scholarly journals A conceptual model-based sediment connectivity assessment for patchy agricultural catchments

2021 ◽  
Author(s):  
Pedro Batista ◽  
Peter Fiener ◽  
Simon Scheper ◽  
Christine Alewell
Keyword(s):  
Surface Waters ◽  
Road Network ◽  
Input Data ◽  
Sediment Yields ◽  
The Road ◽  
Sediment Loads ◽  
Water Courses ◽  
Sediment Transfer ◽  
Sediment Connectivity ◽  
Swiss Plateau

Abstract. The accelerated sediment supply from agricultural soils to riverine and lacustrine environments leads to negative off-site consequences. In particular, the sediment connectivity from agricultural land to surface waters is strongly affected by landscape patchiness and the linear structures that separate field parcels (e.g. roads, tracks, hedges, and grass-buffer-strips). Understanding the feedbacks between these structures and sediment transfer is therefore crucial for minimising off-site erosion impacts. Although soil erosion models can be used to understand lateral sediment transport patterns, model-based connectivity assessments are hindered by the uncertainty in model structures and input data. In particular, the representation of linear landscape features in numerical soil redistribution models is often compromised by the spatial resolution of the input data and the quality of the process descriptions. Here we adapted the WaTEM/SEDEM model using high resolution spatial data (2 m × 2 m) to analyse the sediment connectivity in a very patchy mesoscale catchment (73 km2) of the Swiss Plateau. Specifically, we used a global sensitivity analysis to explore model structural assumptions about how linear landscape features (dis)connect the sediment cascade. Furthermore, we compared model simulations of hillslope sediment yields from five sub-catchments to tributary sediment loads, which were calculated with long-term water discharge and suspended sediment measurements. Our results showed that roads were the main regulators of sediment connectivity in the catchment. In particular, the sensitivity analysis revealed that the assumptions about how the road network (dis)connects the sediment transfer from field-blocks to water courses had a much higher impact on modelled sediment yields than the uncertainty in model parameters. Moreover, model simulations showed a higher agreement with tributary sediment loads when the road network was assumed to directly connect sediments from hillslopes to water courses. Our results ultimately illustrate how a high-density road network combined with an effective drainage system increase sediment connectivity from hillslopes to surface waters in this representative catchment of the Swiss Plateau. This further highlights the importance of considering linear structures in soil erosion and sediment connectivity models.

A model-based sediment connectivity assessment for patchy agricultural catchments

2021 ◽  
Author(s):  
Pedro Velloso Gomes Batista ◽  
Peter Fiener ◽  
Simon Scheper ◽  
Christine Alewell
Keyword(s):  
Sensitivity Analysis ◽  
Sediment Transport ◽  
Surface Waters ◽  
Road Network ◽  
Input Data ◽  
Landscape Patterns ◽  
Model Parameters ◽  
Agricultural Catchments ◽  
Model Based ◽  
Sediment Connectivity

<p>Sediment connectivity is highly influenced by landscape patchiness. In particular, linear features such as roads, ditches, and terraces, modify landscape patterns and affect sediment transport from hillslopes to surface waters. Connectivity patterns are commonly assessed by spatially-distributed models, which rely on semi-qualitative indices or numerical simulations of soil erosion and sediment transport. However, model-based connectivity assessments are hindered by the uncertainty in model structure and parameter estimation. Moreover, representing linear landscape features is often limited by the spatial resolution of the model input data. Here we demonstrate how a global sensitivity analysis of the WaTEM/SEDEM model can be used to improve our understanding of sediment connectivity in patchy agricultural catchments of the Swiss Plateau. Specifically, we explored model structural connectivity assumptions regarding road drainage and the presence of edge-of-field buffer strips, as well as the uncertainty in the input data, by means of a Monte Carlo simulation and a high resolution 2 m x 2 m DEM. Our results showed that roads are the main regulators of sediment connectivity in ameliorated Swiss landscapes. That is, our sensitivity analysis revealed that assumptions about how the road network (dis)connects sediment transport from cropland to water courses had a much higher impact on modelled sediment loads than the uncertainty in model parameters. These results illustrate how a high-density road network combined with an effective drainage system increases sediment connectivity from arable land to surface waters in Switzerland. Additionally, our approach underlines the usefulness of sensitivity and uncertainty analysis for identifying relevant processes in model-based sediment connectivity assessments.</p>

The impact of selective commercial logging on stream hydrology, chemistry and sediment loads in the Ulu Segama rain forest, Sabah, Malaysia

1992 ◽  
Vol 335 (1275) ◽  
pp. 397-406 ◽  
Keyword(s):  
Rain Forest ◽  
Drainage System ◽  
Flood Plain ◽  
Sediment Yields ◽  
The Road ◽  
Sediment Loads ◽  
Commercial Logging ◽  
Three Stages ◽  
The Impact ◽  
Degree Of Recovery

Three stages of selective commercial logging in a 0.54 km 2 catchment in the Ulu Segama caused great changes in the output of sediment and water over a 27-month period from June 1988. The ratio of monthly suspended sediment yield from the logged catchment to that from a nearby undisturbed catchment changed from the order of 1:1 before disturbance; to 4:1 after a logging road had been built across the head of the catchment; to 5:1 after logging within 37 m of the road; and to 18:1 in the five months after logging of the remainder of the catchment. A year after logging had ceased the largest monthly sediment yields of the whole period were only 3.6 times those of the undisturbed catchment, indicating a degree of recovery. Sediment accumulated in the channel bed and on the narrow flood plain remained to be evacuated, and gullies on abandoned logging trails continued to supply sediment to the drainage system.

scholarly journals Estimation of the susceptibility of a road network to shallow landslides with the integration of the sediment connectivity

2018 ◽  
Author(s):  
Massimiliano Bordoni ◽  
M. Giuseppina Persichillo ◽  
Claudia Meisina ◽  
Stefano Crema ◽  
Marco Cavalli ◽  
...  
Keyword(s):  
Land Use ◽  
Road Network ◽  
Slope Angle ◽  
Drainage System ◽  
Shallow Landslides ◽  
Mitigation Measures ◽  
Explanatory Variables ◽  
The Road ◽  
Genetic Algorithm Method ◽  
Sediment Connectivity

Abstract. Landslides causes severe damages to the road network of a hit zone, in terms of both direct (partial or complete destruction of a road trait, blockages) and indirect (traffic restriction, cut-off of a certain area) costs. Thus, the identification of the parts of the road network which are more susceptible to landslides is fundamental to reduce the risk to the population potentially exposed and the money expense caused by road damaging. For these reasons, this paper aimed to develop and test a data-driven model based on the Genetic Algorithm Method for the identification of road sectors that are susceptible to be hit by shallow landslides triggered in slopes upstream to the infrastructure. This work also analyzed the importance of considering or not the sediment connectivity on the estimation of the susceptibility. The study was carried out in a catchment of north-eastern Oltrepò Pavese (northern Italy), where several shallow landslides affected roads in the last 8 years. The random partition of the dataset used for building the model in two parts (training and test subsets), within a 100-fold bootstrap procedure, allowed to select the most significant explanatory variables, providing a better description of the occurrence and distribution of the road sectors potentially susceptible to damages induced by shallow landslides. The presented methodology allows the identification, in a robust and reliable way, of the most susceptible road sectors that could be hit by sediments delivered by landslides. The best predictive capability was obtained using a model which took into account also the index of connectivity, calculated according to a linear relationship. Most susceptible road traits resulted to be located below steep slopes with a limited height (lower than 50 m), where sediment connectivity is high. Different scenarios of land use were implemented in order to estimate possible changes in road susceptibility. Land use classes of the study area were characterized by similar connectivity features with a consequent loss of variations also on the susceptibility of the road networks according to different scenarios of distribution of land cover. Larger effects on sediment connectivity and, as a consequence on road susceptibility, could be due to modifications in the morphology of the slopes (e.g. drainage system, modification of the slope angle) caused by the abandonment or by the recovery of cultivations. The results of this research demonstrate the ability of the developed methodology in the assessment of susceptible roads. This could give to the managers of an infrastructure information on the criticality of the different road traits, thereby allowing attention and economic budgets to be shifted towards the most critical assets, where structural and non-structural mitigation measures could be implemented.

scholarly journals Estimation of the susceptibility of a road network to shallow landslides with the integration of the sediment connectivity

2018 ◽  
Vol 18 (6) ◽  
pp. 1735-1758 ◽  
Author(s):  
Massimiliano Bordoni ◽  
M. Giuseppina Persichillo ◽  
Claudia Meisina ◽  
Stefano Crema ◽  
Marco Cavalli ◽  
...  
Keyword(s):  
Land Use ◽  
Road Network ◽  
Slope Failure ◽  
Shallow Landslides ◽  
Mitigation Measures ◽  
Bootstrap Procedure ◽  
Explanatory Variables ◽  
The Road ◽  
Bootstrap Model ◽  
Sediment Connectivity

Abstract. Landslides cause severe damage to the road network of the hit zone, in terms of both direct (partial or complete destruction of a road or blockages) and indirect (traffic restriction or the cut-off of a certain area) costs. Thus, the identification of the parts of the road network that are more susceptible to landslides is fundamental to reduce the risk to the population potentially exposed and the financial expense caused by the damage. For these reasons, this paper aimed to develop and test a data-driven model for the identification of road sectors that are susceptible to being hit by shallow landslides triggered in slopes upstream from the infrastructure. This model was based on the Generalized Additive Method, where the function relating predictors and response variable is an empirically fitted smooth function that allows fitting the data in the more likely functional form, considering also non-linear relations. This work also analyzed the importance, on the estimation of the susceptibility, of considering or not the sediment connectivity, which influences the path and the travel distance of the materials mobilized by a slope failure until hitting a potential barrier such as a road. The study was carried out in a catchment of northeastern Oltrepò Pavese (northern Italy), where several shallow landslides affected roads in the last 8 years. The most significant explanatory variables were selected by a random partition of the available dataset in two parts (training and test subsets), 100 times according to a bootstrap procedure. These variables (selected 80 times by the bootstrap procedure) were used to build the final susceptibility model, the accuracy of which was estimated through a 100-fold repetition of the holdout method for regression, based on the training and test sets created through the 100 bootstrap model selection. The presented methodology allows the identification, in a robust and reliable way, of the most susceptible road sectors that could be hit by sediments delivered by landslides. The best predictive capability was obtained using a model in which the index of connectivity was also calculated according to a linear relationship, was considered. Most susceptible road traits resulted to be located below steep slopes with a limited height (lower than 50 m), where sediment connectivity is high. Different land use scenarios were considered in order to estimate possible changes in road susceptibility. Land use classes of the study area were characterized by similar connectivity features. As a consequence, variations on the susceptibility of the road network according to different scenarios of distribution of land cover were limited. The results of this research demonstrate the ability of the developed methodology in the assessment of susceptible roads. This could give the managers of infrastructure information about the criticality of the different road traits, thereby allowing attention and economic budgets to be shifted towards the most critical assets, where structural and non-structural mitigation measures could be implemented.

CONSTRUCTING A MODEL OF THE ROAD NETWORK (S. SUVOROV)

2015 ◽  
Vol 2 (1) ◽  
pp. 283-285 ◽  
Author(s):  
Минкин ◽  
I. Minkin ◽  
Пышный ◽  
V. Pyshnyy
Keyword(s):  
Road Network ◽  
Input Data ◽  
Model Building ◽  
The Road

The article describes the preparation of input data and model building of the road network as a graph using the software and analytical complex Transnet

ANALISIS PENGARUH PEMBANGUNAN JALAN LAYANG JANTI TERHADAP PERKEMBANGAN TATA RUANG KAWASAN JANTI STUDI KASUS : KAWASAN JANTI, DESA CATURTUNGGAL, KABUPATEN SLEMAN, D. I. YOGYAKARTA

2017 ◽  
Vol 11 (3) ◽  
pp. 255
Author(s):  
Jeky El Boru
Keyword(s):  
Road Network ◽  
Open Space ◽  
Qualitative Description ◽  
Analysis Method ◽  
Open Spaces ◽  
The Road ◽  
Before And After ◽  
Linkage Method ◽  
The Impact ◽  
Parking Place

Abstract: This research aims to analyze the impact of Janti Flyover Construction toward the growth of layout at Janti Urban Area, including structured space, open space, and linkage. Method used for data collecting are observation, air photograph monitoring, and interview, whereas the analysis method is qualitative description, which is the superimposed method of two layers, that are the layout condition before and after flyover construction. The result shows that the impact of Janti Flyover construction can be seen on building mass (solid), the increasing number of open spaces, including the road network, parking place, and park, whereas the relation between spaces, visually and structurally, can be seen on the growth of buildings which have new shapes and styles, therefore the performance of the overall building does not have a proportional shape. Considering Janti Street at the collective relation, its role is getting stronger as the main frame road network.Keywords: Flyover construction, layout changing, Janti AreaAbstrak: Penelitian ini bertujuan untuk menganalisis pengaruh pembangunan Jalan Layang Janti terhadap perkembangan tata ruang Kawasan Janti, meliputi ruang terbangun, ruang terbuka, serta hubungan antar ruang (“linkage”). Metode pengumpulan data dilakukan melalui observasi, pengamatan foto udara, dan wawancara; sedangkan metode analisis melalui deskripsi secara kualitatif yang berupa “superimposed method” dari dua lapisan kondisi lahan, yakni kondisi tata ruang sebelum dan sesudah pembangunan jalan layang. Hasil penelitian menunjukkan bahwa pengaruh pembangunan Jalan Layang Janti terdapat pada massa bangunan (“solid”), pertambahan ruang terbuka yang berupa jaringan jalan, parkir, dan taman; sedangkan pada hubungan antar ruang ̶ secara visual dan struktural ̶ yakni tumbuhnya bangunan dengan bentuk dan gaya baru, sehingga bentuk tampilan bangunan secara keseluruhan tidak proporsional. Pada hubungan kolektif, Jalan Janti semakin kuat perannya sebagai kerangka utama jaringan jalan.Kata kunci : Pembangunan jalan layang, tata ruang, Kawasan Janti

STUDY OF MOVEMENTS MOBILITY-IMPAIRED POPULATION GROUPS IN PEDESTRIAN ZONES OF THE STREET-ROAD NETWORK (in the example of city of Kiev)

2017 ◽  
Author(s):  
Oleksandra Cherednichenko ◽  
Keyword(s):  
European Union ◽  
Comparative Analysis ◽  
Road Network ◽  
Actual State ◽  
The European Union ◽  
Regulatory Requirements ◽  
Population Groups ◽  
The Road ◽  
Mobility Impaired

The results of the study of the main elements of unobstructed space are presented and the compliance of the actual state with the regulatory requirements of measures to ensure a safe, comfortable, accessible and informative pedestrian zone of the road network is analyzed. A comparative analysis of the main regulatory requirements for access ramps on the legislation of Ukraine and the European Union is carried out.

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