. Stream water is often exchanged between the stream channel and surrounding subsurface locations - this process is known as hyporheic exchange. While stream water is moving through the hyporheic zone, solutes and nutrients may undergo important chemical reactions that are not possible in the main stream channel. Further, because the hyporheic zone is composed of porous media (sand, sediment, alluvium, etc.), flow inherently slows down and the exchanging water has ample opportunity to interact with mineral grain surfaces and biofilms.

Download Full-text

Field measurements, sediment tracer study, and numerical modeling at Coos Bay Inlet, Oregon

10.21079/11681/27606 ◽

2018 ◽

Author(s):

Honghai Li ◽

Tahirih Lackey ◽

Tanya Beck ◽

Hans Moritz ◽

Katharine Groth ◽

...

Keyword(s):

Numerical Modeling ◽

Field Measurements ◽

Tracer Study ◽

Coos Bay ◽

Sediment Tracer

Download Full-text

Robust, spatially scanning, open-path TDLAS hygrometer using retro-reflective foils for fast tomographic 2-D water vapour concentration field measurements

Atmospheric Measurement Techniques Discussions ◽

10.5194/amtd-7-12827-2014 ◽

2014 ◽

Vol 7 (12) ◽

pp. 12827-12849 ◽

Cited By ~ 1

Author(s):

A. Seidel ◽

S. Wagner ◽

A. Dreizler ◽

V. Ebert

Keyword(s):

Water Vapour ◽

Single Channel ◽

Greenhouse Gas Emission ◽

Concentration Field ◽

Field Measurements ◽

Tunable Diode Laser ◽

Environmental Research ◽

Soil Physics ◽

Water Vapour Concentration ◽

Vapour Concentration

Abstract. We have developed a fast, spatially direct scanning tunable diode laser absorption spectrometer (dTDLAS) that combines four polygon-mirror based scanning units with low-cost retro-reflective foils. With this instrument, tomographic measurements of absolute 2-D water vapour concentration profiles are possible without any calibration using a reference gas. A spatial area of 0.8 m × 0.8 m was covered, which allows for application in soil physics, where greenhouse gas emission from certain soil structures shall be monitored. The whole concentration field was measured with up to 2.5 Hz. In this paper, we present the setup and spectroscopic performance of the instrument regarding the influence of the polygon rotation speed and mode on the absorption signal. Homogeneous H2O distributions were measured and compared to a single channel, bi-static reference TDLAS spectrometer for validation of the instrument. Good accuracy and precision with errors of less than 6% of the absolute concentration and length and bandwidth normalized detection limits of up to 1.1 ppmv · m · √Hz−1 were achieved. The spectrometer is a robust and easy to set up instrument for tomographic reconstructions of 2-D-concentration fields that can be considered a good basis for future field measurements in environmental research.

Download Full-text