Papers by Swapnali Barman
Advances in sustainability science and technology, Jun 18, 2022
ABSTRACT: The Majuli Island of Assam which is regarded as the largest river island of the world i... more ABSTRACT: The Majuli Island of Assam which is regarded as the largest river island of the world is getting eroded continuously due to the erosive nature of the rivers Brahmaputra on its south and Subansiri on its north. The main factor for which it has become the centre of attraction is its stream bank erosion. But, surface soil erosion should also be considered equally. It is well known that Assam is a land of heavy rainfall. So, it is obvious that rainfall plays an important role in surface soil erosion. Again, the change in land use/land cover also plays an important role in surface soil erosion, more specifically, the change in vegetation. In this study, an attempt has been made to determine the combined effect of rainfall and LULC change as well as the impact of change in vegetation alone on soil erosion. For this, the Morgan, Morgan and Finney model was used. Various input parameter to the model were derived using RS and GIS using ILWIS software and finally soil erosion was es...
International Journal of Emerging Trends in Engineering Research, Feb 15, 2021
Using five different CMIP5 climate models under the scenarios of RCP4.5 and RCP8.5, we analysed m... more Using five different CMIP5 climate models under the scenarios of RCP4.5 and RCP8.5, we analysed maximum, minimum and mean temperature over Puthimari river basin, that covers parts of Bhutan and Northeastern region of India. Historical period from 1970-2005 and future three periods, 2025-49, 2050-74 and 2075-99 were considered to understand the effect of global warming in the basin. Monthly Maximum, minimum and mean temperature variations analysis showed increase in temperature from 1970 to 2099 for all the models under both the scenarios. The study indicates that the average maximum, minimum and mean temperature over the basin will rise by 1.13-2.49°C, 1.3-2.64°C and 1.21-2.6°C respectively from in 2075-99 compared to the historical period under RCP 4.5. Again, these temperatures will increase by 2.68-3.89°C, 2.85-4.74°C and 2.76-4.53°C under RCP8.5 towards the end of the century. The linear trend analysis of maximum, minimum and mean temperature indicates rising trends in future over the basin.
SSRG International Journal of Civil Engineering, 2021
Severe bank erosion by river Brahmaputra along the south bank of Majuli island of northeast India... more Severe bank erosion by river Brahmaputra along the south bank of Majuli island of northeast India, the largest inhabited river island in the world, is a burning issue that needs immediate attention from the scientific community. The present study aims to analyze the bank stability of Majuli along the south bank based on the engineering properties of the bank materials. Vulnerable and stable bank locations were identified based on temporal migration of river Brahmaputra along the bank of Majuli from 1975 to 2018, and soil samples were collected from the field, which was tested to be either silt with low compressibility or silt with medium compressibility types. Considering both saturated and unsaturated conditions of the soils, three distinguished zones, stable, unstable, and at-risk, have been created to analyze the bank stability of the island. The results demonstrated that samples collected from extreme erosionprone locations fell either in unstable or at-risk zones, and samples collected from less eroded places fell in the stable zone that supports the practical utility of the study. The outcome of the study is expected to be helpful in acquiring elementary information required for riverbank management practices along the bank of Majuli island.
The Majuli Island of Assam which is regarded as the largest river island of the world is getting ... more The Majuli Island of Assam which is regarded as the largest river island of the world is getting eroded continuously due to the erosive nature of the rivers Brahmaputra on its south and Subansiri on its north. The main factor for which it has become the centre of attraction is its stream bank erosion. But, surface soil erosion should also be considered equally. It is well known that Assam is a land of heavy rainfall. So, it is obvious that rainfall plays an important role in surface soil erosion. Again, the change in land use/land cover also plays an important role in surface soil erosion, more specifically, the change in vegetation. In this study, an attempt has been made to determine the combined effect of rainfall and LULC change as well as the impact of change in vegetation alone on soil erosion. For this, the Morgan, Morgan and Finney model was used. Various input parameter to the model were derived using RS and GIS using ILWIS software and finally soil erosion was estimated sp...
Using remote sensing and GIS technique, we analyse the change detection of different land use/lan... more Using remote sensing and GIS technique, we analyse the change detection of different land use/land cover (LULC) types that has taken place in Puthimari river basin during a two-decade period from 1999 to 2019. Supervised classification method with maximum likelihood algorithm have been applied to prepare the LULC maps. The LULC change detection has been performed employing a post-classification detection method. Puthimari is a north bank sub-catchment of River Brahmaputra, the northern part of which falls in Bhutan and the rest falls in the Assam state of India. The primary LULC types of the basin are, dense vegetation which is predominant in the upper catchment, crop land and rural settlement. Thus, five different classes have been considered for the analysis, viz., dense vegetation, water bodies, silted water, cropland and rural settlement. The results showed that the rural settlement and water bodies in the basin increased by 42.70% and 30.31% from 1999 to 2019. However, dense ve...
Majuli, the largest inhabited river island bounded by the river Subansiri to the north and mighty... more Majuli, the largest inhabited river island bounded by the river Subansiri to the north and mighty Brahmaputra River to the south, is one of the subdivisions of the Jorhat district, Assam. Erosion of the island is a continuous process since historical times and posses a significant concern. The present approach have been made to study the erosion-deposition processes with the help of data resource generated from the Survey of India (SOI) toposheets and Indian Remote Sensing (IRS) satellite imagery spanning the period from 1966-1975 to 2008 in a Geographical Information System (GIS) environment. The observation has revealed a dramatic change in reduction of land area of the Majuli Island. The land area as evidenced till 1966-1975, 1998 and 2008 were 706.14, 578.38 and 484.34km respectively. The total average annual rate of erosion and deposition covering the entire period were 8.76 km/yr and 1.87 km/yr. It can clearly be attributed that the island mass suffered significant rate of ero...
Journal of Water and Climate Change
The River Subansiri, one of the largest tributaries of the Brahmaputra, makes a significant contr... more The River Subansiri, one of the largest tributaries of the Brahmaputra, makes a significant contribution towards the discharge at its confluence with the Brahmaputra. This study aims to investigate an appropriate model to predict the future flow scenario of the river Subansiri. Two models have been developed. The first model is an artificial neural network (ANN)-based rainfall-runoff model where rainfall has been considered as the input. The future rainfall of the basin is calculated using a multiple non-linear regression-based statistical downscaling technique. The proposed second model is a hybrid model developed using ANN and the Soil Conservation Service (SCS) curve number (CN) method. In this model, both rainfall and land use/land cover have been incorporated as the inputs. The ANN models were run using time series analysis and the method selected is the non-linear autoregressive model with exogenous inputs. Using Sen's slope values, the future trend of rainfall and runoff ...
Himalaya is the largest body of glaciers outside the Polar Regions. Due to the Global Warming, gl... more Himalaya is the largest body of glaciers outside the Polar Regions. Due to the Global Warming, glaciers in many parts of this region have undergone significant retreat which in turn leads to increase in discharge of the Himalayan Rivers. In this paper, an attempt has been made to study how the snow covered area of the Brahmaputra River Basin changes the discharge of the River Brahmaputra. For this, MODIS image MOD09A1.5 (MODIS/Terra Surface Reflectance 8-Day L3 Global 500m SIN Grid) of 500m resolution consisting of seven bands has been taken to prepare the Normalized Difference Snow Index Maps. The NDSI map is then used to obtain the areal extent of snow in the Himalayan region. The NDSI maps are prepared starting from 2002 to 2012 at three months interval, i.e. January, April, July and October. To study its effect on discharge, discharge data of the Pandu Gauge Site for the Brahmaputra River has been taken starting from 2002 to 2012.
Due to the climate change, glaciers in many parts of the Himalaya have undergone significant retr... more Due to the climate change, glaciers in many parts of the Himalaya have undergone significant retreat which in turn leads to increase in discharge of the Himalayan Rivers. River Brahmaputra is originated from the Himalayas and some parts of the River Basin are covered by snow and glaciers. In this paper, an attempt has been made to study how the snow cover area of the Brahmaputra River Basin changes with respect to the change in temperature. For this, MODIS image MOD09A1.5 (MODIS/Terra Surface Reflectance 8-Day L3 Global 500m SIN Grid) of 500m resolution consisting of seven bands has been taken to prepare the Normalized Difference Snow Index Maps of the study area. The NDSI map is then used to obtain the areal extent of snow in the Brahmaputra River Basin. The NDSI maps are prepared starting from 2002 to 2012 for three different months, i.e. January, April and October. For, temperature data, HadCM3 data of spatial resolution 2.5˚ X 3.75˚ (latitude by longitude) has been used. From th...
Environmental Systems Research, 2015
Background: The discharge of the River Brahmaputra is highly affected by the melting of snow at t... more Background: The discharge of the River Brahmaputra is highly affected by the melting of snow at the upper part of its catchment. Increase in discharge due to significant retreat of snow in turn affects the downstream flow characteristics of the river giving rise to severe catastrophic problems such as flood and erosion. Rising temperature is one of the major reasons of melting of snow at the upper Brahmaputra catchment. Keeping in mind such issue, in this paper, a study has been conducted to see how the snow cover area of the Brahmaputra river basin changes with respect to the change in temperature. MODIS image MOD09A1.5 (MODIS/Terra Surface Reflectance 8-Day L3 Global 500 m SIN Grid) of 500 m resolution consisting of seven bands has been taken to prepare the normalized difference snow index maps of the study area. The normalized difference snow index map is then used to obtain the areal extent of snow in the Brahmaputra catchment area. The normalized difference snow index maps were prepared starting from 2002 to 2012 for four different months, viz. January, April, July and October. For temperature data, HadCM3 data of spatial resolution 2.5° × 3.75° (latitude by longitude) has been used. Results: The evaluation of the results shows that the snow cover area of the basin shows decreasing trends with respect to the increasing trend of temperature except for the month of January. Further, this study also shows that MODIS data can efficiently be used for snow cover area variation study. Conclusions: Variation of snow cover area is an indication of climate change as the melting of snow clearly reflects the rise in temperature. The attenuation of river flow due to the melting of snow in the river Brahmaputra basin may affect the downstream discharge of the river giving rise to severe flood and erosion problem. It has also been observed that MODIS data can efficiently be used in mapping snow cover of large areas, because of its good spatial as well as high temporal resolution.
International Journal of Scientific Research in Science, Engineering and Technology
Mountainous watersheds are constantly under pressure of huge amount of soil loss due to soil eros... more Mountainous watersheds are constantly under pressure of huge amount of soil loss due to soil erosion. Pare watershed is situated in the eastern Himalayan ranges of Arunachal Pradesh, India, which is subjected to such soil losses and its sub-watersheds are being degraded in many places. Watershed management programs are required in the area in which prioritization of sub-watersheds is one of the first steps. A study has been carried out to address this issue in the area to prioritize 26 sub-watersheds of Pare through morphometric analysis. The study used digital elevation model (DEM) to determine several morphometric parameters of the watershed. The analysis revealed that Pare river is of the 7th order comprising of 6127 stream segments running over the watersheds for about 2448 km. Based on the results obtained, the study area is an elongated well dissected watersheds with high relief and great presence of streams all over the watershed indicating faster runoff peak attainment which...
Covering a total length of 520 km and a drainage area of approximately 34,000 sq. km. up to the c... more Covering a total length of 520 km and a drainage area of approximately 34,000 sq. km. up to the confluence of the River Brahmaputra, the river Subansiri is considered as the largest tributary of Brahmaputra. Recently a series of hydro-power dams have been planned on this tributaries of River Brahmaputra. One of the project is already under construction. Considering the construction of these important projects, it is necessary to evaluate the possible impact of climate change on the flow scenario of the river. Rainfall plays an important role in variation of discharge. In this study, an attempt has been made to downscale the rainfall at Subansiri river basin using multiple linear, non-linear regression based statistical downscaling method and Artificial Neural Network model. APHRODITE gridded rainfall data available at 0.25˚ x 0.25˚ resolutions from 1960 to 2007 at 24 different points have been used as the predictand and climatic parameters of HadCM3 GCM of resolution 2.5˚ x 3.75˚ (l...
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Papers by Swapnali Barman