scholarly journals Exploring Environmental Factors That Drive Diel Variations in Tree Water Storage Using Wavelet Analysis

2021 ◽  
Vol 3 ◽  
Author(s):  
Ryan E. Harmon ◽  
Holly R. Barnard ◽  
Frederick D. Day-Lewis ◽  
Deqiang Mao ◽  
Kamini Singha
Keyword(s):  
Electrical Conductivity ◽  
Wavelet Analysis ◽  
Ponderosa Pine ◽  
Water Storage ◽  
Time Lapse ◽  
Time Lags ◽  
Storm Events ◽  
Trunk Diameter ◽  
Xylem Fluid ◽  
Internal Water

Internal water storage within trees can be a critical reservoir that helps trees overcome both short- and long-duration environmental stresses. We monitored changes in internal tree water storage in a ponderosa pine on daily and seasonal scales using moisture probes, a dendrometer, and time-lapse electrical resistivity imaging (ERI). These data were used to investigate how patterns of in-tree water storage are affected by changes in sapflow rates, soil moisture, and meteorologic factors such as vapor pressure deficit. Measurements of xylem fluid electrical conductivity were constant in the early growing season while inverted sapwood electrical conductivity steadily increased, suggesting that increases in sapwood electrical conductivity did not result from an increase in xylem fluid electrical conductivity. Seasonal increases in stem electrical conductivity corresponded with seasonal increases in trunk diameter, suggesting that increased electrical conductivity may result from new growth. On the daily scale, changes in inverted sapwood electrical conductivity correspond to changes in sapwood moisture. Wavelet analyses indicated that lag times between inverted electrical conductivity and sapflow increased after storm events, suggesting that as soils wetted, reliance on internal water storage decreased, as did the time required to refill daily deficits in internal water storage. We found short time lags between sapflow and inverted electrical conductivity with dry conditions, when ponderosa pine are known to reduce stomatal conductance to avoid xylem cavitation. A decrease in diel amplitudes of inverted sapwood electrical conductivity during dry periods suggest that the ponderosa pine relied on internal water storage to supplement transpiration demands, but as drought conditions progressed, tree water storage contributions to transpiration decreased. Time-lapse ERI- and wavelet-analysis results highlight the important role internal tree water storage plays in supporting transpiration throughout a day and during periods of declining subsurface moisture.

scholarly journals Internal water storage buffering maintains plant function under drought as described by a general hydraulic model

2020 ◽  
Author(s):  
Avigail Kaner ◽  
Yakir Preisler ◽  
José M Grünzweig ◽  
Yair Mau
Keyword(s):  
Drought Stress ◽  
Sap Flow ◽  
Water Storage ◽  
Safety Margin ◽  
Environmental Drivers ◽  
Individual Plant ◽  
Time Lags ◽  
Flow Measurements ◽  
Internal Water ◽  
Internal Storage

Internal water storage is of crucial importance for plants under drought stress, allowing them to temporarily maintain transpiration higher than root-uptake flow, thus potentially keeping a positive carbon balance. A deep understanding of this adaptation is key for predicting the fate of ecosystems subjected to climate change-induced droughts of increasing intensity and duration. Using a minimalistic model, we derive predictions for how environmental drivers (atmospheric demand and soil water availability) interplay with the water storage, creating time lags between the flows in the plant, and granting the plant increased hydraulic safety margin protecting its xylem from embolism. We parametrize our model against transpiration and sap flow measurements in a semi-arid pine forest during seasonal drought. From the parametrized whole-stand traits, we derive a 3.7-hour time lag between transpiration and sap flow, and that 31% of daily transpiration comes directly from the plant's internal water storage, both corroborated by the measurements. Due to the model simplicity, our results are useful for interpreting, analyzing, and predicting the effects of the internal storage buffering from the individual plant to the ecosystem scale. Because internal storage produces survival-enhancing behavior in sub-daily time scales, it is an indispensable component for modeling ecosystems under drought stress.

scholarly journals Time-lapse cross-hole electrical resistivity tomography (CHERT) for monitoring seawater intrusion dynamics in a Mediterranean aquifer

2019 ◽  
Author(s):  
Andrea Palacios ◽  
Juan José Ledo ◽  
Niklas Linde ◽  
Linda Luquot ◽  
Fabian Bellmunt ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Seawater Intrusion ◽  
Electrical Resistivity Tomography ◽  
Low Cost ◽  
Heavy Rain ◽  
Time Lapse ◽  
Resistivity Tomography ◽  
Bulk Electrical Conductivity ◽  
Spatial Coverage

Abstract. Surface electrical resistivity tomography (ERT) is a widely used tool to study seawater intrusion (SWI). It is noninvasive and offers a high spatial coverage at a low cost, but it is strongly affected by decreasing resolution with depth. We conjecture that the use of CHERT (cross-hole ERT) can partly overcome these resolution limitations since the electrodes are placed at depth, which implies that the model resolution does not decrease in the zone of interest. The objective of this study is to evaluate the CHERT for imaging the SWI and monitoring its dynamics at the Argentona site, a well-instrumented field site of a coastal alluvial aquifer located 40 km NE of Barcelona. To do so, we installed permanent electrodes around boreholes attached to the PVC pipes to perform time-lapse monitoring of the SWI on a transect perpendicular to the coastline. After two years of monitoring, we observe variability of SWI at different time scales: (1) natural seasonal variations and aquifer salinization that we attribute to long-term drought and (2) short-term fluctuations due to sea storms or flooding in the nearby stream during heavy rain events. The spatial imaging of bulk electrical conductivity allows us to explain non-trivial salinity profiles in open boreholes (step-wise profiles really reflect the presence of fresh water at depth). By comparing CHERT results with traditional in situ measurements such as electrical conductivity of water samples and bulk electrical conductivity from induction logs, we conclude that CHERT is a reliable and cost-effective imaging tool for monitoring SWI dynamics.

Comparing Bioretention Designs With and Without an Internal Water Storage Layer for Treating Highway Runoff

2014 ◽  
Vol 86 (5) ◽  
pp. 387-397 ◽  
Author(s):  
Ming-Han Li ◽  
Mark Swapp ◽  
Myung Hee Kim ◽  
Kung-Hui Chu ◽  
Chan Yong Sung
Keyword(s):  
Water Storage ◽  
Highway Runoff ◽  
Internal Water

Inferring saline tracer transport characteristics from time-lapse GPR experiments

2021 ◽  
Author(s):  
Peter-Lasse Giertzuch ◽  
Alexis Shakas ◽  
Bernard Brixel ◽  
Joseph Doetsch ◽  
Mohammadreza Jalali ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Velocity Field ◽  
Nuclear Waste ◽  
Time Lapse ◽  
Transport Processes ◽  
Nuclear Waste Repository ◽  
Tracer Transport ◽  
Tracer Injection ◽  
Flow And Transport ◽  
Conductivity Sensor

<p>Monitoring and characterization of flow and transport processes in the subsurface has been a key focus of hydrogeological research for several decades. Such processes can be relevant for numerous applications, such as hydrocarbon and geothermal reservoir characterization and monitoring, risk assessment of soil contaminants, or nuclear waste disposal strategies.</p><p>Monitoring of flow and transport processes in the subsurface is often challenging, as they are usually not directly observable. Here, we present an approach to monitor saline tracer migration through a weakly fractured crystalline rock mass by means of Ground Penetrating Radar (GPR), and we evaluate the data quantitatively in terms of a flow velocity field and localized difference GPR breakthrough curves (DRBTC).</p><p>Two comparable and repeated tracer injection experiments were performed within saturated rock on the decameter scale. Time-lapse single-hole reflection data were acquired from two different boreholes during these experiments using unshielded and omnidirectional borehole antennas. The individual surveys were analyzed by difference imaging techniques, which allowed ultimately for tracer breakthrough monitoring at different locations in the subsurface. By combining the two complimentary GPR data sets, the 3D tracer velocity field could be reconstructed.</p><p>Our DRBTCs agree well with measured BTCs of the saline tracer at different electrical conductivity monitoring positions. Additionally, we were able to calculate a DRBTC for a location not previously monitored with borehole sensors. The reconstructed velocity field is in good agreement with previous studies on dye tracer data at the same research locations. Furthermore, we were able to resolve separate flow paths towards different monitoring locations, which could not be inferred from the electrical conductivity sensor data alone. The GPR data thus helped to disentangle the complex flow field through the fractured rock.</p><p>Out technique can be adapted to other use cases such as 3D monitoring of fluid migration (and thus permeability enhancement) during hydraulic stimulation and tracing fluid contaminants – e.g. for nuclear waste repository monitoring.</p>

scholarly journals Time-lapse cross-hole electrical resistivity tomography (CHERT) for monitoring seawater intrusion dynamics in a Mediterranean aquifer

2020 ◽  
Vol 24 (4) ◽  
pp. 2121-2139 ◽  
Author(s):  
Andrea Palacios ◽  
Juan José Ledo ◽  
Niklas Linde ◽  
Linda Luquot ◽  
Fabian Bellmunt ◽  
...  
Keyword(s):  
Electrical Conductivity ◽  
Electrical Resistivity ◽  
Seawater Intrusion ◽  
Electrical Resistivity Tomography ◽  
Low Cost ◽  
Heavy Rain ◽  
Time Lapse ◽  
Resistivity Tomography ◽  
Bulk Electrical Conductivity ◽  
Spatial Coverage

Abstract. Surface electrical resistivity tomography (ERT) is a widely used tool to study seawater intrusion (SWI). It is noninvasive and offers a high spatial coverage at a low cost, but its imaging capabilities are strongly affected by decreasing resolution with depth. We conjecture that the use of CHERT (cross-hole ERT) can partly overcome these resolution limitations since the electrodes are placed at depth, which implies that the model resolution does not decrease at the depths of interest. The objective of this study is to test the CHERT for imaging the SWI and monitoring its dynamics at the Argentona site, a well-instrumented field site of a coastal alluvial aquifer located 40 km NE of Barcelona. To do so, we installed permanent electrodes around boreholes attached to the PVC pipes to perform time-lapse monitoring of the SWI on a transect perpendicular to the coastline. After 2 years of monitoring, we observe variability of SWI at different timescales: (1) natural seasonal variations and aquifer salinization that we attribute to long-term drought and (2) short-term fluctuations due to sea storms or flooding in the nearby stream during heavy rain events. The spatial imaging of bulk electrical conductivity allows us to explain non-monotonic salinity profiles in open boreholes (step-wise profiles really reflect the presence of freshwater at depth). By comparing CHERT results with traditional in situ measurements such as electrical conductivity of water samples and bulk electrical conductivity from induction logs, we conclude that CHERT is a reliable and cost-effective imaging tool for monitoring SWI dynamics.

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