CC BY
1
Ziyaev R.R., PhD.
docent
Land hydrology department National University of Uzbekistan named after Mirzo Ulugbek
Uzbekistan, Tashkent Dovulov N.L.
PhD candidate Land hydrology department National University of Uzbekistan named after Mirzo Ulugbek
Uzbekistan, Tashkent
QUANTITATIVE ASSESSMENT OF RIVER PISCOM FEED
RESOURCES
Annotation. In the article, the average multi-year water consumption observed in the period 1965-2020 at the Piskom River Mullala hydrological station was analyzed, and the years with characteristic water content were selected. The hydrograph of the river was drawn for the typical wet years and the sources of saturation were determined.
Key words: river, river basin, water consumption, characteristic years, high-water, average-water, low-water years, underground, melted snow, glaciers, rainwater, Schultz coefficient, quantitative assessment.
Introduction. According to the United Nations, 1.2 billion of the more than 7 billion people on Earth need clean drinking water, or 2.3 billion people are forced to use unsanitary water. Another problem is that 4 out of 10 of the world's population live in areas without access to clean drinking water. Currently, in different countries on Earth, 3 liters to 790 liters of water are used for 1 person per day. The amount of water consumed per capita is 550-600 liters in developed countries, 60-150 liters in developing countries, and 15-25 liters in their rural areas [4].
More than 80 percent of our country's water resources are formed due to snow and glaciers in the territory of Kyrgyzstan and Tajikistan. Certain works are being carried out in our republic regarding the effective use of these existing water resources. For this, special programs are adopted and their implementation is ensured. In particular, in the Strategy of Actions for the Development of the Republic of Uzbekistan, important tasks are defined in the context of"... taking systematic measures to mitigate the negative impact of global climate change and the drying up of the Aral Sea on agricultural development and the life of the population" [6].
In the performance of these tasks, studies aimed at studying the hydrological regime of rivers forming in the territories of Uzbekistan and its
neighboring countries, improving the methods of calculating their main hydrological indicators are of urgent importance.
The main goal of this study is to quantitatively estimate the sources of saturation of the Piskom River for typical wet years and to use them in practice.
Classification of the sources of saturation of rivers according to the sources of saturation at the expense of underground, melted snow, glaciers and rainwater is carried out by dividing the hydrograph into vertical sections according to the Schultz coefficient.
Atmospheric precipitation is the main source of saturation of all rivers on earth. Atmospheric precipitation falling on the earth's surface in the form of rain creates a flow on the earth's surface and is a direct source of river saturation. If the precipitation falls in the form of snow, it accumulates on the surface of the earth and melts as the air temperature rises. The waters formed from the melting of snow also participate in the saturation of rivers.
In general, the snow that falls on the high mountain part of the earth's surface does not melt in one summer season. As a result, it enriches the appearance of the snow there and leads to the formation of glaciers and permanent snows. The water of centuries-old snows and glaciers in these high mountains is another main source of river saturation.
A part of the water formed by the melting of rainwater, snow and glaciers seeps underground and is added to ground and underground water. Groundwater and ground water are also slowly added to the river bed, resulting in constant water availability in the rivers. Thus, there are the following four sources of river saturation: rains, snow cover, centuries-old snow and glaciers in high mountains, and groundwater.
The amounts of water added to the rivers from the above-mentioned sources have different values in different regions. Its amount varies according to the seasons, mainly depending on the climatic conditions of the river basin.
Determining the amount of contributions of certain sources in the siltation of rivers is a rather complicated task. Because in a number of regions, a large part of rain and snow water is added to the river network not in the form of surface water flow, but as ground water formed as a result of absorption of these waters into the underground layers. Such cases are especially characteristic for mountainous regions.
A flow hydrograph is usually used to determine the amount of sources of saturation of the river (Figures 1).
Sources of river water saturation are quantitatively assessed by analyzing the flow hydrograph by dividing it into vertical sections by some sources of saturation. Such an assessment was made for the first time by the famous hydrologist V.G. Glushkov.
There are several ways to divide the flow hydrograph into vertical sections depending on the sources of saturation. One of the simplest methods is to connect
the lowest points of all low water periods on a hydrograph between the pre-spring and flood water periods by straight lines.
In this case, failure to take into account the regime of groundwater entering the river leads to some errors. Due to this, as a result of the researches of the following years, several methods were created to take into account the regime of groundwater flowing into the rivers.
It is somewhat difficult to divide the flow hydrograph for mountain rivers into vertical sections according to the sources of saturation. Because mountain rivers have a more complicated relationship between snow water, rain water, glacial water and underground water than plain rivers. Therefore, the assessment of the contribution of sources of saturation in them is carried out by comparing the drawings of precipitation and air temperature fluctuations during the year drawn together with the flow hydrograph (complex). Below, the quantitative assessment of the sources of saturation of the river is studied on the example of the Mullala hydrological station of the Piscom River.
At the Mullala water measuring station of the Piskom River, the typical wet years, i.e. 1969 with high water, 1981 with average water, and 2020 with low water, were studied on the basis of daily water consumption data (Table 1).
In order to carry out the research, the following tasks were defined.
1) an annual hydrograph was drawn for the characteristic water years of the studied river based on daily water consumption data;
2) the following was determined from the hydrograph:
a) contribution of underground water;
b) contribution of rainwater;
c) contribution of melted snow water;
g) the contribution of waters formed by the melting of glaciers.
3) the amount of annual flow was determined.
4) according to the classification of V.L.Shults, the type of the studied river was determined in this study based on the data of the last years.
5) based on the results obtained from the completed work, the quantitative assessment of the Piskom River's sources of saturation for typical wet years will be carried out and analyzed.
1. An annual hydrograph of the river was drawn based on the data of the daily water consumption table. Hydrograph drawing is done for typical wet years (Figures. 1).
2. Based on the hydrograph, quantitative assessment of the sources of saturation of the river was carried out.
We begin the quantitative assessment of the sources of river saturation from the hydrograph by determining the contribution of groundwater.
Figure 1. Determining the amount of sources of saturation of the river in typical wet years from the hydrograph. Piskom - Mullala
The main focus is on the beginning and end of the low water period. Then the contributions of snow, glacier and rain water are determined. Calculations are performed in Table 1.
Table 1
Determining the amount of river saturation sources from the hydrograph for _typical wet years_
Extreme wet years Bigness Undergrou nd m3/s Snow waters, m3 It's raining waters, m3 Ice, m3/s Year, 3 m3
AS, 106 m3 17,28 17,28 17,28 17,28 -
N 103 88 3 41 235
A lot of water 1969 W,106 m3 1779,8 1520,6 51,8 708,5 4060,7
W, % 43,9 37,4 1,3 17,4 100 %
Average water year 1981 AS, 106 m3 8,64 8,64 8,64 8,64 -
N 113 99 1,2 37 250,2
W,106 m3 976,3 855,3 10,3 319.6 216,1
W, % 45,1 39,5 4,7 14,7 100 %
Low water 2020 year AS, 106 m3 8,64 8,64 8,64 8,64 -
N 101 80 1 36 146
W,106 m3 872,6 691,2 8,64 311,0 1883,4
W, % 46,3 36,7 0,46 16,5 100
Explanation: AS = 1 cm2, its value is determined on the scale of the hydrograph; N-the number of cells with an area equal to 1cm2; The volume of W-saturation sources.
3. The annual flow amounts for typical wet years were determined. Annual flow volumes are calculated as the sum of the identified quantities of Piscom River saturation sources. As can be seen from Table 1 above, the calculated annual flow volume of the high water year 1969 was found to be Wy = 4060.7 • 106 m3, while the calculated annual flow volume for the low water year 1981 was Wy = 216.1 • 106 m3. In the year 2020 with low water, the annual flow volume was calculated to be equal to Wy = 1883.4 • 106 m3.
4. It was determined to which type the studied river belongs according to the classification of V.L.Shults.
We use the following criteria to determine the type of river according to this classification:
a) based on the data of Table 1, the value of the coefficient of V.L.Shults is determined:
s = _X _ 192 9 5,4 . 106 m3 _QS6 Wm_n 22819 • 106 M3 ' '
b) on the basis of the data in the above table, the percentage values of the flow volume in July-September compared to the annual flow are estimated:
_ Wm. 100 %_ 19295,4 . 106 M3 . 100 % g m_IX,% W 4 0 60,7 .106 M3 '
c) based on the data of Table 1, the months with the most water were also determined:
- 507,0 m3/sec in June;
- 458,0 m3/sec in July.
For this studied Piskom river, it was determined that in 1969, it belongs to the type of rivers fed by snow-glacier waters according to the first two criteria, and it belongs to the type of rivers fed by glacial-snow waters according to the third criterion.
based on the data of Table 1, the value of the coefficient of V.L.Schults is determined separately for the year 1981 with average water:
3 _ Wm _ 11131,1 . 106 m3 _009 Wm_„ 12541,3 . 106 m3 ' '
a) on the basis of the data in the table, the percentage values of the flow volume in July-September compared to the annual flow are also estimated:
w _Wm. 100%_11131,1 . 106 m3 . 100% =5150/o
niWy 216,1.106 m3 '
c) based on the data of Table 1, the months with the most water were determined:
- 240,0 m3/sec in July;
- 228,0 m3/sec in July.
In particular, in 1981, the average water under study belongs to the type of rivers fed by snow-rainwater according to two criteria, and according to the third criterion, it belongs to the type of rivers fed by glacier-snow water.
According to the calculation results, the following calculation results were determined in 2020 with low water in the study.
a) based on the data of Table 1, the value of the coefficient of V.L.Shults is determined:
s = Wm_ 8684,4 . 106 m3 _Q gJ;
Wm_„ 10658,2 • 106 m3 ' '
b) based on the data of this table, the volume of flow in July-September is estimated as a percentage of the annual flow:
_ Ww. 100 % _8684,4 . 106 m3 . 100 % -IX'% W 18 83,4 .106 m3 '
c) based on the data of Table 1, the months with the most water were determined:
- 219.0 m3/sec in July;
- 198.0 m3/sec in July.
Conclusion: Summarizing the results obtained in the study, we note the following:
According to the first two criteria, the Piskom-Mullala river belongs to the type of rivers fed by snow-glacial waters, and according to the third criterion, it can be separately explained that it belongs to the type of rivers fed by glacial-snow waters.
In this study, the following sources of saturation were determined from the hydrograph of the studied river:
a) contribution of snow water;
b) contribution of glacial waters;
c) contribution of rainwater;
g) contribution of underground water.
Annual flow amounts were calculated as their sum. The results of the main calculations are summarized in Table 1 above. From this table, it can be seen from
the results of calculating the values of V.L.Shults coefficient ), Wii-ix) and determining the months with the highest flow that the Piskom-Mullala river under study is the type of rivers saturated with snow-glacial waters according to the first two criteria for the characteristic water years, and according to the third criterion and it can be noted that it has the type of rivers fed by glacier-snow waters.
Such a result shows that the classification of V.L.Shults, which was implemented almost 50 years ago, has not been improved. According to O.P.Sheglova's classification carried out much later than this classification, more precisely, in the 60 s of the last century, it was determined in the research that the Piskom-Mullala river is a type of rivers saturated with snow-glacial and glacial-snow waters. The results of the study revealed that the conclusion obtained from this study is much closer to the truth.
References:
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