Azizdzhan fazilovich babadjanov

Hydrography. The main water artery of the studied area is the Kashkadarya River, the drainage basin of which is located in the area of development of the Zarafshan and Gissar mountain ranges. It originates at the Aba-Zorkak and Podum passes of the Zarafshan Range at an altitude of 2088 m. The river valley is not clearly expressed in most of the section. The gentle slopes of the valley do not have edges and smoothly merge with the adjacent relief. The river bed cuts into the plain, forming river terraces. The width of the channel is about 100 m, the depth is 1.0 m, the banks are steep, 1–3 m high.
The average annual discharge of the Kashkadarya River during the period under review varied from 8.98 m ³ /s in 2002–2003. up to 2.2 m ³ /s in 2010–2011 According to the intra-annual distribution of runoff, Kashkadarya belongs to the rivers of snow supply with a maximum runoff in April - May, the ratio of the runoff volume for July - September to the volume for March - June is within 0.27 - 0.18 and the runoff for July - September is 16 - 12% from annual. During the period under review, the maximum flow of the river at the Varganza site ¹was observed in 60% of cases in April, in 20% in May, and in 20% the maximum flow shifted to March (Table 2.1). When leaving the mountains, Kashkadarya receives tributaries of the Djinydarya, Akdarya, Tankhazdarya, Yakkabagdarya. The tributaries of the Kashkadarya are rivers with a snow-glacial type of nutrition with a maximum flow in May - June.
Table 2.1
Average monthly and average annual discharges of the Kashkadarya River - Varganza settlement for 2001–2017 hydrological years

Hydrological year	Average monthly costs, m ^3/ s												Average annual flow, m ^3/ s
	X	XI	XII	I	II	III	IV	V	VI	VII	VIII	IX
200 1– 200 2	1,65	1,76	6,60	5,18	7,00	10,02	21,97	19,18	8,93	3,86	2,90	2,12		7,60
2002–2003	2,16	2,19	2,74	3,07	10,25	19,83	20,83	23,64	11,42	5,12	3,63	2,85		8,98
2003–2004	3,08	3,04	4,00	4,52	5,14	7,98	16,19	12,63	5,48	2,69	1,49	1,56		5,65
2004–2005	2,00	5,87	6,32	3,53	5,87	6,90	7,93	5,98	2,60	1,56	0,93	0,86		4,20
2005–2006	1,06	1,59	1,87	1,98	3,19	7,27	11,43	7,25	3,33	2,05	0,94	0,83		3,57
2006–2007	0,98	0,96	1,57	1,65	2,10	6,49	12,53	15,73	5,46	1,75	1,07	0,66		4,25
2007–2008	0,94	1,37	1,79	3,46	11,99	11,74	12,28	23,98	13,45	5,90	2,43	2,02		7,61
2008–2009	2,31	2,27	3,36	4,03	7,01	11,58	19,81	9,57	4,08	2,78	1,57	1,21		5,80
2009–2010	1,56	3,51	5,25	4,18	4,42	5,88	7,78	3,35	1,36	0,96	0,96	1,06		3,36
2010–2011	1,70	1,67	2,48	2,34	2,53	6,55	4,08	1,74	1,10	0,90	0,86	0,57		2,21
2011–2012	1,57	1,64	2,51	2,93	5,38	11,89	21,54	16,91	8,85	2,83	2,04	1,81		6,66
2012–2013	0,61	0,79	1,86	2,11	4,64	18,10	22,70	12,60	6,14	2,44	1,60	1,61		6,27
2013–2014	1,83	2,26	2,51	8,96	7,67	12,30	12,20	9,73	13,17	1,79	1,51	1,62		6,30
2014–2015	1,32	2,45	7,63	7,84	7,69	21,49	14,84	10,10	5,03	2,56	2,25	2,12		7,11
2015–2016	2,18	2,46	1,80	2,30	11,67	10,38	10,93	5,89	1,92	1,33	1,05	0,64		4,38
2016–2017	0,86	2,07	2,42

During the period under review, the Tankhazdarya and Yakkabagdarya rivers show a decrease in the share of runoff for July–September ( W _{VII - IX} ) in the annual flow of rivers (Fig. 2.4). In the middle reaches of the Kashkadarya (from the Chimkurgan reservoir in the east to the city of Karshi) in the west, the only tributary is the Guzardarya River. Kashkadarya has no permanent tributaries from the right bank.
To the west of the Chirakchi meridian to the city of Karshi, the Kashkadarya river has no permanent tributaries. In this section, Kashkadarya provides water to small canals that irrigate the cotton fields located on the surface of the second and third terraces. Near the city of Karshi, the Kashkadarya river splits like a fan into a dense network of natural and artificial channels. From the Chirakchi post to the city of Karshi, the Kashkadarya river drains groundwater throughout the year, significantly changing its hydrochemical exchange, from the site slightly higher than the city of Karshi and below, within the modern delta, it feeds groundwater. In recent years, in the area of the Karshi oasis, 2-3 km upstream from the city of Karshi (hydroelectric complex), the waters of the Kashkadarya River are completely taken up by irrigation canals for irrigation (Fig. 2.4).

Figure. 2.4. Change in the share of runoff for July - September in the annual runoff of the tributaries of Kashkadarya
One of the main water arteries of the city of Karshi is the Karshi Main Canal (KMK), which transfers water from the Amudarya River to the Karshi steppe. The left-bank canal originates from the Kashkadarya River (waterworks) and runs from east to west through the central part of the city. Its width is 20 m, depth is 3.6 m. The channel is lined with concrete. Water consumption is about 3.0 m³/s. Water from all sprinklers is used mainly for irrigation of land.
For many years, a collector-drainage network has been built on the territory of the city and outside it to reduce the level of groundwater and improve the reclamation state of lands with a depth of 2.5 to 3.0 m and a width of 7.0-8.0 m. The main canals of the city of Karshi have the following water supply on average for six months of 2020: Left-bank canal - 9.1 m ³ / s, Ayrum canal (Karshi branch) - 9.6 m ³ / s. The Yuldash pumping station takes 20.0 m ³ /s of water from the Karshi main canal for irrigation.
Relief. The surface of the earth's crust of the region was formed as a result of the combined effects of internal (endogenous) and external (exogenous) geological processes, mainly of the Quaternary period. According to the structure and degree of dissection of the relief with different absolute marks, according to the complex of forms, taking into account their origin, two main types of relief are distinguished within the described region: low hills (folded hills); plains (piedmont plumes, flat plain, plain of the modern valley of the Kashkadarya river).
Geomorphology. The area under consideration is the lower part of the Kashkadarya basin, bounded from the northeast by the Karatyube mountains, which are spurs of the Zarafshan ridge, and from the southeast by the Southwestern spurs of the Gissar ridge.
Within the area under consideration, two main geomorphological types are distinguished: A - low elevations; B - plains.
Within the indicated geomorphological types, taking into account their origin, one can distinguish: A - low elevations: 1) folded (dome-shaped) elevations; B - plains: 1) proluvial-deluvial piedmont trails; 2) proluvial weakly undulating plain; 3) proluvial flat plain; 4) the alluvial plain of the modern valley of the Kashkadarya river [ 57;17-27-p. ].
A-1. The Kungurtau hill is located 7 km north of the city of Karshi on the right bank of the Kashkadarya River and is represented by two parallel ridges stretching in the direction from the southwest to the northeast. The northern ridge is 5–6 km long and 1.5–2.0 km wide. The slopes of Kungurtau are dissected by transverse say, hollows, which have either a V -shaped or a trough-shaped shape. The total area of the Kungurtau mountains is 70–80 km² .
B-1. Proluvial-deluvial piedmont trails are slightly developed around the folded domed upland of Kungurtau. The width of the piedmont plume is variable and varies from 200 to 1000 m. The depth of the ravines reaches 10–15 m.
B-2. The proluvial weakly undulating plain is distributed in the northeastern part of the described region. The undulating nature of the plain is due to the combination of ravine hollows and watersheds formed by temporary currents. In the study area, the maximum absolute elevation of the surface is 411.3 m. The general slope of the proluvial weakly undulating plain to the southwest is within 0.001–0.004.
B-3. The proluvial flat plain is genetically similar to the wavy plain, it develops similarly to the first valley of the Kashkadarya River along the right bank and left bank.
Along the right bank, the proluvial flat plain can be traced in a strip 8–10 km from the northern slope of the Kungurtau mountains to the north-northwest, between the undulating plain in the east and the second floodplain terrace of the Kashkadarya River in the southwest. On the left bank of the valley of the Kashkadarya river, the proluvial flat plain has a wider development, being traced by a strip from 10 to 20 km from the line of the city of Karshi - the village of Takhtapul to the south-west at a distance of over 35 km. From the north and northwest, the flat plain is limited by the second floodplain terrace of the Kashkadarya River. In the area from the village of Takhtapul to the northwestern outskirts of the city of Karshi, the border is expressed by a clear ledge up to 6–7 m high.
B-4. The alluvial plain of the Kashkadarya river valley occupies a narrow strip stretched along the modern channel of the Kashkadarya river on both its banks. From the east of the city of Karshi, the modern alluvial valley of the Kashkadarya River is bounded by the slopes of a wavy and flat plain, traced by a strip 3 to 6 km wide. The northern boundary of the modern alluvial valley of the Kashkadarya River from the east to the village of Aktepa is expressed in places by a gentle, in some places by a steep ledge 3–5 to 7 m high. The southern boundary of the valley to the meridian of the city of Karshi is expressed by a ledge up to 8 m high. three terraces are distinctly expressed – the floodplain, the first above-floodplain and the second above-floodplain terraces. Of all three terraces, the second terrace above the floodplain, which represents the modern valley of the Kashkadarya River, has the main development.
The first terrace above the floodplain does not have a continuous distribution. Its excess above the water level in the rivers is 1–1.5 m, its width varies from several meters to 0.5–1.0 km.
The second terrace above the floodplain can be traced both on the left and on the right bank of the river. Its width from east to west gradually increases and reaches 6 km.
The third terrace above the floodplain is located on the left bank of the river and occupies the main area of the study area. The boundary between terraces II and III above the floodplain is clearly traced in the east and northeast of the territory. In the central part and in the west, it is almost planned and therefore passes conditionally. The surface of the terraces is flat, and only in irrigated areas the flat character is disturbed by the incisions of irrigation canals, collectors and dumps along their sides, as well as by artificial mounds. The absolute elevations of the surface within the study area vary from 345.3 to 393.6 m with a general slope from east to west. The average slope is 0.25%.