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A GIS-based study on the changing course of the River Jiadhal in the Dhemaji district, India
14-27Views:225River bank-erosion, deposition and channel-shifting are considered most dynamic and significant geomorphological processes formed by complex geological, hydrological, and anthropogenic factors. In the present study, river Jiadhal is one of the main sub-tributary of the River Brahmaputra in the Dhemaji district of Assam that changes its channel course frequently due to bank-erosion and sediment-deposition in the intermediate part and lower course of the channel. A study on the changing course of the river Jiadhal was carried out using satellite imageries for the years 1987, 1997, 2007 and 2017. The study found that the changes in the river vary from time to time and the bank-erosion and sediment-deposition fluctuate from place to place. The total area of bank-erosion is 13.34 km2 from 1987 to 2017 and the total area of sediment-deposition is 14.59 km2 from 1987 to 2017. This paper evaluates how the shape, size and position of the Jiadhal River have changed from the years 1987 to 2017 using remote sensing and GIS techniques. The study is also necessary for effective management along the side of the river Jiadhal to control bank erosion and to mitigate the adverse impact of erosion and channel-shifting.
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Population an land cover dinamics of Sundarbans impact zone is Bangladesh
1-13Views:381Sundarbans is the largest mangrove forest of the world that lies in Bangladesh and India. This paper examined the correlation among population dynamics of Sundarbans impact zone (SIZ) from 1974 to 2011; impact of climate change on the forest; and changes in land cover of the forest from 1973 to 2010. Population size of SIZ was increased by 1.6 times between 1974 and 2011, whereas decreased by 2% during 2001 to 2011. During 1973 to 2010, water bodies, barren land and vegetated land reduced by 7.35%, 49.56% and 15.92% respectively; while grass land increased by 228.14% during the same period. But both population size and vegetated land declined during 2001 and 2011. This was due to the landfall of two severe cyclones in 2007 and 2009 through Sundarbans which resulted thousands of human casualties and out migration, and destruction of the forest. In addition, anthropogenic interventions like low flow from Ganges River and policy constraints also contributed to the demolition of Sundarbans. Thus, population growth, climate change and anthropogenic interventions are playing a decisive role to the depletion of forest resources from the Sundarbans mangrove forest.
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Urbanization induced land use/land cover change and its impact on land surface temperature in Bhubaneshwar city, India
43-62Views:281The study was conducted in Bhubaneswar City, the capital of the Indian state of Odisha. The impact of the increase in surface temperature on the city was studied by retrieving LST, Normalized Difference Vegetation Index (NDVI), and Normalized Difference Vegetation Index (NDBI) values of Bhubaneswar using Landsat 5 and Landsat 8 data for 2001, 2011, and 2021. The surface urban heat island (SUHI) effect was also studied to identify temperature changes and hotspots in the city. There was a rise of 3.93℃ and 1.55℃ in the maximum and minimum LST in Bhubaneshwar city from 2001 to 2021. The heating effect of the built-up and cooling effect of vegetation was ascertained through correlation analysis between LST and NDBI (positive) and between LST and NDVI (negative). The results of this study will help the government and urban planners to identify heat stress and vulnerable areas, thereby contributing to better monitoring and future planning of the city. Thus, this will lead to efficient heat strategies and action plans such as developing green spaces in and around the city.
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Quantitative Morphometric Analysis of Streams in Extreme Humid Areas: A Case Study of the Um-Mawiong River Basin, Mawsynram, Meghalaya
59-75Views:234Quantitative morphometric analysis of the drainage system is essential to characterising a watershed, as all the hydrologic and geomorphic processes occur within the watershed. Consequently, this plays a crucial role in understanding the geo-hydrological attributes of a drainage basin to the terrain feature and its flow patterns, thus enabling the estimate of the incidence of infiltration and runoff and other related hydrological characteristics of a watershed, which strongly impacts natural resource conservation. The study area selected is the Um-Mawiong River basin in Mawsynram, Meghalaya. The basin shows a dendritic pattern that highlights the homogeneity in the texture of the basin. Results suggest that the stream frequency of the basin is 19.10 km², suggesting a faster surface runoff and less infiltration. In addition, it has an Elongation ratio of 0.75 indicating an elongated basin shape. The current study demonstrates that the implementations of GIS techniques are trustworthy, efficient, and capable of managing extensive databases for managing river basins. The present study tries to analyse the linear, areal and relief aspects of the basin using a GIS environment and manipulated for different calculations. The analysis reveals that the total number of stream segments and length are maximum in first-order streams and decrease as stream order increases. The drainage density exhibits a high degree of positive correlation, i.e., 0.87, with its frequency suggesting an increase in stream population concerning increasing drainage density and vice versa.