In this article, the situation in the selected area was completely investigated to avoid problems that arise when the water distribution facility is in a faulty position. The condition of the hydrotechnical constructions was evaluated. The priority of work on repair and construction of hydraulic structures was defined. As a result of the proper operation of hydrotechnical constructions, a uniform distribution of the volume of water necessary for irrigation of crops throughout the canal, in its upper, middle, and lower parts, was achieved. To implement these activities, first of all hydraulic engineers were trained in the management, repair, and construction of new hydraulic structures. The project documentation (business plan) for the repair hydraulic structures and construction of a new one was developed. On this basis, the repair and construction of new hydraulic structures were carried out. There were given recommendations to the specialists on improving the durability of hydrotechnical constructions. According to the recommendations it is planned to check the state of hydrotechnical constructions after each water and to register them. Several concepts have been proposed to extend the life of the hydrotechnical construction. By repairing and building new hydrotechnical constructions, in the middle and bottom of the canal, and all water distribution canals the water supply to 1015 beneficiaries has been improved. It was achieved an increase in crop yield by 15% and 22% of water savings.

Studies have found that the sub-surface method of winter wheat irrigation halves the number of irrigations and reduces the crop water consumption by 970-1015 m3, inter-row treatment procedures, and the consumption of fuels and lubricants. The productivity of winter wheat grain in comparison with the control (without sub-surface irrigation) is increased by 0.9 t/ha, environmental pollution from agrochemicals is prevented. The sub-surface irrigation method in conditions of meadow soils with a groundwater level of 1-3 m and mineralization of 1-3 g/l experimented in this paper and the influence of this method on the development dynamics of winter wheat (Polovchanka) on obtaining high yields was also tested. The number of irrigations increased to 6-7 times instead of 3-4. Therefore, on such lands, we recommend while designing the drainage system, the designers should plan the depth of the drains no more than 1.5 meters. Sub-surface irrigation is a temporary closure of closed drainage during the growing season of winter wheat, leading to an increase in groundwater level (80-130 cm), thereby leading to an increase in the moisture reserve in the soil.

In Uzbekistan, more than half of population lives in rural area, their well-being depends on quality of land and water resources availability. Quality of land is determined by ameliorative indicators: ground water depth level, ground water salt amount and salinity of soil. These factors do not appear naturally but rather due to the human activity. Inefficient irrigation and excessive consumption of irrigation water on irrigated land in Boyavut District of Syrdarya region of Uzbekistan within several decades have led to a salinization of soil. The primary objective of this article is determination of the level of salinity of soil for modelling spatial distribution of soil salinity throughout an irrigated land by using GIS technology. This technology is focused on automation of development and creation of ameliorative maps, while totally eliminating manual operations. Nowadays, ameliorative expedition specialists still create cadastral map using tracing paper over the marginal areas within irrigated lands based on their ameliorative conditions and by selecting from the three thematic maps and then selecting the poorest conditions of ameliorative indicators. The suggested technology is designed for professionals of cadastral subdivisions of regional ameliorative expeditions, who use the GIS-based software, such as ArcView 3.2. or ArcGIS 10x; their duties include creating of thematic maps based on salinity levels of irrigated lands. Exact coordinates of collection sites of soils samples (collected in 2018-2019) were determined using GPS. The Inverse Distance Weighting (IDW) interpolation method was applied to use that data to create ameliorative maps categorized by the salinity levels (non-saline, slightly saline, saline area and highly saline areas). Those maps were then analysed to develop procedures on how to improve ameliorative conditions of irrigated areas.

At present, the study of natural objects without modern information technologies is almost impossible. The use of GIS for monitoring spatial features of irrigation systems uncovers broad opportunities. The development of the organizational structure, the selection of the necessary software tools for the collection, storage, processing and analysis of semantic data integrated with spatial objects is an urgent task and has important scientific and practical value. The irrigated lands located in the southeast of Kazakhstan within the Almaty region are the object of research. Monitoring of these land salinization is carried out, including hydrogeological and hydrological observations and soil reclamation studies. The article discusses the methodology for creating a geographic information and analytical system to monitor irrigated lands, and describes its organizational structure. The content of the database, the composition of functional components, the basic properties and capabilities of laboratory processing and analyzes of field materials are described. The cartographic material component describes its basic properties, including properties intended for analysis of database objects and their spatial point analogues. Also, the possibilities for ArcGIS application modules to automate the process of constructing maps of the hydrogeological and reclamation conditions of irrigated objects, and the possibilities for automated calculation of areas in specified gradations of depth and groundwater salinity to assess the reclamation state of these lands are shown.

Determination of the actual crop evapotranspiration (ETc) during the growing period is important for accurate irrigation scheduling in arid and semi-arid regions. Development of a crop coefficient (Kc) can enhance ETc estimations in relation to specific crop phenological development. This research was conducted to determine ETc values as well as daily and growth-stage-specific Kc for cotton, winter wheat and maize for silage at fields in Fergana Valley (Uzbekistan). The soil water balance model-BUDGET with integration of the dual crop procedure of the FAO-56 was used to estimate the ETc and separate it into evaporation (Ec) and transpiration (Tc) components. An empirical equation was developed to determine the daily Kc values based on the estimated Ec and Tc. The Kc determination and comparison to existing FAO Kc values were performed based on 10, 5 and 6 study cases for cotton, wheat and maize, respectively. Mean seasonal amounts of crop water requirement in terms of ETc were 560 ± 50, 509 ± 27 and 243 ± 39 mm for cotton, wheat and maize, respectively. Estimated ETc for these crops were 1.10-fold, 1.09-fold and 0.73-fold of recommended irrigation norm according to currently used hydromodule zoning (GMR) under semi-hydromorphic reclamation regime in Fergana province. The growth-stage-specific Kc for cotton, wheat and maize was 0.15, 0.27 and 0.11 at initial; 1.15, 1.03 and 0.56 at mid; and 0.45, 0.89 and 0.53 at late season stages. These Kc values correspond to those reported by the FAO-56. Development of site specific Kc helps tremendously in irrigation management and furthermore provides precise water applications in the region. The developed simple approach to estimate daily Kc for the three main crops grown in the Fergana region was a first attempt to meet this issue.