Spatiotemporal land use and land cover change and future projection in the Suti River Basin, India

Large-scale changes in land-use and land-cover (LULC) have been driven by rapid population growth and urbanisation in the lower Gangetic delta. For non-perennial river systems, this has had serious repercussions. In the Suti River Basin of West Bengal, a heavily silted and ecologically delicate distributary of the Bidyadhari system, the current study examines LULC dynamics during 30 years (1990–2020). The work estimates spatial transformations across six major LULC categories using multi-temporal Landsat imagery, Support Vector Machine (SVM) based classification, and post-classification change detection. According to the analysis, between 2000 and 2010, fallow land decreased drastically (from 52.04 to 11.48%), agricultural land and Homestead Vegetation steadily increased, and urban settlement accelerated. The highest urbanisation phase has been recognised during this time by the Urban Expansion Intensity Index (UEII) and Land Use Dynamic Degree (K%). Extensive landscape transformation is revealed by reach-wise evaluation, especially in Reaches 1 and 2, where agricultural and urban settlement areas continuously border the horizon, growing at the expense of aquaculture and fallow land. In 2030, the LULC scenarios were predicted using a Markov Chain model, which was verified using chi-square and Kappa statistics (κ = 0.861). Overall, the study illustrates a rapidly changing, transitory state in the river basin, where the riparian system as a whole is shifting toward heavily utilised landscapes. The results also indicate chronic river degradation due to siltation, encroachment, and hydrological obstruction, alongside ongoing urban expansion and agricultural intensification. The current state of affairs underscores the need for integrated basin management, ecological restoration, and sustainable land-use planning to protect the socio-ecological functions of the Suti River.