scholarly journals A sprinkling experiment to quantify celerity–velocity differences at the hillslope scale

2017 ◽  
Vol 21 (11) ◽  
pp. 5891-5910 ◽  
Author(s):  
Willem J. van Verseveld ◽  
Holly R. Barnard ◽  
Chris B. Graham ◽  
Jeffrey J. McDonnell ◽  
J. Renée Brooks ◽  
...  
Keyword(s):  
Input Signal ◽  
Soil Depth ◽  
Exit Time ◽  
Subsurface Flow ◽  
Model Analysis ◽  
Hydrologic Model ◽  
Effective Porosity ◽  
Wetting Front ◽  
Soil Fraction ◽  
Mass Transfer Parameter

Abstract. Few studies have quantified the differences between celerity and velocity of hillslope water flow and explained the processes that control these differences. Here, we asses these differences by combining a 24-day hillslope sprinkling experiment with a spatially explicit hydrologic model analysis. We focused our work on Watershed 10 at the H. J. Andrews Experimental Forest in western Oregon. Celerities estimated from wetting front arrival times were generally much faster than average vertical velocities of δ2H. In the model analysis, this was consistent with an identifiable effective porosity (fraction of total porosity available for mass transfer) parameter, indicating that subsurface mixing was controlled by an immobile soil fraction, resulting in the attenuation of the δ2H input signal in lateral subsurface flow. In addition to the immobile soil fraction, exfiltrating deep groundwater that mixed with lateral subsurface flow captured at the experimental hillslope trench caused further reduction in the δ2H input signal. Finally, our results suggest that soil depth variability played a significant role in the celerity–velocity responses. Deeper upslope soils damped the δ2H input signal, while a shallow soil near the trench controlled the δ2H peak in lateral subsurface flow response. Simulated exit time and residence time distributions with our hillslope hydrologic model showed that water captured at the trench did not represent the entire modeled hillslope domain; the exit time distribution for lateral subsurface flow captured at the trench showed more early time weighting.

scholarly journals A sprinkling experiment to quantify celerity-velocity differences at the hillslope scale

2017 ◽  
Author(s):  
Willem J. van Verseveld ◽  
Holly R. Barnard ◽  
Chris B. Graham ◽  
Jeffrey J. McDonnell ◽  
J. Renée Brooks ◽  
...  
Keyword(s):  
Input Signal ◽  
Soil Depth ◽  
Exit Time ◽  
Subsurface Flow ◽  
Total Porosity ◽  
Model Analysis ◽  
Hydrologic Model ◽  
Effective Porosity ◽  
Wetting Front ◽  
Mass Transfer Parameter

Abstract. The difference between celerity and velocity of hillslope water flow is poorly understood. We assessed these differences by combining a 24-day hillslope sprinkling experiment with a spatially explicit hydrologic model analysis. We focused our work at Watershed 10 at the H. J. Andrews Experimental Forest in western Oregon. δ2H label was applied at the start of the sprinkler experiment. Maximum event water (δ2H labeled water) contribution was 26 % of lateral subsurface flow at 20 h. Celerities estimated from wetting front arrival times were generally much faster (on the order of 10–377 mm h−1) than average vertical velocities of δ2H (on the order of 6–17 mm h−1). In the model analysis, this was consistent with an identifiable effective porosity (fraction of total porosity available for mass transfer) parameter, indicating that subsurface mixing was controlled by an immobile soil fraction, resulting in an attenuated δ2H in lateral subsurface flow. Furthermore, exfiltrating bedrock groundwater that mixed with lateral subsurface flow captured at the experimental hillslope trench caused further reduction in the δ2H input signal. Our results suggest that soil depth variability played a significant role in the velocity-celerity responses. Deeper upslope soils damped the δ2H input signal and played an important role in the generation of the δ2H breakthrough curve. A shallow soil (~ 0.30 m depth) near the trench controlled the δ2H peak in lateral subsurface flow response. Simulated exit time and residence time distributions with the hillslope hydrologic model were consistent with our empirical analysis and provided additional insights into hydraulic behavior of the hillslope. In particular, it showed that water captured at the trench was not representative for the hydrological and mass transport behavior of the entire hillslope domain that generated total lateral subsurface flow, because of different exit time distributions for lateral subsurface flow captured at the trench and total lateral subsurface flow.

scholarly journals A hydroclimatological approach to predicting regional landslide probability using Landlab

2018 ◽  
Vol 6 (1) ◽  
pp. 49-75 ◽  
Author(s):  
Ronda Strauch ◽  
Erkan Istanbulluoglu ◽  
Sai Siddhartha Nudurupati ◽  
Christina Bandaragoda ◽  
Nicole M. Gasparini ◽  
...  
Keyword(s):  
Soil Depth ◽  
Probability Distributions ◽  
Probability Model ◽  
Subsurface Flow ◽  
Bimodal Distribution ◽  
Shallow Landslide ◽  
Hydrologic Model ◽  
Infinite Slope Stability Model ◽  
Physically Based ◽  
Temporal Dimensions

Abstract. We develop a hydroclimatological approach to the modeling of regional shallow landslide initiation that integrates spatial and temporal dimensions of parameter uncertainty to estimate an annual probability of landslide initiation based on Monte Carlo simulations. The physically based model couples the infinite-slope stability model with a steady-state subsurface flow representation and operates in a digital elevation model. Spatially distributed gridded data for soil properties and vegetation classification are used for parameter estimation of probability distributions that characterize model input uncertainty. Hydrologic forcing to the model is through annual maximum daily recharge to subsurface flow obtained from a macroscale hydrologic model. We demonstrate the model in a steep mountainous region in northern Washington, USA, over 2700 km2. The influence of soil depth on the probability of landslide initiation is investigated through comparisons among model output produced using three different soil depth scenarios reflecting the uncertainty of soil depth and its potential long-term variability. We found elevation-dependent patterns in probability of landslide initiation that showed the stabilizing effects of forests at low elevations, an increased landslide probability with forest decline at mid-elevations (1400 to 2400 m), and soil limitation and steep topographic controls at high alpine elevations and in post-glacial landscapes. These dominant controls manifest themselves in a bimodal distribution of spatial annual landslide probability. Model testing with limited observations revealed similarly moderate model confidence for the three hazard maps, suggesting suitable use as relative hazard products. The model is available as a component in Landlab, an open-source, Python-based landscape earth systems modeling environment, and is designed to be easily reproduced utilizing HydroShare cyberinfrastructure.

scholarly journals A hydro-climatological approach to predicting regional landslide probability using Landlab

2017 ◽  
Author(s):  
Ronda Strauch ◽  
Erkan Istanbulluoglu ◽  
Sai Siddhartha Nudurupati ◽  
Christina Bandaragoda ◽  
Nicole M. Gasparini ◽  
...  
Keyword(s):  
Soil Depth ◽  
Probability Distributions ◽  
Probability Model ◽  
Subsurface Flow ◽  
Grid Cell ◽  
Bimodal Distribution ◽  
Shallow Landslide ◽  
Hydrologic Model ◽  
Model Parameters ◽  
Infinite Slope Stability Model

Abstract. We develop a hydro-climatological approach to modeling of regional shallow landslide initiation that integrates spatial and temporal dimensions of parameter uncertainty to estimate an annual probability of landslide initiation. The physically-based model couples the infinite slope stability model with a steady-state subsurface flow representation and operates on a digital elevation model. Spatially distributed raster data for soil properties and a soil evolution model and vegetation classification from National Land Cover Data are used to derive parameters for probability distributions to represent input uncertainty. Hydrologic forcing to the model is through annual maximum recharge to subsurface flow obtained from a macroscale hydrologic model, routed on raster grid to develop subsurface flow. A Monte Carlo approach is used to generate model parameters at each grid cell and calculate probability of shallow landsliding. We demonstrate the model in a steep mountainous region in northern Washington, U.S.A., using 30-m grid resolution over 2,700 km2. The influence of soil depth on the probability of landslide initiation is investigated through comparisons among model output produced using three different soil depth scenarios reflecting uncertainty of soil depth and its potential long-term variability. We found elevation dependent patterns in probability of landslide initiation that showed the stabilizing effects of forests in low elevations, an increased landslide probability with forest decline at mid elevations (1,400 to 2,400 m), and soil limitation and steep topographic controls at high alpine elevations and post-glacial landscapes. These dominant controls manifest in a bimodal distribution of spatial annual landslide probability. Model testing with limited observations revealed similar model confidence for the three hazard maps, suggesting suitable use as relative hazard products. Validation of the model with observed landslides is hindered by the completeness and accuracy of the inventory, estimation of source areas, and unmapped landslides. The model is available as a component in Landlab, an open-source, Python-based landscape earth systems modeling environment, and is designed to be easily reproduced utilizing HydroShare cyberinfrastructure.

scholarly journals Assessment of the Timing of Daily Peak Streamflow during the Melt Season in a Snow-Dominated Watershed

2016 ◽  
Vol 17 (8) ◽  
pp. 2225-2244 ◽  
Author(s):  
Xing Chen ◽  
Mukesh Kumar ◽  
Rui Wang ◽  
Adam Winstral ◽  
Danny Marks
Keyword(s):  
Water Flux ◽  
Subsurface Flow ◽  
Hydrologic Model ◽  
Daily Streamflow ◽  
Penn State ◽  
Integrated Hydrologic Model ◽  
Interseasonal Variability ◽  
Peak Streamflow ◽  
Surface And Subsurface Flow ◽  
Temporal Shifts

Abstract Previous studies have shown that gauge-observed daily streamflow peak times (DPTs) during spring snowmelt can exhibit distinct temporal shifts through the season. These shifts have been attributed to three processes: 1) melt flux translation through the snowpack or percolation, 2) surface and subsurface flow of melt from the base of snowpacks to streams, and 3) translation of water flux in the streams to stream gauging stations. The goal of this study is to evaluate and quantify how these processes affect observed DPTs variations at the Reynolds Mountain East (RME) research catchment in southwest Idaho, United States. To accomplish this goal, DPTs were simulated for the RME catchment over a period of 25 water years using a modified snowmelt model, iSnobal, and a hydrology model, the Penn State Integrated Hydrologic Model (PIHM). The influence of each controlling process was then evaluated by simulating the DPT with and without the process under consideration. Both intra- and interseasonal variability in DPTs were evaluated. Results indicate that the magnitude of DPTs is dominantly influenced by subsurface flow, whereas the temporal shifts within a season are primarily controlled by percolation through snow. In addition to the three processes previously identified in the literature, processes governing the snowpack ripening time are identified as additionally influencing DPT variability. Results also indicate that the relative dominance of each control varies through the melt season and between wet and dry years. The results could be used for supporting DPTs prediction efforts and for prioritization of observables for DPT determination.

Effect of Intermittent Water Application from Trickle Source on The Water Movement and Moisture Distribution in Layered Soil

2020 ◽  
Vol 27 (4) ◽  
pp. 87-97
Author(s):  
haqqi Yasin ◽  
abdul alsattar Al-Dabagh
Keyword(s):  
Sandy Loam ◽  
Soil Depth ◽  
Layered Soil ◽  
Moisture Distribution ◽  
Silty Clay ◽  
Horizontal Distance ◽  
Clay Loam ◽  
Water Application ◽  
Wetting Front ◽  
Silty Clay Loam

The aim of this research is to study the effect of intermittent water application on the wetting pattern and soil moisture distribution for homogeneous and layered soils under trickle source. Thirty experiments were conducted to monitor the advance of the wetting front in the soil profiles. Measurements of soil moisture content were also made at selected locations to evaluate the moisture distribution in soil. Four types of soil profiles were built; the first was sandy loam soil, the second was silty clay loam soil, the third was (silty clay loam/ sandy loam) layered soil, and the fourth was (sandy loam/ silty clay loam) layered soil. Three water application rates were used for each soil profile. Three continuous or intermittent applications were used; continuous applications, equally intermittent applications, and different intermittent applications. In addition, several cylindrical infiltration tests were conducted to describe some characteristics of each soil. Empirical relations to predict each of vertical (under trickle source) and horizontal (at soil surface) wetting front advance were found in this study. Empirical relations to predict the percentage of applied water volume in horizontal strips as a function of soil depth and in vertical strips as a function of horizontal distance from the trickle emitter were also found. The study showed that the wetted soil volume increases as either the water application rate increases, or the intermittent application ratio increases. Also, it showed that the ratio of horizontal advance to vertical advance of wetting front increases as either the water application rate increases, or the intermittent application ratio decreases. The study demonstrated that the accumulated ratio of water application volume at a certain soil depth from trickle source increases as the intermittent application ratio decreases. Also, it demonstrated that the accumulated ratio of water application volume at a certain horizontal distance from trickle source decreases as the intermittent application ratio decreases.

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.

scholarly journals A steady-state saturation model to determine the subsurface travel time (STT) in complex hillslopes

2010 ◽  
Vol 14 (6) ◽  
pp. 891-900 ◽  
Author(s):  
T. Sabzevari ◽  
A. Talebi ◽  
R. Ardakanian ◽  
A. Shamsai
Keyword(s):  
Steady State ◽  
Travel Time ◽  
Soil Depth ◽  
Subsurface Flow ◽  
Average Flow Rate ◽  
Recharge Rate ◽  
Zone Length ◽  
Average Flow ◽  
Saturation Zone ◽  
Saturation Capacity

Abstract. The travel time of subsurface flow in complex hillslopes (hillslopes with different plan shape and profile curvature) is an important parameter in predicting the subsurface flow in catchments. This time depends on the hillslopes geometry (plan shape and profile curvature), soil properties and climate conditions. The saturation capacity of hillslopes affect the travel time of subsurface flow. The saturation capacity, and subsurface travel time of compound hillslopes depend on parameters such as soil depth, porosity, soil hydraulic conductivity, plan shape (convergent, parallel or divergent), hillslope length, profile curvature (concave, straight or convex) and recharge rate to the groundwater table. An equation for calculating subsurface travel time for all complex hillslopes was presented. This equation is a function of the saturation zone length (SZL) on the surface. Saturation zone length of the complex hillslopes was calculated numerically by using the hillslope-storage kinematic wave equation for subsurface flow, so an analytical equation was presented for calculating the saturation zone length of the straight hillslopes and all plan shapes geometries. Based on our results, the convergent hillslopes become saturated very soon and they showed longer SZL with shorter travel time compared to the parallel and divergent ones. The subsurface average flow rate in convergent hillslopes is much less than the divergent ones in the steady state conditions. Concerning to subsurface travel time, convex hillslopes have more travel time in comparison to straight and concave hillslopes. The convex hillslopes exhibit more average flow rate than concave hillslopes and their saturation capacity is very low. Finally, the effects of recharge rate variations, average bedrock slope and soil depth on saturation zone extension were investigated.

scholarly journals The effects of stemflow on redistributing precipitation and infiltration around shrubs

2018 ◽  
Vol 66 (1) ◽  
pp. 79-86 ◽  
Author(s):  
Shengqi Jian ◽  
Xueli Zhang ◽  
Dong Li ◽  
Deng Wang ◽  
Zening Wu ◽  
...  
Keyword(s):  
Soil Moisture ◽  
Root Zone ◽  
Soil Depth ◽  
Rainfall Threshold ◽  
Chinese Loess Plateau ◽  
Wetting Front ◽  
Deep Soil ◽  
Soil Layers ◽  
Chinese Loess ◽  
Caragana Korshinskii

Abstract The experiments of stemflow of two semiarid shrubs (Caragana korshinskii and Hippophae rhamnoides) and its effect on soil water enhancement were conducted from 1st May to 30th September of 2009-2013 in the Chinese Loess Plateau. Stemflow values in C. korshinskii and H. rhamnoides averaged 6.7% and 2.4% of total rainfall. The rainfall threshold for stemflow generation was 0.5 and 2.5 mm for C. korshinskii and H. rhamnoides. When rainfall was less than 17.0 mm, the funnelling ratios were highly variable, however, stable funnelling ratios were found for rainfall greater than 17.0 mm for C. korshinskii. The funnelling ratios of H. rhamnoides first increased until a threshold value of 10.0 mm and then the funnelling ratios begin stabilize. The wetting front depths in the area around stem was 1.4-6.7 and 1.3-2.9 times deeper than area outside the canopy for C. korshinskii and H. rhamnoides. Soil moisture at soil depth 0-200 cm was 25.6% and 23.4% higher in soil around stem than that outside canopy for C. korshinskii and H. rhamnoides. The wetting front advanced to depths of 120 and 100 cm in the area around stem and to depths of 50 cm in the area outside the canopy for C. korshinskii and H. rhamnoides suggested that more rain water can be conserved into the deep soil layers through shrub stemflow. Soil moisture was enhanced in the area outside the shrub canopy, only when rainfall depth is > 4.7 and 5.1 mm, which is an effective rainfall for the area for C. korshinskii and H. rhamnoides. While for the area around stem of C. korshinskii and H. rhamnoides, the corresponding threshold values are 3.2 and 4.3 mm. These results confirmed that stemflow has a positive effect on soil moisture balance of the root zone and the enhancement in soil moisture of deeper soil layers.

scholarly journals A steady-state saturation model to determine the subsurface travel time (STT) in complex hillslopes

2009 ◽  
Vol 6 (6) ◽  
pp. 7179-7212 ◽  
Author(s):  
T. Sabzevari ◽  
A. Talebi ◽  
R. Ardakanian ◽  
A. Shamsai
Keyword(s):  
Steady State ◽  
Travel Time ◽  
Soil Depth ◽  
Subsurface Flow ◽  
Average Flow Rate ◽  
Recharge Rate ◽  
Zone Length ◽  
Average Flow ◽  
Saturation Zone ◽  
Saturation Capacity

Abstract. The travel time of subsurface flow in complex hillslopes (hillslopes with different plan shape and profile curvature) is an important parameter in predicting the subsurface flow in catchments. This time depends on the hillslopes geometry (plan shape and profile curvature), soil properties and climate conditions. The saturation capacity of hillslopes affect the travel time of subsurface flow. The saturation capacity, and subsurface travel time of compound hillslopes depend on parameters such as soil depth, porosity, soil hydraulic conductivity, plan shape (convergent, parallel or divergent), hillslope length, profile curvature (concave, straight or convex) and recharge rate to the groundwater table. An equation for calculating subsurface travel time for all complex hillslopes was presented. This equation is a function of the saturation zone length (SZL) on the surface. Saturation zone length of the complex hillslopes was calculated numerically by using the hillslope-storage Boussinesq (hsB) model in the steady state conditions, so an analytical equation was presented for calculating the saturation zone length of the straight hillslopes and all plan shapes geometries. Based on our results, the convergent hillslopes become saturated very soon and they showed longer SZL with shorter travel time compared to the parallel and divergent ones. The subsurface average flow rate in convergent hillslopes is much less than the divergent ones in the steady state conditions. Concerning to subsurface travel time, convex hillslopes have more travel time in comparison to straight and concave hillslopes. The convex hillslopes exhibit more average flow rate than concave hillslopes and their saturation capacity is very low. Finally, the effects of recharge rate variations, average bedrock slope and soil depth on saturation zone extension were investigated.

scholarly journals Chemical and Spectroscopic Investigation of Different Soil Fractions as Affected by Soil Management

2020 ◽  
Vol 10 (7) ◽  
pp. 2571 ◽  
Author(s):  
Francesco De Mastro ◽  
Claudio Cocozza ◽  
Gennaro Brunetti ◽  
Andreina Traversa
Keyword(s):  
Diffuse Reflectance ◽  
Soil Depth ◽  
Soil Layer ◽  
Mineralogical Composition ◽  
Coarse Fraction ◽  
Soil Fractions ◽  
Soil Fraction ◽  
Drift Analysis ◽  
Diffuse Reflectance Infrared ◽  
Conventional Ct

The interaction of organic matter with the finest soil fractions (<20 μm) represents a good way for its stabilization. This study investigates the effects of conventional (CT), minimum (MT), and no (NT) tillage, fertilization, and non-fertilization, and soil depth (0–30, 30–60, and 60–90 cm) on the amount of organic carbon (OC) in four soil fractions. Diffuse reflectance infrared Fourier transform spectroscopy (DRIFT) was performed to obtain information about the OC quality and the mineralogical composition of these fractions. The CT shows the highest amount of the finest fraction while the fertilization enhances the microbial community with the increase of soil micro-aggregates (250–53 μm). The coarse fraction (>250 μm) is highest in the upper soil layer, while the finest fraction is in the deepest one. The greatest OC content is observed in the topsoil layer and in the finest soil fraction. DRIFT analysis suggests that organic components are more present in the finest fraction, calcite is mainly localized in the coarse fraction, quartz is in micro-aggregates and 53–20 μm fraction, and clay minerals are in the finest fraction.

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