Geospatial modeling to assess the past and future land use‑land cover changes in the Brahmaputra Valley, NE India, for sustainable land resource management

Environmental Science and Pollution Research 所収
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Satellite remote sensing and geographic information system (GIS) have revolutionalized the mapping, quantifying, and
assessing the land surface processes, particularly analyzing the past and future land use-land cover (LULC) change patterns.
Worldwide river basins have observed enormous changes in the land system dynamics as a result of anthropogenic
factors such as population, urbanization, development, and agriculture. As is the scenario of various other river basins, the
Brahmaputra basin, which falls in China, Bhutan, India, and Bangladesh, is also witnessing the same environmental issues.
The present study has been conducted on the Brahmaputra Valley in Assam, India (a sub-basin of the larger Brahmaputra
basin) and assessed its LULC changes using a maximum likelihood classification algorithm. The study also simulated the
changing LULC pattern for the years 2030, 2040, and 2050 using the GIS-based cellular automata Markov model (CAMarkov)
to understand the implications of the ongoing trends in the LULC change for future land system dynamics. The
current rate of change of the LULC in the region was assessed using the 48 years of earth observation satellite data from
1973 to 2021. It was observed that from 1973 to 2021, the area under vegetation cover and water body decreased by 19.48
and 47.13%, respectively. In contrast, cultivated land, barren land, and built-up area increased by 7.60, 20.28, and 384.99%,
respectively. It was found that the area covered by vegetation and water body has largely been transitioned to cultivated
land and built-up classes. The research predicted that, by the end of 2050, the area covered by vegetation, cultivated land,
and water would remain at 39.75, 32.31, and 4.91%, respectively, while the area covered by built-up areas will increase by
up to 18.09%. Using the kappa index (ki) as an accuracy indicator of the simulated future LULCs, the predicted LULC of
2021 was validated against the observed LULC of 2021, and the very high ki observed validated the generated simulation
LULC products. The research concludes that significant LULC changes are taking place in the study area with a decrease
in vegetation cover and water body and an increase of area under built-up. Such trends will continue in the future and shall
have disastrous environmental consequences unless necessary land resource management strategies are not implemented.
The main factors responsible for the changing dynamics of LULC in the study area are urbanization, population growth,
climate change, river bank erosion and sedimentation, and intensive agriculture. This study is aimed at providing the policy
and decision-makers of the region with the necessary what-if scenarios for better decision-making. It shall also be useful in
other countries of the Brahmaputra basin for transboundary integrated river basin management of the whole region.

Suraj Kumar