A GIS based study on bank erosion by the river Brahmaputra around Kaziranga National Park, Assam, India

Abstract

The Kaziranga National Park is a forest-edged riverine grassland inhabited by the world's largest population of one-horned rhinoceroses, as well as a wide diversity of animals. The park is situated on the southern bank of the Brahmaputra River at the foot of the Mikir Hills. National Highway 37 forms the southern boundary and the northern boundary is the river Brahmaputra and covers an area of about 430 km<sup>2</sup>. The Brahmaputra River flows by Kaziranga National Park in a braided course for about 53 km. Sequential changes in the position of banklines of the river due to consistent bank erosion have been studied from Survey of India topographic maps of 1912–1916 and 1972, satellite IRS LISS III images from 1998 to 2008 using GIS. Study of bank line shift due to the bank erosion around Kaziranga has been carried out for the periods 1912–1916 to 1972, 1972 to 1998 and 1998 to 2008. The amounts of the bank area lost due to erosion and gained due to sediment deposition are estimated separately. The total area eroded during 1912–1916 to 1972 was more (84.87 km<sup>2</sup>) as compared to accretion due to sediment deposition (24.49 km<sup>2</sup>), the total area eroded was also more in 1972–1998 (44.769 km<sup>2</sup>) as compared to accretion (29.47 km<sup>2</sup>) and the total area eroded was again more in 1998–2008 (20.41 km<sup>2</sup>) as compared to accretion (7.89 km<sup>2</sup>). The rates of erosion during 1912–1916 to 1970, 1970 to 1998, and 1998 to 2008 were 1.46, 1.59 and 1.021 km<sup>2</sup> per year, respectively. During the entire period (1912–1916 to 2008) of study the erosion on the whole was 150.04 km<sup>2</sup> and overall accretion was 61.86 km<sup>2</sup> resulting in a loss of 88.188 km<sup>2</sup> area of the park. The maximum amounts of shift of the bankline during 1912–1916 to 1970, 1970 to 1998, and 1998 to 2008 were 4.58 km, 3.36 km, and 1.92 km, respectively, which amount to the rates of shift as 0.078, 0.12 and 0.096 km per year, respectively. A lineament and a few faults have controlled the trend of the course of the Brahmaputra around Kaziranga area. The main cause of erosion of the Brahmaputra is the loose non-cohesive sediments of the bank throughout the park. The braided channel of the river strikes the bank directly and undermines the silty bank causing overhanging blocks to be carried away easily by the river current. In future deposition is likely to be more in upstream or eastern part of Kaziranga and erosion in middle part of Kaziranga national park area due to the river Brahmaputra. Antierosion measures have been adopted only in a few places to check bank erosion at Kaziranga

Riverbank Erosion and Channel Width Adjustments across a Meandering Channel of North Bengal, India

“…In a previous study of the Diana river, the authors have found almost similar processes of bank erosion at its lower courses (Chakraborty and Mukhopadhyay, 2014). At a regional scale the observed bank erosion processes are more or less similar to the processes of bank failure documented along the Brahmaputra river (Kotoky et al, 2005;Dutta et al, 2010;Sarma and Acharjee, 2012) and Ganga river (Thakur et al, 2012); while at broad global scales this resembles although to a little extent to the processes operating along the Devonian streams (Hooke, 1979), the Swale-Ouse river system (Lawler et al, 1999), and the Nile river (Ahmed and Fawzi, 2011) etc. More or less similar effects of riparian vegetation on bank erosion of the Duduya river makes us capable of connecting it to the Central Sacramento River of California (Micheli et al, 2004) and to the Daintree and other tropical rivers of Queensland, Australia (Bartley et al, 2008).…”

Exploring the Drivers of Vulnerability Among Disadvantaged Internal Migrants in Riverbank Erosion Prone Areas in North-West Bangladesh

“…The Asian picture of riverbank erosion and displacement is particularly bad due to these countries' higher population density. Historically, riverbank erosion in the lower Mekong basins (see Miyazawa et al, 2008), the Yellow River (Huang He) erosion in China (see Ma et al, 2012), the Irrawaddy and Chindwin rivers in central Myanmar and the River Ganges and Brahmaputra in India caused massive landscape degradation displacing millions of people (Sarma & Acharjee, 2012;Mili et al, 2013).…”

Land cover dynamics and their driving factors in a protected floodplain ecosystem

“…The BR is well known for its dynamic hydro-geomorphic characteristics (Coleman, 1969;Kotoky et al, 2005;Sarma & Acharjee, 2012;Sarma & Phukan, 2006). Owing to its braidedness and instability accompanied by huge sediment transport, the multi-channels of the BR push its bankline laterally instigating bank erosion (Coleman, 1969).…”