The purpose of the study is to establish an analytical relationship between the irrigation norm and the sum of positive temperatures which will allow optimizing and rationalizing the use of natural resource potential without affecting the productivity of forage crops. There is established that the dynamics of soil moisture during the vegetation season on the meadow-alluvial soils of the Aral Sea region and sierozem soils of the south of Kazakhstan with the sum of positive temperatures is greater than 10°C. To justify the period of vegetation irrigation according to the indicators of the sum of effective temperatures, field studies were conducted and the materials obtained were analyzed. In addition, the establishment of pre-irrigation antecedent soil moisture based on preliminary calculations allows you to stabilize the microclimate of the irrigated area and increase the gross crop yield, save irrigation water. On cotton crops, irrigation must be carried out when the sum of the effective temperatures is 500...550°C, 800...850°C, 1100-1150°C and 1400°C from the beginning of sowing. At the same time, the excess yield control of raw cotton in production conditions is about 4.9 c/ha. On forage crops, watering should be carried out according to the accumulation of the sum of effective temperatures of400°C, subsequent watering every 200°C-250°C.. It follows from the calculations that the maize irrigation season should start from the second decade of May and end in late June with a watering rate of 650 to 800 m³/ha. Carrying out irrigation in accordance with the sum of positive temperatures allows you to save up to 2-3 watering with a total irrigation rate of1400 to 2400 m³/ha. and increases the gross yield of agricultural crops.

The aim of the study is to study the possibility of obtaining agricultural products from non-irrigated lands in arid climatic conditions of mountain areas, depending on the natural moisture supply. The possibility of assessing the natural moisture supply on the basis of average long-term precipitation, conditional indicators of annual natural atmospheric moisture and the water balance equation is considered. However, with current hydrological knowledge of the Sanaa basin area in the absence of the necessary data for calculating the water balance of the productive soils, there is proposed the a methodology for assessment of components of water balance and calculation of natural moisture provision of arable landson the level of «black box» with an accuracy sufficient for assessment of land productivity under natural moistening and a possibility of intensification of dry farming.

The features of the survey, design and operation of irrigation and drainage systems in the area of t he international airport «Zhukovsky» located in the Moscow region, Russia. Design surveys included an ornithological survey of the reclaimed area. Bird species, nesting sites and the number of nests were identified. The number of nests before reclamation averaged 200 ± 1.5 (mean ± standard error). Hydro reclamation in the airport area eliminated local swamping areas and nesting areas disappeared. Draining was carried out by open drains. The distance between the open drains is 120 m, the length is from 700 to 1200 m. There are no capital irrigation and drainage facilities. On the polder site the project provides for open drains and drains. The state of the land reclamation system has been deteriorating since 2001. Periodic waterlogging of a part of the polder area and the formation of a nesting area for black-headed gulls are noted. Airbus A321 aircraft fly over the chicks while feeding at an altitude of 231.5 m, the size of which in the eyes of the chicks is comparable to the size of the parent gulls. The chicks develop a stable conditioned reflex «flying plane - friendly object». A group of young black-headed gulls that are not afraid of aircraft pose a threat to flight safety.

The article discusses an advanced method for cleaning closed horizontal drainage systems in the irrigation zone. The technological process of cleaning from sediment is carried out by dragging winches of a special cable with a ruff, previously laid inside the horizontal closed drainage during primary cleaning with the help of the PDT-200 machine, through adjustable and fixed blocks. While the ruff has the ability to deviate and rotate along the longitudinal axis of the drainage pipe, and the mounting frames are installed in the inspection wells, fixed with bolts and sequentially re-installed from one well to another. The use of this method allows you to reduce the labor intensity, reduce the number of expensive reclamation machines used, special hoses and pumping equipment, as well as the use of manual labor and the consumption of a large amount of water. The improved method will significantly increase the productivity, quality and reliability of the technological process by eliminating the shortcomings in the spring and autumn cleaning of closed horizontal drainage. The effectiveness of the improved method is to increase the productivity and quality of cleaning the closed horizontal drainage from sediments, as well as to a sharp decrease in the level of mineralized groundwater.

The aim of the study is to reduce the negative impact of sewage sludge from the production of cardboard and paper products on the soil by dewatering them with a dehydrator and preparing them for further disposal. Large-scale wastewater sludge from industrial enterprises during utilization is placed at disposal landfills which inevitably leads to a negative impact on the soil cover, littering of territories and withdrawal of the land fund from the economic turnover. In the course of the performed study, the well-known methods of dehydration of moisture-containing material were investigated and there was considered a technical solution to reduce the volume of formation of this type of waste using the example of cardboard and paper production. An electroosmotic installation is proposed, comprising an electrical insulation housing with electrodes: an anode made in the form of a current conductive cover and a cathode made in the form of a conductive perforated bottom of the housing which have a space between them for dehydrated waste. To study the process of sludge dewatering, a series of experiments was carried out on the dehydrator unit with variable voltage parameters between the electrodes. The results of the experimental study were the basis for statistical expressions of the mutual voltage influence between the electrodes, the duration of waste processing, the amount of removed moisture. A model has been obtained that describes the amount of moisture removed during waste treatment. The most productive operating mode of the installation, the time for treatment of waste portion have been established. It has been proven that with the help of an electroosmotic device, up to 70% of moisture is effectively removed from the volume of waste sludge. This makes it possible to significantly decrease their volumes, reduce areas for possible or temporary placement and reduce the ecological load on the environment.

The article analyzes the indicators of the gross harvest of potatoes in the Moscow region in recent years. It has been proven that an increase in acreage does not always lead to an increase in gross harvest. It is equally important to provide comfortable conditions for the growth and development of plants. Precipitation in the Moscow region in the spring and summer period falls extremely unevenly: days with heavy rains forming a layer of precipitation of tens of millimeters alternate with non-precipitating days and weeks. The necessity of additional irrigation to create an optimal water - air balance for the development of plants is substantiated and the advantages of using drip irrigation for these purpose which allows the delivery of irrigation water directly to the root zone of the plant are estimated. It is recommended to combine operations on the formation of potato ridges with the laying of a drip tape since in the initial period of development the plant has enough moisture reserves of the mother tuber and additional watering is not required. The design of the drip tape stacker based on the Grimme GF-75/4 ridge former has been developed to increase the degree of mechanization when laying the drip tape. At a working speed of 3.2...5.5 km/h the productivity of the machine was 0.51.0.97 ha/h. In the course of further research the irrigation rate was calculated taking into account the elliptical shape of the humidification contour which made it possible to exclude excessive watering. After the installation of the drip irrigation system, irrigation was carried out at a constant rate when the moisture capacity reached 70% of the uultimate field moisture capacity with the adjustment of the time between irrigations. The use of the drip irrigation system made it possible to increase the yield of potatoes of the varieties Red Scarlett and Zhukovsky Early by 26.5% ... 28%, respectively.

At the stage of the life cycle, ensuring the operational reliability and safety of pressure head hydraulic structures is an urgent task. One of the serious threats at the present stage is the destruction of hydraulic structures by the impact of non-stationary loads, by directed explosions in the immediate vicinity of the structures or on their surface. Shock waves pose a serious threat to hydraulic structures. Impulse short-term impact on the solid surfaces of hydraulic structures or on the aquatic environment characterizes the specifics of the problem under consideration, as the nonstationary of the process of motion of continuous media into which, in a short time interval, a volume of energy can be released that can deform or completely destroy them. Scenarios of this kind can occur either in the immediate vicinity of a hydraulic structure or as a result of the collision of solid bodies on its surface. Water upstream of the hydro technical structure and its body is a complex liquid because many of its characteristics differ significantly in size from similar characteristics of other liquids or have so-called anomalies on pressure and temperature dependences.

Corner retaining walls are one of the most common structures of waterworks. Most of them were designed and built several decades ago and have been in operation for a long time. In some cases, there is a deviation from the design prerequisites and the strengthening of reinforced concrete structures of retaining walls is required. The main reason for these deviations is incomplete consideration of the characteristic features of retaining wall structures (including horizontal inter-block joints and secondary inclined cracks), as well as the nature of the loads acting on them. As a result, design horizontal transverse reinforcement is practically not installed in retaining walls that is not required by calculation based on traditional calculation methods. Traditional reinforcement schemes for retaining walls do not provide for the presence of horizontal inter-block joints and horizontal transverse reinforcement. As a result of the research carried out, the method for calculating the stress-strain state and strength of reinforced concrete structures of corner retaining walls with inter-block joints has been improved taking into account secondary stresses. Reinforcement schemes for retaining walls have also been improved.

The article presents the results of surveys of 311 class IV hydraulic structures carried out in 2016-2020 in the Moscow region. All the reservoirs of the surveyed hydraulic units were classified according to their characteristic features, the technical condition of culverts and dams was assessed, there was established the safety level of both separate structures and hydraulic units as a whole. During the surveys, the technical parameters of the surveyed structures were established, the state of each structure and the hydraulic unit as a whole was assessed, a possibility of their accident and a risk level for the downstream areas were considered. At the same time, recommendations were developed for the elimination of serious damage and, with the help of an examination, the amount of the cost of the necessary repair work was determined. The paper also assesses the issues of the ecological state of the areas where the hydraulic units are located and the hydraulic units themselves as blocks of the ecological framework of the territories.

The issues of ensuring the safety and operational reliability of the functioning of irrigation and drainage systems with a long service life are considered. It has been established that the service life of irrigation and drainage systems in the south of Russia is about 40-50 years, the average wear is 72%. In the Krasnodar territory the rate of wear of reservoirs, ponds and canals is about 80-100% which indicates to a significant siltation and loss of throughput capacity. Depreciation of dams and dikes is 35-40%. The main damages of the HTS are erosion of the upper slope, malfunction of the spillway and silting of the reservoir bowl (pond) which leads to increased filtration through the dam body, an increase in the level of the depression curve and complication of the passage of flood water. Changes in the rules for the operation of hydraulic structures, in particular, a decrease in the normal retaining level in comparison with the design level is not a rare occurrence. At the same time, the HTS operation in the sparing mode can be considered a temporary measure used until repair or reconstruction is carried out. The operational efficiency of hydraulic structures with a high degree of wear at the level of ultimate loads and impacts below the design values is noticeably getting reduced. The use of constant monitoring, as well as forecasting the reliability of hydraulic structures, can reduce the severity of the problem. Safe and efficient operation of hydraulic structures with a high degree of wear during the period preceding repair or reconstruction can be ensured by introducing a system for automated monitoring of hydraulic structures in combination with a decision support system (DSS).

The results of experimental studies are presented which make it possible to correct the technological parameters of laying the concrete mixture in the cladding of newly erected or reconstructed water supply canals. The studies were carried out on an experimental stand simulating the cannel profile with a variable slope angle from 15° to 90°. The stand slope is covered with a conditional soil model in the form of a rough surface. To determine the relationship between the speed of the vibromold movement, the parameters of the concrete mixture, the profile of the canal and the parameters of the concrete paver, mathematical models of the technological process have been developed. The analysis of the obtained results shows that accelerating additives significantly reduce the duration of the concrete reaching its critical strength, in other words, it reduces the duration of the curing of the concrete under the formwork. The study of the obtained surface of the cladding on the stand shows that it contains some irregularities due to the absence of a smoothing strip. Therefore, under production conditions, concrete pavers must be equipped with smoothing devices, and the concrete mixture must be placed through a special hopper that regulates the height of the concrete mixture supply. For the construction of concrete linings on mobile concrete mixtures, it is recommended to use accelerating additives or their preliminary heating to a temperature of 50 ... 60°C.

The work of the spillway variant No. 2 of the Boguchanskaya HPP (GES) with a smooth drain face with a jump-bucket for jet discharge into the lower pond is considered. The disadvantage of the Boguchansky dam layout with a spillway No. 2 is its close adjoining to the HPP building and the absence of the separation wall between them preventing from the influence of its operation on the work of HPP. One of the ways to reduce this influence is to remove the left border of the discharge flow from the HPP water area. To implement this task there is considered a variant with a planned deviation of the jet of the first span of spillway No. 2 to the right, in the direction of spillway No. 1. For this purpose, the end section of the left wall of spillway No. 2 in the plan is made as curved, and the jump-bucket is stepped, which could make it possible to more effectively control the planned trajectory of the jet of the first span. In the zone of the maximum rise of the jet of the 1st span its deviation from the rectilinear trajectory was equal to its width. At the same time, there was studied the effect of priority gate opening to the soil erosion depth downstream, for which tere were conducted two cycles of erosion: at opening the gates from the first to the fifth and in the reverse order. The specific design of the surface spillway No. 2 is its placement on the end section of the base with large blocks of fractured rock coming to the surface with a gentle falling angle towards the upstream. Behind the site with large-block blocks there is an array with medium - and small-block blocks, covered in the channel part with sediments with a diameter of 0.3 m or less. Modeling of the foundation soil was performed with crushed stone material, the size of which was selected by modeling the erosion rate of the natural material.

The results of the analysis of the problems associated with the development of the world solar energy are presented. It is noted that at the present stage of the electric power industry, the potential of renewable energy sources (RES) is still poorly realized. The specific issues of water-energy modes of operation of hydroelectric power plants (HPPs), operating in symbiosis with solar photovoltaic installations (SPEU) have been identified, the schedule of which should be the same. It is shown that the operation of hydroelectric power plants and SPEU in the joint electric load schedule makes it possible to obtain a constructive and economic effect due to the fuel saving of power plants of various types, including thermal ones. The maximum capacity of the HPP-SPEU power complex is optimized by the installed capacity of the HPP while observing the full duplication of the SPEU capacity by other power plants of the energy system. It is shown on the example of the Lagdo hydroelectric complex in the northern Cameroon that under the conditions of developing countries with a large solar and hydraulic potential (Cameroon, Zimbabwe, Uganda, etc.), as well as for the southern regions of Russia, SPEU can produce up to 75% of the annual electricity generation during the low-water period of the year at its joint work in the energy complex with the hydroelectric power plant. This makes it possible to facilitate the redistribution of the river flow during the entire low-water period without attracting additional useful storage capacity of the reservoir. The developed methodology for optimizing the water-energy regulation regime can also be applied during the operation of the HPP of the HPP-SPEU energy complex along the watercourse, i.e. with daily flow regulation.

Theory of turbulence is an important part of the open flow dynamics. The interest in the research of experimental turbulence increased with the development of mathematical modeling of open flows and the need to obtain materials for the parameters of turbulence models, with numerical modeling of turbulent flows. The purpose of this research was to study characteristics of the turbulent flow during the planned expansion with the formation of whirlpool zones and to obtain practical recommendations for the analysis and calculation of the kinematic structure of such flows. There was used an experimental research method. Experimental graphs for determining the turbulent shear stresses at the interface were obtained and dependences were given for determining the coefficients of turbulent mixing. There were identified zones of intense pulsation of speed which is of a practical interest and allows to predict an increase in the erosion ability of the flow in these places and to obtain recommendations for strengthening the channel and extinguishing energy in the downstream. The results allow us to use this data in further study of the conditions of origination, development and decaying of turbulence, to consider the mechanism of turbulence of energy transformation.

The article presents an analysis of the impact of climate change on the main characteristics of ice phenomena, snow cover and the water regime in the Small Northern Dvina River basin occurring in recent decades. Recently, a significant climate warming has been observed in the basin. As a result, winters are getting warmer and shorter. There is also an increase in winter precipitation and the number of thaws. Climate warming directly affects the duration of snow cover, which decreases both due to the later formation and to the earlier destruction of snow. There is also a slight downward trend in the annual values of the maximum snow water equivalent, which may be the result of an increase in the number of thaws in winter, when a part of the snow cover melts contributing to the winter river runoff. The analysis of the main characteristics of the ice cover on the rivers of the studied basin shows that their changes are similarly to changes in the snow cover: there is a reduction in the freeze-up period due to its later formation and earlier complete destruction. The maximum ice thickness on the rivers of the basin also tends to decrease. There is an increase in winter and a decrease in spring runoff. Predictive estimates of changes in the observed trends in the future are presented in the final part of the article based on the CMIP5project data.

A critical assessment of the methodological decisions taken by the scientific community in the development of thematic maps-schemes of forest zoning is given. It is indicated that in most cases the authors operate with landscape, climatic and geobotanical characteristics of territories, do not rely on the concepts of taxa as elementary territorial units united in homogeneous groups. Most of the zoning schemes recommended for practical use are based on the intuitive and subjective judgments of the authors and, often, do not have a criterion-proven statistical reliability. Most of the zoning schemes recommended for practical use are based on the intuitive and subjective judgments of the authors and, often, do not have a criterion-proven statistical reliability. The article, using the example of the Nizhny Novgorod region, presents a methodology for developing models of multidimensional zoning of forests growing in 40 forest areas (taxa), endowed with 35 indicators characterizing the geographical coordinates of forest centers, soil productivity in 6 classes, climate in 7 indicators, the structure of forest lands in 17 categories, productivity and closeness of plantings under 3 types of forests. In the multidimensional classification (grouping) of forest areas, the methods of factor, cluster and discriminant analysis were used. As a result of analytical calculations, 7 typical forest areas were identified on the territory of the subject of the Russian Federation. The reliability of the classification of forest areas and the resulting zoning map-scheme is confirmed by the statistical criteria of the total intercluster and intracluster distance of Mahalanobis, the Wilkes lambda and Pearson’s Chi-square criteria