scholarly journals Form and function in hillslope hydrology: characterization of subsurface flow based on response observations

2017 ◽  
Vol 21 (7) ◽  
pp. 3727-3748 ◽  
Author(s):  
Lisa Angermann ◽  
Conrad Jackisch ◽  
Niklas Allroggen ◽  
Matthias Sprenger ◽  
Erwin Zehe ◽  
...  
Keyword(s):  
Preferential Flow ◽  
Explanatory Power ◽  
Subsurface Flow ◽  
Time Lapse ◽  
Storm Event ◽  
Monitoring Methods ◽  
Catchment Scale ◽  
Flow Paths ◽  
Form And Function ◽  
And Function

Abstract. The phrase form and function was established in architecture and biology and refers to the idea that form and functionality are closely correlated, influence each other, and co-evolve. We suggest transferring this idea to hydrological systems to separate and analyze their two main characteristics: their form, which is equivalent to the spatial structure and static properties, and their function, equivalent to internal responses and hydrological behavior. While this approach is not particularly new to hydrological field research, we want to employ this concept to explicitly pursue the question of what information is most advantageous to understand a hydrological system. We applied this concept to subsurface flow within a hillslope, with a methodological focus on function: we conducted observations during a natural storm event and followed this with a hillslope-scale irrigation experiment. The results are used to infer hydrological processes of the monitored system. Based on these findings, the explanatory power and conclusiveness of the data are discussed. The measurements included basic hydrological monitoring methods, like piezometers, soil moisture, and discharge measurements. These were accompanied by isotope sampling and a novel application of 2-D time-lapse GPR (ground-penetrating radar). The main finding regarding the processes in the hillslope was that preferential flow paths were established quickly, despite unsaturated conditions. These flow paths also caused a detectable signal in the catchment response following a natural rainfall event, showing that these processes are relevant also at the catchment scale. Thus, we conclude that response observations (dynamics and patterns, i.e., indicators of function) were well suited to describing processes at the observational scale. Especially the use of 2-D time-lapse GPR measurements, providing detailed subsurface response patterns, as well as the combination of stream-centered and hillslope-centered approaches, allowed us to link processes and put them in a larger context. Transfer to other scales beyond observational scale and generalizations, however, rely on the knowledge of structures (form) and remain speculative. The complementary approach with a methodological focus on form (i.e., structure exploration) is presented and discussed in the companion paper by Jackisch et al.(2017).

scholarly journals Identification of runoff formation with two dyes in a mid-latitude mountain headwater

2017 ◽  
Vol 21 (6) ◽  
pp. 3025-3040 ◽  
Author(s):  
Lukáš Vlček ◽  
Kristýna Falátková ◽  
Philipp Schneider
Keyword(s):  
Pipe Flow ◽  
Preferential Flow ◽  
Subsurface Flow ◽  
Peat Bog ◽  
Catchment Scale ◽  
Tree Roots ◽  
Flow Paths ◽  
Runoff Formation ◽  
Shallow Subsurface ◽  
Preferential Flow Paths

Abstract. Subsurface flow in peat bog areas and its role in the hydrologic cycle has garnered increased attention as water scarcity and floods have increased due to a changing climate. In order to further probe the mechanisms in peat bog areas and contextualize them at the catchment scale, this experimental study identifies runoff formation at two opposite hillslopes in a peaty mountain headwater; a slope with organic peat soils and a shallow phreatic zone (0.5 m below surface), and a slope with mineral Podzol soils and no detectable groundwater (> 2 m below surface). Similarities and differences in infiltration, percolation and preferential flow paths between both hillslopes could be identified by sprinkling experiments with Brilliant Blue and Fluorescein sodium. To our knowledge, this is the first time these two dyes have been compared in their ability to stain preferential flow paths in soils. Dye-stained soil profiles within and downstream of the sprinkling areas were excavated parallel (lateral profiles) and perpendicular (frontal profiles) to the slopes' gradients. That way preferential flow patterns in the soil could be clearly identified. The results show that biomat flow, shallow subsurface flow in the organic topsoil layer, occurred at both hillslopes; however, at the peat bog hillslope it was significantly more prominent. The dye solutions infiltrated into the soil and continued either as lateral subsurface pipe flow in the case of the peat bog, or percolated vertically towards the bedrock in the case of the Podzol. This study provides evidence that subsurface pipe flow, lateral preferential flow along decomposed tree roots or logs in the unsaturated zone, is a major runoff formation process at the peat bog hillslope and in the adjacent riparian zone.

Field observations of subsurface flow path evolution over 10 Millennia

2020 ◽  
Author(s):  
Anne Hartmann ◽  
Ekaterina Semenova ◽  
Markus Weiler ◽  
Theresa Blume
Keyword(s):  
Preferential Flow ◽  
Subsurface Flow ◽  
Soil Surface ◽  
Flow Path ◽  
Physical Characteristics ◽  
Swiss Alps ◽  
Spatial And Temporal Variability ◽  
Hydrological Process ◽  
Flow Paths ◽  
Soil Physical Characteristics

<p>Where water goes when it rains, is to a large part controlled by subsurface storage and subsurface flow paths. While these aspects are essential for basic hydrological process understanding, their large spatial and temporal variability makes both systematic studies and extraction of generalizable results challenging.<br>We investigate systematically how subsurface storage and flow paths change during the temporal evolution of hillslopes. In order to do so we selected 4 moraines of different ages (30, 160, 3000 and 10.000 years) in a glacial foreland in the Swiss Alps. We then studied both soil physical characteristics as well as flow path evolution across this chronosequence by extensive sampling and soil physical laboratory analyses on the one hand and 36 in-situ dye tracer experiments (Brilliant Blue)  on the other hand.<br>We find that soil physical characteristics change significantly over the millennia. However, vegetational development seems to have a similarly strong effect on flow path evolution. Flow paths evolve from mainly matrix flow at the youngest moraine to increasingly more dominant preferential flow. At the oldest moraine we furthermore find increased subsurface storage, especially in the now strongly developed organic horizon. At intermediate ages preferential flow is less dominated by flow in macropores but is initiated at the soil surface through spatially variable vegetation and microtopography. With this study we provide a first systematic and detailed study of flow path evolution across the first ten millennia of hillslope evolution.</p>

scholarly journals Form and function in hillslope hydrology: in situ imaging and characterization of flow-relevant structures

2017 ◽  
Vol 21 (7) ◽  
pp. 3749-3775 ◽  
Author(s):  
Conrad Jackisch ◽  
Lisa Angermann ◽  
Niklas Allroggen ◽  
Matthias Sprenger ◽  
Theresa Blume ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Hydraulic Conductivity ◽  
Soil Water ◽  
Time Lapse ◽  
Saturated Hydraulic Conductivity ◽  
Form And Function ◽  
And Function ◽  
Hillslope Scale

Abstract. The study deals with the identification and characterization of rapid subsurface flow structures through pedo- and geo-physical measurements and irrigation experiments at the point, plot and hillslope scale. Our investigation of flow-relevant structures and hydrological responses refers to the general interplay of form and function, respectively. To obtain a holistic picture of the subsurface, a large set of different laboratory, exploratory and experimental methods was used at the different scales. For exploration these methods included drilled soil core profiles, in situ measurements of infiltration capacity and saturated hydraulic conductivity, and laboratory analyses of soil water retention and saturated hydraulic conductivity. The irrigation experiments at the plot scale were monitored through a combination of dye tracer, salt tracer, soil moisture dynamics, and 3-D time-lapse ground penetrating radar (GPR) methods. At the hillslope scale the subsurface was explored by a 3-D GPR survey. A natural storm event and an irrigation experiment were monitored by a dense network of soil moisture observations and a cascade of 2-D time-lapse GPR trenches. We show that the shift between activated and non-activated state of the flow paths is needed to distinguish structures from overall heterogeneity. Pedo-physical analyses of point-scale samples are the basis for sub-scale structure inference. At the plot and hillslope scale 3-D and 2-D time-lapse GPR applications are successfully employed as non-invasive means to image subsurface response patterns and to identify flow-relevant paths. Tracer recovery and soil water responses from irrigation experiments deliver a consistent estimate of response velocities. The combined observation of form and function under active conditions provides the means to localize and characterize the structures (this study) and the hydrological processes (companion study Angermann et al., 2017, this issue).

scholarly journals Hydrochemical and Isotopic Difference of Spring Water Depending on Flow Type in a Stratigraphically Complex Karst Area of South Korea

2021 ◽  
Vol 9 ◽  
Author(s):  
Soonyoung Yu ◽  
Gitak Chae ◽  
Junseop Oh ◽  
Se-Hoon Kim ◽  
Dong-Il Kim ◽  
...  
Keyword(s):  
Carbonate Rocks ◽  
Subsurface Flow ◽  
Spring Water ◽  
Karst Area ◽  
Storm Event ◽  
Hydrograph Separation ◽  
Deep Groundwater ◽  
Mountain Areas ◽  
Flow Paths ◽  
Karst Terrain

Characterizing the subsurface flow in karstic areas is challenging due to distinct flow paths coexisting, and lithologic heterogeneity makes it more difficult. A combined use of hydrochemical, environmental isotopic, and hydrograph separation study was performed to understand the subsurface flow in a karst terrain where Ordovician carbonate rocks overlie Jurassic sandstone and shale along thrusts. Spring water collected was divided into Type Ⅰ (n = 11) and Ⅱ (n = 30) based on flow patterns (i.e., low and high discharge, respectively). In addition, groundwater (n = 20) was examined for comparison. Three Type Ⅱ springs were additionally collected during a storm event to construct hydrographs using δ18O and δD. As a result, Type Ⅱ had higher electrical conductivity, Mg2+, HCO3−, and Ca2+/(Na+ + K+) than Type Ⅰ and was mostly saturated with calcite, similar to deep groundwater. The hydrochemical difference between Types Ⅰ and Ⅱ was opposite to the expectation that Type Ⅱ would be undersaturated given fast flow and small storage, which could be explained by the distinct geology and water sources. Most Type Ⅱ springs and deep groundwater occurred in carbonate rocks, whereas Type Ⅰ and shallow groundwater occurred in various geological settings. The carbonate rocks seemed to provide conduit flow paths for Type Ⅱ given high solubility and faults, resulting in 1) relatively high tritium and NO3− and Cl−via short-circuiting flow paths and 2) the similar hydrochemistry and δ18O and δD to deep groundwater via upwelling from deep flow paths. The deep groundwater contributed to 83–87% of the discharge at three Type Ⅱ springs in the dry season. In contrast, Type Ⅰ showed low Ca2+ + Mg2+ and Ca2+/(Na+ + K+) discharging diffuse sources passing through shallow depths in a matrix in mountain areas. Delayed responses to rainfall and the increased concentrations of contaminants (e.g., NO3−) during a typhoon at Type Ⅱ implied storage in the vadose zone. This study shows that hydrochemical and isotopic investigations are effective to characterize flow paths, when combined with hydrograph separation because the heterogenous geology affects both flow paths and the hydrochemistry of spring water passing through each pathway.

FURTHER OBSERVATIONS ON AMOEBOID HAEMOCYTES IN BLABERUS GIGANTEUS (L.) (ORTHOPTERA: BLATTIDAE)

1961 ◽  
Vol 39 (5) ◽  
pp. 755-766 ◽  
Author(s):  
J. W. Arnold
Keyword(s):  
Cell Body ◽  
Time Lapse ◽  
Flat Surfaces ◽  
Variable Form ◽  
Form And Function ◽  
Projection Analysis ◽  
Rapid Elongation ◽  
Wing Veins ◽  
And Function

The movements of amoeboid haemocytes in vivo in wing veins of B. giganteus were studied with the aid of time-lapse cinephotomicrography and projection analysis. They are described here in detail and discussed in relation to haemocyte form and function. Haemocyte motion included non-migratory as well as migratory aspects. Non-migratory motion comprised the slow to turbulent cytoplasmic motion and intermittent probing movements of stationary cells. Active migration occurred in the more or less typical amoeboid fashion and also in the more peculiar contractile manner which involved the projection of hyaline, tactile pseudopodia of variable form and often resulted in extreme and relatively rapid elongation of the cell body. Haemocytes were thus able to move on flat surfaces, to extend themselves across spaces, and to force their way into narrow tissue interstices. These activities demonstrate the versatility of the cells and provide a means of accounting for certain of their functions.

scholarly journals The relationship between sternum variation and mode of locomotion in birds

BMC Biology ◽  
2021 ◽  
Vol 19 (1) ◽  
Author(s):  
Talia M. Lowi-Merri ◽  
Roger B. J. Benson ◽  
Santiago Claramunt ◽  
David C. Evans
Keyword(s):  
Body Shape ◽  
Explanatory Power ◽  
Critical Element ◽  
Form And Function ◽  
Avian Flight ◽  
Flight Muscles ◽  
Ecological Importance ◽  
And Function ◽  
Future Work ◽  
The Relationship

Abstract Background The origin of powered avian flight was a locomotor innovation that expanded the ecological potential of maniraptoran dinosaurs, leading to remarkable variation in modern birds (Neornithes). The avian sternum is the anchor for the major flight muscles and, despite varying widely in morphology, has not been extensively studied from evolutionary or functional perspectives. We quantify sternal variation across a broad phylogenetic scope of birds using 3D geometric morphometrics methods. Using this comprehensive dataset, we apply phylogenetically informed regression approaches to test hypotheses of sternum size allometry and the correlation of sternal shape with both size and locomotory capabilities, including flightlessness and the highly varying flight and swimming styles of Neornithes. Results We find evidence for isometry of sternal size relative to body mass and document significant allometry of sternal shape alongside important correlations with locomotory capability, reflecting the effects of both body shape and musculoskeletal variation. Among these, we show that a large sternum with a deep or cranially projected sternal keel is necessary for powered flight in modern birds, that deeper sternal keels are correlated with slower but stronger flight, robust caudal sternal borders are associated with faster flapping styles, and that narrower sterna are associated with running abilities. Correlations between shape and locomotion are significant but show weak explanatory power, indicating that although sternal shape is broadly associated with locomotory ecology, other unexplored factors are also important. Conclusions These results display the ecological importance of the avian sternum for flight and locomotion by providing a novel understanding of sternum form and function in Neornithes. Our study lays the groundwork for estimating the locomotory abilities of paravian dinosaurs, the ancestors to Neornithes, by highlighting the importance of this critical element for avian flight, and will be useful for future work on the origin of flight along the dinosaur-bird lineage.

scholarly journals Identification of runoff formation with two dyes in a mid-latitude mountain headwater

2017 ◽  
Author(s):  
Lukáš Vlček ◽  
Philipp Schneider ◽  
Kristýna Falátková
Keyword(s):  
Preferential Flow ◽  
Hydrological Cycle ◽  
Subsurface Flow ◽  
Sodium Fluorescein ◽  
Peat Bog ◽  
Catchment Scale ◽  
Tree Roots ◽  
Runoff Formation ◽  
Shallow Subsurface ◽  
Preferential Flowpaths

Abstract. Subsurface flow in Peat Bog areas and its role in the hydrological cycle has garnered increased attention as water scarcity and floods have increased due to a changing climate. In order to further probe the mechanisms in Peat Bog areas and contextualize them at the catchment scale, this experimental study identifies runoff formation at two opposite hillslopes in a peaty mountain headwater; a slope with organic Peat soils and a shallow phreatic zone (0.5 m below surface) and a slope with mineral Podzol soils and no detectable groundwater (> 2 m below surface). Similarities and differences in infiltration, percolation, and preferential flowpaths between both hillslopes could be identified by sprinkling experiments with Brilliant Blue and Sodium-Fluorescein. To our knowledge, this is the first time these two dyes have been compared in their ability to stain preferential flowpaths in soils. Dye-stained soil profiles within and downstream of the sprinkling areas were excavated parallel (lateral profiles) and perpendicular (frontal profiles) to the slopes' gradients. That way preferential flow patterns in the soil could be clearly identified. The results show that biomat flow, shallow subsurface flow in the organic topsoil layer, occurred at both hillslopes, however at the Peat Bog hillslope it was significantly more prominent. The dye solutions infiltrated into the soil and continued either as lateral subsurface pipeflow in the case of the Peat Bog, or percolated vertically towards the bedrock in the case of the Podzol. This study provides evidence that subsurface pipeflow, lateral preferential flow along decomposed tree roots or logs in the unsaturated zone, is a major runoff formation process at the Peat Bog hillslope and in the adjacent riparian zone.

scholarly journals Groundwater, Soil, and Vegetation Interactions at Discrete Riparian Inflow Points (DRIPs) and Implications for Boreal Streams

2021 ◽  
Vol 3 ◽  
Author(s):  
Stefan W. Ploum ◽  
Jason A. Leach ◽  
Hjalmar Laudon ◽  
Lenka Kuglerová
Keyword(s):  
Aquatic Ecosystems ◽  
Peat Soil ◽  
Subsurface Flow ◽  
Groundwater Chemistry ◽  
Riparian Zones ◽  
Biological Interactions ◽  
Catchment Scale ◽  
Flow Paths ◽  
Groundwater Levels ◽  
Convergence Zones

Hydrological processes at hillslope and catchment scales explain a large part of stream chemistry dynamics through source-transport mechanisms from terrestrial to aquatic ecosystems. Riparian zones play a central role, as they exert a strong influence on the chemical signature of groundwater discharge to streams. Especially important are riparian areas where upslope subsurface flow paths converge, because they connect a large part of the catchment to a narrow section of the stream. Recent research shows that both in terrestrial and aquatic ecosystems, riparian convergence zones fulfill important biogeochemical functions that differ from surrounding riparian zones. Most catchment-scale conceptual frameworks focus on generalized hillslope-riparian-stream transects and do not explicitly consider riparian convergence zones. This study integrates collective work on hydrology, groundwater chemistry, vegetation and soils of discrete riparian inflow points (DRIPs) in a boreal landscape. We show that compared to adjacent riparian forests, DRIPs have groundwater levels that are consistently near the surface, and supply organic-rich water to streams. We suggest that interactions between hydrology, wetland vegetation, and peat soil development that occur in DRIPs leads to their unique groundwater chemistry and runoff dynamics. Stream-based studies show that across flow conditions, groundwater inputs from DRIPs to headwater reaches influence stream temperature, water chemistry and biology. As such, accounting for DRIPs can complement existing hillslope and stream observations, which would allow better representation of chemical and biological interactions associated with convergence of subsurface flow paths in riparian zones.

Ground-penetrating radar monitoring of fast subsurface processes

Geophysics ◽  
2020 ◽  
Vol 85 (3) ◽  
pp. A19-A23 ◽  
Author(s):  
Niklas Allroggen ◽  
Daniel Beiter ◽  
Jens Tronicke
Keyword(s):  
Ground Penetrating Radar ◽  
Preferential Flow ◽  
Temporal Dynamics ◽  
Time Lapse ◽  
Monitoring Methods ◽  
Attribute Analysis ◽  
Accessible Information ◽  
Spatial And Temporal Dynamics ◽  
Flow Processes ◽  
Ground Penetrating

Earth and environmental sciences rely on detailed information about subsurface processes. Whereas geophysical techniques typically provide highly resolved spatial images, monitoring subsurface processes is often associated with enormous effort and, therefore, is usually limited to point information in time or space. Thus, the development of spatial and temporal continuous field monitoring methods is a major challenge for the understanding of subsurface processes. We have developed a novel method for ground-penetrating-radar (GPR) reflection monitoring of subsurface flow processes under unsaturated conditions and applied it to a hydrological infiltration experiment performed across a periglacial slope deposit in northwest Luxembourg. Our approach relies on a spatial and temporal quasicontinuous data recording and processing, followed by an attribute analysis based on analyzing differences between individual time steps. The results demonstrate the ability of time-lapse GPR monitoring to visualize the spatial and temporal dynamics of preferential flow processes with a spatial resolution in the order of a few decimeters and temporal resolution in the order of a few minutes. We observe excellent agreement with water table information originating from different boreholes. This demonstrates the potential of surface-based GPR reflection monitoring to observe the spatiotemporal dynamics of water movements in the subsurface. It provides valuable, and so far not accessible, information for example in the field of hydrology and pedology that allows studying the actual subsurface processes rather than deducing them from point information.

scholarly journals In situ investigation of rapid subsurface flow: Temporal dynamics and catchment-scale implication

2016 ◽  
Author(s):  
Lisa Angermann ◽  
Conrad Jackisch ◽  
Niklas Allroggen ◽  
Matthias Sprenger ◽  
Erwin Zehe ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Preferential Flow ◽  
Temporal Dynamics ◽  
Subsurface Flow ◽  
Time Lapse ◽  
Small Scale ◽  
Response Behavior ◽  
In Situ Investigation ◽  
Flow Processes ◽  
Hillslope Scale

Abstract. Preferential flow is omnipresent in natural systems. It links multiple scales from single pores to entire hillslopes and potentially influences the discharge dynamics of a catchment. However, there is still a lack of appropriate monitoring techniques and thus, process understanding. In this study, a promising combination of 2D time-lapse ground-penetrating radar (GPR) and soil moisture monitoring was used to observe preferential flow processes in highly structured soils during a hillslope-scale irrigation experiment. The 2D time-lapse GPR data were interpreted using structural similarity attributes, highlighting changes between individual time-lapse measurements. These changes are related to soil moisture variations in the subsurface. In combination with direct measurements of soil moisture, the spatial and temporal characteristics of the resulting patterns can give evidence about subsurface flow processes. The response dynamics at the hillslope were compared to the runoff response behavior of the headwater catchment. The experiment revealed a fast establishment of hillslope-scale connectivity despite unsaturated conditions, with high response velocities of up to 10−3 m s−1 or faster, and a high portion of mobile water. These processes substantially impact the overall catchment response behavior. While the presented approach is a good way to observe the temporal dynamics and general patterns, the spatial characteristics of small-scale preferential flow path could not be fully resolved.

Sign in / Sign up

Export Citation Format

Share Document