Azizdzhan fazilovich babadjanov

Operating conditions of existing drainage structures and evaluation of their effectiveness. In 1982, 377.4 thousand hectares were irrigated within the Kashkadarya region, in 2007 - 500 thousand hectares, in 2016 - 2017. irrigated area increased to 514.9 thousand hectares, and the area provided with drainage amounted to 307.6 thousand hectares. The main sources of irrigation are the Kashkadarya, Dzhinydarya, Akdarya, Tankhazdarya, Kizildarya, Lyangardarya, Guzardarya and Amudarya rivers, from which water is supplied by a cascade of pumping stations, and the Zarafshan River, from which water is supplied through the Eski-Angar canal. The main supply channels in the delta part are the Karshi and Mirishkor main MK-3, Pravoberezhny, Levoberezhny, Faiziabad, Pulaty, Kasan, Sarik, etc.
According to the water use department of the Regional Water Resources Department, water supply for irrigation in 2006 amounted to 5052.0 million m ³ . In recent years, in the Kashkadarya region, observations of water discharges are carried out on 140 collectors and drains, of which 72 collectors belong to the upper irrigated zone (upper and middle reaches of the Kashkadarya River), and 68 collectors belong to the lower irrigated zone (lower reaches of the Kashkadarya river and the Karshi steppe) .
Most of the collector-drainage water (c-d-c) from the territory of the Kashkadarya steppe is diverted through the Southern collector system (the modern name is Zhanubiy). Its length is 180 km with a capacity of up to 60 m ³ /s. The temporary water intake of the Janubiy collector was natural depressions in the Sundukli sands. In total, 1.3 - 1.9 km ^{3 of} water is carried out by collectors per year . The largest amount of water is carried out by the Janubiy (up to 0.8 km ³ ), Shimolii (0.08 km ³ ), Glavny (0.05 km ³ ) and Killisoy (0.05 km ³ ) collectors.
During the period under review, the change in water supply is characterized by a decrease in its volume in most areas and a change in its intra-annual distribution. Despite the reduction in the average annual water supply, during the non-vegetation period it grows in almost all districts, with the exception of Dekhkanobad.
In the process of designing drainage systems to prevent or eliminate flooding of territories, it is necessary to comply with the requirements of SP 104.13330.2016 [80; 48-p.]. When designing drainage systems, preference is given to drainage systems with gravity drainage. Drainage systems with forced pumping of water require additional costs. Depending on the hydrogeological conditions, horizontal, vertical and combined drainages are arranged. The construction of horizontal drainage by open trench and trenchless methods is determined by economic feasibility. In all cases of vertical drainage, its water intake should be built in soils with high water permeability. During the construction of any type of drainage, hydrogeological and engineering-geological surveys and auxiliary technological processes and operations are carried out.
K.P. Pulatov, Yu. -s., 80; 48-s.]. For the construction of a horizontal closed drainage, the main processes include making a trench or slot to a given depth with a design slope, laying drainage pipes, installing a filtering protective layer, connecting drains to a collector, primary filling of drainage pipes, quality control of construction work. This will lead to a preliminary lowering of groundwater levels, which practically makes it possible to solve almost all the problems that arise during industrial and urban construction in areas that require protection from flooding.
On the territory of the city of Karshi, groundwater is withdrawn for industrial and technical water supply from 61 wells - 2.76 thousand m ³ / day, and 82 wells are operated for land irrigation with a withdrawal of 3.63 thousand m ³ / day.
There are more than 90 vertical drainage wells in the city of Karshi to lower the groundwater level. Of these, 68 wells are operating with a flow rate of 22.3 thousand m ³ /day. The waters are discharged into sewers and open streams.
The results of observations of the groundwater level in the studied area showed that in the northern and eastern parts of the city the groundwater level is at a depth of 3–5 m or more, and in the central and southwestern parts of the city, in the area of the military camp, the regional trauma hospital, settlement Shibaev and Mekhanizatorov, in the area of the railway station and airport, the groundwater level is above critical levels (above 2.0 m). In the west of the irrigated areas, the groundwater level is from 2.0 to 3.0 m. This is due to the increase in water supply for irrigation. At the same time, it should be noted that the mineralization of groundwater in these areas depends on the water supply. The surface waters of the Karshi main canal have a mineralization of about 0.6–1.5 g/l. Due to the increase in water supply for irrigation, the groundwater level rises by an average of 0.5–0.8 m; and the dense residue in groundwater decreases from 5.0–6.0 g/l to 3.0–4.0 g/l.