Том 45, № 1 (2018)

During preliminary flood risk assessment in Lithuania 54 significant flood areas (SFA) were identified. The detailed flood hazard and risk maps were prepared for these areas in 2014. European Union Floods Directive does not indicate the concrete criteria for SFA delineation. The uncertainty analysis shows that the total length of SFA is not very sensitive to used methodology. In some rivers the uncertainties of 100 year flood peek discharge (Q_1%) were large, but the variation of SFA boundary location was relatively small due to properties of hydrological network. The catchment area and Q_1% change rapidly near the junction with large tributaries, so the boundaries of SFA are usually attached to these junctions. The formal criteria are mostly used to evaluate the possibility of significant floods, but the delineation of SFA is usually based on subjective decision.

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.

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.

Headcut, known as knickpoint migration too, is developed due to sudden change in channel bed followed by bed scour and erosion which progressing upstream. The results are the downstream morphological change and transporting massive sediment to the downstream reservoir. Most of the past studies focus on non-cohesive soils, although many problems occur because of cohesive soils. In this study, 10 different samples of cohesive soils in long term consolidation with different composition of silt and clay were tested under different circumstances of waterfall height and flow velocity to investigate the neck migration rate and the sediment yield. Tests were continued to reach a constant migration rate. One of the effective phenomena in all tests was tensional cracks on soil surface. The size and number of these cracks have inverse relation with percent of clay. Because of these cracks, massive erosion occurs at the beginning of all tests. By reducing percent of clay, headcut, waterfall height and sediment yield were increased and by reducing waterfall height and flow velocity these parameters were reduced. In lower percent of clay, headcut erosion will occur quickly with more slants. Caving phenomenon was not observed in any tests and massive erosion rate was more quickly.

The Olenek Artesian Basin contains in its subsurface huge reserves of hydromineral resources with extremely high concentrations of many useful components. The presented estimates of prospective reserves of brines drained by a large diamond-mining quarry proves the extremely high potential of the use of “liquid ore” as an alternative to solid mineral deposits.

Observations of 2006–2013 were used to characterize water in the Eastern Bosporus Strait (Peter the Great Gulf, the Sea of Japan) by dissolved oxygen concentration and its biochemical demand. The mean monthly concentrations of oxygen in bottom water layer were found to have decreased considerably compared with the mean values in 1981–1985, and its minimal values were observed within four months—from July to October. The low oxygen concentrations in summer were found to be due mostly to oxygen-deficient water from Amursky Bay.

The ion-exchange properties of terrigenous rocks have been studied, and physicochemical modeling has been used to study the formation of sulfate sodium water in the Volga–Ural Basin of the Russian Plate and the Kartalinskii Basin of the Caucasian hydrogeological folded area. Hydrogeochemical experiments have shown that the exchange-adsorption interaction between gypsum water and adsorbed Na⁺ of terrigenous rocks in the water–rock system involves many stages, resulting in the accumulation in solution of considerable amounts of Na₂SO₄ (up to 9–17 g/dm³).

A universal procedure is proposed for integral assessment of water management activity in a region based on geoinformation technology. The stages of study are described including the natural–economic zoning of the territory, ranking by the rate of total anthropogenic load on water objects and river basins, and the zoning of the territory to optimize the purpose-oriented use of water resources. A GIS of water use in Baikal basin, based on materials of federal statistical observation is presented. A system of measures is proposed for optimizing water use in zones of purpose-oriented water resources management.

The article offers a new approach to the selection of a treatment plant, based on the optimization of biogeochemical matter flows. The existing treatment facilities of Bali are analyzed. The authors propose several process schemes for domestic wastewater treatment, depending on the technology of utilization of biogenic elements from the wastewater for agricultural production. These are based on water treatment technologies that have been in use in Moscow for more than 100 years.