scholarly journals Can Lumped Characteristics of a Contributing Area Provide Risk Definition of Sediment Flux?

Water ◽  
2020 ◽  
Vol 12 (6) ◽  
pp. 1787
Author(s):  
Barbora Jáchymová ◽  
Josef Krása ◽  
Tomáš Dostál ◽  
Miroslav Bauer

Accelerated soil erosion by water has many offsite impacts on the municipal infrastructure. This paper discusses how to easily detect potential risk points around municipalities by simple spatial analysis using GIS. In the Czech Republic, the WaTEM/SEDEM model is verified and used in large scale studies to assess sediment transports. Instead of computing actual sediment transports in river systems, WaTEM/SEDEM has been innovatively used in high spatial detail to define indices of sediment flux from small contributing areas. Such an approach has allowed for the modeling of sediment fluxes in contributing areas with above 127,484 risk points, covering the entire Czech Republic territory. Risk points are defined as outlets of contributing areas larger than 1 ha, wherein the surface runoff goes into residential areas or vulnerable bodies of water. Sediment flux indices were calibrated by conducting terrain surveys in 4 large watersheds and splitting the risk points into 5 groups defined by the intensity of sediment transport threat. The best sediment flux index resulted from the correlation between the modeled total sediment input in a 100 m buffer zone of the risk point and the field survey data (R2 from 0.57 to 0.91 for the calibration watersheds). Correlation analysis and principal component analysis (PCA) of the modeled indices and their relation to 11 lumped characteristics of the contributing areas were computed (average K-factor; average R-factor; average slope; area of arable land; area of forest; area of grassland; total watershed area; average planar curvature; average profile curvature; specific width; stream power index). The comparison showed that for risk definition the most important is a combination of morphometric characteristics (specific width and stream power index), followed by watershed area, proportion of grassland, soil erodibility, and rain erosivity (described by PC2).

2016 ◽  
Vol 47 (1) ◽  
pp. 264 ◽  
Author(s):  
I. Ilia ◽  
D. Rozos ◽  
I. Koumantakis

The main objective of this paper is to classify landforms in Kimi municipality area of Euboea Island, Greece using advanced spatial techniques. Landform categories were determined by conducting morphometric analysis through the use of advanced GIS functions. In particular, the process of classifying the landscape into landform categories was based on Topographic Position Index (TPI). The main topographic elements such as slope inclination, aspect, slope shape (curvature), topographic wetness index and stream power index were obtained from the DEM file of the study area. Landform classification was obtained using TPI grids and the classes were related with the geological pattern and the land cover by sophisticated spatial analysis function. The knowledge obtained from the present study could be useful in identifying areas prone to land degradation and instability problems in which landforms are identified as an essential parameter


2020 ◽  
Author(s):  
Luděk Strouhal ◽  
Petr Kavka ◽  
Hana Beitlerová ◽  
Daniel Žížala

<p>Czech soil data is a mess. Modelling infiltration, or its probably most watched companion - runoff, has been quite a painful process for any researcher or practitioner studying any site larger or more heterogeneous than a few parcels of arable land. There are at least three main national soil databases in the Czech Republic, each of different age, scope, classification system and - most unfortunately - different administrator. So far Research Institute for Soil and Water Conservation has taken good care of data for agricultural land, while The Forest Management Institute did his job considering forest soils. A few other research institutes manage their own specific databases. There has been no service available providing consistent data for the whole country, nor methodology giving some guidelines on how to cope with differences in existing datasets, though a few large-scale applications and studies do exist. This contribution presents preliminary results of a running project TJ02000234 - Physical and hydropedological soil properties of the Czech Republic. It aims at harmonizing and combining available datasets and deriving layers of soil texture and hydropedological properties. Next the project aims at gathering available measurements of hydraulic properties of Czech soil types and their partial validation and extending with field measurements in the scope limited by the 2-years of project duration. The derived database and data products will be published in the form of a certified map as well as offered to professionals through an online GIS portal. Design planners in the Land consolidation, flood and soil erosion mitigation projects as well as professionals in public administration and researchers in environmental disciplines will benefit from the publication of this consistent data.</p>


2020 ◽  
Vol 15 (No. 2) ◽  
pp. 116-124
Author(s):  
Petra Bíla ◽  
Bořivoj Šarapatka ◽  
Ondřej Horňák ◽  
Jaroslava Novotná ◽  
Martin Brtnický

Soil erosion, especially water erosion, is one of the most widespread types of soil degradation, not only worldwide, but also within the Czech Republic, where it endangers more than a half of the agricultural land. In addition to farming, the landscape structure has a significant impact on soil erosion in the conditions under study, where, especially in the post-war period, the collectivisation of large-scale arable land was accompanied by the abolition of the associated landscape elements. The agricultural production area of South Moravia is one of the most endangered areas in the Czech Republic, therefore, it was selected for our research, whose main objective was to verify the sensitivity of the selected physical, chemical and biochemical characteristics to identify the changes in the soil properties in the erosion processes at the identified erosion areas. The testing was carried out within a period of 5 years in 60 locations with Chernozems with cultivated corn. To assess the quality of the soil properties, indicators of soil quality from the physical, chemical and biological – biochemical groups were selected. The results of the analyses and the subsequent statistical evaluation showed that the chemical characteristics, especially those related to the quantity and quality of the organic matter, were the most sensitive to the changes in the soil properties. From the biochemical indicators, some enzymes, particularly dehydrogenase and acid phosphatase, reacted sensitively. The physical characteristics were not significantly affected by the erosion processes.


2021 ◽  
Author(s):  
Sarita Gajbhiye Meshram ◽  
Ali reza Ildoromi ◽  
Mehdi Sepehri

Abstract Flood is one of the major problems of the sad ekbatan watershed, northern of Hamadan province, Iran. This problem imposes high damages to the economic issue. Therefore, prioritization of the study area based on the flooding degree can be considered for identifying hot spot flooded areas for performing soil and water conservation practices. In this study, in order to prioritize sub-watersheds of the case study from viewpoint of flooding degree, five flood-related criteria i.e. entropy of drainage network (En), index of connectivity (IC), stream power index (SPI), curvature (C) and curve number (CN) were considered, then fuzzy based Best Worse Multi Criteria Decision Making (F-BWM) Method was used to assigning weights to used criteria and combination them to achieve flooding degree for each sub-watershed. The results of prioritization of sub-watersheds indicated that the sub-watersheds 14 and 21 are most and least susceptibility areas to flooding correspondingly.


2013 ◽  
Vol 15 ◽  
pp. 69-76 ◽  
Author(s):  
Chandra Prakash Poudyal

The decision tree is one of the new methods used for the determination of landslide susceptibility in the study area. The Phidim area is selected for the application of this method. The total surface area is 168.07 sq. km, and is located at the eastern part of Nepal. There are total of 10 different data bases used for this study which are; geological formation, elevation, slope, curvature, aspect, stream power index, topographic wetness index, distance from drainage, lineaments, and slope length, and are considered as landslide conditioning factors. Geographical information system (GIS) is used as basic tools and ARC/View is used for the processing data analysis and final map preparation. For the decision tree analysis the PASW 18 (statistical tool) is used to generate values of each factor. According to the results of decision tree, two geological formations; stream power index and slope are found as the most effective parameters on the landslide occurrence in the study area. Using the predicted values, the landslide susceptibility map of the study area is produced. To assess the performance of the produced susceptibility map, the area under curve (AUC) is drawn. The AUC value of the produced landslide susceptibility map has been obtained as 95.9%. According to the results of the AUC evaluation, the produced map has showed a good performance. As to wrap up, the produced map is able to be used for medium scaled and regional planning purposes. DOI: http://dx.doi.org/10.3126/bdg.v15i0.7419 Bulletin of the Department of Geology, Vol. 15, 2012, pp. 69-76


The success of the Program of housing stock renovation in Moscow depends on the efficiency of resource management. One of the main urban planning documents that determine the nature of the reorganization of residential areas included in the Program of renovation is the territory planning project. The implementation of the planning project is a complex process that has a time point of its beginning and end, and also includes a set of interdependent parallel-sequential activities. From an organizational point of view, it is convenient to use network planning and management methods for project implementation. These methods are based on the construction of network models, including its varieties – a Gantt chart. A special application has been developed to simulate the implementation of planning projects. The article describes the basic principles and elements of modeling. The list of the main implementation parameters of the Program of renovation obtained with the help of the developed software for modeling is presented. The variants of using the results obtained for a comprehensive analysis of the implementation of large-scale urban projects are proposed.


2021 ◽  
Vol 13 (5) ◽  
pp. 2950
Author(s):  
Su-Kyung Sung ◽  
Eun-Seok Lee ◽  
Byeong-Seok Shin

Climate change increases the frequency of localized heavy rains and typhoons. As a result, mountain disasters, such as landslides and earthworks, continue to occur, causing damage to roads and residential areas downstream. Moreover, large-scale civil engineering works, including dam construction, cause rapid changes in the terrain, which harm the stability of residential areas. Disasters, such as landslides and earthenware, occur extensively, and there are limitations in the field of investigation; thus, there are many studies being conducted to model terrain geometrically and to observe changes in terrain according to external factors. However, conventional topography methods are expressed in a way that can only be interpreted by people with specialized knowledge. Therefore, there is a lack of consideration for three-dimensional visualization that helps non-experts understand. We need a way to express changes in terrain in real time and to make it intuitive for non-experts to understand. In conventional height-based terrain modeling and simulation, there is a problem in which some of the sampled data are irregularly distorted and do not show the exact terrain shape. The proposed method utilizes a hierarchical vertex cohesion map to correct inaccurately modeled terrain caused by uniform height sampling, and to compensate for geometric errors using Hausdorff distances, while not considering only the elevation difference of the terrain. The mesh reconstruction, which triangulates the three-vertex placed at each location and makes it the smallest unit of 3D model data, can be done at high speed on graphics processing units (GPUs). Our experiments confirm that it is possible to express changes in terrain accurately and quickly compared with existing methods. These functions can improve the sustainability of residential spaces by predicting the damage caused by mountainous disasters or civil engineering works around the city and make it easy for non-experts to understand.


2020 ◽  
Vol 30 (Supplement_5) ◽  
Author(s):  
M Nishigaki ◽  
C Koga ◽  
M Hanazato ◽  
K Kondo

Abstract Introduction Older adult's depression is a public health problem. In recent years, exposure to local greenspace is beneficial to mental health via increased physical activity in people. However, few studies approach the relationship between greenspace and depression while simultaneously considering the frequency, time, and the number of types of physical activity, and large-scale surveys targeting the older adults. Methods Cross-sectional data conducted in 2016 by the Japan Gerontological Evaluation Study was used. The analysis included older adults aged 65 and over who did not require care or assistance, and a total of 126,878 people in 881 School districts. The explanatory variable is the percentage of the greenspace of the area, and the greenspace data used is data created from satellite photographs acquired by observation satellites of the Japan Aerospace Exploration Agency. The objective variable was depression (Geriatric Depression Scale 5 points or more). The analysis method was a multi-level logistic regression analysis. Physical activity was the number of sports-related hobbies, the frequency of participation in sports meetings, and walking time in daily life. Other factors such as personal attributes, population density of residential areas, and local climate were also considered. Results Depression in the survey was 20.4%. The abundance of greenspace was still associated with depression, considering all physical activity. The odds ratio of depression in areas with more greenspace was 0.92 (95% CI 0.87 - 0.98) compared to areas with less greenspace. Conclusions It became clear that areas with many greenspace were still associated with low depression, even considering the frequency, time and number of physical activities. It is conceivable that the healing effect of seeing greenspace, the reduction of air pollution and noise, etc. are related to the lack of depression without going through physical activity. Key messages In Japan, older adults are less depressed when there are many local greenspace. It became clear that areas with many greenspace were still associated with low depression, even considering physical activities.


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