Simulating Flash Floods in Small Rivers of the Northern Caucasus with the Use of Data of Automated Hydrometeorological Network

Water Resources - Examples are given for numerical modeling of rain-induced flash floods in mountain areas based on actual and forecast data on precipitation. The calculated hydrographs are...     

How did the suspended sediment load change in the North Caucasus during the Anthropocene?

Quantifying and understanding catchment sediment fluxes is crucial both from a scientific and environmental management perspective. To deepen the understanding of landuse impacts and climate change on sediment load, we explore factors controlling the suspended sediment load formation in the Northern Caucasus during the Anthropocene. We examine how sediment flux of various river basins with different land-use/landcover and glacier cover changes during the 1925–2018 period. Our analysis is based on observed mean annual suspended sediment discharges (SSD, kg s⁻¹) and annual fluxes (SSL, t year⁻¹) from 33 gauging stations of The Federal Service for Hydrometeorology and Environmental Monitoring (Russia). SSL series have been analysed to detect statistically significant changes during the 1925–2018 period. The occurrence of abrupt change points in SSD was investigated using cumulative sum (CUSUM) charts. We found that SSL has decreased by −1.17% per year on average at most gauges. However, the decline was not linear. Several transition years are expected in the region increasing trends from the 1950s and decreasing trends from 1988 to 1994. Correlation analyses showed that variation in SSL trend values is mainly explained by gauging station altitude, differences in landuse (i.e. the fraction of cropland), and catchment area. Nonetheless, more accurate quantifications of SSL trend values and more refined characterizations of the catchments regarding (historical) landuse, soil types/lithology, weather conditions, and topography may reveal other tendencies.     

Numerical Modeling of the Behavior of a Destructive Rain Flood on a Mountain River

Water Resources - The objective of this study was to provide the most accurate presentation of the behavior of a disastrous rain flood, which had resulted in destruction of a dam, casualties, and...     

New data on the basement of Franz Josef Land,Arctic region

We have studied pebbles of igneous rocks from the Lower Jurassic sedimentary succession of Hall Island, Franz Josef Land. Pebbles are represented by felsic intrusive and extrusive rocks, often cataclased and greisenized. The U–Pb age of crystallization for zircons of the studied samples yielded the Latest Devonian–Early Carboniferous and Early–Middle Permian ages. In addition, the studied zircons demonstrate a broad scatter of ages, from Middle Paleozoic to Mesozoic, suggesting repeated thermal reworking and metamorphism of granites. It is shown that coeval Late Paleozoic magmatism indicates the similarity of the geological evolution of the northern Barents Sea and the Severnaya Zemlya archipelago.     

Possibilities of Flood Forecasting in the West Caucasian Rivers Based on FCM Model

The results of hydrophysical studies of the soda Doroninskoe Lake (Uletovskii raion, Zabaikal’skii krai) are presented. Conclusions are presented regarding the character of heat and mass exchange and the causes of formation and stability of the meromictic regime of the water body. The main factors are revealed that affect the character of lake hydrological regime in winter and summer. The seasonal dynamics of the chemocline is shown to be determined by a joint effect of many external and internal factors and to be an integral indicator of physical, chemical, and biochemical processes in the lake.     

Many-year variations of river runoff in the Selenga basin

Many-year variations of river runoff in the Selenga basin are analyzed along with precipitation, potential evapotranspiration, and basin water storages. Data of ground-based (1932–2015) and satellite observations, as well as the analysis of literature data suggest the presence of within-century cycles in the series of annual and minimum runoff. Compared with 1934–1975, the Selenga Basin shows a general tendency toward a decrease in the maximum (by 5–35%) and mean annual (up to 15%) runoff at an increase in the minimum runoff (by 30%), a decrease in the mean annual precipitation (by 12%), and an increase in potential evapotranspiration by 4% against the background of a decrease in evaporation because of lesser soil moisture content and an increase in moisture losses for infiltration because of permafrost degradation. The observed changes in water balance may have unfavorable environmental effects.     

Measures of the Vertical Size of River Systems as Indicators of Their Formation Conditions: Case Study of Mountains of Crimea and Caucasian Black Sea Coast

Water Resources - The main measure of a river system is commonly accepted to be its catchment area, which determines its main function, i.e., collecting precipitation. However, the river basin also...     

Hydrological hazards in Russia: origin,classification, changes and risk assessment

Hydrological extreme events pose an imminent risk to society and economics. In this paper, various aspects of hydrological hazards in Russia are analysed at different scales of risk assessment. It is shown that the number of hydrological and meteorological hazards in Russia has been growing every year. The frequency of economic losses associated with extreme low flow in this century has increased by factor five compared to the last decade of the previous century. With regard to floods, an interesting spatial patter can be observed. On the one hand, the number of floods in the Asian part of the country has increased, whereas on the other hand, the number and intensity of floods in estuarine areas in the European part of Russia have significantly reduced since the middle of the twentieth century, especially in the 2000s. This decrease can be attributed to runoff flooding in the mouths of regulated rivers, with an effective system of flood and ice jam protection. The analysis shows that there is an 8–12-year periodicity in the number of flood occurrences and that flood surges have intensified over the last 110 years, especially on the European territory of Russia. An integrated index that accounts for flood hazards and socio-economic vulnerability was calculated for each region of Russia. A classification of flood risk was also developed, taking into account more than 20 hydrological and social–economic characteristics. Based on these characteristics, hazard and vulnerability maps for entire Russia were generated which can be used for water management and the development of future water resources plans.

     

Forecasting Water Levels in Krasnodar Krai Rivers with the Use of Machine Learning

Water Resources - The potential of construction of machine learning models was considered as applied to water level forecasting in mountain river reaches in Krasnodar Krai based on observation data...     

Inundatios on the Black Sea coast of Krasnodar krai

Inundatios on the Black Sea coast of Krasnodar krai between 1945 and 2013 have been analyzed. The main genetic types of inundations on the coast have been identified. The specific features and regularities of inundation wave transformation along the rivers and over time have been studied. Seasonal and maximal runoff of Black Sea rivers has been analyzed over a long-term period. Regularities in the variations of the number of inundatios and their characteristics over the coastal area have been revealed both at the annual and long-term scales. Quantitative estimates are given to the hazard and damage to the population and economic activity due to inundations in the valleys of Black Sea rivers.