International Journal of Engineering Technology Science and Research IJETSR www.ijetsr.com ISSN 2394 – 3386 Volume 4, Issue 10 October 2017

A Study on Land Use Land Cover Mapping of Subansiri River in

Mukul Kalita 1, Utpal Kumar Nath 2, Animesh Bhuyan3, Kasturi Bora4 1 Assistant Professor, Department of Civil Engineering, Assam Don Bosco University, Guwahati 2 Associate Professor, Department of Civil Engineering, Assam Engineering College, Guwahati 3 Post Graduate Student, Department of Civil Engineering, Assam Don Bosco University, Guwahati 4 Post Graduate Student, Department of Civil Engineering, Assam Don Bosco University, Guwahati

ABSTRACT This study documents the land-use changes driven by river dynamics along Subansiri River in Assam. Planform changes for a period of 16 years are documented using topographical map and Landsat data, and the associated land-use change is assessed by utilizing hybrid classification in GIS environment. Land-use change shows that there is an increase in settlement and agriculture and a decrease in the grassland. The area affected by erosion–deposition and river migration comprises primarily of the agricultural land. Effect of river dynamics on settlements is also evident. Loss of agricultural land and homestead led to the loss of livelihood and internal migration in the floodplains. The observed pattern of river dynamics and the consequent land-use change in the recent decades have thrown newer environmental challenges. Keywords Land-use, Subansiri, GIS, erosion, floodplains

1. INTRODUCTION Subansiri River, better known as the "Gold River" is a large of the in . It flows through Assam, Arunachal Pradesh and the of China. The length of the Subansiri River is 442 kilometres and the area of the drainage basin of Subansiri River is 32,640 square kilometres. The largest tributary of the Brahmaputra River i.e. the Subansiri River has observed a discharge of 18,799 cubic metres per seconds of water. It contributes 7.92% of the Brahmaputra's total flow. Originated from the Himalaya Mountains, it flows towards the East and the South East portion of the state and then flows to the Assam Valley. Finally, it joins to the Brahmaputra River in of Assam. Near the Subansiri River, there are dense hilly population forming the different districts in Arunachal Pradesh. The construction of Subansiri Lower Hydroelectric Project (SLHEP) began in the year 2007. It was originally conceptualized as a flood control project, but eventually it turned out to be a power project.A 135 meter high hydroelectric dam is constructed to provide the hydroelectric power supply in the adjoining villages and also for Tibet and Bhutan. This river is specially known as the "future powerhouse". According to a 2001 study of the Central Electricity Authority (CEA) of , there are 168 hydro projects and a potential of 63.328 MW have been identified in the Brahmaputra river basin. This includes 22 projects having potential of 15,191 Megawatt in the Subansiri River. The 200 Megawatt Lower Subansiri hydel power project had been proposed to come up at Gerukamukh on the Assam - Arunachal Pradesh border. It was the first large hydroelectric power project being taken up in the Subansiri River basin. The objective of this study is to investigate the change of Land Use Land Cover of Subansiri River over 16 years through change detection analysis to realise the population pressure on a specific area that reflects not only the human interventions on the land area but also on other resources like forest canopy, wetlands and other water bodies and biodiversity. Land Use Land Cover analysis is done in different levels using software like Google earth, ArcGIS etc. Satellite based remote sensing data are used to extract different thematic layers

854 Mukul Kalita, Utpal Kumar Nath, Animesh Bhuyan, Kasturi Bora International Journal of Engineering Technology Science and Research IJETSR www.ijetsr.com ISSN 2394 – 3386 Volume 4, Issue 10 October 2017 to interpret the specific area. Another objective is to analyse the LULC pattern and visualize the population pressure on the land and their related activities that bring about changes to that specific landscape.

2. METHODOLOGY This work adopts the regularly used approach of Remote Sensing and GIS techniques to understand the different geological features that has changed in the recent years for the definite area of interest.The coordinates of the area i.e. 27° 43' 50.0376'' N and 94° 19' 46.4124'' E are obtained with the help of GPS device and are imported via Garmin software to Google earth in order to create the digitization platform.A buffer of 2.5 kilometres is produced from the centre point of the area of interest. Digitization of different features was done and was saved in ‘.kml’ format.The ‘.kml’ files were converted to ‘.shp’ files in ArcGIS. Different polylines marked were converted to polygon features. With the help of data management tool the projection and attribute table was done. Description of the different land use and land cover area was identified carefully. The change in area for the subsequent years has been calculated with the help of MS Excel. Pie charts and tabular data were created to facilitate the understanding of LULC pattern of the SubansiriRiver along with lower Subansiri dam. Finally the map of LULC change pattern was finalized with ArcGIS.

Fig. 1: Step by step procedure for change detection analysis carried out with ArcGIS

855 Mukul Kalita, Utpal Kumar Nath, Animesh Bhuyan, Kasturi Bora International Journal of Engineering Technology Science and Research IJETSR www.ijetsr.com ISSN 2394 – 3386 Volume 4, Issue 10 October 2017

3. RESULTS AND INTERPRETATION Table 1. Calculation of Land Use Land Cover Classes for year 2000 Sl. No. Classes Area in sq. km Percentage (%)

1 Built-up Area 0.01 0.05

2 Degraded 0.09 0.46 3 Forest 17.36 90.91 4 Grassland 0.39 1.99 5 River 0.85 4.33 6 River Canal 0.01 0.05 7 River Sand 0.4 2.04 8 Shadow 0.02 0.10 9 Tree Patch 0.0005 0.03 10 Wasteland 0.01 0.05 Total 19.645 100

Fig. 2: LULC Map of Subansiri for year 2000

856 Mukul Kalita, Utpal Kumar Nath, Animesh Bhuyan, Kasturi Bora International Journal of Engineering Technology Science and Research IJETSR www.ijetsr.com ISSN 2394 – 3386 Volume 4, Issue 10 October 2017

Percentage Area of LULC

Built-up Area Degraded Forest Grassland River River Canal River Sand Shadow Tree Patch Wasteland

Fig. 3: Pie Chart for LULC Classes for year 2000 In the year 2000, the percentage of area covered by forest was considerably larger as compared to built-up area or degraded area. No construction area was developed during that time. Table 2. Calculation of Land Use Land Cover Classes for year 2016

Sl. No. Classes Area in sq. km Percentage (%)

1 Built-up Area 0.42 2.14

2 Construction Area 0.03 0.15 3 Degraded 0.13 0.66 4 Disturbed Forest 0.02 0.10 5 Forest 17.56 89.4 6 Grassland 0.18 0.92 7 Open Field 0.01 0.05 8 Open Forest 0.01 0.05 9 River 0.91 4.63 10 River Canal 0.06 0.31 11 River Sand 0.22 1.12 12 Sand 0.02 0.10 13 Tree Patch 0.03 0.15 14 Waste Land 0.03 0.15 15 Wetland 0.01 0.05 16 Wet Sand 0.002 0.01 Total 19.642 100

857 Mukul Kalita, Utpal Kumar Nath, Animesh Bhuyan, Kasturi Bora International Journal of Engineering Technology Science and Research IJETSR www.ijetsr.com ISSN 2394 – 3386 Volume 4, Issue 10 October 2017

Fig. 4: LULC Map of Subansiri for year 2016 Percentage Area of LULC Built-up Area Construction Area Degraded Disturbed Forest Forest Grassland Open Field Open Forest River River Canal River Sand Sand Tree Patch Waste Land Wetland Wet Sand

Fig. 5: Pie Chart for LULC classes for year 2016

858 Mukul Kalita, Utpal Kumar Nath, Animesh Bhuyan, Kasturi Bora International Journal of Engineering Technology Science and Research IJETSR www.ijetsr.com ISSN 2394 – 3386 Volume 4, Issue 10 October 2017

4. CONCLUSION The total area of the study site in the year 2000 and 2016 is slightly different from each other, i.e., 0.003 square kilometers which is negligible. The built-up area has increased by 1.99% in 16 years whereas the forest area has decreased by 1.51%. During this period grassland has decreased by 1.07%. Moreover, it can be seen that there was no construction area in the year 2000 but in the year 2016, 0.15% construction area was found in the study site. Roads were also very limited in 2000.From the change detection study it can be concluded that the Subansiri Lower Hydroelectric Project (SLHEP) is causing soil erosion in the area considered. As a result of degradation of forest, settlement area has increased significantly during this period. The study reveals that the increase in sand accumulation over these yearsis causing severe damage to the area where it has been constructed.

REFERENCES [1] Congalton, R. G., A review of assessing the accuracy of classifications of remotely sensed data, 1991 [2] Goswami, U., Sarma, J.N., Patgiri, A. D., River channel changes of the Subansiri in Assam, India, 1999 [3] Bocco, G., Mendoza, M., Velazquez, A., Remote sensing and GIS-based regional geomorphological mapping - A tool for land use planning in developing countries, 2001 [4] Coppin, P., Jonckheere, I., Nackaerts, K., Muys, B., Lambin, E.,Digital change detection methods in ecosystem monitoring: A review, 2004 [5] Boori, M. S., Vozenilek, V., Choudhary, K.,Land use/cover disturbance due to tourism in Jeseniky Mountain, Czech Republic: A remote sensing and GIS based approach, 2015

859 Mukul Kalita, Utpal Kumar Nath, Animesh Bhuyan, Kasturi Bora