Characterizing Riverbed Heterogeneity across Shifts in River Discharge through Temporal Changes in Electrical Resistivity

2020 ◽  
Vol 25 (4) ◽  
pp. 581-587
Author(s):  
Weston J. Koehn ◽  
Stacey E. Tucker-Kulesza ◽  
David R. Steward
Keyword(s):  
Electrical Resistivity ◽  
Temporal Changes ◽  
Coarse Grained ◽  
Arkansas River ◽  
Alluvial Deposits ◽  
Fine Grained ◽  
Surrounding Matrix ◽  
Aquifer Depletion ◽  
Fine Grained Soil ◽  
The Individual

The fluxes between groundwater and surface water play a significant role in quantifying water balance along stream reaches to continent scales. Changes in these dynamics are occurring due to aquifer depletion, where pre-development baseflow conditions have transitioned to losing conditions. This problem is studied along the Arkansas River in Western Kansas across a stream reach that transitions from near steady state to losing conditions, and contributes focused recharge to a depleting Ogallala Aquifer. Existing hydrologic data illustrates the lack of understanding they provide related to the control of fluxes exerted by alluvial deposits. Electrical resistivity imaging (ERI) surveys were conducted along this river transect to elucidate the dynamic hydrologic connection existing between the Arkansas River and underlying Arkansas Alluvial and Ogallala Aquifers. Temporal changes in ERI profiles are associated with the transient hydrologic conditions below the water-sediment interface, and complement the hydrogeologic interpretations of the individual ERI profiles. Additionally, fine grained soil inclusions may become revealed by temporal changes in resistivity due to differences in their water holding capacity relative to that of a surrounding matrix of coarser grained soil across changes in recharge. These findings corroborate the role of river-aquifer connectivity and riverbed heterogeneity on localized recharge through embedded assemblages of fine and coarse grained soils.

scholarly journals Technical Note: Deciphering the Hydrologic Response of Riverbeds across Changes in Recharge with Electrical Resistivity Imaging

2018 ◽  
Author(s):  
Weston J. Koehn ◽  
Stacey E. Tucker-Kulesza ◽  
David R. Steward
Keyword(s):  
Electrical Resistivity ◽  
Surface Water ◽  
Coarse Grained ◽  
Electrical Resistivity Imaging ◽  
High Plains ◽  
High Plains Aquifer ◽  
Arkansas River ◽  
Alluvial Deposits ◽  
Near Surface ◽  
Resistivity Imaging

Abstract. The fluxes between groundwater and surface water play a significant role in quantifying water balance along stream reaches to continent scales. Changes in these dynamics are occurring due to aquifer depletion, where river flow from predevelopment baseflow conditions with groundwater to surface water have evolved to enhanced recharge through streambeds of ephemeral flows to groundwater. This problem is studied along the Arkansas River in Western Kansas across a stream reach that transitions from near equilibrium of fluxes to a losing river that contributes recharge to a depleting High Plains Aquifer. Existing hydrologic data illustrates the lack of understanding they provide related to the control of fluxes exerted by alluvial deposits. We employ electrical resistivity imaging (ERI) along this river transect to elucidate the intricate pathways of hydrologic connectivity existing between the Arkansas River and underlying Arkansas Alluvial and Ogallala Aquifers. Time-lapse ERI profiles quantify the temporal changes in resistivity across the riverbed, and these changes are associated with the distribution of soil physical properties and hydrologic conditions below the water-sediment interface. Results utilize a recently discovered vadose zone property whereby fine grained inclusions may become revealed by their different water holding capacity relative to that of a surrounding matrix of coarser grained soil across changes in recharge (caused by changes in stream discharge). These findings corroborate the role of large-scale geologic features in maintaining streamflow in regions of near-surface impermeable layers, and the localized recharge that occurs to the High Plains Aquifer through embedded assemblages of fine and coarse grained soils.

Plasticity in extended phenotypes: how the antlion Myrmeleon crudelis adjusts the pit traps depending on biotic and abiotic conditions

2019 ◽  
Vol 66 (1-2) ◽  
pp. 41-47 ◽  
Author(s):  
Alejandro G. Farji-Brener ◽  
Sabrina Amador-Vargas
Keyword(s):  
Abiotic Factors ◽  
Plant Cover ◽  
Coarse Grained ◽  
Abiotic Conditions ◽  
Fine Grained ◽  
Fine Soil ◽  
Fine Grained Soil ◽  
Trap Size ◽  
Pit Depth ◽  
Pit Design

Abstract The physical structures built by animals are considered extended phenotypes that reflect how organisms make decisions and deal with changes in their biotic and abiotic environment. We summarize the results of several studies on Myrmeleon crudelis, a neuropteran larva that digs pit-traps in the soil to capture small arthropods (mostly ants) in the tropical dry forests of Costa Rica. Specifically, we showed how this species responds to varying biotic and abiotic conditions with changes in the design and/or location of its pit traps. Several experiments and field comparisons indicate that: 1) antlions adjust the pit design according to the abundance and type of prey. When prey is scarce, antlions increased trap diameter, an architectural adjustment that enhances the probability of prey encounter. Antlions that experienced high prey abundance, but the prey easily escaped, then increased pit depth, an adjustment that increases the chance of prey retention; 2) soil compaction strongly reduced pit-trap size and abundance; 3) antlions preferred soils with high proportion of fine-particle size to build pits. In fine-grained soil, pit-traps are larger and more efficient to capture prey than traps in coarse-grained soils; and 4) pit-traps may also be affected through indirect effects of soil structure and vegetation cover. Areas with fine-soil presented less plant cover, and plant cover could be beneficial for antlions because it acts as a shelter against direct sunlight and rainfall, or it may represent a cost because it is a source of leaflitter falling in the pits. The works summarized here how trap-building predators can exhibit considerable flexibility in trap construction in response to various biotic and abiotic factors, emphasizing how the study of extended phenotypes can be a useful approach to better understand the flexibility of foraging behaviors.

Microstructural Interpretation of Water Content and Dry Density Influence on the DC-Electrical Resistivity of a Fine-Grained Soil

2011 ◽  
Vol 34 (6) ◽  
pp. 103763
Author(s):  
L. D. Suits ◽  
T. C. Sheahan ◽  
Yves-Laurent Beck ◽  
Sérgio Palma Lopes ◽  
Valéry Ferber ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Water Content ◽  
Dry Density ◽  
Dc Electrical Resistivity ◽  
Fine Grained ◽  
Fine Grained Soil

Electrical resistivity of frozen and petroleum-contaminated fine-grained soil

2001 ◽  
Vol 32 (2-3) ◽  
pp. 107-119 ◽  
Author(s):  
Allan J. Delaney ◽  
Paige R. Peapples ◽  
Steven A. Arcone
Keyword(s):  
Electrical Resistivity ◽  
Fine Grained ◽  
Fine Grained Soil

Spatial variations in sediment systems

2009 ◽  
Author(s):  
John S. Gray ◽  
Michael Elliott
Keyword(s):  
Spatial Scales ◽  
Coarse Grained ◽  
Anthropogenic Effects ◽  
Individual Species ◽  
Physical Disturbance ◽  
Fine Grained ◽  
The Past ◽  
The Individual ◽  
General Physical

In this chapter the primary emphasis is on spatial scales of disturbances, and we will follow on from our earlier discussions on the mechanisms of competition and predation and the controversy over their importance in controlling species richness. Huston (1994) realized that the effects of competition, predation, and general physical disturbance were similar in that individuals were removed from the assemblage. We now show that there is a need to link these aspects with the tolerances of individual species, for example to determine in which of these cases the organisms are absent because the conditions now fall outside the optimal tolerance ranges. Thus we discuss disturbance as a general phenomenon which includes the effects of any processes that lead to a reduction in numbers of individuals and/or biomass. Disturbance includes physical disturbance as well as biological processes such as the effects of competition and predation on assemblages. The spatial scales covered range from micrometres to many hundreds of kilometres for the effects of bottom trawling, which is now considered to be one of the most serious and damaging threats to sediment habitats and assemblages. Disturbance effects caused by trawling and by pollution are considered in the following chapters. First, it is necessary to consider scale since many new insights have developed in the past few years of research. In the past couple of decades a new branch of ecology, landscape ecology, has developed, devoted to considering patterns over large areas, and a terminology of spatial scales has been defined. Grain is the first level of spatial resolution; it relates to the individual data unit and can be described as fine-grained to coarse-grained. Extent refers to the overall size of the study area. A map of 100 km2 and one of 100 000 km2 differ in extent by a factor of 1000. Grain and extent are illustrated in Fig. 6.1. A third component is lag, which is the betweensample distance. Figure 6.2 summarizes temporal and spatial scales of disturbances (modified from Zajac et al. 1998). The figure shows the main types of disturbances affecting soft-sediment systems, and separates them into natural and anthropogenic effects (see also Chapter 11, which indicates some of the management responses to these effects).

Laboratory Testing of Full-Scale Pipes Partially Embedded in Soil to Study Soil-Pipe Interaction of Offshore Seabed Oil and Gas Pipelines: Initial Observations

2014 ◽  
Author(s):  
Ruslan S. Amarasinghe ◽  
Dharma Wijewickreme ◽  
Hisham T. Eid
Keyword(s):  
Oil And Gas ◽  
Full Scale ◽  
Coarse Grained ◽  
Gas Pipelines ◽  
Steel Pipes ◽  
Fine Grained ◽  
Oil And Gas Pipelines ◽  
Fine Grained Soil ◽  
Geotechnical Aspect ◽  
Soil Pipe

The geotechnical aspect of the design of off-shore oil and gas pipelines is a challenge due to inherent uncertainties in predicting soil-pipe interaction behaviour. Physical modeling is often sought after to gain insight into such problems. This is especially true for pipelines laid in deep waters that are partially embedded in the seabed. This paper presents initial observations arising from full-scale laboratory simulations of typical soil-pipe interaction scenarios of partially buried steel pipes. Bare and epoxy-coated NPS18 steel pipes, each measuring 2.5 m in length, were separately tested in a soil chamber by simulating: (i) lateral pipe displacement; and (ii) longitudinal pipe displacement, under partial embedment in two idealized soil bed models, i.e., in a coarse-grained soil bed model with full drainage, and a fully-saturated fine-grained soil bed model with partial drainage.

scholarly journals Features of terraces and the incision rate along the lower reaches of the Yarlung Zangbo River east of Namche Barwa: Constraints on tectonic uplift

2020 ◽  
Vol 12 (1) ◽  
pp. 1645-1652
Author(s):  
Chao Xie ◽  
Bengang Zhou ◽  
Zhengfang Li ◽  
Fan Yang ◽  
Wei Pang ◽  
...  
Keyword(s):  
Tectonic Uplift ◽  
Luminescence Dating ◽  
Coarse Grained ◽  
Alluvial Deposits ◽  
Fine Grained ◽  
Rock Fragments ◽  
Base Level ◽  
Yarlung Zangbo River ◽  
Elevation Difference ◽  
Namche Barwa

AbstractAlong the lower reaches of the Yarlung Zangbo River, scattered alluvium sections appear on T1 and T2 terraces. The alluvial deposits on the T1 terrace in Linduo and Ximogou and the T2 terrace in Guoguotang are composed principally of coarse-grained sand particles and rock fragments, with no observable fine-grained components. The T1 terrace alluvium section is dominated by clay and silt and occurs near the town of Dexing, and optically stimulated luminescence dating of sample from this site revealed an age of 18.2 kyear, which indicates that the incision rate of the Yarlung Zangbo River has been 4.7 mm/year since the formation of this section. On the basis of the component characteristics of terraces in Motuo County, the provenance for the terraces is probably related to the breaking of the palaeo-dammed lakes in the middle reaches of the Yarlung Zangbo River. A 430 m elevation difference still exists between the study area and the local base level downstream of the Yalung Zangbo River (Assam Plain), although this river has a strong incision capability (4.7 mm/year), which suggests that tectonic uplift remains very intense east of the Namche Barwa syntaxis.

scholarly journals Procedures for Residual Stress Analysis in Textured and in Coarse Grained Materials

1995 ◽  
Vol 23 (3) ◽  
pp. 173-183 ◽  
Author(s):  
W. Reimers ◽  
R. Dupke
Keyword(s):  
Residual Stress ◽  
Elastic Constants ◽  
Elastic Anisotropy ◽  
Orientation Distribution ◽  
Coarse Grained ◽  
Fine Grained ◽  
Experimental Strain ◽  
Anisotropic Elastic ◽  
The Individual ◽  
Experimental Findings

For the investigation of residual stresses by means of X-ray diffraction, special procedures for the registration and evaluation of the experimental strain data are necessary for textured and coarse grained materials. In both cases inhomogeneous diffraction intensity patterns are present which lead to the formation of intensity poles or even to Bragg reflections. Such experimental findings indicate also that the material properties within the investigated gauge volume are anisotropic so that the evaluation of the experimental strain up to stress values requires the introduction of anisotropic elastic constants. For the residual stress investigation of textured and fine grained materials averaging procedures using short wavelength radiation are discussed. A more detailed insight also in the microstress states may be obtained from the measurement of several different reflections whereby the effects of the elastic anisotropy may be corrected for by including the orientation distribution function as calculated from different poles figures. For coarse grained materials it is experimentally possible to determine the strain state of the individual crystallites so that their anisotropy is directly included in the evaluation of the stress data by using the single crystal elastic constants. The macroscopic residual stress values may then be obtained from the averaging over stress values of several crystallites.

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