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Assessment of Geomorphic Evolutionary Pathways and Hydrological Connectivity of Kaabar Tal (Wetland) Using Multi-Source Remotely Sensed Datasets
  • Manudeo Singh,
  • Rajiv Sinha
Manudeo Singh
Indian Institute of Technology Kanpur

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Rajiv Sinha
Indian Institute of Technology Kanpur
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Abstract

The alluvial wetlands are one of the most important ecosystems of the world and are in abundance in the vast Indo-Gangetic plains. The wetlands of this region are of variable sizes and characteristics but currently face similar problems of drying-out and fragmentation. It is empirical to understand the evolutionary pathways and hydrological connectivity of these wetlands for planning and execution of management and restoration for them. These pathways have been studied for a wetland namely, the Kaabar Tal, situated in the Kosi-Gandak interfan region of the eastern Gangetic plains. Its geomorphic evolutionary pathways have been established using satellite imageries, DEMs, toposheets, and high resolution aerial imagery obtained using unmanned aerial vehicle (UAV). Various geomorphic units characterized by an assemblage of geomorphic features have been mapped for the Kaabar Tal and its surroundings. Seasonal, annual, and decadal variability in the hydrological status of this wetland were estimated for a time-period of 1976-2017 using the historical Landsat datasets. Seasonal variability in hydrological connectivity structure of the wetland with its catchment for the time-period of 1989 to 2017 was estimated in a GIS framework. The structural connectivity was estimated using the technique of diffusion kernel interpolation. The dynamic connectivity was estimated using the Getis-Ord Gi* statistic and Mann-Kendall trend test using the concepts of space-time cubes. The detailed geomorphic mapping revealed that this wetland primarily originated through fluvial processes. A historical reconstruction of its hydrological status revealed that in the recent times the wetland is getting fragmented, and the connectivity potential of different areas of the catchment is a function of the prevalent land-use and land-cover (LULC) pattern and seasonality. Therefore, the heterogeneity and complexity of the geomorphic units of the wetland and the historical LULC patterns of the catchment should be considered in designing any management and restoration plan.