Toxicity assessment of bottom sediments in watercourses in Selenga River basin on the territory of Mongolia

Bioassay methods are used to assess the toxicity of bottom sediments in the main watercourses of the Selenga River basin and Lake Orog in Mongolia. Toxic bottom sediments are found in a brook in the region of the Erdenet Mining and Concentration Complex, as well as in the Eroo and Bukhlyn rivers, which experience the effect of intense gold mining. The conclusion is drawn that the Selenga River water flowing from the territory of Mongolia cannot directly affect the quality of water in Lake Baikal.     

Transformation of estimated characteristics of the annual and maximal runoff in the major tributaries of Lake Baikal

Hydrometric data of recent years were used to evaluate the parameters of distribution of the annual and maximal runoff in the major tributaries of Lake Baikal: the Selenga, Upper Angara, and Barguzin. The estimates of the mean water content, maximal water discharges of spring flood and rain freshets were obtained. The comparison with analogous data of an earlier period often shows significant difference. Variations of the characteristics under consideration are taking place against the background of warming in the region since the early 1970s. The results of the current transformation of river runoff variations is a change in Baikal water regime, which determines the restructuring of hydrological processes in the lake.     

Multi-Model Approach to Quantify Future Sediment and Pollutant Loads and Ecosystem Change in Selenga River System

Water Resources - The Selenga River, which originates in Mongolia, contributes about 50% of the total inflow into Lake Baikal. Hydroclimatic development and abrupt landscape evolution due to...     

Assessing possible changes in Selenga R. water regime in the XXI century based on a runoff formation model

The runoff of the Selenga R., the largest tributary of Lake Baikal, in recent two decades corresponds to a low-water period. Such decrease can be due to the global climate processes, which have an effect on the amounts of precipitation onto and evaporation from Selenga drainage basin, which is located in arid climate zone. The adaptation of Ecomag software complex to simulating river runoff in the Selenga Basin based on global databases (relief, soils, vegetation, and weather information) is described. The model was calibrated and verified, and the statistical estimates of calculation efficiency were constructed. The obtained model of runoff formation in the Selenga Basin was used to assess the possible changes in the climate and water regime in the XXI century with the use of data of global climate models under different scenarios of greenhouse gas emissions. Throughout the XXI century, the Selenga R. runoff may decrease by 10–40%, depending on the forecasted climate conditions.     

Quantifying the actual sediment load flux into Lake Baikal: A case study of the main tributary – The Selenga River (Russia)

The significant reduction of sediment load flux into Lake Baikal from its main tributary – the Selenga River began in the mid-1970s, and can be explained by climate change and socio-economic activities. Integrated analysis was done of changes in hydro-meteorological parameters (water discharge, sediment load, air temperature, and precipitation) and their tendencies over periods of 1946–1975 (baseline) and 1976–2017 (warming). Changes in natural processes and human activity were negligible during the baseline period. In the warming period, against the background of an increase in temperature, the water discharge had a slight decreasing trend (?13%) whereas the sediment load has significantly decreased (?53%) these are consist with the precipitation change (?9.4%). Analysis of hydro-climatic data using statistical methods showed that in the warming period the greatest reduction in river sediment runoff occurred in the interval 1996–2017. In this period the sediment load was 768 × 10³ t/yr, which is less than the average value during the warming period – 1048 × 10³ t/yr. Considering sedimentation in the Selenga River delta, the actual sediment load flux from the Selenga River into Lake Baikal amounted to 515 × 10³ t/yr, which is three times less than the average multiyear value 1535 × 10³ t/yr for observation period (1946–2017).     

Sedimentation patterns in the Selenga River delta under changing hydroclimatic conditions

The Selenga River delta (Russia) is a large (>600 km²) fluvially dominated fresh water system that transfers water and sediment from an undammed drainage basin into Lake Baikal, a United Nations Educational, Scientific, and Cultural Organization World Heritage Site. Through sedimentation processes, the delta and its wetlands provide important environmental services, such as storage of sediment‐bound pollutants (e.g., metals), thereby reducing their input to Lake Baikal. However, in the Selenga River delta and many other deltas of the world, there is a lack of knowledge regarding impacts of potential shifts in the flow regime (e.g., due to climate change and other anthropogenic impacts) on sedimentation processes, including sediment exchanges between deltaic channels and adjacent wetlands. This study uses field measurements of water velocities and sediment characteristics in the Selenga River delta, investigating conditions of moderate discharge, which have become more frequent over the past decades (at the expense of peak flows, Q > 1,350 m³ s^?1). The aims are to determine if the river system under moderate flow conditions is capable of supporting sediment export from the main distributary channels of the delta to the adjacent wetlands. The results show that most of the deposited sediment outside of the deltaic channels is characterized by a large proportion of silt and clay material (i.e., <63 μm). For example, floodplain lakes function as sinks of very fine sediment (e.g., 97% of sediment by weight < 63 μm). Additionally, bed material sediment is found to be transported outside of the channel margins during conditions of moderate and high water discharge conditions (Q ≥ 1,000 m³ s^?1). Submerged banks and marshlands located in the backwater zone of the delta accumulate sediment during such discharges, supporting wetland development. Thus, these regions likely sequester various metals bound to Selenga River sediment.     

太湖流域LUCC对水文过程的影响

基于1971年枯水年、1989年丰水年、2000年平水年3类典型代表年的逐日降雨量、逐日蒸发量以及不同时期地表覆盖遥感分类数据,以城市化快速发展地表覆盖变化明显的太湖流域为研究区域,利用太湖流域河网水量模型进行了土地利用/覆被变化的水文响应研究,分析了太湖流域1990 2000年与2000 2006年间的土地利用/覆被变化及其对水位过程的影响.不仅有利于对城市化地区水文特征变化规律深入了解,也为典型城市化地区防洪减灾提供科学可靠的依据.研究表明,太湖流域城镇化进程的加快引起了土地利用/覆被变化的主要表现是水田、水域等面积向城镇面积转化,城镇化进程加快,2000 2006年期间的城镇化速度大于1990 2000年间;下垫面的变化对太湖流域水文过程产生了明显的影响,随着城市化进程地表覆盖的变化,水位有整体升高的趋势,并且增幅加大,与城镇化速率变化趋势相一致,城镇化程度高的地方水位上升更为明显;降雨量也是水位过程的影响因素之一.     

Inter- and intra-annual trend analysis of water level and flow in the middle and lower reaches of the Ganjiang River,China

ABSTRACT

The Ganjiang River is the largest tributary of Poyang Lake in China, and its hydrological regime variation greatly affects the utilization of regional water resources and the ecological environment of the lake. In this study, a novel trend analysis method, the Moving Average over Shifting Horizon (MASH), was applied to investigate the inter- and intra-annual trends of flow and water level from 1976 to 2016 at the Xiajiang and the Waizhou hydrological stations in the Ganjiang River. The Significant Change Rate Method (SCRM) was proposed to determine the MASH averaging parameters. The trend analysis results show a statistically significant decrease in water level series throughout the year and the relationship of flow and water level have changed greatly at the Waizhou station. The sediment load reduction, large-scale sand mining and water level decrease of Poyang Lake are identified as the main causes for the water level decrease.     

邛海入湖河流水质及其湖区响应特征(2011—2021年)

邛海是云贵高原水域面积>25 km²的11个天然湖泊之一。基于邛海入湖河流与湖区水质监测数据,揭示入湖河流水质特征,并探究其湖区响应。结果表明:2021年,邛海入湖河流水质空间异质性显著,且分为自然型、农业型和城镇型3种类型河流。官坝河等3条自然型河流水质优良,而高仓河等8条城镇型和农业型河流(R4～R11)水质较差,污染物浓度超标严重。2011—2021年,邛海主要入湖河流(官坝河、鹅掌河、小青河)的营养盐浓度呈下降或先增加后下降趋势,水质逐渐改善。流域土地利用变化是导致邛海入湖河流水质空间异质性的主要因素,同时也是河流水质在2011—2021年改善的原因之一。受湖泊水文环境与入湖河流污染类型影响,2017—2021年邛海湖区水环境及其与河流水质响应关系差异性明显:高枧湾水域(L5)水深浅、水环境容量小,主要受纳城镇污水,因而湖区营养盐与叶绿素a浓度高,在2021年达富营养状态;官坝河、鹅掌河与小青河入湖影响区(L1～L3)与小渔村(L4)水域湖水深、水环境容量大,污染物浓度与营养状态指数低,但因汇入的河流污染类型不同,湖区营养水平与河流水质响应存在季节性...     

新疆艾比湖流域地表水丰水期和枯水期水质分异特征及污染源解析

采用2015年艾比湖流域54个采样点的10个地表水水质指标数据,首先利用水质指数模型(WQI)和地统计学方法对流域水质污染情况进行全局评价,然后利用层次聚类法、判别分析法和因子分析法分析艾比湖流域地表水丰水期和枯水期水质分异特征.在水质时空分异特征研究的基础上,利用主成分回归分析法对艾比湖流域水质进行污染源解析.结果表明:艾比湖流域丰水期WQI值介于38~70之间,枯水期WQI值介于31~71之间,艾比湖流域丰水期的地表水水质污染情况比枯水期严重,而艾比湖、博尔塔拉河和精河靠近艾比湖湖区的河道污染程度均比其他河道严重.由聚类分析和判别分析得出艾比湖流域丰水期和枯水期的水质采样点在空间上均被分成A、B两组,A组包括艾比湖湖区西部、奎屯河、古尔图河和四棵树河,B组包括艾比湖湖区东部、精河和博尔塔拉河.艾比湖流域丰水期和枯水期的水体主要受到化学需氧量、溶解氧、氨氮和悬浮物浓度等指标的影响,B组水质污染指标的值相比于A组的值偏高,B组区域内存在高污染企业,艾比湖流域水环境治理工作需主要集中在B组所包括的艾比湖湖区、博尔塔拉河和精河.(4)艾比湖湖区、精河和博尔塔拉河地表水体的污染主要来自于有机物污染和营养物质污染,其次为工矿业污染;而奎屯河、古尔图河、四棵树河地表水体的污染主要来自于有机物污染,其次为营养物质污染,生物污染的影响较为微弱.该研究结果可为艾比湖流域地表水水环境改善和治理提供一定参考.     

Effects of land‐use changes on hydrological processes in the middle basin of the Heihe River,northwest China

The effects of land‐use changes on the runoff process in the midstream plain of this arid inland river basin are a key factor in the rational allocation of water resources to the middle and lower reaches. The question is whether and by how much increasingly heavy land use impacts the hydrological processes in such an arid inland river basin. The catchment of the Heihe River, one of the largest inland rivers in the arid region of northwest China, was chosen to investigate the hydrological responses to land‐use change. Flow duration curves were used to detect trends and variations in runoff between the upper and lower reaches. Relationships among precipitation, upstream runoff, and hydrological variables were identified to distinguish the effects of climatic changes and upstream runoff changes on middle and downstream runoff processes. The quantitative relation between midstream cultivated land use and various parameters of downstream runoff processes were analysed using the four periods of land‐use data since 1956. The Volterra numerical function relation of the hydrological non‐linear system response was utilized to develop a multifactor hydrological response simulation model based on the three factors of precipitation, upstream runoff, and cultivated land area. The results showed that, since 1967, the medium‐ and high‐coverage natural grassland area in the midstream region has decreased by 80·1%, and the downstream runoff has declined by 27·32% due to the continuous expansion of the cultivated land area. The contribution of cultivated land expansion to the impact on the annual total runoff is 14–31%, on the annual, spring and winter base flow it is 44–75%, and on spring and winter discharge it is 23–64%. Once the water conservation plan dominated by land‐use structural adjustments is implemented over the next 5 years, the mean annual discharge in the lower reach could increase by 8·98% and the spring discharge by 26·28%. This will significantly alleviate the imbalance between water supply and demand in both its quantity and temporal distribution in the middle and lower reaches. Copyright © 2006 John Wiley & Sons, Ltd.     

云南星云湖水质变化及其人文因素驱动力分析

星云湖目前存在水污染加重、富营养化进程加快、水体功能受损等问题.以星云湖为研究对象,根据星云湖2005-2015年的水质数据、社会经济统计数据和遥感影像图,运用目视解译、叠加分析、污染足迹模型及主成分分析法,分析了星云湖流域近10年以来水质变化趋势、入湖河流污染物污染足迹及其人文因素驱动力.结果表明:(1)水质数据趋势表明,从月变化看,3月份水质最好,9月份水质最差;从年变化看,2005-2015年间,2008年水质状况最好,2014年的水质状况最差,从2008-2014年水质持续变差,到2015年好转.(2)2015年有机物、氮和磷的污染足迹分别为583.26、705.88和494.11 km~2.污染足迹前4位的入湖河流依次为:大街河东西大河东河渔村河东西大河西河,占星云湖流域总污染足迹的66.21%.污染程度大的大街河、东西大河和渔村河周边土地利用类型为水田、旱地和村庄.(3)星云湖水质影响因素第1主成分(总人口、播种面积、农村人口、化肥使用量、农膜使用量、大牲畜存栏量)与农村生活和农业面源污染有关;第2主成分(人均GDP、第一产业产值、第二产业产值、第三产业产值)与社会经济发展有关.因此,星云湖流域水质变化的人文因素驱动力为农村生活和农业面源污染类和社会经济发展类,其中第1主成分的贡献率是84.389%,农村生活和农业面源污染是水质变化的主要驱动力.     

北方半干旱区土地利用/覆被变化对湖泊水质的影响:以岱海流域为例(2000—2018年)

土地利用/覆被变化对明晰气候变化和人类活动对湖泊水环境的影响有重要作用.以北方典型农牧交错的岱海流域为研究对象,基于遥感解译技术、马尔可夫转移矩阵、综合污染指数法等方法,对2000-2018年岱海流域土地利用/覆被和湖泊水质的变化进行分析,并结合冗余分析法和计量分析模型探究长时间序列尺度下土地利用/覆被变化对湖泊水质的影响.结果表明:近20年来,岱海流域的土地利用/覆被类型以耕地和草地为主,其变化特征主要是草地和林地转化为耕地,水域转化为季节性河流,岱海转化为内陆滩涂、沼泽草地和灌丛沼泽;岱海湖泊水质因子高锰酸盐指数、五日生化需氧量、总磷和总氮浓度存在不同程度的超标现象;岱海、湿地、林地对水质具有积极的改善作用,耕地、草地、建设用地是加剧水质污染的主要原因.该研究为岱海湖泊流域土地资源合理利用、湖泊水质改善和生态保护提供了一定的科学理论依据.     

Land use scenario development and stakeholder involvement as tools for watershed management within the Havel River Basin

The implementation of the European Water Framework Directive (WFD) will address land use issues in river catchments in order to reduce diffuse pollution and work towards the aim of achieving good ecological status, or good ecological potential in surface water bodies. The WFD also requires the active involvement of all interested parties in developing the best approach to achieve its objectives. The paper demonstrates how scenario analysis can be applied to investigate the impacts of land use changes and how stakeholder interviews can be used to evaluate the results of the scenarios.The study was carried out in the Havel Basin in the northeast of Germany. ‘Landscape-ecological spatial units’ were derived from similar characteristics of soil and groundwater conditions, ground relief and inundation to enable spatial allocation of potential land use and link different scales when describing possible changes in land use. As a first step, in three sub-catchments of the Havel River (distinguished by different physical characteristics) detailed surveys were carried out to investigate the various interests of the stakeholders. The interviews were used to identify the key problems of each area with respect to water quality and quantity and facilitated stakeholder engagement with the catchment planning issues in the Havel River Basin. The information from the stakeholder interviews was used to determine the initial conditions for the land use scenarios which were developed to demonstrate possible changes to land use for achieving better water quality. The land use scenarios also were required as an input into the hydrological modelling of their effects on water quality and to calculate their socio-economic effects. In a second survey, the results of the scenarios and the hydrological modelling were presented to the stakeholders. The consultation process identified the priorities of the stakeholders which could then be taken into account when developing management options.     

近百年鄱阳湖湿地格局演变研究

鄱阳湖是我国最大淡水湖和长江中游仅存的两个通江湖泊之一,重建其近百年自然通江的湖泊湿地演变过程,对于鄱阳湖湿地生态修复与保护具有重要意义.本研究基于两期历史时期地形图和遥感产品,构建了 1930s、1970s、1990s、2000s和2010s鄱阳湖湿地格局变化数据集,探究了土地利用方式改变和水文连通变化对鄱阳湖湿地变...     

Responses of runoff to climate change and human activities in the Ebinur Lake Catchment,western China

Based on hydrological and climatic data covering the period from 1961 to 2008, this paper studies the hydrological responses to climate change and to human activities in the Ebinur Lake Catchment. The results show that the annual runoff of three rivers in Ebinur Lake Catchment exhibited different change trends. Specifically, in Jinghe River and Kuytun River exhibited a slightly increasing trend, but an adverse trend in Bortala River, and the variation trend has been the most dramatic since the mid-1990s. The observed variation in the runoff was resulted from the elevated alpine precipitation, rather than rising temperature, and that precipitation is a major factor for runoff generation. The runoff CAR model proposed by this paper can be used to predict the annual runoff in three rivers, and demonstrated annual runoff in Bortala River and Jinghe River will display an increased trend, while a less decreasing trend in Kuytun River under the climate change scenarios of warm-humid variation. In addition, the exploitation of the area of cultivated land led to more water resources consumption, primarily for agriculture irrigation, is the cause of the persistently ecoenvironment degradation, which have reached in a critical state thus, a more pressing concern is the development a scientifically reasonable and administratively practical water resource management scheme.     

太湖水质及其保护

Lake Taihu, the third largest fresh water lake in China, with a surface area of 2 338 km², is located in the Changjiang River Delta, the most advanced economic zone in China. During the last two decades, the rapid economic development of local agriculture and industry both in the urban and rural areas of the region has made great advances. Great quantieis of pollutants have been discharged into the lake, its nutrient content has increased continuously, and phytoplankton blooms have occurred in some areas. Water quality protection in Lake Taihu is very important because of its close relation with economical development and people''s daily life. It is urgent to have comprehensive pollution control in Lake Taihu. Based on water quality monitoring data in Lake Taihu from 1987 to 1994, the dynamic variations of water quality and eutrophication trends have been analyzed, showing obvious spatial and temporal variations. The main water quality factors were compared with the standard for drinking water and indicate considerable change with the seasons. Some basic strategies to protect water quality and prevent eutrophication are discussed.     

Impact of environmental factors on water quality at multiple spatial scales and its spatial variation in Huai River Basin,China

Quantitative assessment of water quality and its spatial variation identification, as well as the discernment of primary factors affecting water quality are in its urgent in water environment management. In this study, four key water quality indicators,namely, ammonia nitrogen(NH_4~+-N), permanganate index(COD_(Mn)), total phosphorus(TP) and total nitrogen(TN) at 71 sampling sites were selected to evaluate water quality and its spatial variation identification. More concerns were emphasized on the anthropogenic factors(land use pattern) and natural factors(river density, elevation and precipitation) to quantify the overall water quality variations at different spatial scales. Results showed that the Yi-Shu-Si River sub-basin had a better water quality status than the Huai River sub-basin. The moderate polluted area nearly distributed in the upper and middle reaches of the Shaying River and Guo River. The high cluster centers which were surrounded with COD_(Mn), NH_4~+-N, TN and TP mainly also distributed in the upper and middle reaches of the Shaying River and Guo River. Redundancy analysis showed that the 200 m buffer area acted as the most sensitive area, which was easily subjected to pollution. The precipitation was identified as the most important variables among all the studied hydrological units, followed by farmland, urban land or elevation. The point source pollution was still existed although the non-point source pollution was also identified. The urban surface runoff pollution was severer than farmland fertilizer loss at the sub-basin scale in flood season, while the farmland showed "small-scale" effects for explaining overall water quality variations. This research is helpful for identifying the overall water quality variations from the scale-process interactions and providing a scientific basis for pollution control and decision making for the Huai River Basin.