Laboratory Flume and Numerical Modeling Experiments show Log Jams and Branching Channels increase Hyporheic Exchange

2021 ◽  
Author(s):  
K. Wilhelmsen ◽  
A.H. Sawyer ◽  
A. Marshall ◽  
S. McFadden ◽  
K. Singha ◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Hyporheic Exchange ◽  
Laboratory Flume

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

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).  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>

Mapping increases in hyporheic exchange from channel-spanning logjams

2020 ◽  
Author(s):  
Kamini Singha ◽  
Megan Doughty ◽  
Sawyer McFadden ◽  
Audrey Hucks Sawyer ◽  
Ellen Wohl
Keyword(s):  
Numerical Modeling ◽  
Hyporheic Zone ◽  
Single Channel ◽  
Tracer Tests ◽  
Field Measurements ◽  
Hyporheic Exchange ◽  
Exchange Flow ◽  
Stream Monitoring ◽  
Solute Retention ◽  
Flow Pathways

<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>

Numerical modeling of bed form induced hyporheic exchange

2014 ◽  
Vol 12 (S1) ◽  
pp. 89-97 ◽  
Author(s):  
Du Han Lee ◽  
Young Joo Kim ◽  
Samhee Lee
Keyword(s):  
Numerical Modeling ◽  
Hyporheic Exchange ◽  
Bed Form

Prediction of LPCVD silicon film microstructure from local operating conditions using numerical modeling

1999 ◽  
Vol 09 (PR8) ◽  
pp. Pr8-181-Pr8-188 ◽  
Author(s):  
A. Dollet ◽  
B. Caussat ◽  
J. P. Couderc
Keyword(s):  
Numerical Modeling ◽  
Silicon Film ◽  
Operating Conditions ◽  
Film Microstructure

Investigation of Morphosedimentary Processes on a Schematic Louisiana Barrier Island Using Process-Based Numerical Modeling

2007 ◽  
Author(s):  
T. Campbell ◽  
B. de Sonneville ◽  
L. Benedet ◽  
D. J. W. Walstra ◽  
C. W. Finkl
Keyword(s):  
Numerical Modeling ◽  
Barrier Island

Numerical Modeling of Hurricane-Induced Extreme Wave Heights in Pensacola Bay

2013 ◽  
Author(s):  
Wenrui Huang ◽  
Yuan He ◽  
Shuguang Liu
Keyword(s):  
Numerical Modeling ◽  
Extreme Wave ◽  
Wave Heights

SIMULATION OF ELECTRICAL MONITORING OF DAMS WITH LEAKAGE WITH A TRANSVERSE PLACEMENT OF THE MEASURING INSTALLATION

2020 ◽  
Vol 8 (4) ◽  
pp. 69-82
Author(s):  
D.S. Rakisheva ◽  
◽  
B.G. Mukanova ◽  
I.N. Modin ◽  
◽  
...  
Keyword(s):  
Numerical Modeling ◽  
Water Level ◽  
Electrical Resistivity Tomography ◽  
Resistivity Tomography ◽  
Measuring Installation ◽  
Basic Functions ◽  
Tomography Method ◽  
Dam Monitoring ◽  
The Mathematical Model ◽  
Measurement Line

Numerical modeling of the problem of dam monitoring by the Electrical Resistivity Tomography method is carried out. The mathematical model is based on integral equations with a partial Fourier transform with respect to one spatial variable. It is assumed that the measurement line is located across the dam longitude. To approximate the shape of the dam surface, the Radial Basic Functions method is applied. The influence of locations of the water-dam, dam-basement, basement-leakage boundaries with respect to the sounding installation, which is partially placed under the headwater, is studied. Numerical modeling is carried out for the following varied parameters: 1) water level at the headwater; 2) the height of the leak; 3) the depth of the leak; 4) position of the supply electrode; 5) water level and leaks positions are changing simultaneously. Modeling results are presented in the form of apparent resistivity curves, as it is customary in geophysical practice.

Numerical modeling to well-head protection area delineation, an example in Veneto Region (NE Italy)

2015 ◽  
Vol 35 ◽  
pp. 232-235 ◽  
Author(s):  
Leonardo Piccinini ◽  
Paolo Fabbri ◽  
Marco Pola ◽  
Enrico Marcolongo ◽  
Alessia Rosignoli
Keyword(s):  
Numerical Modeling ◽  
Veneto Region ◽  
Ne Italy ◽  
Head Protection ◽  
Protection Area

Numerical modeling of regional groundwater flow in the Adda-Ticino Basin: advances and new results

2016 ◽  
Vol 41 ◽  
pp. 10-13 ◽  
Author(s):  
Luca Alberti ◽  
Martino Cantone ◽  
Silvia Lombi ◽  
Alessandra Piana
Keyword(s):  
Numerical Modeling ◽  
Groundwater Flow ◽  
Regional Groundwater
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