N. I. Alekseevskii

Long-Term Variations of Maximal Water Levels in the Lower Amur

The specific features of formation of maximal water levels in the lower Amur R. are studied. They are correlated with streamflow formation factors in different parts of the Amur Basin and Zeya R. flow regulation. Water level variations in high-water season of the year were analyzed for 1955−2013, including the periods of natural runoff variations (1955−1979) and after the start of Zeya Hydroengineering Structure operation (1980−2013). Five phases of seasonal level rise and water discharge increase in the Lower Amur are identified, and the role of higher discharge, which forms in the river basin in years with different water abundance, is assessed in the absence and presence of the effect of economic activity on the annual streamflow distribution.

Hazardous hydrological processes in the dutch delta and measures for mitigation of their adverse effect on the population, economy, and ecosystems: 2. Experience in the mitigation of the adverse effect of hazardous hydrological processes on the population, economy, and ecosystems

Experience in mitigating the hazard of hydrological processes in the joint mouth area of the Rhine, Meuse, and Scheldt rivers is discussed. This experience is of use for the creation and implementation of regional programs for reducing the social, economic, and environmental losses under other natural conditions.

The structure of streams in the Lena delta and its influence on streamflow transformation processes

The structure of the stream network in the Lena delta has been studied, and its quantitative characteristics have been obtained for the first time. Taking into consideration the discharge of the branches as well as their width, we determined the conventional delta stream orders decreasing in a regular fashion toward the margin of the delta because of channel bifurcation. They have been used as the basis for determining the structural parameters of delta streams and studying the transformation characteristics of the flows of some materials and heat in the Lena delta.

Hazardous hydrological processes in the Dutch Delta and measures aimed to reduce their adverse effect on the population, economy and ecosystems: 1. Geographic-hydrological conditions

Nature Management in the Dutch Delta, comprising the delta-channel systems of the Rhine, Meuse, and Scheldt rivers, under the manifestation of various hazardous hydrological processes is discussed. The main types of such processes and the specific features of their adverse effect on the population, economy, and ecosystems are identified.

Sources of alimentation and variability of their contribution to river runoff formation in European Russia

The genetic conditions of water runoff formation are studied for rivers in European Russia, whose basins are located in the zones of taiga, mixed forests, forest-steppe and steppe, and semi-deserts and deserts, as well as in the Northern Caucasus foothills. The genetic roles of rain, snowmelt, and subsurface waters are determined from results of the runoff hydrograph analysis based on the method developed by B. I. Kudelin. The effects of river dimensions, water abundance of the year, and local factors (the relative areas of forests and lakes and the elevation of watersheds) on the contribution of various sources of river alimentation to the formation of river water runoff are evaluated.

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.

Small Rivers and the Ecological State of an Area

Data from surveying small rivers in Moscow and Tver oblasts are used to assess the anthropogenic load on their watersheds. Expert estimates of the effect of such load onto the state of surface water are made. Integral characteristics and similarity criteria of the hydroecological conditions of small rivers are substantiated.

Sediment Yield of Kamchatka Krai Rivers into the Pacific Ocean and the Seas of Bering and Okhotsk

Sediment yield of Kamchatka Krai rivers into the Pacific Ocean and the seas of Bering and Okhotsk, is evaluated, including that from the drainage basins that are not covered by regular observations. Regression dependences of specific suspended sediment yield (SSSY) on factors determining it were constructed for erosion regions identified in Kamchatka Krai. The total average many-year yield of suspended sediments of Kamchatka Krai rivers into the Pacific is 11.4 × 106 t/year, 73.9% of which is transported by rivers of the eastern coast and 26.1%, by those of the western coast. Among other factors, such distribution is attributed to the location of the majority of volcanoes on Kamchatka eastern coast. About one third of all sediments transported from Kamchatka Krai territory is discharged by the two largest rivers in the region, i.e., the Penzhina and Kamchatka.

Morphology and dynamics of active bed forms in the Terek R. Channel

Active bed forms of three major classes are formed in Terek lower reaches during summer floods. They include ripples, dunes of the first order, and dunes of the second order (from smaller to larger), which commonly form an incomplete hierarchy. The morphology of the bed forms is essentially stochastic and can be adequately described by probability distribution functions of bed form characteristics for some narrow ranges of hydraulic flow characteristics. At the same time, the mean values of bed form morphometric characteristics (length, height, and asymmetry) show stable relationships with flow velocity and depth. The celerity of active dunes can be adequately described by a modified Snishchenko–Kopaliani formula. The channelforming sediments that move as bed forms in Terek lower reaches account for 7% of sediment transport rate of all channel-forming sediments, a value near the lower limit for rivers with sand alluvium.

Space and time variations of the runoff of Kamchatka Krai rivers

The current features of the space and time variations of river runoff in Kamchatka Krai have been considered. Two relatively long cycles have been shown to exist in water runoff variations in the major portion of the examined rivers. The renewable water resources were increasing until 1970–1980, while in the following years (up to 2010), they were gradually decreasing. Current data on river runoff were used to prove the existence of three zonal types of water regime in Kamchatka Krai; five azonal types of annual runoff distribution are characterized. One of them (nearly uniform annual distribution caused by the predominance of groundwater recharge) has been theoretically predicted in the classification proposed by M.I. L’vovich, though without factual confirmation. The specific features of water regime of rivers whose basins lie on the slopes of active volcanoes are considered for the first time. This type of regime typically shows alternating periods of the presence and absence of surface runoff in river channels, corresponding to the inflow of snowmelt or rainfall runoff at high level of subsoil water (when channel deposits are fully saturated with water) or at its low position (when moisture is deficient).