Abstract: River bank erosion within Murshidabad district is a tragedy, which happens haphazardly along the bank of the Padma River system. The main objective of the study is to analyze the changing river course and its impact on society. By comparing the toposheet and Landsat (5 and 8) images of the Padma River of the Murshidabad district from the years 1924, 1990, and 2020, it is clearly observed that there have been significant changes on the southern portion of the river since 1924 (Bhagawangola II, Raninagar II, and Jalangi Block), while less changes occur on the central part of the river, which is near the Lalgola block. But in the year 2020 significant changes have been found in the northern and middle portion of the district near Samserganj and Lalgola block. Those parts belong to a highly vulnerable zone of bank erosion. This study analyzed some factors, such as soil stratification of the river bank and human encroachment as an obstruction to the natural river flow, also responsible for bank failure. The river has been consuming the vast portions of the right bank every year due to its increasing sinuosity. The victims are mostly in the Samserganj, Lalgola, Bhagawangola II, Raninagar II and Jalangi blocks, who suffered greatly from 1924 to 2020 due to moving of river course by 27% on the right side, which is notified from cross sectional analysis. Additionally, the predicted erosional impact of the region highlights the socio-economic perspective of the research area.
Abstract: The study of flood risk in Algerian cities has become essential given the multiple issues at stake (urbanization, urban sprawl, easements, infrastructure, soil structure, etc.), which constitute vulnerable elements, as well as their frequen-cy and repetition in time and space. This has become a problem for the city and the urban environment, particularly in large metropolises such as Constantine. The watershed of Oued Ziad located in the northwestern part of the city of Constantine has experienced exceptional flooding, causing loss of life and property in the Jebli Ahmed agglomeration in the Hamma Bouziane township. The main objective of this research is to identify the factors aggravating the risk of flooding in the Oued Ziad watershed, to analyze the frequency of maximum daily rainfall to determine peak flows for different return periods of 10, 20, 50, 100 and 1000 years, and to map the extent of the flood hazard in the Oued Ziad watershed for a centennial flow, using geographic information systems and HecRas software. The simulation results show the overflow of Oued Ziad on national road N°27, affecting a part of the agglomeration located downstream by a centennial peak flow equal to 50. 98 m3/s and a water height exceeding 3 m, which confirms the extent of the area exposed to risk during the flood that occurred on 19/9/2018. The field survey shows that several anthropic factors in-crease the risk of flooding while the capacity of the existing hydraulic structures is insufficient to evacuate water during floods, which requires the development of this watercourse and its banks to protect the population and its property from the risk of flooding and to reduce the impact on the city’s environment and socio-economic activities.
Abstract: The Land use/Land cover (LULC) has a substantial role in planning and monitoring natural resource utilization, in the framework of the ongoing surge in human demands in the current ecosystem. Satellite remote sensing provides modern methods for locating and mapping Land use/Land cover patterns and their spatial changes. This paper discusses the evaluation of the LULC classes characteristic of Keti Bunder during the years 2015 and 2020, by using satellite remote sensing; the paper also uses Geo-informatics to study and investigate the temporal LULC variations that occurred over time. According to the empirical findings, there have been significant spatial changes, with less dry mudflats and unoccupied land overall. In comparison, the findings of the research point to inter-conversion of the area between LULC classes, i.e. mangrove areas, turbid water, wet mudflat, dry mudflat and barren land/vacant land. Overall, these geographical alterations show that the environment has been significantly impacted due to recent extreme weather events in the region.
Abstract: Land-use change is one of the challenges that exacerbate environmental problems. Understanding the scope of land-use and land-cover change, past and present drivers and consequences is crucial for properly managing land resources. This study applies the supervised classification maximum likelihood algorithm in ArcGIS 10.8 software to detect changes in land use and cover in Hoa Binh city, Hoa Binh province, Vietnam using multimedia satellite data obtained from Landsat 7-ETM+, Landsat 5-TM and Landsat 8-OLI for the years 2000, 2010 and 2020 respectively. In addition, for each satellite scene we also applied spectral indices (NDVI-Normalized Differential Vegetation Index and NDWI-Normalized Differential Water Index) to classify and evaluate the change of LULC. The study area, located in the Northwest mountainous region of Vietnam, is classified into five land-use/cover classes: Agriculture, Forest, Water, Urban or built-up land and Bare soil or rock. The results reveal significant changes in the study area between 2000 and 2020. Accounting for the largest proportion of total area, the forest area has decreased from 243.20 km2 in 2000 to 217.40 km2 in 2020. Conversely, the urban/built-up land area has increased continuously for the last 20 years, from 9.31 km2 in 2000 to 13.27 km2 in 2010 and 51.80 km2 in 2020. Changes in land use and cover have severe environmental impacts, such as climate change, loss of biodiversity, deterioration of water availability and quality, and reduced crop yields. Therefore, appropriate measures must be taken to limit drastic land-use changes and harmonize environmental conservation and human livelihoods.
Abstract: The major focus of the current study is a spatio-temporal analysis of land use and land cover changes in Balurghat Municipality, West Bengal, using remote sensing and geographic information systems (G.I.S.) from 1990 to 2020. The primary goals are to identify changes in land use and land cover and to look at the key influences and how they affect the dynamics of the landscape. The Landsat images of the study area are classified into five categories with the help of GIS software and Google verified and validated by the process of accuracy assessment. An image has been classified digitally with the help of the Supervised Image Classification method under Maximum Likelihood Classification techniques which also helps to identify the transformation of land from vegetation cover to built up area.