scholarly journals Causes and Controlling Factors of Valley Bottom Gullies

Land ◽  
2019 ◽  
Vol 8 (9) ◽  
pp. 141 ◽  
Author(s):  
Amare ◽  
Keesstra ◽  
van der Ploeg ◽  
Langendoen ◽  
Steenhuis ◽  
...  
Keyword(s):  
Subsurface Flow ◽  
Rate Of Change ◽  
Valley Bottom ◽  
Flow Paths ◽  
Concentrated Flow ◽  
Effective Implementation ◽  
Subsurface Flows ◽  
Integrated Landscape Approach ◽  
Remedial Actions ◽  
Rehabilitation Measures

Valley bottomland provides diverse agricultural and ecosystem benefits. Due to concentrated flow paths, they are more vulnerable to gully erosion than hillslope areas. The objective of this review was to show what caused valley bottoms gullies and to present deficiencies in existing rehabilitation measures. From the literature review, we found the following general trends: watershed characteristics determine location of valley bottom gullies; an increase in water transported from the watershed initiates the formation of gullies; the rate of change of the valley bottom gullies, once initiated, depends on the amount of rainfall and the soil and bedrock properties. Especially in humid climates, the presence of subsurface flow greatly enhances bank slippage and advancement of gully heads. Valley bottom gully reclamation measures are generally effective in arid and semi-arid areas with the limited subsurface flow and deep groundwater tables, whereas, for (sub) humid regions, similar remedial actions are not successful as they do not account for the effects of subsurface flows. To ensure effective implementation of rehabilitation measures, especially for humid regions, an integrated landscape approach that accounts for the combined subsurface and surface drainage is needed.

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 Large-scale lateral saturated soil hydraulic conductivity as metric for the connectivity of the subsurface flow paths at hillslope scale

2021 ◽  
Author(s):  
Mario Pirastru ◽  
Massimo Iovino ◽  
Hassan Awada ◽  
Roberto Marrosu ◽  
Simone Di Prima ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Hydraulic Conductivity ◽  
Spatial Scale ◽  
Water Table ◽  
Subsurface Flow ◽  
Lateral Flow ◽  
Saturated Soil ◽  
Flow Paths ◽  
Soil Hydraulic Conductivity ◽  
Hillslope Scale

Lateral saturated soil hydraulic conductivity, Ks,l, is the soil property governing subsurface water transfer in hillslopes, and the key parameter in many numerical models simulating hydrological processes both at the hillslope and catchment scales. Likewise, the hydrological connectivity of lateral flow paths plays a significant role in determining the intensity of the subsurface flow at various spatial scales. The objective of the study is to investigate the relationship between Ks,l and hydraulic connectivity at the hillslope spatial scale. Ks,l was determined by the subsurface flow rates intercepted by drains, and by water table depths observed in a well network. Hydraulic connectivity of the lateral flow paths was evaluated by the synchronicity among piezometric peaks, and between the latter and the peaks of drained flow. Soil moisture and precipitation data were used to investigate the influence of the transient hydrological soil condition on connectivity and Ks,l. It was found that the higher was the synchronicity of the water table response between wells, the lower was the time lag between the peaks of water levels and those of the drained subsurface flow. Moreover, the most synchronic water table rises determined the highest drainage rates. The relationships between Ks,l and water table depths were highly non-linear, with a sharp increase of the values for water table levels close to the soil surface. Estimated Ks,l values for the full saturated soil were in the order of thousands of mm h-1, suggesting the activation of macropores in the root zone. The Ks,l values determined at the peak of the drainage events were correlated with the indicators of synchronicity. The sum of the antecedent soil moisture and of the precipitation was correlated with the indicators of connectivity and with Ks,l. We suggest that, for simulating realistic processes at the hillslope scale, the hydraulic connectivity could be implicitly considered in hydrological modelling through an evaluation of Ks,l at the same spatial scale.

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.

scholarly journals Concentrated flow paths in riparian buffer zones of southern Illinois

2011 ◽  
Vol 84 (2) ◽  
pp. 191-205 ◽  
Author(s):  
R. C. Pankau ◽  
J. E. Schoonover ◽  
K. W. J. Williard ◽  
P. J. Edwards
Keyword(s):  
Riparian Buffer ◽  
Buffer Zones ◽  
Flow Paths ◽  
Southern Illinois ◽  
Concentrated Flow ◽  
Riparian Buffer Zones

scholarly journals SIMULTANEOUS SURFACE AND SUBSURFACE AIR AND WATER FLOWS MODELLING IN THE SWASH ZONE

2012 ◽  
Vol 1 (33) ◽  
pp. 56 ◽  
Author(s):  
Jonathan Desombre ◽  
Denis Morichon ◽  
Mathieu Mory
Keyword(s):  
Numerical Simulation ◽  
Laboratory Data ◽  
Subsurface Flow ◽  
Momentum Equation ◽  
Coarse Grained ◽  
Swash Zone ◽  
Data Set ◽  
Water Flows ◽  
Subsurface Flows ◽  
The University

This study presents the results of the numerical simulation of a bore-driven swash flow over a permeable coarse- grained beach, carried out using the THETIS code. This code, based on a VOF-RANS approach, was previously used to simulate the swash flow over an impermeable beach (Desombre et al. 2013). For the present study, the code is extended to account for infiltration and exfiltration into a permeable immobile beach using the Volume-Averaged momentum equation that solves simultaneously the surface and subsurface flows. The results are compared with a laboratory data set from an experiment performed in the swash facility of the University of Aberdeen (Steenhauer et al. 2011). Comparisons between measurements and model results show the ability of the model to simulate the main features of subsurface flow during an entire swash cycle.

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.

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 A three-component hydrograph separation based on geochemical tracers in a tropical mountainous headwater catchment in northern Thailand

2014 ◽  
Vol 18 (2) ◽  
pp. 525-537 ◽  
Author(s):  
C. Hugenschmidt ◽  
J. Ingwersen ◽  
W. Sangchan ◽  
Y. Sukvanachaikul ◽  
A. Duffner ◽  
...  
Keyword(s):  
Surface Runoff ◽  
Subsurface Flow ◽  
Close Relation ◽  
Hydrograph Separation ◽  
Runoff Generation ◽  
Flow Paths ◽  
Northern Thailand ◽  
Tropical Regions ◽  
Geochemical Tracers ◽  
Shallow Subsurface

Abstract. Land-use change in the mountainous parts of northern Thailand is reflected by an increased application of agrochemicals, which may be lost to surface and groundwater. The close relation between flow paths and contaminant transport within hydrological systems requires recognizing and understanding the dominant hydrological processes. To date, the vast majority of studies on runoff generation have been conducted in temperate regions. Tropical regions suffer from a general lack of data, and little is known about runoff generation processes. To fill this knowledge gap, a three-component hydrograph separation based on geochemical tracers was carried out in a steep, remote and monsoon-dominated study site (7 km2) in northern Thailand. Silica and electrical conductivity (EC) were identified as useful tracers and were applied to calculate the fractions of groundwater (similar to pre-event water), shallow subsurface flow and surface runoff on stormflow. K+ was a useful indicator for surface runoff dynamics, and Ca2+ provided insights into groundwater behaviour. Nevertheless, neither measure was applicable for the quantification of runoff components. Cl- and further parameters (e.g. Na+, K+, and Mg2+) were also not helpful for flow path identification, nor were their concentrations distinguishable among the components. Groundwater contributed the largest fractions to stormflow (62–80%) throughout all events, followed by shallow subsurface flow (17–36%) and surface runoff (2–13%). Our results provide important insights into the dynamics of the runoff processes in the study area and may be used to assess the transport pattern of contaminants (i.e. agrochemicals) here.

scholarly journals Using stable isotope tracers to assess hydrological flow paths, residence times and landscape influences in a nested mesoscale catchment

2005 ◽  
Vol 9 (3) ◽  
pp. 139-155 ◽  
Author(s):  
P. Rodgers ◽  
C. Soulsby ◽  
S. Waldron ◽  
D. Tetzlaff
Keyword(s):  
Stream Water ◽  
Spatial Scales ◽  
Isotopic Signature ◽  
Residence Times ◽  
Catchment Scale ◽  
Valley Bottom ◽  
Flow Paths ◽  
Isotope Tracers ◽  
Periodic Regression ◽  
Stream Waters

Abstract. δ18O measurements in precipitation and stream waters were used to investigate hydrological flow paths and residence times at nested spatial scales in the mesoscale (233 km2) River Feugh catchment in the northeast of Scotland over the 2001-2002 hydrological year. Precipitation δ18O exhibited strong seasonal variation, which although significantly damped within the catchment, was reflected in stream water at six sampling sites. This allowed δ18O variations to be used to infer the relative influence of soil-derived storm flows with a seasonally variable isotopic signature, and groundwater of apparently more constant isotopic composition. Periodic regression analysis was then used to examine the sub-catchment difference using an exponential flow model to provide indicative estimates of mean stream water residence times, which varied between approximately 3 and 14 months. This showed that the effects of increasing scale on estimated mean stream water residence time was minimal beyond that of the smallest (ca. 1 km2) headwater catchment scale. Instead, the interaction of catchment soil cover and topography appeared to be the dominant controlling influence. Where sub-catchments had extensive peat coverage, responsive hydrological pathways produced seasonally variable δ18O signatures in runoff with short mean residence times (ca. 3 months). In contrast, areas dominated by steeper slopes, more freely draining soils and larger groundwater storage in shallow valley-bottom aquifers, deeper flow paths allow for more effective mixing and damping of δ18O indicating longer residence times (>12 months). These insights from δ18O measurements extend the hydrological understanding of the Feugh catchment gained from previous geochemical tracer studies, and demonstrate the utility of isotope tracers in investigating the interaction of hydrological processes and catchment characteristics at larger spatial scales.

scholarly journals Simulating Coupled Surface-Subsurface Flows with ParFlow v3.5.0: Capabilities, applications, and ongoing developmentof an open-source, massively parallel, integrated hydrologic model

2019 ◽  
Author(s):  
Benjamin N. O. Kuffour ◽  
Nicholas B. Engdahl ◽  
Carol S. Woodward ◽  
Laura E. Condon ◽  
Stefan Kollet ◽  
...  
Keyword(s):  
Open Source ◽  
Land Surface ◽  
Subsurface Flow ◽  
Hydrologic Model ◽  
Time Step ◽  
The Core ◽  
Simulation Engine ◽  
Common Land Model ◽  
Subsurface Flows ◽  
Integrated Hydrologic Model

Abstract. Surface and subsurface flow constitute a naturally linked hydrologic continuum that has not traditionally been simulated in an integrated fashion. Recognizing the interactions between these systems has encouraged the development of integrated hydrologic models (IHMs) capable of treating surface and subsurface systems as a single integrated resource. IHMs is dynamically evolving with improvement in technology and the extent of their current capabilities are often only known to the developers and not general users. This article provides an overview of the core functionality, capability, applications, and ongoing development of one open-source IHM, ParFlow. ParFlow is a parallel, integrated, hydrologic model that simulates surface and subsurface flows. ParFlow solves Richards’ equation for three-dimensional variably saturated groundwater flow and the two-dimensional kinematic wave approximation of the shallow water equations for overland flow. The model employs a conservative centered finite difference scheme and a conservative finite volume method for subsurface flow and transport, respectively. ParFlow uses multigrid preconditioned Krylov and Newton-Krylov methods to solve the linear and nonlinear systems within each time step of the flow simulations. The code has demonstrated very efficient parallel solution capabilities. ParFlow has been coupled to geochemical reaction, land surface (e.g. Common Land Model), and atmospheric models to study the interactions among the subsurface, land surface, and the atmosphere systems across different spatial scales. This overview focuses on the current capabilities of the code, the core simulation engine, and the primary couplings of the subsurface model to other codes, taking a high-level perspective.

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