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The major natural reserves of inland water resources in the Russian Federation have high fishing value and allow large-scale fishing activities. One of the regions where these water resources are localized is the Irkutsk Region. Within its borders there are parts of the largest Baikal-Angarsk and Verkhnelensk water basins with a very developed river network, with reservoirs and lakes, where dozens of fish species live in natural conditions, including those of industrial importance. This article provides a brief overview of the structure and reserves of the water resources, their distribution over the territory of the Irkutsk Region. The main fishing areas are specified and the assessment regarding their fishing potential and commercial stocks is made. An overview of the fishing potential of the Irkutsk water area of Lake Baikal and large reservoirs of the Angara cascade of hydroelectric power plants is given. The history of the development of fishing industry in the region is demonstrated. The article concludes that in the water bodies of the region there are stocks of commercial fish species, which are currently poorly developed or almost not used (being practically untouched in natural conditions). The poor development is due to both natural and climatic and economic and geographical reasons.

Turbulence is the fundamental mechanism governing energy transfer in river flows that was conventionally examined in laboratory flumes. Recently, a trend has been observed for constructing larger scale and outdoor facilities that tend to avoid the problems of upscaling of experimental results. This paper presents the results of an experimental study performed on a river reach used as an environmental field laboratory. The study is focused on the understanding of the spatial arrangement of the flow structure and its dependency on the temporal variability of the flow. Detailed measurements were taken using acoustic Doppler velocimeters and their analysis was completed applying the theory of open-channel flows. The obtained results reveal that the flow structure on the river reach resembles characteristics of a typical three-dimensional open-channel flow. Away from the riverbanks, the flow behaves as a quasi-two-dimensional fully developed turbulent open-channel flow thus providing conditions favorable for field experimental studies of shallow mixing layers and flows over patches of submerged aquatic plants. An interesting observation in the seasonal dynamics of turbulent shear stress patterns was that the height of the roughness layer was reduced in the central part of the flow, though the overall roughness coefficient was increased. At the same time, the structure of the secondary flow near the banks was also substantially altered as the secondary circulations observed at low water levels were replaced by flow separation and internal boundary layers at medium water levels. DOI: 10.1061/(ASCE)HY.1943-7900.0000267 CE Database subject headings: Turbulence; Rivers; Hydrodynamics; Field tests; Shear stress; Fluid dynamics. Author keywords: Turbulence; River hydrodynamics; Field study; Turbulent shear stresses.

Interactions of aquatic plants with turbulent flows in fluvial systems have attracted considerable interest. While there have been recent advances in theories that describe vegetation-flow interactions in idealized laboratory flows, their practical application is still problematic due to limited knowledge of effects caused by heterogeneously (patchy) distributed plants in naturally formed vegetative mosaics in rivers. This paper reports on a study in a lowland river, aimed at quantification and parameterization of vegetation effects on redistribution of mean and turbulent characteristics of the flow and their consequences for hydraulic resistance. The measurements were carried out in summer on a river reach with a patchy mosaic dominated by submerged flexible aquatic plants and repeated at the same water level in early spring before the plants start growing. This design of the study allowed for quantitative evaluation of the effects caused by flow-plants interactions on bulk flow parameters at comparable submergences of riverbed roughness elements (sediment grains and sand bars). The study indicates that symmetrical quasi-two-dimensional open-channel flow structure in unvegetated riverbed was transformed into highly fragmented complex flow pattern spatially arranged by patches and free paths in the mosaic. Despite complexities and three dimensionality of the flow, normalized mean velocity profiles in the patches were satisfactory described by hyperbolic tangent function while flow in the free paths, similarly to unvegetated channel, was in a reasonable agreement with the conventional logarithmic law. DOI: 10.1061/(ASCE)HY.1943-7900.0000195 CE Database subject headings: Vegetation; Rivers; Hydrodynamics; Measurements; Shear stress; Turbulence. Author keywords: Aquatic plants; River hydrodynamics; Field measurements; Shear stresses.

This study presents measurements and analysis of three-dimensional turbulent flow structure and characteristics of suspended particulate matter distribution. Measurements of velocity vectors provided accurate mapping of the flow pattern inside the groyne field. Although the velocity distributions reveal the validity of the power law for depth range 0.1 < z/h < 0.5, the reduction of velocity magnitude to zero value was observed near the flow free surface. The turbulent kinetic energy distributions follow the slope of the semitheoretical description at 0.1 CE Database subject headings: Scour; Sediment deposits; Groins, structures; Turbulence; Turbulent flow; Flow measurement.