EFFECT OF DEM RESOLUTION ON LS FACTOR COMPUTATION

Abstract. LS factor plays a key role in soil erosion risk assessment using widely adopted empirical models such as RUSLE (Revised Universal Soil Loss Equation). The study was carried out to estimate the impact of varying DEM resolutions on LS factor values in a small hilly watershed near Dehradun, India. The impact of various computational algorithms as well as varying slope exponents on LS factor values were also estimated. DEMs of different resolutions such as ASTER (30m), CARTOSAT (10m and 30m), SRTM (30m) and UAV generated DEM (18cm) were used for comparison. On comparison, LS factor generated using varying resolution DEMs including UAV generated DEM yielded similar results indicated by similar mean values, even though the maximum values in the study area varied slightly. Use of spatially distributed slope exponent values resulted in higher mean LS factor values from all the DEMs, except UAV generated one, when compared to the use of a constant, slope exponent value. All DEMs except UAV generated DEM, yielded lower LS factor values when multi-flow direction (MFD) algorithm was used for computation instead of single flow direction (SFD). The variations in results when using UAV DEM may be due to its ability to capture the micro topographical variations on the ground, which affects the various computational procedures. The LS factor results obtained using different computational procedures and algorithms needs to be validated using ground collected information of LS factor, for wider acceptability and use by soil erosion and geospatial modelling communities.

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Assessment of Soil Erosion and Its Impact on Agricultural Productivity by Using the RMMF Model and Local Perception: A Case Study of Rangun Watershed of Mid-Hills, Nepal

Applied and Environmental Soil Science ◽

10.1155/2021/5747138 ◽

2021 ◽

Vol 2021 ◽

pp. 1-10

Author(s):

Dinesh Bhandari ◽

Rajeev Joshi ◽

Raju Raj Regmi ◽

Nripesh Awasthi

Keyword(s):

Soil Erosion ◽

Soil Loss ◽

Group Discussion ◽

Agricultural Productivity ◽

Weighted Mean ◽

Risk Area ◽

Barren Land ◽

Erosion Risk ◽

Risk Areas ◽

The Impact

Soil erosion is a major concern for the environment and natural resources leading to a serious threat to agricultural productivity and one of the major causes of land degradation in the mid-hills region of Nepal. An accurate assessment of soil erosion is needed to reduce the problem of soil loss in highly fragile mountainous areas. The present study aimed to assess spatial soil loss rate and identified risk areas and their perceived impact on agricultural productivity by using the Revised Morgan–Morgan–Finney (RMMF) model and social survey in the Rangun watershed of Dadeldhura district, Nepal. Soil erosion was assessed by using data on soil, digital elevation model, rainfall, land use, and land cover visually interpreted from multitemporal satellite images, and ILWIS 3.3 academic software was used to perform the model. A household questionnaire survey (n = 120) and focus group discussion (n = 2) in identified risk areas were carried out to understand the people’s perception towards soil erosion and its impact on agricultural productivity. The predicted average soil erosions from the forest, agriculture, and barren land were 2.7 t ha−1 yr−1, 53.73 t ha−1 yr−1, and 462.59 t ha−1 yr−1, respectively. The erosion risk area under very low to low, moderate to moderately high, and high to very high covers 92.32%, 4.96%, and 2.73%, respectively. It indicates that the rate of soil erosion was lower in forest areas, whereas it was higher in the barren land. The cropped area of the watershed has been reduced by 2.96 ha−1 yr−1, and productivity has been decreased by 0.238 t ha−1 yr−1. The impacts such as removal of topsoil (weighted mean = 4.19) and gully formation (weighted mean = 3.56) were the highest perceived factors causing productivity decline due to erosion. People perceived the impact of erosion in agricultural productivity differently ( ∗ significant at P ≤ 0.05 ). The study concluded that, comparatively, barren and agricultural lands seem more susceptible to erosion, so the long-term conservation and management investment in susceptible areas for restoration, protection, and socioeconomic support contribute significantly to land rehabilitation in the Rangun watershed.

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Assessing the Impact of Floods Disaster on Soil Erosion Risk Based on the RUSLE-GloSEM Approach in Western Iran

10.21203/rs.3.rs-775510/v1 ◽

2021 ◽

Author(s):

Morteza Akbari ◽

Ehsan Neamatollahi ◽

Hadi Memarian ◽

Mohammad Alizadeh Noughani

Keyword(s):

Climate Change ◽

Land Use ◽

Soil Erosion ◽

Land Use Change ◽

Agricultural Development ◽

Erosion Risk ◽

Before And After ◽

Global Soil ◽

Major Floods ◽

The Impact

Abstract Floods cause great damage to ecosystems and are among the main agents of soil erosion. Given the importance of soils for the functioning of ecosystems and development and improvement of bio-economic conditions, the risk and rate of soil erosion was assessed using the RUSLE model in Iran’s Lorestan province before and after a period of major floods in late 2018 and early 2019. Furthermore, soil erosion was calculated for current and future conditions based on the Global Soil Erosion Modeling Database (GloSEM). The results showed that agricultural development and land use change are the main causes of land degradation in the southern and central parts of the study area. The impact of floods was also significant since our evaluations showed that soil erosion increased from 4.12 t ha-1 yr-1 before the floods to 10.93 t ha-1 yr-1 afterwards. Field surveying using 64 ground control points determined that erodibility varies from 0.17 to 0.49% in the study area. Orchards, farms, rangelands and forests with moderate or low vegetation cover were the most vulnerable land uses to soil erosion. The GloSEM modeling results revealed that climate change is the main cause of change in the rate of soil erosion. Combined land use change-climate change simulation showed that soil erosion will increase considerably in the future under SSP1-RCP2.6, SSP2-RCP4.5, and SSP5-RCP8.5 scenarios. In the study area, both natural factors, i.e. climate change and human factors such as agricultural development, population growth, and overgrazing are the main drivers of soil erosion.

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Effects of Roughness Coefficients and Complex Hillslope Morphology on Runoff Variables under Laboratory Conditions

Water ◽

10.3390/w11122550 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2550 ◽

Cited By ~ 2

Author(s):

Masoud Meshkat ◽

Nosratollah Amanian ◽

Ali Talebi ◽

Mahboobeh Kiani-Harchegani ◽

Jesús Rodrigo-Comino

Keyword(s):

Soil Erosion ◽

Peak Discharge ◽

Control Measures ◽

P Value ◽

Rainfall Runoff ◽

Runoff Generation ◽

Mean Values ◽

Time Of Concentration ◽

Significant Difference ◽

The Impact

The geometry of hillslopes (plan and profile) affects soil erosion under rainfall-runoff processes. This issue comprises of several factors, which must be identified and assessed if efficient control measures are to be designed. The main aim of the current research was to investigate the impact of surface Roughness Coefficients (RCs) and Complex Hillslopes (CHs) on runoff variables viz. time of generation, time of concentration, and peak discharge value. A total of 81 experiments were conducted with a rainfall intensity of 7 L min−1 on three types of soils with different RCs (i.e., low = 0.015, medium = 0.016, and high = 0.018) and CHs (i.e., profile curvature and plan shape). An inclination of 20% was used for three replications. The results indicate a significant difference (p-value ≤ 0.001) in the above-mentioned runoff variables under different RCs and CHs. Our investigation of the combined effects of RCs and CHs on the runoff variables shows that the plan and profile impacts are consistent with a variation in RC. This can implicate that at low RC, the effect of the plan shape (i.e., convergent) on runoff variables increases but at high RC, the impact of the profile curvature overcomes the plan shapes and the profile curvature’s changes become the criteria for changing the behavior of the runoff variables. The lowest mean values of runoff generation and time of concentration were obtained in the convex-convergent and the convex-divergent at 1.15 min and 2.68 min, respectively, for the soil with an RC of 0.015. The highest mean of peak discharge was obtained in the concave-divergent CH in the soil with an RC of 0.018. We conclude that these results can be useful in order to design planned soil erosion control measures where the soil roughness and slope morphology play a key role in activating runoff generation.

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LiDAR derived high resolution topography: the next challenge for the analysis of terraces stability and vineyard soil erosion

Journal of Agricultural Engineering ◽

10.4081/jae.2013.258 ◽

2013 ◽

Vol 44 (2s) ◽

Cited By ~ 5

Author(s):

Federico Preti ◽

Paolo Tarolli ◽

Andrea Dani ◽

Simone Calligaro ◽

Massimo Prosdocimi

Keyword(s):

High Resolution ◽

Soil Erosion ◽

Slope Failure ◽

Flow Direction ◽

Laser Scanner ◽

Airborne Lidar ◽

Wall Structure ◽

Terrestrial Laser Scanner ◽

Erosion Risk ◽

Soil Erosion Risk

The soil erosion in the vineyards is a critical issue that could affect their productivity, but also, when the cultivation is organized in terraces, increase the risk due to derived slope failure processes. If terraces are not correctly designed or maintained, a progressively increasing of gully erosion affects the structure of the walls. The results of this process is the increasing of connectivity and runoff. In order to overcome such issues it is really important to recognize in detail all the surface drainage paths, thus providing a basis upon which develop a suitable drainage system or provide structural measures for the soil erosion risk mitigation. In the last few years, the airborne LiDAR technology led to a dramatic increase in terrain information. Airborne LiDAR and Terrestrial Laser Scanner derived high-resolution Digital Terrain Models (DTMs) have opened avenues for hydrologic and geomorphologic studies (Tarolli et al., 2009). In general, all the main surface process signatures are correctly recognized using a DTM with cell sizes of 1 m. However sub-meter grid sizes may be more suitable in those situations where the analysis of micro topography related to micro changes is critical for slope failures risk assessment or for the design of detailed drainage flow paths. The Terrestrial Laser Scanner (TLS) has been proven to be an useful tool for such detailed field survey. In this work, we test the effectiveness of high resolution topography derived by airborne LiDAR and TLS for the recognition of areas subject to soil erosion risk in a typical terraced vineyard landscape of “Chianti Classico” (Tuscany, Italy). The algorithm proposed by Tarolli et al. (2013), for the automatic recognition of anthropic feature induced flow direction changes, has been tested. The results underline the effectiveness of LiDAR and TLS data in the analysis of soil erosion signatures in vineyards, and indicate the high resolution topography as a useful tool to improve the land use management of such areas. The stability conditions have been analyzed under the influence of the measured geometry alterations of the wall structure.

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Time Scale Effects and Interactions of Rainfall Erosivity and Cover Management Factors on Vineyard Soil Loss Erosion in the Semi-Arid Area of Southern Sicily

Water ◽

10.3390/w11050978 ◽

2019 ◽

Vol 11 (5) ◽

pp. 978 ◽

Cited By ~ 12

Author(s):

Giorgio Baiamonte ◽

Mario Minacapilli ◽

Agata Novara ◽

Luciano Gristina

Keyword(s):

Soil Erosion ◽

Soil Loss ◽

Scale Effects ◽

Management Practice ◽

Temporal Analysis ◽

Temporal Scale ◽

Rainfall Erosivity ◽

Erosion Risk ◽

Best Management ◽

The Impact

Several authors describe the effectiveness of cover crop management practice as an important tool to prevent soil erosion, but at the same time, they stress on the high soil loss variability due to the interaction of several factors characterized by large uncertainty. In this paper the Revised Universal Soil Loss Equation (RUSLE) model is applied to two Sicilian vineyards that are characterized by different topographic factors; one is subjected to Conventional Practice (CP) and the other to Best Management Practice (BMP). By using climatic input data at a high temporal scale resolution for the rainfall erosivity (R) factor, and remotely sensed imagery for the cover and management (C) factor, the importance of an appropriate R and C factor assessment and their inter and intra-annual interactions in determining soil erosion variability are showed. Different temporal analysis at ten-year, seasonal, monthly and event scales showed that results at events scales allow evidencing the interacting factors that determine erosion risk features which at other temporal scales of resolution can be hidden. The impact of BMP in preventing soil erosion is described in terms of average saved soil loss over the 10-year period of observation. The evaluation of soil erosion at a different temporal scale and its implications can help stakeholders and scientists formulate better soil conservation practices and agricultural management, and also consider that erosivity rates are expected to raise for the increase of rainfall intensity linked to climate change.

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Soil erosion hazard map for river basin managers: An example for the water bodies of the Loire river basin (France)

Zeitschrift für Geomorphologie ◽

10.1127/zfg/2020/0643 ◽

2020 ◽

Author(s):

Clément Chabert ◽

Francesca Degan ◽

Sébastien Salvador-Blanes ◽

Olivier Evrard ◽

Rosalie Vandromme ◽

...

Keyword(s):

Water Quality ◽

Soil Erosion ◽

River Basin ◽

Water Bodies ◽

Rainfall Erosivity ◽

Erosion Risk ◽

Erosion Hazard ◽

Management Plans ◽

The Impact ◽

Loire River

Abstract: Soil erosion on agricultural land is associated with deleterious off-site impacts including the siltation andthe pollution of the receiving water bodies. To better manage this situation, local/regional water agencies needspatially-distributed information to compare the sensitivity to erosion of the areas draining into these water bodiesand supplying the vast majority of sediment and associated pollutants leading to this water quality impairment.These soil erosion hazard maps are now often included in the latest versions of the basin management plans thatmust be designed to meet the water quality objectives of the EU Framework Directive. However, the resolution ofthese maps is often too coarse to meet the practical needs of these agencies. Accordingly, the current research usedthe latest input databases to improve the MESALES model outputs in one of the largest French River basins (Loire,117,000 km2), with the implementation of three main modifications. First, the seasonal variations of land coverwere incorporated into the model through a revised set of expert rules based on the agricultural census data. Second,the discrimination of the soil textures was improved within the infiltration and erodibility module of the model.Third, variations in rainfall erosivity across the study area were described taking into account the latest erosivitymap available at the European scale. Then, the model results obtained with the updated model version were comparedwith those generated by the previous version. Overall, the simulated soil erosion hazard changed for 35% ofthe pixels of the Loire River basin, with a significant increase of the lowest hazard classes during all seasons exceptsummer. When aggregating the results at the scale of water bodies, the simulated erosion hazard changed for 49%of these management units. Although 28% of these water bodies were associated with a lower hazard, 23% of theriver systems were attributed a higher erosion risk. The implications of these model/map revisions for the localdecision makers were discussed, taking the strategy of concentrating the management budget on those water bodiesassociated with the highest erosion risk as an example. In the future, this model could be used to compare the soilerosion hazard in contrasted regions of Europe and to simulate the impact of management plans designed todecrease this risk to support the decisions of water agencies

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Impact of Land Use and Land Cover Change on Soil Erosion Using Rusle Model And Gis: A Case of Temeji Watershed, Western Ethiopia

10.21203/rs.3.rs-100340/v1 ◽

2020 ◽

Author(s):

Mitiku Badasa Moisa ◽

Daniel Assefa Negash ◽

Biratu Bobo Merga ◽

Dessalegn Obsi Gemeda

Keyword(s):

Land Use ◽

Soil Erosion ◽

Land Cover ◽

Water Conservation ◽

Soil Loss ◽

Mitigation Strategies ◽

Cultivated Land ◽

Rusle Model ◽

Erosion Risk ◽

The Impact

Abstract BackgroundThe impact of Land Use/Land Cover (LULC) conversion on soil resources is getting global attention. Soil erosion is one the critical environmental problems worldwide with high severity in developing countries due to land degradation. This study integrates the Revised Universal Soil Loss Equation (RUSLE) model with a Geographic Information Systems (GIS) to estimate the impacts of LU/LC conversion on the mean annual soil loss in Temeji watershed. In this study, LU/LC change of Temeji watershed were assessed from 2000 to 2020 by using 2000 Landsat ETM+ and 2020 Landsat OLI/TIRS images and classified using supervised maximum likelihood classification algorithms. ResultsResults indicates that majority of the LU/LC in the study area is vulnerable to soil erosion. Our findings show that cultivated land had the highest average soil loss rate in Temeji watershed. High soil loss is observed when grass and forest land were converted into cultivated land with mean soil loss of 88.8t/ha/yr and 86.9t/ha/yr in 2020. Results revealed that about 6608.5ha (42.8%) and 8391.8ha (54.4%) were categorized under severe classes in 2000 and 2020, respectively.ConclusionsThe results can definitely support policy makers and environmental managers in implementation of soil and water conservation practices and erosion risk prevention and mitigation strategies in Temeji watershed.

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Assessing the Impact of Man–Made Ponds on Soil Erosion and Sediment Transport in Limnological Basins

Water ◽

10.3390/w11122526 ◽

2019 ◽

Vol 11 (12) ◽

pp. 2526

Author(s):

Mario J. Al Sayah ◽

Rachid Nedjai ◽

Konstantinos Kaffas ◽

Chadi Abdallah ◽

Michel Khouri

Keyword(s):

Sediment Transport ◽

Soil Erosion ◽

Assessment Tool ◽

Swat Model ◽

Erosion Risk ◽

Sediment Yields ◽

Risk Zones ◽

Transport Patterns ◽

Scientific Attention ◽

The Impact

The impact of ponds on basins has recently started to receive its well-deserved scientific attention. In this study, pond-induced impacts on soil erosion and sediment transport were investigated at the scale of the French Claise basin. In order to determine erosion and sediment transport patterns of the Claise, the Coordination of Information on the Environment (CORINE) erosion and Soil and Water Assessment Tool (SWAT) models were used. The impact of ponds on the studied processes was revealed by means of land cover change scenarios, using ponded versus pondless inputs. Results show that under current conditions (pond presence), 12.48% of the basin corresponds to no-erosion risk zones (attributed to the dense pond network), while 65.66% corresponds to low-erosion risk, 21.68% to moderate-erosion risk, and only 0.18% to high-erosion risk zones. The SWAT model revealed that ponded sub-basins correspond to low sediment yields areas, in contrast to the pondless sub-basins, which yield appreciably higher erosion rates. Under the alternative pondless scenario, erosion risks shifted to 1.12%, 0.52%, 76.8%, and 21.56% for no, low, moderate, and high-erosion risks, respectively, while the sediment transport pattern completely shifted to higher sediment yield zones. This approach solidifies ponds as powerful human-induced modifications to hydro/sedimentary processes.

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Assessment of Soil Erosion and its Impact on Humus Spatial and Temporal Dynamics.

Bulletin of University of Agricultural Sciences and Veterinary Medicine Cluj-Napoca Agriculture ◽

10.15835/buasvmcn-agr:8677 ◽

2012 ◽

Vol 69 (1) ◽

Author(s):

Cristian Valeriu PATRICHE ◽

Radu Gabriel PáŽRNÄ‚U ◽

Bogdan ROȘCA ◽

Dan Laurentiu STOICA

Keyword(s):

Standard Deviation ◽

Soil Erosion ◽

Soil Surface ◽

Mean Value ◽

Soil Profiles ◽

Surface Erosion ◽

Study Region ◽

Erosion Risk ◽

The Mean ◽

The Impact

The purpose of this study is to quantify soil surface erosion using the Universal Soil Loss Equation in GIS environment and to assess its impact on soil humus reserve. The quantifying of soil surface erosion was performed by integrating in GIS the thematic raster representations of the erosion control parameters which exhibit spatial variability within the limiÂ ts of the study region (DobrovÄƒÅ£ Basin, The Central Moldavian Plateau, eastern Romania). Soil erodibility was computed according to ICPA (1987) standards, on the basis of soil type, texture and erosion degree, using a soil map of the basin at scale 1: 5000. Slope length was derived from a 20m resolution digital elevation model using SAGA-GIS software, while slope factor was determined according to the Romanian methodology by raising the slope values at the power of 1.5. Finally, the vegetation factor was computed on the basis of the normalized difference vegetation index derived from a 2001 Landsat image, using the equation proposed by Van der Knijff et al. (1999). Subsequently, we derived the potential soil erosion, controlled exclusively by soil-relief factors and the effective soil erosion, by integrating the effect of vegetation. The potential soil erosion show a mean value of 15.6 t/ha yr and a standard deviation of 16.6 t/ha yr. The integration of the vegetation effect decreases the mean value to 5.4 t/ha yr and the standard deviation to 6.7 t/ha yr. Most of the basinâ€™s surface (48.7%) falls into the reduced erosion risk class (2-8 t/ha yr), while the high and very high erosion risk classes group 7.3% of the basin. The assessment of the erosion impact on soil carbon stock was performed by coupling the USLE model with a HÃ©ninÂ -Dupuis mono-compartmental humus evolution model. The simulation was performed for the first 20cm of the soil profile, using a database of 224 soil profiles. The results of the simulation show that 76% of the soil profiles display a regressive evolution of the humus reserve under the impact of the soil erosion. The mean humus loss for these profiles is 36.3 t/ha for 100 years of simulation.

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Assessing the Impact of Man–Made Ponds on Soil Erosion and Sediment Transport in Limnological Basins

10.20944/preprints201910.0206.v1 ◽

2019 ◽

Author(s):

Mario J. Al Sayah ◽

Rachid Nedjai ◽

Konstantinos Kaffas ◽

Chadi Abdallah ◽

Michel Khouri

Keyword(s):

Sediment Transport ◽

Soil Erosion ◽

Swat Model ◽

Erosion Risk ◽

Sediment Yields ◽

Erosion Rates ◽

Risk Zones ◽

Transport Patterns ◽

Scientific Attention ◽

The Impact

The impact of ponds on basins has recently started to receive its well–deserved scientific attention. In this study, pond–induced impacts on soil erosion and sediment transport were investigated at the scale of the French Claise basin. In order to determine erosion and sediment transport patterns under current conditions, the CORINE erosion and SWAT models were used. The impact of ponds on the studied processes was revealed by means of land cover change scenarios, using ponded versus pondless inputs. Results show that under current conditions (pond presence), 12.48% of the basin corresponds to no–erosion risk zones (attributed to the dense pond network), while 65.66% corresponds to low–erosion risk, 21.68% to moderate–erosion risk and only 0.18% to high–erosion risk zones. The SWAT model revealed that ponded sub–basins correspond to low sediment yields areas, in contrast to the pondless sub–basins, which yield appreciably higher erosion rates. Under the alternative scenario, erosion risks shifted to 1.12%, 0.52%, 76.8% and 21.56% for no, low, moderate and high–erosion risks, respectively, while the sediment transport pattern of the Claise completely shifted to higher sediment yield zones. This approach solidifies ponds as powerful man–induced modifications to hydro/sedimentary processes.

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