Vol 43, No 5 (2016)

The results of testing algorithms designed for generalizing the mathematical description of processes and averaging ECOMAG model parameters at scale aggregation during simulation in large river basins are illustrated by the case of simulation of soil moisture field dynamics, snow water equivalent, and runoff hydrographs in the Volga Basin. The calculated fields are compared with data collected by route snow measurements and measurements of available moisture in the monitoring network of agrohydrometeorological stations. The results of numerical experiments were used to study the effects of model grid scaling on the results of simulating the hydrological characteristics and to establish the minimal and maximal sizes of model cells for simulating runoff formation processes.

Data on several river deltas are used to analyze the regularities in their dynamics in the context of variations of water and sediment runoff, sea level, and hydroengineering activities in delta areas. The basis for this analysis includes the results of many-year studies of river deltas in Russia and the world. The specific features of the evolution of the structure and morphometry of bayhead deltas, forming in bays, lagoons, and estuaries are shown in the case of the Alikazgan delta in the Terek mouth area and the deltas of two watercourses in the Mississippi mouth area. Data on many-year variations of the morphometric characteristics of modern protruding deltas in open coastal zones are systematized, and the factors that have an effect on these changes are analyzed. The types of delta formation processes and the types of deltas are considered with regard to the factors involved. The majority of modern river deltas are found to slow down their progradation into seas under the effect of anthropogenic runoff decline; moreover, some deltas have started retreating and degrading.

Many-year variations of water pollution and the state of more than two hundred of rivers (or their segments) in different latitudinal zones in European Russia are estimated. In accordance with latitudinal zonality, space and time trends in variations of water quality and the state of rivers are identified. By the level of water pollution, most river ecosystems (or their segments) were classified as polluted and very polluted, very polluted and dirty, dirty and very dirty. A tendency toward water quality improvement could be seen in the recent decade. More than 50% of the examined river ecosystems are at the transitional state of passing from natural (and/or equilibrium) to crisis state.

Variations of the trophic status of lakes Batorino, Myastro, and Naroch were analyzed over a long period of 1978–2013. The lakes form a system of interconnected water bodies with a wide range of trophic states. In the period under consideration, the trophic conditions in the lakes varied from highly eutrophic (Lake Batorino) to oligotrophic (Lake Naroch), making it possible to analyze the long-term changes in the trophic state of the lakes with the use of different variants of evaluating the Carlson index (trophic state index, TSI), to assess the relationship between the three versions of the index with one another, with phytoplankton biomass, and with hydroecological characteristics, such as the concentrations of total N, seston, and organic matter and biochemical oxygen demand. The possibility to evaluate the index by other characteristics, including phytoplankton biomass, was also considered.

The isotopic features of Lake Trekhtsvetnoe in the White Sea coast area were studied in 2012–2015 in both winter and summer. Lake Trekhtsvetnoe is a water body, separating from the sea, with constant vertical stratification throughout the observation period. Its isotopic, hydrophysical, and biological characteristics have been studied. By the isotopic profile of lake water body, three zones can be identified in the lake: (1) 0–1 m: mixolimnion zone with δ¹⁸O varying from–12 to–11.1‰; (2) 1.0–3.0 m: zone with transitional properties with δ¹⁸O varying from–11.1 to–5.5‰; (3) 3.0–7.6 m: monimolimnion zone with highest values of δ¹⁸O—from–5.5 to–4.7‰.

A method is proposed for multicriteria performance assessment of water supply and disposal systems. Approaches are proposed for improving the utilization efficiency of water resources in plants processing hydrocarbon materials based on the potential of main-production technological processes and in-plant systems of heat and water supply, as well as industrial waste utilization. Engineering solutions are given for involving regenerated wastewater in the production cycle and reducing water consumption from external natural sources, and their system efficiency is evaluated.