Brazilian biomes are hotspots of global biodiversity, important biomass producers and, consequently, help maintain the world’s carbon balance. Net primary production (NPP) is a variable used to determine carbon uptake by land cover. As environmental factors and human activities vary, net primary production increases or decreases. This study aimed to evaluate NPP in three Brazilian biomes – Atlantic Forest, Cerrado, and Caatinga – in the state of Bahia for the last 17 years, and to understand its relationship with human activities by analyzing burned areas, as well as interrelated environmental factors, such as climate variability and soil heat flux, using remote sensing. Using the MOD17 dataset, we find evidence that the Atlantic Forest biome is the one that absorbs more carbon in comparison to the Caatinga and Cerrado biomes, with a mean annual net primary production in each one of these three biomes equal to 1,227.89 g C m-2, 913.81 g C m-2, and 803.56 g C m-2, respectively. The years of El Niño influenced all biomes, and the results showed a strong relationship between climate and NPP in the studied biomes, especially in Caatinga, which is the most sensitive to climatic variations. Besides these results, we find evidence that, in all these biomes, the NPP dynamics have been affected by the increase in land use for agricultural and livestock activities, mainly because of deforestation and burning.

An analysis of the spatial organization of vegetation cover has been carried out for the Altai-Sayan orobiome in connection with climatic conditions in the Southern Siberian mountains based on original relevés of plant communities at the 4 altitudinal spectra. Basic bioclimatic parameters on the altitudinal spectra of vegetation have been determined according to latitudinal and longitudinal differentiation of climate. Correlation and discriminate analyses allowed to identify the regional features of altitudinal gradients in species diversity of the spectra as well as the role of parameters in the structure of typological diversity of vegetation for belts of high-mountain tundra, alpine and subalpine meadows and sparse forests, dark coniferous mountain taiga forests, chern-taiga forests, small leave – light coniferous subtaiga forests, forest-steppe. A compiled bioclimatic scheme characterizes the spatial organization of orobiome’s vegetation by basic bioclimatic parameters on the regional level (continentality index, average temperature of January). This scheme shows regional features of the diversity of vegetation in Southern Siberia, in adjacent plain and mountain regions according to climatic conditions. Identified patterns determine unity of the Altai-Sayan orobiome as well as regional differentiation that reflected on the development of types of vegetation zonality. They can be used to analysis of vegetation forming in different mountain systems.

Ecosystem services provided by urban parks play a significant role in visitors’ well-being. The provision of these services depends upon the well-designed green spaces built to fulfil the needs of people. As these services are linked with visitors’ well-being, particular emphasis to indicate them is needed. However, minimal documentation is found regarding these valuable services, particularly in the context of Lahore. So, in this study, an effort was made to highlight visitors’ preferences for the available ecosystem services provided by urban parks in Lahore, Pakistan. These ecosystem services are beneficial in enhancing the well-being of people. Fifteen parks in Lahore were selected in this study to highlight the visitors’ preferences in visiting the parks. A questionnaire-based survey was conducted in these parks to collect information. The questionnaire was compiled to record socio-demographical profiles, usage patterns, choices, and visitors’ opinions about the services provided by the parks. A total of 300 responses were recorded to depict the survey findings. The result highlights that 60-80% of visitors like to come to the parks having maximum services regardless of how distant is from their residence. It also reveals that large-sized parks with maximum facilities attract more visitors than small and medium-sized parks. As in these parks, people only from neighbouring areas visit due to their accessibility. The findings will be helpful for the managers and planners of the urban park to improve the ecosystem services for the well-being of people. It will also indicate the choices of people based on that information, the status of parks can be improved, and new parks can be developed to meet the visitors’ needs.

The islands Iturup and Urup of Kuril Archipelago have been understudied in respect of seagrasses. The research aimed to fill this gap. In 2019 during the expedition of the Russian Geographical Society a part of the coastline has been surveyed by walking, the beached remains of seagrasses and the seagrasses growing on the littoral have been registered. The length of the routes was 95 km. The possible sources of negative anthropogenic impact have been examined. Herbarium collections of several institutions (LE, LECB, MHA, MW, MWG, SAK, Kamchatka Branch of Pacific Geographical Institute of the RAS, the Herbarium of Kronotsky Nature Reserve) have been explored. Three species of seagrasses occur at Iturup and Urup: Zostera marina L., Zostera asiatica Miki, and Phyllospadix iwatensis Makino. The last two species are of particular interest as they are threatened and distributed over a relatively small area. Unlike the habitats of the main part of their range located at the coasts of Japan and Korea, the habitats of the studied islands do not suffer from anthropogenic pressure. The discovered northern refuge is significant for the seagrasses conservation. Current global warming and increasing anthropogenic pressure on the southern habitat would increase its significance. It is especially important for Phyllospadix iwatensis as it turned out to be rather numerous at the studied islands. The other two species occur in small numbers there.

Palawan Island is home to one of Southeast Asia’s largest, oldest, and most diversified rainforests hence it was called the «Last Frontier.» However, the island province’s forest is contending with increased conversion of forest lands to plantation and household-level agriculture, intensive mineral mining, illegal logging, and other pressures on its ecosystems. Understanding these factors in relation to the prevalence of deforestation and forest degradation in Palawan is imperative. This paper analyzed these drivers of deforestation and forest degradation in Palawan using the social-ecological systems (SES) and institutional analysis development (IAD) frameworks. A literature review was conducted using a variety of web-based databases and sources and additional data were collected from official websites and reports. The identified major drivers of deforestation and forest degradation in the province include increasing population, migration from lowland to upland areas, illegal logging, mining, wide-scale kaingin and oil palm plantation, wildlife poaching, and weak policy implementation and enforcement. These identified drivers can be the target of the government of Palawan for their forest management plans. Additional findings and recommendations of this paper will also aid in the forest management planning in Palawan and other areas where similar settings exist.

Merapi Volcano is one of the active volcanoes in Indonesia, which is located in the Central Java and Yogyakarta Province. The eruption of Merapi Volcano is a threat to people living on the slopes of Merapi, especially on its denselypopulated southern flank. The purpose of this study was to build a webGIS to support volcanic hazard mitigation regarding Merapi Volcano and evaluate the webGIS system for determining the community’s perception. This research was the first to produce a product that is used by government agencies related to volcanic disaster mitigation. webGIS development was carried out using an open source platform. System evaluation was carried out using usability testing. The samples were obtained using systematic the random sampling method of respondents who lived in the villages on the southern flank of Merapi volcano. webGIS was built using LeafletJS and QGIS, combined with spatial data about the evacuation locations, health facilities, evacuation routes, government offices, educational facilities and worship facilities, with a basemap obtained from Openstreet Map and Google Satellite. WebGIS was equipped with a database query feature to make it easier for users to find geographical information. The usability testing results showed that as many as 83% of the respondents were very satisfied with the appearance and information of webGIS, while as many as 82% were very satisfied with the navigation offered via the webGIS display.

As a developing country, Indonesia is experiencing rapid growth, necessitating the use of development-control instruments to achieve sustainable development. Furthermore, information about land reform implementation in Indonesia can only be found in academic journals written in Indonesian. As a result, determining the appropriate development-control model in Indonesia is critical. The appropriate concepts and development-control tools for Indonesia are discovered by reviewing papers that implement development control globally and the state of development-control implementation locally in Indonesia. However, by presenting the concept of controlling spatial development—beginning with defining development control, then capturing its typologies globally, and finally discussing the implementation condition in Indonesia—the model can also be adopted in countries with a similar planning system. The main gaps and challenges in implementing spatial development-control tools in Indonesia were identified in the final section of this article. In the meantime, a regulatory zoning system would be successful, but a discretionary system that includes economic development opportunities can be considered by strengthening human resources and institutions. The three elements in development control are spatial planning, land development, and regulation. Furthermore, the community’s successful traditional spatial development control can be incorporated into the existing control regulations. 

This research analyses the causes of traffic congestion in urban corridors. It specifically studies the intersected relationship between land-use and transportation planning by examining Al-Madina Al Monawara street in Amman, the capital of Jordan, as a case study. Techniques implemented in data collection are personal observations, traffic counts, land use maps and questionnaires. The methods applied in analysing the collected traffic counts are: Level of Service (LOS), Automatic Traffic Counters (ATC) and Trip Attraction Analysis (TAA). The outcome of the research verified the relationship between the high level of traffic, where the traffic exceeds the actual capacity of the street by 43%, and the unregulated land use planning where 85% of the existing buildings along the street are commercial. The findings of this research will help to establish an assessment tool for testing the impacts of transportation and land use in congested developing cities. This study is important since transportation solutions receive little attention by planner’s development agendas in Jordan and the neighbouring countries.

The relevance of the study lies in the need for a scientific search for the possibilities of using new types of Big data in studies of the population vulnerability to solve practical problems of improving the safety of urban spaces from natural and man-made hazards. The object of the study is the administrative districts of Moscow; the subject is the temporal patterns of vulnerability of their population to potential natural and man-made hazards. The research question of the study is to develop a typology of Moscow districts and further assess this sustainability in terms of the population vulnerability to natural and man-made hazards. To achieve this research question, a set of tasks was solved: 1. Processing of the mobile operators’ data array and further construction of a continuous graph of the Moscow population dynamics in 2019 (with a time cycle of 30 minutes, over 36 million measurements in more than 7 thousand time slices); 2. Empirical justification of natural temporal boundaries of daily, weekly, seasonal cycles of population dynamics in Moscow districts; 3. Justification of key factors and parameters of urban population vulnerability; 4. Development and approbation of the dynamic clustering method of Moscow districts using selected variables and periods. The study is based on the impersonal mobile operators’ data on the locations of subscribers for 2019, provided by the Department of Information Technologies of the Moscow city. The method of dynamic cluster analysis is used. Four particular clusterings were obtained that characterize the “behavior” of the settlement system in the main intervals of social time (weekdays and weekends of the cold and warm seasons). Сluster stability matrix allows to identify which of the districts retain their properties during the period under review, and which are characterized by instability of considered indicators of population vulnerability. Depending on the stability of the position of the districts in a particular cluster, “stable”, “conditionally stable” and “nomadic” types of districts were identified. The study showed that the first two types include spatial-settlement structures that are stable in time with approximately the same level of population vulnerability during the year, while the third type requires a special differentiated approach to the development of measures to protect the population from natural and man-made emergencies. Calculations have shown that “nomadic” type of districts concentrate on average from 2.2 million people in the summer season to 3 million people in the winter season, that is, a very significant share of the entire population of the capital.

Flooding is the most common disaster in Indonesia, it is classified as a disaster if it affects humans causing physical and financial losses. Flood damage depends on the type of flood, flow velocity, and duration. The increase in population will cause an increase in infrastructure that will affect the environment, including the carrying capacity of rivers and catchment areas, while flooding in urban areas will also have an impact on infrastructure and assets, increasing flood damage. This study discusses the factors that cause flooding (rainfall, topography, soil type, land slope, distance from rivers, river waste, population density, etc.), as well as various types of floods that occur. The method used in this research was based on the qualitative analysis of the information from the government and literature over the last five years obtained from online databases and search engines. The results of this study can provide a reference for the theory regarding disaster risk assessment and flood hazard prediction in watersheds. This research was conducted in the Ciliwung Watershed (DAS), where the factors and the dominant type of flooding were determined. Knowing the contributing factors can be beneficial for flood risk management. This research focuses on identifying factors that contribute to fluvial flood events and understanding their influence so that a more integrated flood risk management that takes into account the upstream, middle, and downstream parts of the watershed can be arranged in other areas based on the example of measures implemented by the local government in the Ciliwung watershed. This conceptual effort provides a much-needed foundation for developing better mitigation efforts in watersheds.

Prielbrusye National Park is one of the most popular tourist destinations in Russia. In recent years internal tourism development, stimulated by restrictive measures (due to the COVID pandemic and geopolitical situation), resulted in significant growth of tourist flow to the national park’s territory. A surge in anthropogenic load on the park’s geosystems might degrade them and lead to environmental pollution. This research involved chemical studies of natural waters and snow from the south slope of the Elbrus and audit of the most popular tourist trails. The results have shown that in the snow alongside mountain hiking pistes to the Elbrus all the way up to 4,720 m above sea level (a.s.l.) oil stains concentration is up to 38 times higher than maximum acceptable concentration (MAC). Content analysis of heavy metals in snow cover on the Elbrus slopes and in the river Baksan has shown a significant rise in lead load over the period of 2015–2021 from the trace levels to 1.5 MAC, which is the result of increased anthropogenic load on the south slope of the Elbrus mountain. Ground observation of tourist trails has brought to light numerous patches of vegetation trampling, width extension and branching of the main trail, as well as campfire sites. The research results can be used as a rationale to take measures to reduce recreational load, to improve local geosystems’ condition and to develop a plan of action on nature conservation within the park’s territory.

The objective of this research on the relationship between urbanization and road networks in the lower Northeastern region of Thailand was to compare the urban area in 2006, 2013 and 2016 using nighttime light satellite images from the National Oceanic and Atmospheric Administration (NOAA), acquired by the Defense Meteorological Satellite Program (DMSP/OLS) and the Suomi National Polar-orbiting Partnership (Suomi NPP). After that the relationship between urbanization and road network was identified using nighttime light satellite images from these satellites. The nighttime light data was used to determine the urbanization levels, which were then compared with Landsat 8 Satellite images taken in 2016 in order to find the Pearson correlation coefficient. The results indicated that areas with high urbanization identified from the nighttime light satellite images taken by the Suomi NPP Satellite had a day/night band reflectance of 172-255 indicated and were located primarily along the roads. The analysis of these data suggested that urbanization has a significantly positive relationship with the road network at 0.01 level, with R2 values of 0.800 for urbanization and 0.985 for the road network.

The influence of the COronaVIrus Disease 2019 (COVID-19) pandemic lockdown (the period of strict quarantine measures) in the spring of 2020 on the ‘Surface Urban Heat Island’ (SUHI) geographical phenomenon in Moscow has been studied. For this purpose, we used the measurements of the surface temperature TS made by Moderate Resolution Imaging Spectroradiometer (MODIS) radiometer installed on Terra and Aqua satellites. As a result, TS during the 2020 lockdown, both in the city and surrounding rural zone, was found lower than at the same calendar time in the previous 20 years due to the relatively cold spring. The SUHI intensity as the difference between TS inside Moscow and the surrounding rural zone around it during the lockdown was also lower than usual (on average in the previous 20 years), but this decrease is relatively small and nonsignificant. The Normalized Difference Vegetation Index (NDVI) in Moscow and Moscow region during the lockdown was close to its usual values, but the leaf area index (LAI) was significantly lower than its average values in the previous 20 years. Thus, the weakening of the SUHI during the lockdown in 2020 was caused mostly by lower heat loss due to transpiration in the rural zone. This was associated with the slowdown in vegetation development as a result of the cold spring. Besides, an additional possible reason was the reduction of human activity due to the collapse of many anthropogenic heat sources in the city. According to long-term MODIS data, the SUHI intensity in Moscow and the surface temperature in Moscow region, as well as the NDVI and LAI values, do not demonstrate statistically significant long-term trends in the spring season over the past 21 years, despite climate changes. In spring, during faster snow melting in cities, when it still persists in the rural zone, the SUHI intensity can be record high (up to 8 ºC).

This paper provides a short overview of the large river research topics discussed during the 4th World’s Large Rivers Conference and submitted to the Geography Environment Sustainability special issue. The various aspects of hydrology, sediment transport and river morphology issues are presented based on case studies from Eurasia and Africa.

Climate change impact on the water balance components (including river runoff, evapotranspiration and precipitation) of five Arctic river basins (the Northern Dvina, Taz, Lena, Indigirka, and MacKenzie), located in different natural conditions, was investigated using a physically-based land surface model SWAP and meteorological projections simulated at half-degree spatial resolution by five Global Climate Models (GCM) for four Representative Concentration Pathways (RCP) scenarios from 2005 to 2100. After the SWAP model calibration and validation, 20 projections of changes in climatic values of the water balance components were obtained for each river basin. The projected changes in climatic river runoff were analyzed with climatic precipitation and evapotranspiration changes. On average, all rivers’ water balance components will increase by the end of the 21st century: precipitation by 12-30%, runoff by 10–30%, and evapotranspiration by 6-47% depending on the river basin. The partitioning of increment in precipitation between runoff and evapotranspiration differs for the selected river basins due to differences in their natural conditions. The Northern Dvina and Taz river runoff will experience the most negligible impact of climate change under the RCP scenarios. This impact will increase towards eastern Siberia and reach a maximum in the Indigirka basin. Analysis of the obtained hydrological projections made it possible to estimate their uncertainties by applying different GCMs and RCP scenarios. On average, the contribution of GCMs to the uncertainty of hydrological projections is nearly twice more significant than the contribution of scenarios in 2006–2036 and decreases over time to 1.1-1.2 in 2068–2099.

The heat flux of the large rivers flowing into the Arctic seas of Russia plays an essential role in the thermal and ice regime of the lower reaches of these rivers and the southern part of the Arctic seas. However, estimates of the total value of heat flux and its spatial-temporal distribution require clarification. In this research, we analyzed monthly, and yearly water temperature data from 55 gauges and water flow data from 35 gauges in the lower reaches of the rivers of the Russian Arctic northerner of 60 N. These rivers are: Onega, Northern Dvina, Mezen, Pechora, Ob, Nadym, Pur, Taz, Yenisei, Khatanga, Anabar, Olenek, Lena, Yana, Indigirka, Alazeya, Kolyma and their main tributaries. The collected data series covers 1930-2018, focusing more on 1960–2018. We used Spearman trend tests and Mann-Whitney U-test to clarify changes in the thermal regime of study rivers. Our estimations showed that heat flux did not significantly increase in the past three decades on most rivers except Yenisei and Yana lowlands. Water temperatures on rivers monotonically increased after 1960, especially in May and June, but without statistical significance. The role of dams in the water temperature regime is observed for nearly 500 km lower dams, but it is not observed in their lowlands and mouths. We also identified the decrease in water temperatures and heat flux in river lowlands, estuaries and deltas up to 25% for Yenisei lowlands.

The Intergovernmental Panel on Climate Change has predicted that sub-tropical regions are more vulnerable to climate change’s negative effects (CC). Additionally, to CC, land use and land cover (LULC) changes and dam construction, often neglected, play an important role in the spatial and temporal distribution of water balance components (WBC) for agricultural production and socio-ecological equilibrium. This study aimed to analyze and compare the changes in LULC and WBC for the period before Nangbéto dam construction (1964–1986) and the period after its construction (1988–2010) in the Mono River Basin (MRB). To this end, the study used mainly WBC extracted from the validated Soil and Water Assessment Tool and LULC data of 1975–2000 in the MRB to explore their temporal distributions and the link in their changes. The results showed that mean actual monthly evapotranspiration, percolation, water yield, surface runoff, groundwater, and lateral flow represent 51%, 17.5%, 15.9%, 9.4%; 5.7% and 0.4%, respectively, of total water balance between 1964 and 1986. The same components represented 51%, 9.1%, 20.4%, 6.3%, 10.6% and 2.6%, respectively, between 1988 and 2010. The contribution of these WBC in the mean-annual (1964–1986) period was for actual evapotranspiration (31.3%), water yield (25.9%), percolation (17.7%), groundwater (14.71%), surface runoff (9.94%) and lateral flow (0.40%). Meanwhile, between 1988 and 2010, the contribution of actual evapotranspiration, water yield, percolation, groundwater, surface runoff and lateral flow is 49.8%,19.9%, 11.2%, 10.3%, 6.1%, and 2.5%, respectively. The results showed that the peaks of the actual evapotranspiration, surface runoff, percolation and water yield appeared in September, corresponding to a month after the maximum rainfall in August. However, our more detailed analysis showed that a significant decrease in forest and savanna and an increase in croplands led to a decrease in actual evapotranspiration and lateral flow over the second simulation period compared to the first period of simulation over the MRB scale. These findings showed that sustainable management and conservation of natural vegetation are crucial for integrated water resource management and conservation in MRB.

The article describes the methodology for constructing digital elevation models for the vast delta areas of the Don and Volga rivers for further use in mathematical models of flooding from surges. The initial cartographic data and features of the delta regions are described. The methods of information processing are considered in detail. An algorithm for constructing a DEM has been developed to obtain highly detailed digital elevation models. The algorithm is based on combining the DEM of individual key features - land, the depths of the hydrographic network and the bathymetry of the receiving reservoir for the river. The topographic maps, maps of the navigable route depths, hydrographic maps, and satellite images Landsat-8 and Sentinel-2 were used to create the DEM of the Don and Volga river. To build individual DEMs, a raster of the absolute depth of the channels, a hydrography DEM, a land DEM, and a shelf DEM were created using geoinformation systems. To assess the possibility of using obtained DEMs in hydrological models based on HEC-RAS, we conducted training and verification calculations of water level during wind surge phenomena in Don Delta using different surface roughness coefficients. The calculation results show good reproducibility of observed water level fluctuation in the Don Delta using obtained DEM with a roughness coefficient of 0.0125. Also, we carried out similar calculations of storm surge phenomena in the Volga Delta using obtained DEM and combinations of various riverbed and not riverbed roughness coefficients. The combination of 0.007 for riverbed and 0.02 for not riverbed surfaces reproduces the observed water level fluctuation during storm surge phenomena in Volga Delta. The constructed DEMs for the Volga and Don deltas made it possible to reproduce the observed dynamics of river discharges and water level fluctuations during surge events. Such detailed DEMs, taking into account all the complexity of the coastal and delta relief, were created for the first time for the Volga and Don.

Identifying social consequences is an essential aspect of considering emergency flood events. There needs to be more consensus in scientific publications on which social consequences of natural disasters, including emergency flood events, should be singled out and considered for the complete analysis of this issue and for further making the right management decisions. To clarify the structure and dynamics of scientific interest in social consequences, a line-by-line content analysis of more than 100 scientific articles on the five largest emergency floods of the early 2010s that occurred in various global basins of the world in countries with different levels of human development was carried out. As a rule, the cycle of interest in the events is 6-7 years, with a peak in the second or third year. There are exceptions to this trend due to either a completely unexpected event or the overlap of several significant events over several years. Social consequences, as the volume of consideration decreases, can be arranged in the following row (by the level of interest, %): death losses (23,1); social solidarity (18,3); management problems (13,4); horizontal mobility (11,3); psychological state (10,9); vertical mobility (7,0); social conflicts (6,2); social adaptation (5,4); health losses (4,4). The relationship of scientific interest in emergency flood events with the country’s level of development has been evaluated. There are three types of connection. With the growth of the Human Development Index (HDI), interest in social solidarity, death losses and management problems increases (the correlation coefficient is 0,54; 0,42; 0,31, respectively); However, consideration of vertical mobility, social conflicts and health losses is typical for lower HDI (the correlation coefficient is -0,86; -0,70; -0,47, respectively). The third group of social consequences (social adaptation, horizontal mobility, psychological state of the population) is statistically poorly related to the level of HDI.

Anthropogenic stressors have altered the hydromorphological characteristics of rivers worldwide. Environmental guiding principles are essential for planning sustainable river restoration measures. The alpine river Biya, located in the Russian Altai mountains, originates from Lake Teletskoye and joins the Katun near Biysk, forming the Ob. The Biya represents a hydromorphological reference system in anthropogenically ‘least-disturbed’ condition. The presented study aimed to assess the river’s undisturbed morphology in relationship with the geological history of three different river stretches based on an adapted landscape reading approach using remote sensing information (ASTER GDEM v3). The established widths of the active channel, active floodplain and morphological floodplain as well as the longitudinal section were used to explain the differences between upper, middle, and lower Biya. The results confirm differences in the geological origins between the upper Biya, which has previously been described as the least developed and narrowest, and the other two stretches based on the analyses of morphological parameters. Morphological floodplain width could best explain the differences between upper (0-86 km), middle (86-196 km), and lower Biya (196-301 km). The study further showed a clear relationship between the variations in river patterns and adjacent topographic structures (valley confinements, tributary interactions), highlighting that any assessment of river morphology must consider the wider surroundings of a river stretch. The presented morphological observations and analyses of the Biya show that easily obtainable parameters can detect differences in the morphological history of river stretches within the same catchment, supporting process understanding.

The development of bed load calculation methods directly depends on the reliability of the measurement data. The most reliable measurement data remains the data obtained by the volumetric method when observing the filling of reservoirs, borrows, ditches etc. Nevertheless these data are the rarest. In this paper on the base of the data obtained when observing the process of filling of a ditch across the Amur River a comparison of a number of bed load calculation methods is performed. The observations were carried out with a multi-beam echo-sounder during summer floods of 2018, from 21st of July to 22nd of August. Over this time 5 surveys were performed, that allows to have 4 calculation periods for determining bed load yield. The total number of the measurements at different calculation verticals is 108. These data are used for verification of 80 bed load formulas. Four methodological approaches are considered: bed form approach, critical velocity approach, critical water discharge approach and regression approach. The bed form approach has shown the greatest accuracy: 17 formulas out of 26 gave the error less than 60%. For the other 56 methods which were considered only 5 formulas showed the error less than 60%, all of them correspond to the critical velocity approach.

Unraveling sources of sediment supply, their temporal and spatial variability is of key importance to determine origin of deposits and to explore the formation mechanism of Selenga Delta landscape units. From an environmental point of view this solution would help to identify the particle-bound pollution sources. We used geochemical fingerprinting (the FingerPro R package), which is a modern quantitative implementation of the method of sedimentary provenance analysis. The main aim was to recognize the main patterns of sediment and associated particle-bound pollutants transport and deposition within the delta. At the old floodplain from 55% to 90% of sediments were delivered from the eroded floodplain and terrace banks upstream and only about 10-15% originates from the remote basin sources. Sedimentary environment in the Khlystov Zaton reveals a greater variety than on the floodplains. 40% of sediments from the upper 5 cm-layer originated from the flood, taking place in 2013, and 30% were the product of floodplain and terraces banks erosion. Nevertheless, analysis of the fine-grained component of suspended sediment sets the material from eroded floodplain banks as the dominant source of accumulation within the delta. This means that the self-absorption is the leading process in the Selenga delta at the moment. Heavy metals and metalloids accumulates in the lower reaches of the Selenga on the floodplain surface, deltaic lakes and oxbows during high floods. Runoff decrease during floods can lead to the release of pollutants into the Lake Baikal.

Anthropogenic activities can greatly influence the lake ecosystems across the globe. Within these ecosystems, the impacts of human activities are most evident on sedimentation, light and nutrient availability, and disturbance frequency. There have been times of natural environmental healing of reservoirs and the present research aims to explore the variations in the water quality of Tarbela reservoir, Pakistan the largest rock-filled dam of the world, from 1990 to 2020. Landsat imagery (Landsat 4-5, 5, 7 and 8) was used to monitor Land Use Land Cover (LULC), Normalized Difference Chlorophyll Index (NDCI), Normalized Difference Turbidity Index (NDTI) and Normalized Difference Water Index (NDWI) in Tarbela reservoir, and its surrounding area from 1990−2020, on decadal interval. The results indicated a significant increase in built-up area, of about 630 km2 , in the western and eastern parts of the reservoir, whereas turbidity level, revealed a substantial decline with 4% decrease observed in the last decade, 2010-2020 thus confirming improved water quality. The study also presented expanse in the spatial coverage of chlorophyll index and water index, indicating increase in residence time of the water. It is concluded that the water quality continued to deteriorate with time, however, 2020 was a year of environmental healing and there was an overall water quality improvement of the reservoir observed. The study recommends policies to be formulated for sediment flushing and turbidity reduction for longer time duration to enhance the life of this mega reservoir.