Selenga River Basin Research Articles

Assessment of runoff, water and sediment quality in the Selenga River basin aided by a web-based geoservice

The Selenga River is the main artery feeding Lake Baikal. It has a catchment of ~450000 km² in the boundary region between Northern Mongolia and Southern Siberia. Climate, land use and dynamic socioeconomic changes go along with rising water abstractions and contaminant loads originating from mining sites and urban wastewater. In the future, these pressures might have negative impacts on the ecosystems of Lake Baikal and the Selenga River Delta, which is an important wetland region in itself and forms the last geobiochemical barrier before the Selenga drains into Lake Baikal. The following study aims to assess current trends in hydrology and water quality in the Selenga-Baikal basin, identify their drivers and to set up models (WaterGAP3 framework and ECOMAG) for the prediction of future changes. Of particular relevance for hydrological and water quality changes in the recent past were climate and land use trends as well as contaminant influx from mining areas and urban settlements. In the near future, additional hydrological modifications due to the construction of dams and abstractions/water diversions from the Selenga’s Mongolian tributaries could lead to additional alterations.

Синтаксономия степной растительности Республики Бурятия

Синтаксономия степной растительности Республики Бурятия

Уровенный режим озера Байкал: ретроспектива и современное состояние

The Lake Baikal history and the main problems of its regulation have been discussed. Analysis of the lake level alterations over the whole period of instrumental observations (1900–2016) has been carried out. A protracted low-water period was observed in the Baikal basin fromthe middle 90s of XX century. It was the longest for the whole period of instrumental observations. The extreme low-water situation in the lake basin in 2014–2015 has been studied. A statistically significant trend of the temperature increase and precipitations decrease has been stated. Atmospheric precipitations affect the river runoff many-year fluctuations more than other water balance elements. It was stated that the Lake Baikal level directly depends on the Selenga River water content. Minimal runoff during the low-water periods demonstrates a tendency to decrease, just like the annual runoff. It was a perpetual series of the reduced runoff that caused the minimal runoff negative trend, as a result of which the water resources inflow to the Lake Baikal was recordbreaking minimal over the previous years. The Selenga River basin runoff parameters spatial-temporal reconstruction was performed according the hydrometric posts and dendro/climatic stations data. The water runoff reconstruction statistic models show a good agreement between the Archangel fir ring amount of growth and annual water flow. The historic chronicles and moisture regimes have been chronologically compared on the basis of the obtained water regime reconstructions. The historic chronicles analysis is an indirect verification of the obtained time series related to the water flows in the Selenga River basin.

Surface water pathways and fluxes of metals under changing environmental conditions and human interventions in the Selenga River system

This paper presents the results of novel field campaigns in the extensive (447,000 km2) Selenga River basin, through which 304 samples of river water and 308 samples of suspended matter were collected during high and low water periods between 2011 and 2013. The Selenga River is the largest tributary (more than 50% of the inflow) to the Lake Baikal. Due to ongoing hydroclimatic change and human pressures under conditions of economic growth, the rivers of the area experience significant change in water quality. A key issue for improved understanding of regional impacts of the environmental change is to disentangle the influence of climate change from that of other pressures within the catchment. Our research aims to evaluate the pathways and mass flows of heavy metals and metalloids both in dissolved and suspended forms, taking a basin-scale perspective that previously has not been fully pursued in the Lake Baikal region. Results showed quality deterioration over short distances due to strong impact of hot spots from urban and industrial activities, including mining. The determined enrichment of dissolved metals in waters of Selenga River as well as the spatial and temporal variability of water and suspended sediment composition is further analyzed in the context of climatic, hydrological and land use drivers.

Post‐glacial distribution of a Mongolian mayfly inferred from population genetic analysis

Summary The polymitarcyid burrowing mayfly, Ephoron nigridorsum, adapts to extreme continental climate by undergoing egg diapause during the long and cold winter and rapid growth during the short and hot summer. We performed genetic analyses of the mitochondrial COI gene of E. nigridorsum from 10 local populations of the Selenge River basin in Mongolia to examine the historical population dynamics during the last glacial period. We observed high overall genetic diversity and high intra‐population variation. However, we could find no geographic cluster of haplotypes and no correlation between genetic differentiation and geographic distance within the river basin. The long‐chain haplotype network and multimodal mismatch distribution implied that the population size has remained constant for a long period of time. The Bayesian skyline plot indicated an expansion of the population size during cooling through the last glacial period and a stable population size from the post‐glacial period to the present day. Our results suggest that the Selenge River basin provided a comparatively stable habitat for E. nigridorsum during the last glacial period when the decrease in mean air temperature in summer (1–7 °C colder) is smaller than that of winter temperature (7–15 °C colder) according to botanical records. The mayfly has been probably capable of adapting to a more extreme climate – i.e. with a larger temperature difference between winter and summer – during the last glacial period by undergoing egg diapause, as montane and arctic species of cold‐adapted aquatic insects have expanded their distributions and population sizes during this period.

Variations in climatic and hydrological parameters in the Selenga River basin in the Russian Federation

The variations in average annual surface air temperature, precipitation, and runoff in the Selenga River basin (within Russia) are analyzed. It is demonstrated that the considerable increase in average annual temperature of surface air layers occurred in the 1980s-1990s. The decrease in peak water discharge in the rivers and the increase in the frequency of low-water periods were revealed in the forest-steppe and steppe zones of the Selenga River basin in 2001-2010. In the southwestern mountain regions (the Dzhida River basin) the river runoff increased during that period.

Geochemical disturbance of soil cover in the nonferrous mining centers of the Selenga River basin.

The anthropogenic geochemical transformation of soil cover in large nonferrous mining centers of the Selenga River basin was assessed. The results of the geochemical survey of 2010-2012 revealed the spatial distribution patterns and abundances of 18 hazardous heavy metals and metalloids in the soils of Erdenet (Mongolia) and Zakamensk (Buryat republic, Russian Federation). In both cities, mining activities disturbed soil cover which accumulates Mo, Cu, As, Sb, W in Erdenet and Bi, W, Cd, Be, Pb, Mo, Sb in Zakamensk. Maximum accumulation of elements in Erdenet is restricted to the industrial zone. In Zakamensk, it has spread on ½ of the territory with the degree of multielemental pollution exceeding the extremely dangerous level by 16 times. The effect of mining centers on the state of the river system is local and does not spread to the Selenga River. Downstream from Erdenet, an artificial pool intercepts heavy metal and metalloid flows of the Erdenetii-Gol River. By contrast, downstream from the tailing dumps of the Dzhida tungsten-molybdenum plant the concentrations of ore elements W and Mo and their accessories Bi and Cd in the Modonkul River exceed background values by 146, 20, 57, and 21 times, respectively, decreasing by an order of magnitude 30km downstream.

Blackflies (Diptera, Simuliidae) in eastern Trans-Baikal: Taxonomic composition and physiographic distribution

The blackfly fauna and biodiversity of some physiographic regions in eastern Trans-Baikal have been described. The structural characteristics of blackfly communities in the highlands and lowlands in the southern and northern territories of the region have been reported. A regional list of forty seven species in five genera of the Simuliidae family has been produced for the first time. The species distribution in three major river basins, Upper Amur, Lena, and Yenisei, are examined. A comparative cluster analysis of the similarities in species composition between the blackflies in the observed area and the adjacent regions is carried out. The blackfly species composition of the Upper Amur basin is more similar to the population of the Selenga River basin and significantly differs from the fauna in the middle and lower reaches of the Amur River; only three blackfly species typical for the Far East fauna have been indicated.

The Selenga River delta: a geochemical barrier protecting Lake Baikal waters

The protection of Lake Baikal and the planning of water management measures in the Selenga River Basin require a comprehensive understanding of the current state and functioning of the delta’s ecosystem and hydrogeochemical processes. This is particularly relevant in light of recent and expected future changes involving both the hydrology and water quality in the Lake Baikal basin causing spatiotemporal changes in water flow, morphology, and transport of sediments and metals in the Selenga River delta and thus impacting on delta barrier functions. The central part of the delta had been characterized by sediment storage, especially along the main channels, causing a continuous lift of the delta surface by about 0.75 cm/year−1. Theses morphological changes have a significant impact on hydrological conditions, with historical shifts in the bulk discharge from the left to the right parts of the delta which is distinguished by a relatively high density of wetlands. Regions with a high density of wetlands and small channels, in contrast to main channel regions, show a consistent pattern of considerable contaminant filtering and removal (between 77 and 99 % for key metals), during both high-flow and low-flow conditions. The removal is associated with a significant concentration increase (2–3 times) of these substances in the bottom sediment. In consequence, geomorphological processes, which govern the partitioning of flow between different channel systems, may therefore directly govern the barrier function of the delta.

What drives the water quality changes in the Selenga Basin: climate change or socio-economic development?

Lake Baikal is the largest near-surface global freshwater source and of high interest for water quality alterations, as deterioration of water quality is a main global and an increasing issue in the Selenga River Basin. Here, the Selenga River Basin as main contributor to the inflow of Lake Baikal is extremely important. Pressure on ecosystems and water resources increased due to population growth, rapid urbanization and rising industrial activities, particularly in the mining sector. In this study, the large-scale water resources model WaterGAP3 is applied to calculate loadings of conservative substances (total dissolved solids) and non-conservative substances (faecal coliform bacteria and biological oxygen demand) in a spatially explicit way as well as in in-stream concentrations to get an insight into the state of water quality under current and future scenario conditions. The results show a strong increase in loadings in the scenario period and consequently increasing concentration levels. Comparing the sectoral contributions of the loadings, domestic and industrial sectors are by far the main contributors today and expected to be in the future. Furthermore, for all modelled substances and time periods, water quality thresholds are exceeded posing a potential risk to aquatic ecosystems and human health.

МОНГОЛЫН ЗАГАСНЫ АЙМГИЙН ЗАРИМ ТӨРӨЛ ЗҮЙЛИЙГ МОЛЕКУЛ-ФИЛОГЕНЕТИКИЙН АРГААР СУДАЛСАН ДҮНГЭЭС

The Joint Mongolian-Russian Complex Biological Expedition is the biggest biological expedition in iterms of Water ecosystems of Mongolia. Over 40 years, large - scale integrated research has been analysis of natural and antropogenic processes and basic principles of rational exploitation. The aim is to fulfill complex hydrobiological, ichthyological and hydrological estimation of water resources state and propose measures for their protectionInterrelation of global and local geo-climatic changes in territory of Mongolia in Cenozoic Era with evolution of endemic fishes of genera Oreoleuciscus is analysed. It is shown , that all basic stages of geo-climatic transformation directly defined occurrence, formation of species, morpho-ecological specialization and formation of geographic areas of species and their population organization.Evolutionary and population characteristics of the Altai osmans are given on the basis of genetically analysis of locuses mtDNA and the nuclear locuses coding isoenzymes.According to recent findings and investigations fauna of Lampreys and fishes of Mongolia consist of about 75 species of 14 families and 2 orders. 11 new species of fish, including one new invader bream (Abramis brama) were noted in the country waters last 15 years. According to new results two species of the Altai osmans (Oreoleuciscus angusticephalus, O.dsapchynensis) and one species of graylings (Thymallus arcticus) are excluded from the list of fish fauna of Mongolia. Recently Almai osmans were found not only in the waters of the Central-Asian closed basin, but also in rivers and small lakes of the Selenga River basin (Dgebuadze, Dulmaa, Munkhbayar 2003; Dulmaa A.,Munkhbayar Kh.Nakagawa M.,2004).Esseantial climate change and increasing of human impact transformed Mongolian fish population during last 40 years. As a result bias on ratio of ecological guilds, pathology number increasing, local diversity declining, and changes in species distribution, rate of growth and fecundity of many species of fish are observed. One of the main factors, influencing on fish populations, is gold mining in the rivers Arctic Ocean basin. In new conditions more attention demand both commercially important species as taimen, lenok, Baikal and Amur graylings, Amur carp, goldfish, Amur catfish, Amur and northern pikes, minnows, burbot, dace, and endangered and endemic species as Altai osman, Mongolian upper Enisey and Kosogol graylings, stone loaches and sculpin.Anthropogenic load on the water bodies of the Central-Asian closed basin is connected, first of all, with the constraction of hydraulic structures (dams in the basin of the Kobdo and Dzavkhan rivers), increase of pullution, and intensification of fishery. Evaluation of modern condition of water ecosystems and fish population parateters of this basin remains the main purpose of research for the years immediately ahead.

О растительности долины Дзэлтэра и ее месте в ботанико- географическом районировании (бассейн р. Селенга, Монголия). Воспоминания о совместной экспедиции с Р. В. Камелиным

О растительности долины Дзэлтэра и ее месте в ботанико- географическом районировании (бассейн р. Селенга, Монголия). Воспоминания о совместной экспедиции с Р. В. Камелиным

Опыт разработки программы по снижению негативного воздействия вод в бассейне реки Селенги

Outcomes of the investigations of the waters adverse impact in the Selenga River basin and recommendations for measures on engineering protection of the population and facilities with potentially most hazardous rivers the Selenga and its main tributary the Chikoy as study cases have been presented. Results of the territory reconnaissance explorations on revealing the problems and spots of the water negative impact, assessment of the current protection system effectiveness have been considered. The water negative impact volume and the list of economic entities within the boundaries of inhibited locations have been determined on the basis of the flooded zones simulating in case of the rated water level of the pre-set exceeding probability. Estimations of the damage to be caused by 1% probability floods, maximal jam levels and bank caving have been done. Recommendations and measures on the developed territories protection resulted from the obtained quantitative characteristics analysis have been developed and validated; their expedience and efficiency have been assessed and this enables to formulate a program of measures on prioritizing their implementation to mitigate the waters negative impact.

Genetic variation of the mtDNA cyt b locus in graylings (Thymalus sp.: Thymalidae, Pisces) introduced into the Baydrag Gol River of the Valley of Lakes basin (Mongolia)

Based on sequence variation of the mtDNA cyt b gene, an analysis of graylings introduced from the Arctic Ocean basin (Selenga River basin) into one of the rivers of Central Asian inland basin (Baydrag Goal River of the Valley of Lakes basin) was carried out. Morphological and molecular genetic identification was performed, and it was established that the introduced species corresponded to the Baikal grayling. The relationships among Central Asian grayling species are discussed.

Formation of the sediment yield in areas of mining of placer deposits

An assessment is made of the contribution from different sources supplying sediments to the rivers flowing in areas of open-cast mining of placers in places of their contemporary exploitation (using the Russian Federation and Mongolia as an example). We examine the sediment yield transformation processes in conditions of open-cast gold and platinum mining in the valleys of creeks and small and medium-sized rivers where extraction of mineral resources is an exceptionally important kind of activity (the rivers of the Vyvenka basin, Kamchatka krai) or characteristic for a given territory (Tuul river downstream of the city of Ulaanbaatar, Selenge river basin, Mongolia). We summarized the assessments of the sediment yield transformation downstream of the areas of mining placer deposits along the rivers of Russia, Mongolia, USA, India, Australia, and Surinam. It is shown that stream-channel erosion in anthropogenically modified channels is responsible for up to 90% of technogenic changes in sediment yield. The most significant (by several orders of magnitude) increase in sediment yield has been recorded for small rivers. For large rivers that are characterized by low background values of sediment yield, its change is by a factor of 1.1‒1.2 in the case of single mining operations in the drainage area and reaches a factor of five for large-scale mining operations.

Penetration of the Amur form of Lernaea elegans (Crustacea: Lernaeidae) into the Mongolian part of the Selenga River basin and its host-spatial distribution

For the first time, the parasitic copepods Lernaea elegans are registered in the fish of the Mongolian part of the Selenga River basin. They are detected at the cyclopoid-copepodid and adult stages of development. The main hosts of copepods are Cyprinus carpio haematopterus, Esox lucius, Leuciscus leuciscus, and Perca fluviatilis. The highest levels of infection with L. elegans are marked in these fish in the lower reach of the Orkhon River. The probable donor of the alien species of L. elegans is the Amur carp, which self-spread to Mongolia from the Russian part of the Selenga River.

The formation of impact territories the basins of transboundary River Selenga

We consider the impact territories of a regional system of nature management, which are centers of environmental stress in the Selenga River basin. Their studies involve assessing the pollution of natural environments and aims to develop measures to minimize their impact on the environment that will promote a regional system of ecological optimization of nature (RSPP), in general. DOI: http://dx.doi.org/10.5564/mjas.v11i2.239 Mongolian Journal of Agricultural Sciences Vol.11(2) 2013 pp.155-158

Evolution of the hydro-climate system in the Lake Baikal basin

Summary Climatic changes can profoundly alter hydrological conditions in river basins. Lake Baikal is the deepest and largest freshwater reservoir on Earth, and has a unique ecosystem with numerous endemic animal and plant species. We here identify long-term historical (1938–2009) and projected future hydro-climatic trends in the Selenga River Basin, which is the largest sub-basin (>60% inflow) of Lake Baikal. Our analysis is based on long-term river monitoring and historical hydro-climatic observation data, as well as ensemble mean and 22 individual model results of the Coupled Model Intercomparison Project, Phase 5 (CMIP5). Study of the latter considers a historical period (from 1961) and projections for 2010–2039 and 2070–2099. Observations show almost twice as fast warming as the global average during the period 1938–2009. Decreased intra-annual variability of river discharge over this period indicates basin-scale permafrost degradation. CMIP5 ensemble projections show further future warming, implying continued permafrost thaw. Modelling of runoff change, however, is highly uncertain, with many models (64%) and their ensemble mean failing to reproduce historical behaviour, and with indicated future increase being small relative to the large differences among individual model results.

Large-scale monitoring and assessment of metal contamination in surface water of the Selenga River Basin (2007-2009).

An extensive and year-round survey was conducted to assess metal pollution in vast watershed areas of the Selenga River Basin (2007-2009), which provided baseline heavy metal database for the future management. Sources and environmental hazard and risk indices associated with metal pollution were evidenced across the countries of Mongolia and Russia (Buryatia Republic). In general, the concentrations of heavy metals in river water of Mongolia were greater than those of Russia, expect for the upstream of the Dzhida River in Russia. The spatial distribution generally indicated that metal pollution in the Selenga River was mainly associated with the activities in the Mongolian upstream regions. Similar pollution sources of metals between river water and wastewater associated with surrounding activities were found across the industrial and mining areas. Compositional patterns of metals suggested their sources were independent of each other, with hot spots in certain sites. Our measurements indicated that about 63 % of the locations surveyed (48 of 76) exceeded the critical heavy metal pollution index of 100, identifying possible harmful effects on aquatic ecosystems through metal pollution. Zinc was found to be the chemical of priority concern, as more than half of the locations exceeded the corresponding water quality guideline. Other metals including Mn, Fe, Cr, Cu, and As might be problematic in the Selenga River Basin considering the occurrence and their concentrations. Results of our extensive survey during the period of 3 years indicated that urgent action would be necessary in timely manner to improve water quality and mitigate the impact of heavy metals on aquatic environment of the Selenga River Basin.

INTEGRATING MULTI-SCALE DATA FOR THE ASSESSMENT OF WATER AVAILABILITY AND QUALITY IN THE KHARAA - ORKHON - SELENGA RIVER SYSTEM

The environmental and socio-enonomic impacts of water pollution are particularly severe in regions with relatively limited water resources [WWAP, 2012]. Water quantity and quality are closely interlinked aspects which are relevant for surface water ecology, water use, and integrated management approaches. However, an intensive monitoring of both is usually prohibitive for very large areas, particularly if it includes the investigation of underlying processes and causes. For the Kharaa - Orkhon - Selenga River system, this paper combines results from the micro (experimental plots, individual point data), meso (Kharaa River Basin) and macro (Selenge River Basin) scales. On the one hand, this integration allows an interpretation of existing data on surface water quantity and quality in a wider context. On the other hand, it empirically underpins the complimentary character of intensive monitoring in selected model regions with more extensive monitoring in larger areas.