Uzbekistan is an inland country with very dry summers and cold winters. The main course of the economy is agriculture. There are two basic kinds of agriculture in terms of irrigation: rainfed and artificial irrigation systems. Therefore, in long dry summers it is reasonable to build water reservoirs to keep enough water resources for vegetation period. Because of sedimentation transport water reservoirs sometimes quickly filled with sediment. Estimating the effects of potential sediment accumulation in reservoirs is an important element in the planning of the dam project. Sediment accumulation in a reservoir may reduce the useful storage of water in this reservoir, change the water quality near the dam, increase flooding level upstream of the dam due to sediment aggradation, influence the stability of the stream downstream of the dam, affect stream ecology in the dam region, etc. This article provides a correlation between the reservoir volume reduction from the bottom to a given level, based on the amount of water flowing into the Chimkurgan reservoir and the river basin monitoring data. Based on the results of observations and calculations, the current state of the reservoir was formed on the basis of GIS tools. In the first step we constructed a flow duration curve, which is the cumulative distribution curve of the stream runoff passing the dam.

The paper analyzes the dynamics of channel processes in the channel of the supply channels of pumping stations. The results of field studies of the condition of the channel environment in the supply channels of the pumping stations were studied. Based on the results of field inspection and research of the supply channel, recommendations were developed to improve its operation. Analyzed and summarized the results of surveys of the hydraulic and alluvial sediment regimes in the channel of the supply channels. The results of the effects of sediment entry into the chambers of pumping stations are presented. The dynamics of reducing the capacity of the supply channels of pumping stations were analyzed; The effect of sediment on the impellers and other stationary parts of pumping units, leading to a decrease in their performance; Recommended new layout schemes of the route and sedimentation tanks of the supply channels of pumping stations; A device of additional structural elements is proposed that allows improving the operating conditions of the supply channels of pumping stations.

Studies of development of an integrated model that allows calculating the whole range of processes necessary for predicting and managing the water and nutrient regimes of reclaimed soils are considered. Calculated values of the maximum concentrations of nitrate nitrogen in the topsoil during the growing season of plant for Tashkent’s region are shown. Values of field moisture capacity and wilting moisture of the main varieties of irrigated soils are defined.

In the article efficiency of water distribution in the territory of Amu-Surkon basin is analysed and based on the results, provided the recommendations. The study is conducted within the project QH-A-QH-2018-409 “Increase efficiency of water resources management in Surkhandarya region: improve interbasin re-distribution of the water resources of Surkhandarya and Sherabaddarya Rivers” funded by Uzbekistan government. The main problems of water management in the Surkhandarya region are: outdated irrigation systems requiring an urgent modernization; large dependence on pump irrigation; low energy efficiency of pumping stations due to use of the old high energy-consuming equipment; irrational distribution and large unproductive technical and operational water losses. Increase of sensitivity to climate change with forecasting of 50% water deficit by 2050 leads to drought and further desertification, including impact on food security. In the article some results are introduced related to improve water allocation by redistribution of water resources between the river basins in the region aimed to reduce of pumped water use for irrigation.

The article deals with the results of the analysis of long-term studies on the study of soil-protective, water efficiency technologies for the cultivation of crops on eroded soils. For the conditions of irrigated and erosion impacted typical loamy soils of a Chirchik-Angren valley, the law of a pliability of the typical loamy soils impacted by erosion is revealed depening on the form of furrows and the size of a jet. The optimum forms of the furrow and size of a jet are determined for condition of typical loamy soils at growing potatoes. The influence of the form of furrow on the contents of organic matter, total nitrogen, common phosphorus in a liquid and firm drain is established the losses of nutritious substances with a liquid and firm drain are revealed depending on elements of irrigation technology. The growth and development of the potatoes is studied. The economic efficiency is determined at cultivation of a potatoes on typical erosion demaged loamy soils.