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Ivan Kovalchuk

Bio: Ivan Kovalchuk is an academic researcher from National University of Life and Environmental Sciences of Ukraine. The author has contributed to research in topics: Drainage basin & Structural basin. The author has an hindex of 2, co-authored 14 publications receiving 18 citations.

Papers
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Journal ArticleDOI
20 Apr 2019
TL;DR: In this paper, the potential of global open source digital elevation models (SRTM, ASTER, ALOS) and their suitability for using in modeling of erosion processes are assessed in the Shumsky district of Ternopil region in Western part of Ukraine.
Abstract: The relief has a major impact on the landscape`s hydrological, geomorphological and biological processes. Many geographic information systems used elevation data as the primary data for analysis, modeling, etc. A digital elevation model (DEM) is a modern representation of the continuous variations of relief over space in digital form. Digital Elevation Models (DEMs) are important source for prediction of soil erosion parameters. The potential of global open source DEMs (SRTM, ASTER, ALOS) and their suitability for using in modeling of erosion processes are assessed in this study. Shumsky district of Ternopil region, which is located in the Western part of Ukraine, is the area of our study. The soils of Shumsky district are adverselyaffected by erosion processes. The analysis was performed on the basis of the characteristics of the hydrological network and relief. The reference DEM was generated from the hypsographic data(contours) on the 1:50000 topographical map series compiled by production units of the Main Department of Geodesy and Cartography under the Council of Ministers. The differences between the reference DEM and open source DEMs (SRTM, ASTER and ALOS) are examined. Methods of visual detection of DEM defects, profiling, correlation, and statistics were used in the comparative analysis. This research included the analysis oferrors that occurred during the generation of DEM. The vertical accuracy of these DEMs, root mean square error (RMSE), absolute and relative errors, maximum deviation, and correlation coefficient have been calculated. Vertical accuracy of DEMs has been assessed using actual heights of the sample points. The analysis shows that SRTM and ALOS DEMs are more reliable and accurate than ASTER GDEM. The results indicate that vertical accuracy of DEMs is 7,02m, 7,12 m, 7,60 mand 8,71 m for ALOS, SRTM 30, SRTM 90 and ASTER DEMs respectively. ASTER GDEM had the highest absolute, relative and root mean square errors, the highest maximum positive and negative deviation, a large difference with reference heights, and the lowest correlation coefficient. Therefore, ASTER GDEM is the least acceptable for studying the intensity and development of erosion processes. The use of global open source DEMs, compared with the vectorization of topographic maps,greatly simplifies and accelerates the modeling of erosion processes and the assessment of the erosion risk in the administrative district.

9 citations

Journal ArticleDOI
TL;DR: In this article, a comparative analysis of the suggested approaches and their practical approbation have been carried out and the change of land plot spatial characteristics by means of various reallotment scenarios has been analyzed.
Abstract: The study is dedicated to land reallotment in the course of land use alteration in Ukraine. The case of the development of an individual residential block in an agricultural area is considered. The issue of the alteration of the spatial characteristics of land plots and changes in their designated use have been highlighted. The objective of the article is the substantiation of land reallotment at the level of an individual residential block on agricultural land which is privately owned by a number of landowners. The preconditions for the development of land reallotment in a rural‑type settlement in the suburban area of a big city have been substantiated. Alternative approaches to land reallotment have been suggested. A comparative analysis of the suggested approaches and their practical approbation have been carried out. The change of land plot spatial characteristics in the course of reallotment by means of various reallotment scenarios has been analysed. Land plot value after reallotment in each scenario has been specified. The practicability of each approach depending on the initial conditions has been substantiated. The research can be used in the course of rural settlement development planning, the coordination of measures on land use type alteration with landowners and land users, with private landowners or the implementation of local community initiatives.

8 citations

Journal ArticleDOI
TL;DR: In this paper, the authors discuss the issues related to the methodology and technique of landscape-limnological research into lake-basin systems of Ukraine, based on many years of field expedition-based and semipermanent station-based landscape and Limnological investigations, primarily for flat territories of Polissia.

5 citations

Book ChapterDOI
01 Jan 2013
TL;DR: In this article, the main causes of the November 1998 and March 2001 floods were natural hydrometeorological factors reinforced by considerable human impact over the last decades, and the types and drivers of movements are identified.
Abstract: In the Ukrainian Carpathians hydrometeorological and topographical conditions jointly control the geographical distribution of exogenous geomorphic processes. In the region, channel-forming floods occur at daily precipitation intensities of 40–60 mm. Maximum daily amount of precipitation reached 160 mm in 1992 and caused rapid water level rises up to 8.5 m. Similar floods with catastrophic effects happened in 1947, 1957, 1969, 1970, 1980, 1998, and 2001. The main causes of the November 1998 and March 2001 floods were natural hydrometeorological factors reinforced by considerable human impact over the last decades. For landslides 5-year cycles and for mudflows 11-year cycles are observed. Seismic activity also influences landsliding in the Ukrainian Carpathians. The risk of extreme devastation by mudflows is also very high. For dangerous mudflows the precipitation threshold is 30 mm day−1, while disasters only ensue from rainfalls above 100 mm day−1 intensity. Types and drivers of movements are identified. During extreme flash floods, significant changes in riverbed morphology have been observed (bank erosion, channel incision, and sediment accumulation). Bank retreat along the Tysa River, particularly at the confluences of major tributaries, reaches rates of 1 m year−1 (for the Tereblia confluence even 5 m year−1).

5 citations

Journal ArticleDOI
13 Oct 2020
TL;DR: In this article, the authors considered the possibility of further development of the tourist and recreational sphere in the near-Dnister sections of the river basins of Dzhuryn and Nichlava, and proposed the creation of Borshchiv Regional landscape park in the picturesque valley of the Nichlas river.
Abstract: The level of anthropogenization of the natural processes and the geocomponents of the basin geosystems of small rivers in Western Podillya has been estimated and rated as ecologically dangerous from the viewpoint of sustainable and conflict free functioning. The scales of the transformation of the components of natural environment by economic activities since 1774 were revealed using the method of comparative-geographic analysis of cartographic sources. The scales of deforestation were determined, as well as the scales of the influences of drainage meliorations on wetlands, river floodplains and riverbed complexes. It has been established that such transformations of the state of the components of landscape systems have caused the manifestation of a set of unfavorable processes and phenomena (lowering of ground water level, promoting desiccation, soil erosion and deflation, soil dehumification, decreasing landscape and biological diversity, etc.). Calculated indices of the anthropogenic modification of natural components testify that the strongest adversary impacts on river systems and basin landscapes are caused by agriculture, deforestation, and drainage meliorations. Our analysis of the current state of reclaimed lands in the basins of the rivers Dzhuryn and Nichlava confirmed the conclusions of B. I Kozlovsky on the effects of drainage reclamation on groundwater in drained lands and of the formation within them and around drainage systems of negative hydrogeological zones of different widths. In the absence of precipitation for 30-45 consecutive days in summer there is a sharp decrease in groundwater levels, and overdrying of soils, which causes the manifestation and intensification of deflation, shallowing and even drying of the upper reaches of rivers and streams. At the final stage of the study, a system of measures aimed at ensuring the sustainability of river basin geosystems was substantiated. The introduction of an optimization model of land use in the basin geosystem is one of the priority tasks in the context of negative changes in the water regime of watercourses and the water balance of river basin systems. Optimization measures provide for the transformation of the part of degraded and unproductive lands towards the grasslands and the planting of gardens (slopes up to 7°) and afforestation (surface steepness over 7°) to improve the quality of environment and to form the environmentally secure land use system. Regional indices of anthropogenic transformation for the existing and proposed land structure as a normative regional indices of nature utilization optimality are calculated. Substantiation of schemes of basin nature protection networks was based on taking into account the role of protected areas in maintaining certain functional features at the sources, in the middle and lower parts of river basins. Based on the results of field surveys, it is proposed to create nine protected areas within the Dzhuryn Basin and eight protected areas within the Nichlava river basin, which will increase the share of protected areas of the Dzhuryn basin to 8% (compared to present 4.8%) and Nichlava to 19%. At the same time, it is proposed to change the structure of the nature reserve fund of the Nichlava river basin, taking into account the existing high share (77%) of general zoological reserves, inefficient from the standpoint of conservation of natural complexes, instead creating six landscape reserves on an area of about 800 hectares. The paper considers the possibility of further development of the tourist and recreational sphere in the near-Dnister sections of the river basins of Dzhuryn and Nichlava, and proposes the creation of Borshchiv Regional landscape park in the picturesque valley of the Nichlava River.

5 citations


Cited by
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01 May 1991
TL;DR: In this paper, the authors examined the effect of the spatial resolution of digital elevation models (DEMs) on slope and aspect data and found that slope differences concentrate in areas of steep slopes, whereas aspect differences are in generally flat areas with minor landform features.
Abstract: This article examines the effect of the spatial resolution of digital elevation models (DEMs) on slope and aspect data. After a review of computing methods for slope and aspect and such factors as DEM resolution, topographic complexity, and quality of DEM data, the article presents two experiments using DEMs from 8 to 80 m intervals. Results of the experiments show that the accuracy of slope and aspect data, as well as the mean and standard deviation of slope values, decrease with lower DEM resolutions. Comparison of slope and aspect maps generated from different resolutions reveals that slope differences concentrate in areas of steep slopes, whereas aspect differences are in generally flat areas with minor landform features. Slope differences can be explained statistically by relative relief, and aspect differences by relative relief and standard deviation of elevation.

214 citations

Journal ArticleDOI
TL;DR: In this article , the problem of natural agricultural land afforestation with insufficient forest cover of the area is highlighted and the authors identify the main approaches to the issue of agricultural-land afforestation and propose land consolidation aimed at the rationalisation of agricultural and forest land management.
Abstract: The article highlights the problem of natural agricultural-land afforestation with insufficient forest cover of the area. The article purports to substantiate land consolidation aimed at the rationalisation of agricultural and forest land management in such conditions. The authors identify the main approaches to the issue of natural agricultural land afforestation. The afforested areas of agricultural land are suggested for redesignation as a forest resource as a result of a swap and reallotment of land plots. As an example, consolidation of available land, in the conditions of natural afforestation, has been accomplished based on a number of land masses in Chernihiv Oblast’, Ukraine. Resulting from the project implementation, better configuration and improved layout of agricultural land plots have been achieved, while the length and placement of country lanes have been optimized. The reforested agricultural areas within the specific land mass have been redesignated as a forest resource. The advantages and disadvantages of natural afforestation in land consolidation are identified in contrast to alternative approaches.The research findings can be used by territorial communities in the upgrade of land management practices, laying out and redesign of landscape parks and other nature conservation areas that include areas of business activity.

8 citations

Journal ArticleDOI
TL;DR: In this article, the authors evaluated five of the most common digital elevation models and their derived geomorphological features in the Humrat Assahn basin and found a strong relationship between the reference DEM and the aerial photo DEM.
Abstract: A digital elevation model (DEM) is an essential dataset for many land feature analyses, such as geomorphological feature analyses, which are very important for many types of studies The present study involved the evaluation of five of the most common DEMs and their derived geomorphological features in the Humrat Assahn basin A 10-m reference DEM was generated for the study area from a contour map produced at the Royal Jordanian Geographic Center (RJGC) In addition, an aerial photography DEM with a 10-m resolution was generated using PCI Geomatica software Both the second version of the 30-m Advanced Spaceborne Thermal Emission and Reflection Radiometer Global DEM version 2 (ASTER GDEM 2) and a DEM derived from 2000 Google earth (GE) elevation points were evaluated as well The validation process included a comparison of elevation profiles, the calculation of DEM accuracies and statistics, and the evaluation of some delineated geomorphological features such as hill shade and watershed, which are derivatives of each DEM The results revealed a strong relationship between the reference DEM and the aerial photo DEM, and it is found that there is a moderate relationship between the reference DEM and the Shuttle Radar Topography Mission (SRTM), GE, and ASTER GDEM 2 DEMs The root mean square errors (RMSEs) of the aforementioned DEM values were ± 12526 m, ± 40411 m, ± 42332 m, and ± 43383 m, respectively

7 citations

Journal ArticleDOI
28 Mar 2021
TL;DR: According to the results of experimental studies established for the cultivation of hybrid silver and bighead carp in reservoirs, relatively high rates of linear and weight growth are expected, higher than for similar species, which is provided in the conditions of fish ponds.
Abstract: In water reservoirs, the size and characteristics of fish, in the first place, affect – the composition and clarity of food objects, the number of food competitors and predators, their numbers, industry, and others. Besides, the rate of linear and weight growth are the arteries that determine the value of the species as an object of commercial fishing. The hybrid of silver and bighead carp easily adapts to different growing conditions (from the point of view of the formation of fish-biological indicators), protein in different years depending on feeding conditions, in one reservoir indicators of length and body weight of ribs are inadequate. Evaluating the influence of feeding conditions on the linear growth of the rib, the method of generalized evaluation was used. An indicator equal to the sum of potential fish productivity for phyto-zooplankton was used to characterize the foraging status of a particular condition in a certain period. In terms of the quality of growth indicators, the indicator of the absolute weight of nature with differentiation of farms, age groups, and years was used. The results of the research revealed significant variability in the size and weight characteristics of different groups of silver and bighead carp, which were isolated from ponds and reservoirs. According to the results of experimental studies established for the cultivation of hybrid silver and bighead carp in reservoirs, relatively high rates of linear and weight growth are expected, higher than for similar species, which is provided in the conditions of fish ponds.

6 citations

Book ChapterDOI
01 Jan 2013
TL;DR: In this article, the main causes of the November 1998 and March 2001 floods were natural hydrometeorological factors reinforced by considerable human impact over the last decades, and the types and drivers of movements are identified.
Abstract: In the Ukrainian Carpathians hydrometeorological and topographical conditions jointly control the geographical distribution of exogenous geomorphic processes. In the region, channel-forming floods occur at daily precipitation intensities of 40–60 mm. Maximum daily amount of precipitation reached 160 mm in 1992 and caused rapid water level rises up to 8.5 m. Similar floods with catastrophic effects happened in 1947, 1957, 1969, 1970, 1980, 1998, and 2001. The main causes of the November 1998 and March 2001 floods were natural hydrometeorological factors reinforced by considerable human impact over the last decades. For landslides 5-year cycles and for mudflows 11-year cycles are observed. Seismic activity also influences landsliding in the Ukrainian Carpathians. The risk of extreme devastation by mudflows is also very high. For dangerous mudflows the precipitation threshold is 30 mm day−1, while disasters only ensue from rainfalls above 100 mm day−1 intensity. Types and drivers of movements are identified. During extreme flash floods, significant changes in riverbed morphology have been observed (bank erosion, channel incision, and sediment accumulation). Bank retreat along the Tysa River, particularly at the confluences of major tributaries, reaches rates of 1 m year−1 (for the Tereblia confluence even 5 m year−1).

5 citations