Assessment of land use change in riverine ecosystem and utilizing it for socioeconomic benefit

Increasing urbanization has led to diminished agricultural mainland for food production worldwide. Riverine sandbars could be viewed as prospective landmasses which could act as additional agricultural lands. The present study emphasizes sandbar area availability and the scope of utilizing these landmasses through geospatial techniques, modelling studies and questionnaire surveys. Satellite images were derived at decadal scales to determine the change in the land-use land cover (LULC) within the Brahmaputra River in Assam, India. The fluctuations in the landmasses under different streamflow conditions were derived using a hydrodynamic model. The results showed that the percentage of vegetated sandbars has increased from ~27.36% in 1976-1980 to ~44.67% in 2016-2017, and consecutively, the percentage of non-vegetated sandbars has decreased from ~51.18 to ~30.93%. Furthermore, it was found that the area under cropland and vegetated sandbar varied seasonally. To further understand the utilization of these resources, a socioeconomic survey with a structured set of questions was conducted at various sandbars. The survey revealed various aspects of economic benefits, practices of sandbar cultivation, beneficial produce, difficulties faced, and willingness among farmers to expand sandbar cultivation. Coupling the prevailing traditional knowledge of cultivation among the farmers with scientifically derived information obtained from satellite data and mathematical model simulations can lead to a more systematic utilization of the ecosystem. Thus, the study shows the immense potential of utilizing the sandbars of large rivers to sustain food demands, alongside developing links between land-use change, ecosystem behavior, and socio-economic development.