Soil Hydrology and Erosion

A special issue of Geosciences (ISSN 2076-3263). This special issue belongs to the section "Hydrogeology".

Deadline for manuscript submissions: closed (31 January 2019) | Viewed by 75183

Special Issue Editors


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Guest Editor
Natural Science Laboratory, Toyo University, Tokyo 112-8606, Japan
Interests: hydrology; soil physics; vadose zone; hydrologic modeling; monitoring soil water movement; biological effect on water movement in soil
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Guest Editor
Civil & Architectural Engineering, Texas A&M University-Kingsville, Kingsville, TX 78363-8202, USA
Interests: remote sensing; land use hydrolgic impact; ecohydrology; modeling
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The goal of this Special Issue of Geosciences is to gather original research articles and reviews on soil hydrology and Erosion.

Soil hydrological processes are studied in various fields: Agronomy, environmental science, forestry, hydrology, meteorology, and water management. With the increase in the demand of proper water management, and the development of measuring technologies, soil moisture data at various spatial and temporal resolutions can be obtained. Proper understanding and prediction of soil hydrological processes in the vadose zone and aquifers require proper modeling of soil water flow.

Soil conservation practices are aimed at reducing soil loss associated with land use or land use change. To quantify the potential benefits of conservation practices, land managers need reliable tools to predict soil loss under baseline conditions and following land management actions. In recent years, research has been undertaken to develop or enhance hydrology and erosion models to provide such tools. These models have a wide range of spatial and temporal scale, from plot to watershed scale and from rainfall event to annual.

There are many challenges in integrating mathematical modeling of water flow in soil with field-measured soil moisture data, because water flow in soil is affected by various factors, such as interaction with plants and changes in climatic conditions. Moreover, soil hydraulic properties are highly heterogeneous and scale dependent.

Topics of interest of this Special Issue include, but are not limited to: Development and improvement of soil hydrological models; verification of model with numerical simulations; determination of hydraulic parameters with laboratory experiments or field measurements; field measurements to verify soil hydrological models or to gain insight in hydrological processes; and soil hydraulic models coupled with chemical and biological processes.

Dr. Katsutoshi Seki
Dr. Osama Al-Hamdan
Guest Editors

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Keywords

  • Soil hydrology
  • Soil physics
  • Modeling and management of water flow
  • Vadose zone
  • Soil moisture
  • Heterogeneity
  • Chemical fate and transport in soils
  • Soil Erosion
  • Erosion Risk assessment

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Published Papers (12 papers)

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Research

19 pages, 2841 KiB  
Article
Estimation of Soil Erosion in Nepal Using a RUSLE Modeling and Geospatial Tool
by Pooja Koirala, Sudeep Thakuri, Subesh Joshi and Raju Chauhan
Geosciences 2019, 9(4), 147; https://doi.org/10.3390/geosciences9040147 - 29 Mar 2019
Cited by 156 | Viewed by 20504
Abstract
Soil erosion is a major issue, causing the loss of topsoil and fertility in agricultural land in mountainous terrain. Estimation of soil erosion in Nepal is essential because of its agriculture-dependent economy (contributing 36% to national GDP) and for preparing erosion control plans. [...] Read more.
Soil erosion is a major issue, causing the loss of topsoil and fertility in agricultural land in mountainous terrain. Estimation of soil erosion in Nepal is essential because of its agriculture-dependent economy (contributing 36% to national GDP) and for preparing erosion control plans. The present study, for the first time, attempts to estimate the soil loss of Nepal through the application of the Revised Universal Soil Loss Equation (RUSLE) model. In addition, it analyzes the effect of Land Use and Land Cover (LULC) and slope ( β ) exposition on soil erosion. Nation-wide mean annual soil loss of Nepal is estimated at 25 t ha−1 yr−1 with a total of 369 million tonnes (mT) of potential soil loss. Soil erosion based on the physiographic region of the country shows that the Middle Mountains, High Mountains, High Himal, Chure, and Terai have mean erosion rates of 38.0, 32.0, 28.0, 7.0, and 0.1 t ha−1 yr−1. The soil erosion rate by basins showed that the annual erosions of the Karnali, Gandaki, Koshi, and Mahakali River basins are 135, 96, 79, and 15 mT, respectively. The mean soil erosion rate was significantly high (34 t ha−1 yr−1) for steep slopes (β > 26.8%) and the low (3 t ha−1 yr−1) for gentle slopes (β < 5%). Based on LULC, the mean erosion rate for barren land was the highest (40 t ha−1 yr−1), followed by agricultural land (29 t ha−1 yr−1), shrubland (25 t ha−1 yr−1), grassland (23 t ha−1 yr−1), and forests (22 t ha−1 yr−1). The entire area had been categorized into 6 erosion classes based on the erosion severity, and 11% of the area was found to be under a very severe erosion risk (> 80 t ha−1 yr−1) that urgently required reducing the risk of erosion. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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21 pages, 5215 KiB  
Article
Simulating 10,000 Years of Erosion to Assess Nuclear Waste Repository Performance
by Adam L. Atchley, Kay H. Birdsell, Kelly Crowell, Richard S. Middleton and Philip H. Stauffer
Geosciences 2019, 9(3), 120; https://doi.org/10.3390/geosciences9030120 - 8 Mar 2019
Cited by 2 | Viewed by 3987
Abstract
Long-term environmental performance assessments of natural processes, including erosion, are critically important for waste repository site evaluation. However, assessing a site’s ability to continuously function is challenging due to parameter uncertainty and compounding nonlinear processes. In lieu of unavailable site data for model [...] Read more.
Long-term environmental performance assessments of natural processes, including erosion, are critically important for waste repository site evaluation. However, assessing a site’s ability to continuously function is challenging due to parameter uncertainty and compounding nonlinear processes. In lieu of unavailable site data for model calibration, we present a workflow to include multiple sources of surrogate data and reduced-order models to validate parameters for a long-term erosion assessment of a low-level radioactive nuclear waste repository. We apply this new workflow to a low-level waste repository on mesas in Los Alamos National Laboratory in New Mexico. To account for parameter uncertainty, we simulate high-, moderate-, and low-erosion cases. The assessment extends to 10,000 years, which results in large erosion uncertainties, but is necessary given the nature of the interred waste. Our long-term erosion analysis shows that high-erosion scenarios produce rounded mesa tops and partially filled canyons, diverging from the moderate-erosion case that results in gullies and sharp mesa rims. Our novel model parameterization workflow and modeling exercise demonstrates the utility of long-term assessments, identifies sources of erosion forecast uncertainty, and demonstrates the utility of landscape evolution model development. We conclude with a discussion on methods to reduce assessment uncertainty and increase model confidence. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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19 pages, 11618 KiB  
Article
An Instrumented Flume for Infiltration Process Modeling, Landslide Triggering and Propagation
by Gennaro Spolverino, Giovanna Capparelli and Pasquale Versace
Geosciences 2019, 9(3), 108; https://doi.org/10.3390/geosciences9030108 - 28 Feb 2019
Cited by 9 | Viewed by 3121
Abstract
Rainfall is the most common cause of landslides, so it is important to know the processes underlying failure starting with the rainfall infiltration processes into the granular soils, the distribution of the water content and pore pressure in both saturated and unsaturated layers, [...] Read more.
Rainfall is the most common cause of landslides, so it is important to know the processes underlying failure starting with the rainfall infiltration processes into the granular soils, the distribution of the water content and pore pressure in both saturated and unsaturated layers, to include their effects in terms of slope stability. Although the literature is full of simulation models, the complexity of phenomena would impose a more detailed analysis by a well-equipped flume. For that purpose, a meter-scale laboratory experiment at the University of Calabria was designed and built. It is very useful for carrying out complex tests to analyze the response of loose soils or debris in terms of stability. It is composed of two channels: the first one was adopted for analyzing the triggering mechanisms, the second one for the propagation phases. Both channels are equipped with suitable sensors for monitoring the main physical variables, i.e., spray nozzle systems to apply a specific rainfall intensity; minitensiometers and TDR (Time Domain Reflectometry) for measuring, respectively, suction values and water content; miniaturized pressure transducers for pore water pressures; and laser displacement sensors. This paper describes in detail the instrumented flume and explores its potential through the analysis of a homogeneous slope of pyroclastic soil. An experiment was carried out to reproduce landslide triggering in pyroclastic soils, evolving in mudflow, by considering a homogeneous deposit. The measurements carried out allowed testing the apparatus, describing the behavior of the soil after rainfall infiltration and better identifying factors particularly significant in the collapse mechanism and process evolution. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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20 pages, 2757 KiB  
Article
Effect of Compaction on Soil Physical Properties of Differently Textured Landfill Liner Materials
by Steffen Beck-Broichsitter, Horst H. Gerke and Rainer Horn
Geosciences 2019, 9(1), 1; https://doi.org/10.3390/geosciences9010001 - 20 Dec 2018
Cited by 6 | Viewed by 3689
Abstract
Mineral landfill liners require legally-fixed standards including a sufficiently-high available water capacity (AWC) and relatively low saturated hydraulic conductivity values (Ks). For testing locally available and potentially suitable materials with respect to these requirements, the soil hydraulic properties of boulder marl (bm) and [...] Read more.
Mineral landfill liners require legally-fixed standards including a sufficiently-high available water capacity (AWC) and relatively low saturated hydraulic conductivity values (Ks). For testing locally available and potentially suitable materials with respect to these requirements, the soil hydraulic properties of boulder marl (bm) and marsh clay (mc) were investigated considering a defined compaction according to Proctor densities. Both materials were pre-compacted in 20 soil cores (100 cm3) each on the basis of the Proctor test results at five degrees of compaction (bm1–bm5; mc1–mc5) ranging between 1.67–2.07 g/cm3 for bm and 1.09–1.34 g/cm3 for mc. Additionally, unimodal and bimodal models were used to fit the soil water retention curve near saturation and changes in the pore size distribution (PSD). The structural peak of the PSD in the fraction of pore volume between −30 and −60 hPa was more pronounced on the dry side (bm1–2, mc1–2) than on the wet side of the Proctor curve (bm4–5, mc4–5). Therefore, the loss in structural pores can be attributed to an increasing dry bulk density for bm and an increasing gravimetric moisture content during Proctor test for mc. While the mc fulfils the legal standards with AWC values between 0.244–0.271 cm3/cm3, the Ks values for bm between 1.6 × 10−6 m/s and 3.8 × 10−7 m/s and for mc between 7.4 × 10−7 m/s and 1.2 × 10−7 m/s were up to two orders of magnitude higher than required. These results suggest that the suitability of both materials as landfill liner is restricted. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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16 pages, 4078 KiB  
Article
The Influence of Crude Oil on Mechanistic Detachment Rate Parameters
by Manar B. Hasan and Abdul-Sahib T. Al-Madhhachi
Geosciences 2018, 8(9), 332; https://doi.org/10.3390/geosciences8090332 - 4 Sep 2018
Cited by 17 | Viewed by 4103
Abstract
Iraqi soil contamination greatly influenced soil detachment. Previous researchers have not been able to predict the influence of crude oil soil contamination on either the mechanistic dimensional detachment parameter b0 or the threshold parameter b1 of the mechanistic detachment model (Wilson [...] Read more.
Iraqi soil contamination greatly influenced soil detachment. Previous researchers have not been able to predict the influence of crude oil soil contamination on either the mechanistic dimensional detachment parameter b0 or the threshold parameter b1 of the mechanistic detachment model (Wilson model). The aims of this research were (1) to investigate the influence of crude oil on deriving Wilson model parameters, b0 and b1, with two setups at different scales and different soil moisture contents and (2) to predict b0 and b1 in crude oil contaminated dry soils with varying levels of contamination. The “mini” JET apparatus was implemented under laboratory conditions for soil specimens packed at both a small (standard mold) and a large (in-situ soil box) scale. The results showed an inverse correlation between b0 and water content for clean soil. No correlation between b0 and soil moisture content was observed for contaminated soils. There was a huge reduction in the b0 value as the contamination time increased compared to the clean soil. This was related to the role crude oil plays in soil stabilization. Crude oil contamination significantly increased lead contamination level while slightly increasing the pH and total organic carbon. The influence of crude oil on mechanistic soil detachment can be predicted with a priori JET experiments on soils without crude oil based on crude oil parameters. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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17 pages, 3013 KiB  
Article
Modelling Ephemeral Gully Erosion from Unpaved Urban Roads: Equifinality and Implications for Scenario Analysis
by Napoleon Gudino-Elizondo, Trent W. Biggs, Ronald L. Bingner, Yongping Yuan, Eddy J. Langendoen, Kristine T. Taniguchi, Thomas Kretzschmar, Encarnacion V. Taguas and Douglas Liden
Geosciences 2018, 8(4), 137; https://doi.org/10.3390/geosciences8040137 - 17 Apr 2018
Cited by 21 | Viewed by 5092
Abstract
Modelling gully erosion in urban areas is challenging due to difficulties with equifinality and parameter identification, which complicates quantification 0of management impacts on runoff and sediment production. We calibrated a model (AnnAGNPS) of an ephemeral gully network that formed on unpaved roads following [...] Read more.
Modelling gully erosion in urban areas is challenging due to difficulties with equifinality and parameter identification, which complicates quantification 0of management impacts on runoff and sediment production. We calibrated a model (AnnAGNPS) of an ephemeral gully network that formed on unpaved roads following a storm event in an urban watershed (0.2 km2) in Tijuana, Mexico. Latin hypercube sampling was used to create 500 parameter ensembles. Modelled sediment load was most sensitive to the Soil Conservation Service (SCS) curve number, tillage depth (TD), and critical shear stress (τc). Twenty-one parameter ensembles gave acceptable error (behavioural models), though changes in parameters governing runoff generation (SCS curve number, Manning’s n) were compensated by changes in parameters describing soil properties (TD, τc), resulting in uncertainty in the optimal parameter values. The most suitable parameter combinations or “behavioural models” were used to evaluate uncertainty under management scenarios. Paving the roads increased runoff by 146–227%, increased peak discharge by 178–575%, and decreased sediment load by 90–94% depending on the ensemble. The method can be used in other watersheds to simulate runoff and gully erosion, to quantify the uncertainty of model-estimated impacts of management activities on runoff and erosion, and to suggest critical field measurements to reduce uncertainties in complex urban environments. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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13 pages, 5617 KiB  
Article
Effects of pH-Induced Changes in Soil Physical Characteristics on the Development of Soil Water Erosion
by Shinji Matsumoto, Shunta Ogata, Hideki Shimada, Takashi Sasaoka, Akihiro Hamanaka and Ginting Jalu Kusuma
Geosciences 2018, 8(4), 134; https://doi.org/10.3390/geosciences8040134 - 16 Apr 2018
Cited by 24 | Viewed by 7846
Abstract
Soil water erosion is frequently reported as serious problem in soils in Southeast Asia with tropical climates, and the variations in pH affect the development of the erosion. This study investigated the effects of changes in pH on soil water erosion based on [...] Read more.
Soil water erosion is frequently reported as serious problem in soils in Southeast Asia with tropical climates, and the variations in pH affect the development of the erosion. This study investigated the effects of changes in pH on soil water erosion based on changes in the physical properties of the simulated soils with pH adjusted from 2.0 to 10.0 through artificial rainfall tests. The zeta potential was entirely shifted to positive direction at each pH condition due to Al, Ca, and Mg. In the pH range of 6.0 to 2.0, the aggregation of soil particles resulting from the release of Al3+ from clay minerals and/or molecular attraction between soil particles caused the plastic index (IP) of the soil to decrease. The decrease in IP led to the development of soil water erosion at the pH range. When the pH exceeded 6.0, the repulsive force generated by the negative charges on soil particles decreased IP, resulting in accelerated erosion by water. The results suggest that changes in pH causes physical properties of the soil to change through changes of the zeta potential in the clayey soil rich in Al, Ca, and Mg, leading to the development of soil water erosion. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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15 pages, 2733 KiB  
Article
Comparison of Geometric and Volumetric Methods to a 3D Solid Model for Measurement of Gully Erosion and Sediment Yield
by Ingrid Luffman, Arpita Nandi and Benjamin Luffman
Geosciences 2018, 8(3), 86; https://doi.org/10.3390/geosciences8030086 - 3 Mar 2018
Cited by 5 | Viewed by 4771
Abstract
Gully erosion is a global problem that degrades land and reduces its utility for agriculture, development, and water quality. Quantification of sediment yield and control of sediment sources is essential for environmental protection. Five methods to evaluate erosion rates and sediment yield on [...] Read more.
Gully erosion is a global problem that degrades land and reduces its utility for agriculture, development, and water quality. Quantification of sediment yield and control of sediment sources is essential for environmental protection. Five methods to evaluate erosion rates and sediment yield on an east Tennessee, USA, hillslope were compared: (1) physical measurement by removal of accumulated sediment using 10 L buckets; (2) repeated measurement of erosion pins in gully (erosional) and delta (depositional) areas; (3) geometric model using a combination trapezoidal prism-cylinder segment; (4) geometric model using a series of trapezoidal pyramids; and (5) 3D solid computer modeling. The 3D solid model created in SolidWorks was selected as the reference model and all other methods overestimated sediment yield to varying degrees. Erosion pin methods overestimated sediment yield by 368% in deltas and 123% in gullies. Volumetric measurement of sediment using buckets overestimated sediment yield by 160% due to void space in the buckets. The trapezoidal prism-cylinder segment model overestimated sediment yield by 66% and the trapezoidal pyramids method overestimated sediment yield by 5.7%. For estimation of sediment trapped behind an elliptical or circular silt fence dam, use of the trapezoidal pyramid method provides a good approximation comparable to 3D solid computer modeling. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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22 pages, 11742 KiB  
Article
Vadose Zone Modeling in a Small Forested Catchment: Impact of Water Pressure Head Sampling Frequency on 1D-Model Calibration
by Benjamin Belfort, Ivan Toloni, Philippe Ackerer, Solenn Cotel, Daniel Viville and François Lehmann
Geosciences 2018, 8(2), 72; https://doi.org/10.3390/geosciences8020072 - 18 Feb 2018
Cited by 5 | Viewed by 4847
Abstract
The characterization of vadose zone processes is a primary goal for understanding, predicting, and managing water resources. In this study, the issue of soil water monitoring on a vertical profile in the small forested Strengbach catchment (France) is investigated using numerical modeling with [...] Read more.
The characterization of vadose zone processes is a primary goal for understanding, predicting, and managing water resources. In this study, the issue of soil water monitoring on a vertical profile in the small forested Strengbach catchment (France) is investigated using numerical modeling with the long-term sequences 1D-Richards’ equation and parameter estimation through an inverse technique. Three matric potential sensors produce the observation data, and the meteorological data is monitored using an automatic weather station. The scientific questions address the selection of the calibration sequence, the initial starting point for inverse optimization and monitoring frequency used in the inverse procedure. As expected, our results show that the highly variable data period used for the calibration provides better estimations when simulating the long-term sequence. For the starting point of the initial parameters, handmade iterative initial parameters estimation leads to better results than a laboratory analysis or set of ROSETTA parameters. Concerning the frequency of monitoring, weekly and daily datasets provide efficient results compared to hourly data. As reported in other articles, the accuracy of the boundary conditions is important for estimating soil hydraulic parameters and accessing water stored in the layered profile. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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18 pages, 4973 KiB  
Article
Spatially Distributed Evaluation of ESA CCI Soil Moisture Products in a Northern Boreal Forest Environment
by Jaakko Ikonen, Tuomo Smolander, Kimmo Rautiainen, Juval Cohen, Juha Lemmetyinen, Miia Salminen and Jouni Pulliainen
Geosciences 2018, 8(2), 51; https://doi.org/10.3390/geosciences8020051 - 3 Feb 2018
Cited by 21 | Viewed by 5846
Abstract
Several previous studies have discussed the challenges in remotely sensed soil moisture retrievals over northern boreal environments. However, very few studies have focused solely on an evaluation of these products specifically over these areas. This study provides an in-depth evaluation of the European [...] Read more.
Several previous studies have discussed the challenges in remotely sensed soil moisture retrievals over northern boreal environments. However, very few studies have focused solely on an evaluation of these products specifically over these areas. This study provides an in-depth evaluation of the European Space Agency’s (ESA) Climate Change Initiative (CCI) Soil Moisture (SM) product and its components; ACTIVE and PASSIVE soil moisture retrievals. The performance of a spatially distributed soil moisture model (SAC-SMA) is first validated with in situ observations collected from the Finnish Meteorological Institute’s (FMI) multidisciplinary research center near the town of Sodankylä, in Northern Finland. SAC-SMA model top soil layer moisture estimates are then used for spatially distributed ESA CCI SM product evaluation. The study domain covers an area of 155 km by 140 km. Evaluation is performed for thawed/snow-free periods between 2003 and 2015. The ACTIVE product exhibits high correlations with SAC-SMA soil moisture estimates during most analyzed years. The presence of high inter-pixel soil moisture time series cross-correlation, even between pixels with very different soil/vegetation type distributions, as well as the inconsistent performance between analyzed years, is problematic. The PASSIVE product is able to more consistently capture the trend in soil moisture variation; although the trend is seemingly captured, the rapid response to precipitation events is less accurate. Our results indicate that, in contrast to other previous studies, despite the challenges, the ESA CCI SM products do exhibit reasonably good performance, and that further improvements, even with current Earth Observation methods, may be possible. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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14 pages, 7505 KiB  
Article
Assessment of a Simplified Connectivity Index and Specific Sediment Potential in River Basins by Means of Geomorphometric Tools
by Sergio Grauso, Francesco Pasanisi and Carlo Tebano
Geosciences 2018, 8(2), 48; https://doi.org/10.3390/geosciences8020048 - 30 Jan 2018
Cited by 33 | Viewed by 6107
Abstract
Sediment connectivity is a major topic in recent research because of its relevance in the characterization of the morphology of river systems and assessing of sediment transport and deposition. Currently, the connectivity indices found in the literature are generally dimensionless and need to [...] Read more.
Sediment connectivity is a major topic in recent research because of its relevance in the characterization of the morphology of river systems and assessing of sediment transport and deposition. Currently, the connectivity indices found in the literature are generally dimensionless and need to be coupled with quantitative soil-loss data for land management and design purposes. In the present work, a simple methodology is proposed to assess two different indices, namely, the simplified connectivity index (SCI) and the specific sediment potential (SSP), based on geomorphometric tools that are commonly available in commercial and open-source geographic information system (GIS) platforms. The proposed metrics allows us to easily assess both the SCI and the SSP as functions of the estimated soil erosion per unit area of the catchment and of the inverse distance of each unit area from the river outlet, this distance being measured along the network path. The proposed indices have been devised to express, respectively, the potential sediment transfer ability and the sediment mass potentially available at a given section of the drainage network. In addition to other parameters used to describe the catchment characteristics potentially affecting the river sediment delivery capacity, the SCI and SSP indices can help to refine theoretical models in order to assess the sediment yield (SY) in ungauged river basins. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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9 pages, 3036 KiB  
Article
Decomposition of Gasoline Hydrocarbons by Natural Microorganisms in Japanese Soils
by Junko Nishiwaki, Yoshishige Kawabe, Takeshi Komai and Ming Zhang
Geosciences 2018, 8(2), 35; https://doi.org/10.3390/geosciences8020035 - 23 Jan 2018
Cited by 6 | Viewed by 4157
Abstract
Characterizing the mechanisms by which natural microorganisms in soil decompose gasoline hydrocarbons is of fundamental importance for a better understanding of natural attenuation and/or for predicting contaminant transport and fate in soils. To examine whether and how gasoline hydrocarbons can be decomposed under [...] Read more.
Characterizing the mechanisms by which natural microorganisms in soil decompose gasoline hydrocarbons is of fundamental importance for a better understanding of natural attenuation and/or for predicting contaminant transport and fate in soils. To examine whether and how gasoline hydrocarbons can be decomposed under general environmental conditions, the decomposition of 10 major components generally contained in commercially available gasoline was analyzed in three arbitrarily selected Japanese soil samples. Gasoline hydrocarbons, especially aromatic hydrocarbons, are easily adsorbed by the tested Japanese soils, with straight chain hydrocarbons decomposing faster than branched hydrocarbons. Saturated monocyclic hydrocarbons were less easily decomposed than unsaturated monocyclic hydrocarbons. Enhancement of microbial decomposition of gasoline hydrocarbons requires a continuous supply of oxygen together with nutrients for the microorganisms. Full article
(This article belongs to the Special Issue Soil Hydrology and Erosion)
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