Analyzing Area Dynamics on a Protected Floodplain Using Long-Term Sequential Data: The Case of Kaziranga National Park

Abstract

The present work targets a serious information gap created by extant fragmental and intermittent data on river bank erosion and accretion dynamics. Hence, a sequential three-decade profiling of erosion and accretion activities within the Kaziranga National Park—a protected area in the flood plain of the Brahmaputra, was undertaken. Thirty consecutive Landsat images from 1987 to 2016 were analyzed in GIS environment, to evaluate long-term sequential data and derive a baseline reference. Overlay analysis was carried out to estimate the magnitudes and intensities of erosion and accretion in spatiotemporal scale. The resultant mean rates of erosion and accretion have been estimated to be 184.2 ha/year and 93.9 ha/year, respectively. Consequently, the resultant net reduction in the park land area was 2617.7 ha, which projected a mean net rate of 90.3 ha/year. Erosion was therefore annually recurrent and dominant over accretion. The resultant area dynamics, from the assessment of the spatiotemporal scale, provided a reliable, continuous data resource that overcomes the information lacunae from available fragmented studies. In addition, assessment with sequential data displayed a more accurate reflection of actual topography as compared to intermittent data results, which in turn can validate and enrich data resources, on the area dynamics of the Brahmaputra floodplain. Finally, defining a reference perspective derived from long-term sequential data that endorses the twin episodes of erosion and accretion will be vital for floodplain management.