Альфия Загидуллина

This article presents an analysis of long-term changes in key climatic factors and river flow in the Shu-Talas River Basin. The aim of the study is to assess changes in the hydrological regime of rivers under the conditions of contemporary climate change. Long-term data on air temperature, precipitation, snow cover characteristics, and water discharge from the start of observations through 2023 were used. The analysis was performed using linear trends and the Mann–Kendall test, as well as by comparing hydrographs for years with different water contents across two climatic periods: before 1973 and 1974–2023. It was found that in the modern period, there has been a steady increase in the average annual air temperature (0.21–0.42 °C per 10 years), whereas changes in atmospheric precipitation are weak and spatially heterogeneous. Snow cover is characterized by a reduction in duration with insignificant changes in its maximum depth. It is shown that, on an annual scale, changes in river discharge are weak, whereas the intra-annual distribution reveals an earlier onset of the flood season, an increase in the proportion of discharge during the cold period, and a change in the shape of the hydrograph. The results obtained indicate a redistribution of discharge across seasons, with relative stability in its annual volumes.

Floods remain one of the most frequent and destructive natural phenomena, the scale and consequences of which are exacerbated by climate variability and anthropogenic pressure on river systems. The Yertis water basin (Kazakhstan) is an area with high exposure to flood risks, where the dense concentration of settlements and infrastructure is within floodplain areas. This study applies an integrated approach based on the integration of statistical methods for hydrological analysis and GIS-based spatial modeling to assess and delimit potential flood zones. Long-term series of maximum water levels and discharges from hydrological stations for the period 1974–2025 were analyzed using probability distribution functions, including the log-normal, Pearson Type III, and Gumbel distributions. The optimal distribution model for each station was selected based on the Kolmogorov–Smirnov goodness-of-fit test and the Akaike information criterion. Exceedance-probability curves for extreme hydrological events were constructed for 0.1%, 1%, and 10% probabilities. Spatial flood modeling was performed in the ArcGIS 10.8 environment using a hydrologically corrected digital elevation model and interpolated flood levels. The resulting flood zone maps allow for the identification of the highest-risk areas and serve as a tool for scientifically based planning of emergency prevention measures and floodplain area management. The study contributes to the methodological development of probabilistic floodplain mapping through the integration of statistical frequency analysis and GIS technologies and demonstrates the applicability of this approach for flood hazard assessment in large transboundary river systems under conditions of climatic and hydrological variability.

This study examines the spatial patterns of river runoff distribution in the Northern Kazakhstan, focusing on the Tobyl and Yesil river basins. Hydrological investigations in this region are constrained by the predominance of small rivers and temporary watercourses, which have short observation periods insufficient for robust hydrological calculations. However, small rivers are the most sensitive and vulnerable to contemporary climate change and increasing anthropogenic pressure; therefore, determining their mean annual runoff and other hydrological characteristics is both important and challenging. To estimate runoff for poorly studied and unstudied rivers in the region, graphs of regional relationships between the mean annual runoff modulus and catchment area (M₀ = f(F)) were derived for six hydrologically homogeneous zones. These relationships demonstrated acceptable correlation coefficients ranging from 0.60 to 0.94, enabling their use for estimating mean annual runoff of poorly studied and unstudied rivers in the Northern Kazakhstan, as well as for constructing isoline maps of runoff.

The study presents a scenario analysis of the long-term dynamics of the water level of Lake Balkhash, one of the largest closed lakes in Central Asia, taking into account climate change according to CMIP6 scenarios (SSP2-4.5 and SSP5-8.5) and socio-economic factors of water use. Based on historical data (1947–2021) and a water balance model, the contribution of surface runoff, precipitation and evaporation to the formation of the lake’s hydrological regime was assessed. It was established that the main source of water resources for the lake is the flow of the Ile River, which feeds the western part of the reservoir. The eastern part is characterized by extremely limited water inflow, while evaporation remains the main element of water consumption, having increased significantly in recent decades due to rising air temperatures. Increasing intra-seasonal and interannual fluctuations in water levels have been recorded: The amplitude of short-term fluctuations reached 0.7–0.8 m, which exceeds previously characteristic values. The results of water balance modeling up to 2050 show a trend towards a 30% reduction in surface inflow and an increase in evaporation by 25% compared to the 1981–2010 climate norm, which highlights the high sensitivity of the lake’s hydrological regime to climatic and anthropogenic influences. The results obtained justify the need for the comprehensive and adaptive management of water resources in the Balkhash Lake basin, taking into account the transboundary nature of water use and changing climatic conditions.

Гидрологиялық тұрғыдан қарағанда, Жайық-Каспий су шаруашылығы алабы аз зерттелген аудандар катарына жатады. Зерттеу ауданы гидрологиялық бекеттердегі бақылаулардың қысқа мерзімділігі мен олардың аумақ бойынша біркелкі орналаспауымен сипатталады. Гидробекеттердің жартысында бақылау деректері 10 жылға дейін құраса, үштен бір бөлігінде 5 жылдан аспайды. Сонымен қатар, алапта зерттелмеген шағын өзендер мен зерттелген өзендердің салалары болып табылмайтын сайлар көптеп кездеседі. Бұл жағдайда, өзендер режимі туралы ақпарат тек екі-үш жылдық бақылаулар арқылы берілген немесе мүлдем болмағандықтан, аз зерттелген және зерттелмеген өзендердің ағынды нормасын есептеу - гидрологиялық есептеулер тәжірибесіндегі ең күрделі жұмыстардың бірі болып табылады. Жайық-Каспий алабының аз зерттелген және мүлдем зерттелмеген өзендерінің ағынды нормасын анықтау үшін мақалада ағынды модулінің су жинау ауданына байланысты аймақтық тәуелділігі M0=f(F) пайдаланылды. Нәтижесінде, су шаруашылығы алабының гидрологиялық біртекті аудандарын сипаттайтын сегіз аймақтық қисықтары тұрғызылды. Өзен ағынды ресурстарының аумақтық таралу заңдылықтарын зерттеу нәтижелері алаптың ағынды модулі картасын құрастыруға мүмкіндік берді. Ағынды картасының изосызықтары 0,1-3,0 л/с×км² аралығында жүргізілді. Жалпы, ағынды модулінің таралуы климаттық сипаттамалардың солтүстіктен оңтүстікке қарай аймақтық өзгеруіне сәйкес келеді, сонымен қатар жергілікті жер бедерінің ерекшеліктерін ескереді. Алынған нәтижелер бақылаулармен қамтылмаған өзендер үшін ағынды нормасын есептеуге, суды пайдалануды жоспарлауға, экологиялық стандарттарды әзірлеуге және өзгермелі климат жағдайында су шаруашылығы іс-шараларын жүргізуге негіз болады. Зерттеу нәтижелері жоғары практикалық маңыздылыққа ие және гидрологиялық есептеулерде, су объектілерін жобалауда және аймақтық су саясатын қалыптастыруда қолдануға ұсынылуы мүмкін.

This article examines the variability of water flow velocity and volume in the Uzynaral Strait, which divides the Balkhash Lake into the western and eastern parts, based on hydrometric field observations conducted in 2024. The study involved measurements of water movement in the strait, allowing the identification of spatial and temporal patterns in hydrodynamic processes. These measurements included flow direction, velocity, and the cross-sectional profile of the channel. Special attention was given to meteorological factors influencing flow dynamics, such as atmospheric pressure, wind, and air temperature. The analysis of the collected data revealed that the direction and intensity of the water flow are closely linked to these climatic conditions. The findings can be applied to hydrodynamic modeling of the Balkhash Lake, forecasting changes in water level regimes and water balance, and informing strategies for river runoff management in the lake’s catchment area.

This article analyzes the extreme flood situation on the Zhaiyk River in 2024, which affected the territories of Kazakhstan and Russia. The materials from hydrological posts observing the Zhaiyk River’s water levels were studied, graphs of water level changes were constructed, and the passage of a flood wave along the river’s length was analyzed. Graphoanalytic calculation methods were used to determine the time for maximum levels to be reached from the upper to the lower reaches. A transverse profile of the Zhaiyk River was built at the Atyrau alignment. A forecast of the time for the maximum level and flow of the Zhaiyk River to reach the city of Atyrau is provided. Recommendations on flood risk management are given, including the diversion of water into estuaries and canals, as well as the use of modern monitoring technologies.

Under conditions of increasing climatic uncertainty, this scientific study analyzes multi-year trends of seasonal distribution of river flow in the Zhaiyk–Caspian water basin. In specific natural conditions of the territory under consideration, under scarce water resources availability in the vast territory, and exceptional variability of river flow in time, the problem of water supply is especially important. The paper considers multi-year dynamics of runoff-forming factors and flow parameters taking into account phases of different water availability. River flow estimation methods include analyses of average monthly maximum and minimum values of river flow. The assessment of homogeneity of river flow series was carried out on the basis of genetic analysis and statistical analysis, application of Mann–Kendall test, Student's t test, and Fisher criterion. The identified results indicate significant transformations in the river flow in the basin: the share of spring flow has decreased, while the share of low-water flow, especially in winter, has increased. These changes are associated with higher winter temperatures and an increase in the frequency of winter thaws. In the River Elek Basin, the share of spring flow decreased to 40% of the annual value, and in the River Or Basin, to 15%.

This study analyzes and evaluates the relationship of surface and groundwater of the Syrdarya River within Kazakhstan. The share of groundwater recharge of the river was calculated by two methods: by genetically partitioning the total runoff hydrograph and by calculating low f low. The difference of groundwater flow into the river between the selected hydrostations is also calculated. A comparison of the obtained results for the quasi-natural and disturbed periods is made. In natural conditions, the infiltration of river runoff into underground horizons prevailed along the length of the Syrdarya River, however, under the influence of anthropogenic activity, the picture changed to the opposite: the discharge of groundwater prevails along the length of the Syrdarya River, including the emergence of filtration waters below the dam of the Shardara HPP, collector-drainage and discharge waters from irrigation f ields of the adjacent territory. Also, apparently, the truncation of spring flood peaks leads to an increase in the groundwater level and an increase in the share of underground river supply. Recommendations for the application of the methods used in the work are given.

Studies were conducted aimed at the trends in the flow of the main rivers of the Zhaiyk-Caspian water basin. The average annual dynamics of river flow for a long period, their 5-year moving averages, joint tables of air temperature and precipitation values with river flow, as well as long-term dynamics of characteristic (highest, winter and lowest in open channel conditions) water flows were considered. According to the results of the research, two periods were distinguished: from 1940 to 1973 (conditionally natural) and from 1974 to 2020. (modern). In both periods, there is a tendency to reduce runoff against the background of an increase in air temperature, precipitation trends are multidirectional. Since the 1970s, there has been a decrease in the amplitude of fluctuations in annual runoff, since the 2000s there has been a decrease in both the amplitude of fluctuations and the values of maximum water flow. In the values of the lowest summer-autumn and winter water flow, on the contrary, there is a tendency to increase, which began in the late 1980s – early 1990s. For small rivers and temporary watercourses, the summer-autumn and winter periods are periods of maximum runoff depletion, during which drying and freezing phenomena (zero runoff) are characteristic.