Vertical drainage wells in terms of construction technology and design do not differ from wells for irrigation. They are not deeper in-depth than irrigation wells and are generally 40-70 m. The main task of vertical drainage wells is land reclamation. They, depending on natural and economic conditions, serve on 5-120 hectares of area. In many areas, vertical drainage wells serve a dual purpose; land reclamation and irrigation of agricultural crops. Water intake wells, including vertical drainage wells, are characterized by a decrease in their flow rates during operation. To ensure the stable operation of the irrigation and drainage system, where water intake wells are operated, repair and restoration work is carried out on them, aimed at increasing flow rates. For the construction of vertical drainage wells in the Sirdarya river basin, steel pipes and filters are mainly used, which corrode in an aggressive environment. In the water intake zone of the well and the metal corrosion process, the colmatation process also occurs. All of them are the main reasons for the decline in well production rates. The carried out repair and restoration measures are aimed at destroying the structure of corrosion and clogging products. In practice, mechanical, physical, biological, and chemical methods are used to clean the filters of water intake wells. They all have their own technology and equipment. However, all these works do not exclude the repeatability of the process. Repetitive workover will come to ineffective, the stage of good concertation is approaching. It is known that polymeric materials do not corrode. They work steadily in aggressive environments. To prevent the corrosion process, polymeric-seam pipes were used as a filter frame and a casing for the construction of vertical drainage wells. Two pilot wells were built on the territory of the Chiyili district of the Kyzylorda region of the Republic of Kazakhstan. The wells were drilled with a rotary drilling unit with backwash. Pure water (irrigation) was used as drilling fluid. To form a gravel pack in the annular zone of the casing, gravel-sand material from the Jailma quarry was used. The material was brought by rail and road transport. Pipe sections were prepared on the surface of 10 meters. Steel rings were put on the pipe from both ends of each section; their connection in the barrel was made by electric welding. The results showed that in the initial period of operation, a decline process was observed. In further exploitation, the well flow rate stabilized. As a result of construction using pipes and filters made of polymer material, the effect was achieved in terms of water volume more than 3 times and in terms of service life 4.2 times compared to a metal filter well.

The greatest importance in the Republic of Uzbekistan is given to water management. The problem of water resources lies in the irrational use of collector-drainage waters, which lead to a deterioration in the quality of river waters. Of the existing collector-drainage waters in Uzbekistan, water with a salinity of up to 2 g / l makes up 38%, with a salinity of up to 3 g / l makes up 23%, with a salinity of more than 3 g / l, sometimes reaching up to 10 g / l makes up 37% of the total volume of collector-drainage water. With an increase in mineralization, the amount of toxic salts decreases, and these waters also contain a large number of pesticides and herbicides. Some of these waters are used for irrigation, the rest is dumped into depressions or rivers creating an environmentally unfavorable environment. Measures are necessary for the disposal and rational use of collector-drainage water, which will improve the environmental situation and may be an additional source of irrigation in a dry period. The object of research is collector-drainage water forming in the Ferghana region of the Republic of Uzbekistan. To solve this problem, it is necessary to improve the environmental situation and it is recommended that three points be implemented: • study the existing volume of collector-drainage water and use it for irrigation; • apply new technologies aimed at water saving during irrigation; • do not discharge pumped water from vertical drainage wells with good mineralization into the drainage network. Applying these technologies, it is possible not only to improve the condition of irrigation water but also to use water as an additional source of irrigation. By covering the deficit of irrigation water with drainage water and rational redistribution of the water limit from the source between the districts, the water supply in the regions is equalized and will reach 50-70 percent, and the water supply in the region will increase.

In recent years, there has been a shortage of water resources in the basins of the Amu Darya and Syrdarya rivers, which is the result of the development of new lands for irrigation and the inappropriate use of water and land resources. A side effect of irrigation and land reclamation is the increasing flow of collector-drainage waters every year, which leads to a deterioration in the land reclamation state and pollution of water resources, which can lead to the ecological disaster of land and water resources. Currently, in the Republic of Uzbekistan, from the total volume of water resources of the Amu Darya and Syrdarya rivers, up to 68% is used for irrigation. Of this volume on the Republic territory, about 12% of collector-drainage waters of deteriorated quality are formed. With a shortage of water resources, they are used for irrigation. But irrigation with saline waters can lead to a deterioration in the land reclamation state. In this regard, new irrigation technologies are proposed, which can save both irrigation water and it is advisable to use underground pumped water for irrigation. Field experiments were carried out in the farm "Khozhilkhon-hozhi" in the farm named after A. Niyazov, Kuva district, Fergana region. A feature of the soil conditions in this farm is the small thickness of the covered fine earth, underlain by highly permeable gravel, strong and increased water permeability, with a deep groundwater level (GWL> 3 m). Large water losses are observed during irrigation. The calculation task was to determine how many hectares of land can be irrigated from one vertical drainage well, taking into account the irrigation time, inter-irrigation period, etc. The water-salt balance of the reclaimed lands for 2017-2019 was compiled. The water-salt balance showed that water supply and filtration from canals and atmospheric precipitation play the main role in the inlet part. In the consumable part, the main place is occupied by evapotranspiration and drainage flow. In general, a negative balance is formed on the territory annually by the type of a small salt carryover within 2.85 t / ha. On the territory of the farm and the experimental plot, cotton of the S-6524 variety was sown, the flow rate of the well is 30 l / s, the furrow consumption is 0.5 l / s. The composition of hypothetical salts in the pumped-out waters is calculated After the first irrigation of our field, the pumped-out water is diverted to the neighboring fields, while the first inter-irrigation period is 20 days. In the interval of these 20 days until the second irrigation of the cotton of the original field, it is possible to irrigate the same fields 5 hectares 8 times, in total 40 hectares of land. The experiments showed that irrigation with pumped water from vertical drainage wells did not have a negative impact on the yield of cotton. And the use of the recommended irrigation technology will reduce the shortage of irrigation water and improve the ecological situation of water resources.

For the conditions of Uzbekistan, it is necessary to maintain the reclamation condition of irrigated lands constantly and increase soil fertility. It is necessary to study the land reclamation condition in our region. An important factor is that collector-drainage waters are used for irrigation to pay off the shortage of water resources. The object of the study is the collector-drainage waters formed in the Republic of Uzbekistan. The article presents research on the method of statistical data processing, materials analysis, field research, and computer plotting curves and diagrams. As a result of the irrational use of collector-drainage waters, secondary clogging is observed in some areas. Data analysis was carried out from 2005 to 2020. The analysis of long-term studies shows that by 2020 there was a decrease in highly saline lands, which makes 83 thousand hectares. Whereas in 2005, saline lands made up 160 thousand hectares. Also, data analysis shows that areas with different mineralization are almost unchanged and need to develop scientifically based measures. The purpose and objectives of scientific research are to study irrigation with collector-drainage waters, their impact on the reclamation state of irrigation lands, and assess their suitability for irrigation. To increase the reliability of assessments of the quality of collector-drainage waters under various natural and economic conditions, it is recommended to use the relationship between water mineralization and the ratio of chlorine to sulfate. The dependence was built on the results of long-term data on the hydrochemical regime of collector-drainage waters. Estimates of our research have shown that at least 50% of the collector-drainage runoff is suitable for use in places of formation in Uzbekistan. Collector-drainage waters have mainly a sulfate type of salinity, and such waters with mineralization of 2-3 g/l, such waters with mineralization of 2-3 g/l can be used for repeated irrigation. To cover the shortage of irrigation water, drainage waters with increased mineralization by diluting them with fresh water will also be used for reuse.

Due to the scarcity of water resources, there is a need for an additional source of irrigation. Drainage waters can serve as such sources. To use these waters, it is necessary to develop a number of measures. The aim of the study is to reduce the negative consequences by increasing the norms of preventive irrigation. It is vital to fulfilling the tasks set: calculation of additional water supply rates and irrigation regime when designing the use of drainage water for irrigation. As a result of field studies and according to the methodology of classifications developed by the Central Asian Research Institute of Irrigation (SANIIRI) analysis of the suitability for irrigation of pumped water from vertical drainage wells in the areas of the Fergana region. Studies conducted by scientists in Central Asia have shown that one of the methods to prevent soil salinization in the intra-contour use of collector-drainage water is the requirements with the following conditions: the ratio of total water supply to total evaporation and the ratio of drainage flow to the water supply. Taking into account the established coefficient, the irrigation rate must be increased depending on the mineralization of water and the mechanical composition of the soil.