Suspension concentration distribution in a stream constructed by spur No. 19 on the Amu Darya river

The concentration of suspended solids is the main indicator of the flow transporting suspended sediments. Knowing its value, it becomes possible to predict channel processes on rivers, the timing of sedimentation tanks and reservoirs. Establishing patterns of the influence of structures on the redistribution of liquid and solid runoff is also a priority task. The main goal of this work is to establish the regularities of the distribution of the concentration of suspended matter in a stream constrained by a transverse spur. The problem is considered for the second time using materials from field studies conducted on spur No. 19 in 2020 on the left bank of the Amu Darya river. The methodology of field studies remained the same as for the first time on dam No. 30 in 2019. The positions of the sections and verticals during sampling to determine the concentration of suspended matter were assigned based on the hydraulic structure of the constrained flow. Considering the presence of homogeneous zones of a weakly perturbed core, intense turbulent mixing and reverse currents, as is customary in the theory of turbulent jets with an admixture propagating in a confined space. On verticals, samples were taken at two points 0.2H and 0.8H, and at shallow depths at a depth of 0.6H. Field observations established that in the zone of the slightly disturbed core of the distribution of the concentration of suspended matter along the depth, it has the shape of a “boot”; however, the length of the toe is much shorter than that of the dam 30 and is observed only in the sections P-P and O-O, and in the other sections there is a leveling in depth. On other sections, they are close to logarithmic. The maximum concentration of suspended matter was observed in the section of confinement O-O at point 0.8H 7.66 kg / m3, which in the section of confinement under the influence of a new spur occurs deep and lateral erosion of the channel. The distribution in plan in the zone of a weakly disturbed core is close to uniform. Here again, in the zone of intense turbulent mixing, it obeys the theoretical Schlichting-Abramovich dependence for the initial section. With the help of the results obtained, it is possible to predict the siltation of the inter-dam space and the boundaries of the new coastline in the future

Theoretical bases for determining the velocity and suspended matter concentration in the swirling zone beyond the transverse dam

Design dependencies to determine the velocity and concentration of suspended matter in the swirling zone beyond the transverse dam in the presence of the initial section of the jet are proposed in the article, using the main provisions of the theory of turbulent jets, the scheme of dividing the flow into hydraulic homogeneous zones: a weakly perturbed core, intense turbulent mixing and reverse currents. The distribution of velocities and concentration of suspended matter (turbidity) in the zone of intense turbulent mixing are affine and obey the theoretical Schlichting-Abramovich relationships; this was substantiated by laboratory and field studies. The equations of continuity and conservation of solid matter along the flow were used to solve the problem. To establish the adequacy of the dependencies obtained, a test problem was implemented in which the velocities in the core and the depth along the flow were assumed constant. The problem was implemented for the following contraction ratios of flow nc 0,1; 0.2; 0.3; 0.4; 0.5. Tabular and graphic dependencies obtained show that with all contraction ratios of flow, the relative backflow velocities first increase, and at the end of the swirling zone, they sharply decrease. The maximum is observed at the intersection of the outer boundary of the zone of intense turbulent mixing with the protected coast and reaches m = 0.317. Comparison of the calculation results with the experimental ones shows their qualitative and quantitative agreement. The relative concentration of suspended matter in reverse currents remains practically constant along the entire length of the swirling zone. It is close to unity for all contraction ratios of flow

Strength investigations of foundation of allocation of main structures of Pskem hydropower station on Pskem river

This paper presents the results of geomechanical studies of the siltstone massif experimental carried out in the right-bank adit at the site of the Pskem HPP dam. Primary shear experiments were carried out at 6 normal pressures on the stamp σ: 0.5 MPa; 1.0 MPa; 1.5 MPa; 2.0 MPa, 2.5 MPa, and 3.0 MPa

Scientific and practical substantiation of geodetic and topographic works using GIS software in the design of hydraulic structures

In this article, the scientific and practical basis of geodetic and topographic work in the design of hydraulic structures and solutions intended to improve them using GIS (Geoinformation Systems) were analysed. Geodetic and topographic works are the basis for the design, construction and reconstruction of hydraulic structures in Uzbekistan. A systematic approach to the analysis of geodetic and topographic works in the design of hydraulic structures was chosen, which was used to determine the essence of the processes and laws of scientific substantiation of projects of various hydraulic structures. The geological and topographic works were carried out to monitor the condition of the Karshi main canal, and besides, several other irrigation canals in the Kashkadarya region of the Republic of Uzbekistan were studied. The main task of the Karshi main canal is to supply water to various industries, offices, institutions and irrigation canals. After taking the horizontal and vertical topographic data of the Hisorak Reservoir and processing it using the Global Mapper software, a 3D dimensional model of the Hisorak Reservoir was created

Suspension concentration distribution in a stream constructed by spur No. 19 on the Amu Darya river

The concentration of suspended solids is the main indicator of the flow transporting suspended sediments. Knowing its value, it becomes possible to predict channel processes on rivers, the timing of sedimentation tanks and reservoirs. Establishing patterns of the influence of structures on the redistribution of liquid and solid runoff is also a priority task. The main goal of this work is to establish the regularities of the distribution of the concentration of suspended matter in a stream constrained by a transverse spur. The problem is considered for the second time using materials from field studies conducted on spur No. 19 in 2020 on the left bank of the Amu Darya river. The methodology of field studies remained the same as for the first time on dam No. 30 in 2019. The positions of the sections and verticals during sampling to determine the concentration of suspended matter were assigned based on the hydraulic structure of the constrained flow. Considering the presence of homogeneous zones of a weakly perturbed core, intense turbulent mixing and reverse currents, as is customary in the theory of turbulent jets with an admixture propagating in a confined space. On verticals, samples were taken at two points 0.2H and 0.8H, and at shallow depths at a depth of 0.6H. Field observations established that in the zone of the slightly disturbed core of the distribution of the concentration of suspended matter along the depth, it has the shape of a “boot”; however, the length of the toe is much shorter than that of the dam 30 and is observed only in the sections P-P and O-O, and in the other sections there is a leveling in depth. On other sections, they are close to logarithmic. The maximum concentration of suspended matter was observed in the section of confinement O-O at point 0.8H 7.66 kg / m3, which in the section of confinement under the influence of a new spur occurs deep and lateral erosion of the channel. The distribution in plan in the zone of a weakly disturbed core is close to uniform. Here again, in the zone of intense turbulent mixing, it obeys the theoretical Schlichting-Abramovich dependence for the initial section. With the help of the results obtained, it is possible to predict the siltation of the inter-dam space and the boundaries of the new coastline in the future

Theoretical bases for determining the velocity and suspended matter concentration in the swirling zone beyond the transverse dam

Design dependencies to determine the velocity and concentration of suspended matter in the swirling zone beyond the transverse dam in the presence of the initial section of the jet are proposed in the article, using the main provisions of the theory of turbulent jets, the scheme of dividing the flow into hydraulic homogeneous zones: a weakly perturbed core, intense turbulent mixing and reverse currents. The distribution of velocities and concentration of suspended matter (turbidity) in the zone of intense turbulent mixing are affine and obey the theoretical Schlichting-Abramovich relationships; this was substantiated by laboratory and field studies. The equations of continuity and conservation of solid matter along the flow were used to solve the problem. To establish the adequacy of the dependencies obtained, a test problem was implemented in which the velocities in the core and the depth along the flow were assumed constant. The problem was implemented for the following contraction ratios of flow nc 0,1; 0.2; 0.3; 0.4; 0.5. Tabular and graphic dependencies obtained show that with all contraction ratios of flow, the relative backflow velocities first increase, and at the end of the swirling zone, they sharply decrease. The maximum is observed at the intersection of the outer boundary of the zone of intense turbulent mixing with the protected coast and reaches m = 0.317. Comparison of the calculation results with the experimental ones shows their qualitative and quantitative agreement. The relative concentration of suspended matter in reverse currents remains practically constant along the entire length of the swirling zone. It is close to unity for all contraction ratios of flow

Analysis of desertification trends in Central Asia based on MODIS Data using Google Earth Engine

Desertification is a significant environmental issue affecting arid and semi-arid regions globally, including Central Asia. Monitoring and analyzing desertification trends is crucial for understanding the extent of land degradation and implementing effective management strategies. This literature review aims to provide an overview of existing research on analyzing desertification trends in Central Asia using MODIS data and the application of Google Earth Engine for analysis. Remote Sensing and Desertification Monitoring: Remote sensing techniques, particularly those utilizing satellite data, have been widely employed for monitoring desertification processes. The Moderate Resolution Imaging Spectroradiometer (MODIS) sensor onboard various NASA satellites provides valuable data for assessing vegetation dynamics and land cover changes associated with desertification. Central Asia and Desertification: Central Asia, encompassing countries such as Kazakhstan, Uzbekistan, Turkmenistan, Kyrgyzstan, and Tajikistan, faces significant desertification challenges. Studies have highlighted the impacts of climate change, unsustainable land management practices, and population growth on desertification in the region. Monitoring and analyzing desertification trends in Central Asia are essential for developing targeted mitigation and adaptation strategies

Application of modern geodetic tools in the operation of railway reconstructions

This research considers the survey of the circular curve of the operating railway using an electronic total station, which determines the coordinates of points on the curve and calculates the coordinates of the main points of the circular curve. The goal is obtaining information with sufficient accuracy about the spatial position of the parameters of the railway plan, i.e. the device of the railway plan: turning angles, radiuses, lengths of straight lines and curves. Recommendations for determining the elements necessary to locate the main points of curves and their coordinates are considered. The advantage of this method is the simplicity of calculation, which allows the compiled program and high efficiency of determining the main points of curves using a modern geodetic device-the electronic total station Trimble VX (USA)