scholarly journals Surface runoff simulation to mitigate the impact of soil erosion, case study of Třebsín (Czech Republic)

2012 ◽  
Vol 7 (No. 3) ◽  
pp. 85-96 ◽  
Author(s):  
P. Kovář ◽  
D. Vaššová ◽  
M. Janeček
Keyword(s):  
Shear Stress ◽  
Czech Republic ◽  
Soil Erosion ◽  
Surface Runoff ◽  
Model Simulation ◽  
Slope Angle ◽  
Model Parameters ◽  
Physically Based ◽  
The Impact ◽  
Experimental Plots

The relation between soil erosion and its redistribution on land strictly depends on the process of surface runoff formation during intensive rainfall. Therefore, interrupting and reducing continuous surface runoff, using adequate conservation measures, may be implemented in order to reduce the shear stress of flowing water. This paper describes the outcomes of the KINFIL model simulation in assessing the runoff from extreme rainfall on hill slopes. The model is a physically based and parameter distributed 3D model that was applied at the Třebsín experimental station in the Czech Republic. This model was used for the first time to simulate the impact of surface runoff caused by natural or sprinkler-made intensive rains on four of the seven different experimental plots. The plots involved in the analysis contain a variety of soils which are covered with different field crops. At this stage, the model parameters comprise saturated hydraulic conductivity, field capacity, sorptivity, plot geometry and surface roughness reflecting the Třebsín experimental plots. These parameters were verified on observed data. All seven plots had the same slope angle, but two of them were vulnerable to surface runoff due to their soil hydraulic parameters. There were rapidly increasing depths and velocities which consequently caused a higher shear stress for splashing soil particles downstream. The paper provides further information and data concerning the relationships between the depth of water and its velocity on the slopes of certain roughness. It also provides information concerning shear stress and shear velocity values, compared with their critical values depending on the soil particle distribution. This approach is more physically based than the traditional method of Universal Soil Loss Equation (USLE).

Pierre3D: a 3D stochastic rockfall simulator based on random ground roughness and hyperbolic restitution factors

2015 ◽  
Vol 52 (9) ◽  
pp. 1360-1373 ◽  
Author(s):  
Valentin S. Gischig ◽  
Oldrich Hungr ◽  
Andrew Mitchell ◽  
Franck Bourrier
Keyword(s):  
Stochastic Process ◽  
Slope Angle ◽  
Test Site ◽  
Fine Tuning ◽  
Model Parameters ◽  
Observation Data ◽  
Lumped Mass ◽  
Forest Road ◽  
Rockfall Hazard ◽  
The Impact

The use of dynamic computational methods has become indispensable for addressing problems related to rockfall hazard. Although a number of models with various degrees of complexity are available, model parameters are rarely calibrated against observations from rockfall experiments. A major difficulty lies in reproducing the apparent randomness of the impact process related to both ground and block irregularities. Calibration of rigorous methods capable of explicitly modeling trajectories and impact physics of irregular blocks is difficult, as parameter spaces become too vast and the quality of model input and observation data are insufficient. The model presented here returns to the simple “lumped-mass” approach and simulates the characteristic randomness of rockfall impact as a stochastic process. Despite similarities to existing approaches, the model presented here incorporates several novel concepts: (i) ground roughness and particle roughness are represented as a random change of slope angle at impact; (ii) lateral deviations of rebound direction from the trajectory plane at impact are similarly accounted for by perturbing the ground orientation laterally, thus inducing scatter of run-out directions; and (iii) a hyperbolic relationship connects restitution factors to impact deformation energy. With these features, the model is capable of realistically accounting for the influence of particle mass on dynamic behaviour. The model only requires four input parameters, rendering it flexible for calibration against observed datasets. In this study, we calibrate the model against observations from the rockfall test site at Vaujany in France. The model is able to reproduce observed distributions of velocity, jump heights, and runout at observation points. In addition, the spatial distribution of the trajectories and landing points has been successfully simulated. Different parameter sets have been used for different ground materials such as an avalanche channel, a forest road, and a talus cone. Further calibration of the new model against a range of field datasets is essential. This study is part of an extensive calibration program that is still in progress at this first presentation of the method, and focuses on fine-tuning the details of the stochastic process implemented both in two-dimensional (2D) and three-dimensional (3D) versions of the model.

scholarly journals Impact of Rainforest Conversion on Surface Runoff and Soil Erosion in Nopu Upper Catchment of Central Sulawesi

2008 ◽  
Vol 13 (1) ◽  
pp. 59-65 ◽  
Author(s):  
Yayat Hidayat ◽  
Naik Sinukaban ◽  
Hidayat Pawitan ◽  
Suria Darma Tarigan
Keyword(s):  
Soil Erosion ◽  
Surface Runoff ◽  
Model Simulation ◽  
Agroforestry Systems ◽  
Young Age ◽  
Stream Line ◽  
Land Uses ◽  
Agricultural Lands ◽  
Soil And Water Loss ◽  
Central Sulawesi

Rainforest conversion into agricultural lands in Nopu Upper Catchment such as cocoa plantations, maizes, cassava, peanuts, and scrub and bush were significantly increase soil erosions and surface runoffs, which in turn will decrease crops productivity and hydrologic functions of watershed.  Soil erosion from maize and peanut rotation plots are higher 2.061,8% than soil erosions from natural forest plots.  Soil erosions are higher also in intercroping young age cocoa, maize and cassava plots and maize plots respectively 2.023,8% and 2.012,3%.   Where as surface runoffs were increase up to 650,9% in medium age cocoa plots, 380,4% in intercroping young age cacao and cassava plots, and 347,1% in scrub and bush plots.  The result of ANSWERS model simulation using daily C factors were indicate that rainforest conversion into agricultural lands in Nopu Upper Catchment causing soil and water loss respectively 3.190,5 ton/year and  115.441 m3/year.   Application of agroforestry systems in agricultural lands which in line with reforestation in stream line area of Nopu river and steepy agricultural lands (slope > 40%) are effectively reduce soil erosions up to 77,6% compare to soil erosion from existing land uses.

scholarly journals Impact of overland flow on soil characteristics in Třebsín experimental plots

2017 ◽  
Vol 12 (No. 3) ◽  
pp. 187-193
Author(s):  
H. Bačinová ◽  
P. Kovář
Keyword(s):  
Overland Flow ◽  
Extreme Rainfall ◽  
Field Capacity ◽  
Rainfall Runoff ◽  
The Czech Republic ◽  
Physically Based ◽  
Runoff Discharge ◽  
The Impact ◽  
First Time ◽  
Experimental Plots

This paper describes the continuation of simulated outcomes from the plots No. 4 and No. 5 with two different soils, using the KINFIL model to assess the runoff from extreme rainfall. The KINFIL model is a physically-based, parameter-distributed 3D model that has been applied to the Třebsín experimental station in the Czech Republic. This model was used for the first time in 2012 to simulate the impact of overland flow caused by natural or sprinkler-made intensive rains on four of the nine experimental plots. This measurement of a rain simulator producing a high-intensity rainfall involves also hydraulic conductivity, soil sorptivity, plot geometry and granulometric curves to be used for the present analysis. However, since 2012, the KINFIL model has been amended to provide a more effective comparison of the measured and computed results using the values of new parameters such as storage suction factor and field capacity on plot 4 and plot 5. The KINFIL model uses all input data mentioned above, and it produces the output data such as gross rainfall, effective rainfall, runoff discharge hydraulic depths, hydraulic velocities and shear velocities as well as shear stress values depending on the soil particle distribution. These processes are innovative, physically based, and both the measured and the computed results fit reliably.  

A Study of Impacts of Coupled Model Initial Shocks and State–Parameter Optimization on Climate Predictions Using a Simple Pycnocline Prediction Model

2011 ◽  
Vol 24 (23) ◽  
pp. 6210-6226 ◽  
Author(s):  
S. Zhang
Keyword(s):  
Time Scales ◽  
Parameter Optimization ◽  
Time Scale ◽  
Model Simulation ◽  
Coupled Model ◽  
State Parameter ◽  
Model Parameters ◽  
Forecast Errors ◽  
Long Time ◽  
The Impact

Abstract A skillful decadal prediction that foretells varying regional climate conditions over seasonal–interannual to multidecadal time scales is of societal significance. However, predictions initialized from the climate-observing system tend to drift away from observed states toward the imperfect model climate because of the model biases arising from imperfect model equations, numeric schemes, and physical parameterizations, as well as the errors in the values of model parameters. Here, a simple coupled model that simulates the fundamental features of the real climate system and a “twin” experiment framework are designed to study the impact of initialization and parameter optimization on decadal predictions. One model simulation is treated as “truth” and sampled to produce “observations” that are assimilated into other simulations to produce observation-estimated states and parameters. The degree to which the model forecasts based on different estimates recover the truth is an assessment of the impact of coupled initial shocks and parameter optimization on climate predictions of interests. The results show that the coupled model initialization through coupled data assimilation in which all coupled model components are coherently adjusted by observations minimizes the initial coupling shocks that reduce the forecast errors on seasonal–interannual time scales. Model parameter optimization with observations effectively mitigates the model bias, thus constraining the model drift in long time-scale predictions. The coupled model state–parameter optimization greatly enhances the model predictability. While valid “atmospheric” forecasts are extended 5 times, the decadal predictability of the “deep ocean” is almost doubled. The coherence of optimized model parameters and states is critical to improve the long time-scale predictions.

scholarly journals Modelling the Impact of Tillage on Water Quality for Sustainable Agricultural Development in a Savanna Ecological Zone, Kwara State, Nigeria

2021 ◽  
Vol 14 (1-2) ◽  
pp. 15-23
Author(s):  
Toluwalope Mubo Agaja ◽  
Lanre Tajudeen Ajibade ◽  
Micheal Olufemi Agaja
Keyword(s):  
Water Pollution ◽  
Water Quality ◽  
Surface Runoff ◽  
Management Practices ◽  
Assessment Tool ◽  
Block Design ◽  
Favorable Effect ◽  
The Impact ◽  
Experimental Plots ◽  
Tillage Methods

Abstract The aim of the study was to examine the effects of tillage methods on surface runoff and model the pattern and processes of surface water pollution associated with tillage methods using Soil Water Assessment Tool (SWAT). This model was designed to predict the impact of land management practices on water, sediment, and varying tillage types in watersheds over two planting seasons. Traditional heap (T), Plough/Harrow (PH), Plough/Harrow/Ridge (PHR) and No-tillage (NT) methods commonly used in the study area were applied to experimental plots at Unilorin Teaching and Research Farm and National Center for Agricultural Mechanization, Idofian (Nigeria). Using Randomized Complete Block Design (RCBD), each treatment had three replicates making 12 experimental plots at each location for the 2015 and 2016 planting season. Nine biophysical parameters were purposively selected, examined and modelled. The study revealed that four of nine biophysical factors (sediment yield: 10.54 t/ha; groundwater discharge: 174.45 mm; organic nitrogen: 62.62 kg/ha, and nitrogen in surface runoff: 5.15 kg/ha) were higher for traditional heaps, while three parameters (surface runoff: 374.42 mm; evapotranspiration: 752.78 mm, and soil loss: 1.05 kg/ha) were higher under plough/harrow and plough/harrow/ridge cultivation practices. The study concluded that tillage methods have impact on water quality. However, plough/harrow has comparatively more favorable effect on the contribution to surface runoff. It is therefore recommended that this type of tillage should be adopted to reduce water pollution and for sustainable environment.

On the effect of different moss species on soil erosion, percolation and carbon relocation

2021 ◽  
Author(s):  
Corinna Gall ◽  
Lena Grabherr ◽  
Martin Nebel ◽  
Thomas Scholten ◽  
Sonja M. Thielen ◽  
...  
Keyword(s):  
Soil Erosion ◽  
Surface Runoff ◽  
Biological Soil Crust ◽  
Bare Soil ◽  
Individual Species ◽  
Sediment Discharge ◽  
Moss Species ◽  
Moss Cover ◽  
The Impact ◽  
Soil Substrates

<p>For decades, soil erosion has been a major environmental problem as it degrades the most productive soil layers, which threatens, among other things, food production worldwide. Although these effects have been known for a long time, there are still a variety of challenges to mitigating soil erosion in different ecosystems. As climate change progresses, the risk of soil loss increases, making the preparation of effective solutions very urgent. A current research focus is on the restoration of a protective soil cover following disturbances in the vegetation layer, e.g., through the reestablishment of biological soil crust communities. These are often dominated by bryophytes in humid climates. So far, several studies examined the general protective influence of bryophytes against soil erosion, however only few of them addressed how individual species affect specific erosion processes in detail.</p><p>To fill this research gap we investigated the impact of six moss species on soil erosion, percolation and carbon relocation by means of rainfall simulations. Therefore, we used topsoil substrate from four sites in the Schönbuch Nature Park in South Germany which covers different kinds of bedrock and varying soil texture and pH. Subsequently, they were sieved by 6.3 mm and filled into metal infiltration boxes (40 x 30 cm) up to a height of 6.5 cm. The moss species differ in origin (either collected in the field or cultivated in the lab) as well as growth form (pleurocarpous or acrocarpous). Rainfall simulations were performed for bare soil substrates, as well as for moss-covered soil substrates six months later and both in dry and wet conditions. Additionally, we conducted rainfall simulations with leaf and coniferous litter on bare soil substrates. During the simulations we monitored soil moisture in two position - 3 cm depth plus soil surface - with biocrust wetness probes (BWP) and quantified surface runoff, percolation and sediment discharge. Afterwards we determined carbon contents of the sediment and dissolved organic carbon in the liquid phase of runoff and percolated water.</p><p>While surface runoff was increased by 5% due to the litter cover compared to the bare soil substrate, sediment discharge decreased to 97%. Runoff rates could also be mitigated by 90 % as a result of the moss cover. Furthermore, due to the dense moss cover sediment rates were almost reduced to zero. Preliminary results show that there are differences between the moss species in terms of sediment discharge, but not in context with runoff. The analyses of carbon contents in surface runoff and the percolated water are still in progress, as is the evaluation of the BWP measurements. These outcomes will be presented at vEGU21.</p>

scholarly journals The potential for land use change to reduce flood risk in mid-sized catchments in the Myjava region of Slovakia

2017 ◽  
Vol 47 (2) ◽  
pp. 95-112 ◽  
Author(s):  
Peter Rončák ◽  
Evelin Lisovszki ◽  
Ján Szolgay ◽  
Kamila Hlavčová ◽  
Silvia Kohnová ◽  
...  
Keyword(s):  
Land Use ◽  
Soil Erosion ◽  
River Basin ◽  
Surface Runoff ◽  
Management Practices ◽  
Agricultural Land ◽  
Arable Land ◽  
Land Use Management ◽  
Land Use Scenarios ◽  
The Impact

AbstractThe effects of land use management practices on surface runoff are evident on a local scale, but evidence of their impact on the scale of a watershed is limited. This study focuses on an analysis of the impact of land use changes on the flood regime in the Myjava River basin, which is located in Western Slovakia. The Myjava River basin has an area of 641.32 km2and is typified by the formation of fast runoff processes, intensive soil erosion, and muddy floods. The main factors responsible for these problems with flooding and soil erosion are the basin’s location, geology, pedology, agricultural land use, and cropping practices. The GIS-based, spatially distributed WetSpa rainfall-runoff model was used to simulate mean daily discharges in the outlet of the basin as well as the individual components of the water balance. The model was calibrated based on the period between 1997 and 2012 with outstanding results (an NS coefficient of 0.702). Various components of runoff (e.g., surface, interflow and groundwater) and several elements of the hydrological balance (evapotranspiration and soil moisture) were simulated under various land use scenarios. Six land use scenarios (‘crop’, ‘grass’, ‘forest’, ‘slope’, ‘elevation’ and ‘optimal’) were developed. The first three scenarios exhibited the ability of the WetSpa model to simulate runoff under changed land use conditions and enabled a better adjustment of the land use parameters of the model. Three other “more realistic” land use scenarios, which were based on the distribution of land use classes (arable land, grass and forest) regarding permissible slopes in the catchment, confirmed the possibility of reducing surface runoff and maximum discharges with applicable changes in land use and land management. These scenarios represent practical, realistic and realizable land use management solutions and they could be economically implemented to mitigate soil erosion processes and enhance the flood protection measures in the Myjava River basin.

scholarly journals Water budget, performance of evapotranspiration formulations, and their impact on hydrological modeling of a small boreal peatland-dominated watershed

2018 ◽  
Vol 55 (2) ◽  
pp. 206-220 ◽  
Author(s):  
Pierre-Erik Isabelle ◽  
Daniel F. Nadeau ◽  
Alain N. Rousseau ◽  
François Anctil
Keyword(s):  
Water Budget ◽  
Hydrological Modeling ◽  
Distributed Model ◽  
Model Parameters ◽  
Taylor Models ◽  
Physically Based ◽  
Model Efficiency ◽  
The Impact ◽  
Substantial Drop

Peatlands occupy around 13% of the land cover of Canada, and thus they play a key role in the water balance at high latitudes. They are well known for having substantial water loss due to evapotranspiration. Since measurements of evapotranspiration are scarce over these environments, hydrologists generally rely on models of varying complexity to evaluate these water exchanges in the global watershed balance. This study quantifies the water budget of a small boreal peatland-dominated watershed. We assess the performance of three evapotranspiration models in comparison with in situ observations and the impact of using these models in the hydrological modeling of the watershed. The study site (∼1 km2) is located in the eastern James Bay lowlands, Québec, Canada. During summer 2012, an eddy flux tower measured evapotranspiration continuously, while a trapezoidal flume monitored streamflow at the watershed outlet. We estimated evapotranspiration with a combinational model (Penman), a radiation-based model (Priestley–Taylor), and a temperature-based model (Hydro-Québec), and performed the hydrological modeling of the watershed with HYDROTEL, a physically based semi-distributed model. Our results show that the Penman and Priestley–Taylor models reproduce the observations with the highest precision, while a substantial drop in performance occurs with the Hydro-Québec model. However, these discrepancies did not appear to reduce the hydrological model efficiency, at least from what can be concluded from a 3-month modeling period. HYDROTEL appears sensitive to evapotranspiration inputs, but calibration of model parameters can compensate for the differences. These findings still need to be confirmed with longer modeling periods.

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