Control of sandbar development on morphological evolution & channel dynamics of the Mahanadi Delta

The Mahanadi Delta, an arcuate delta along the Bay of Bengal, has experienced notable morphological transformations over the past three decades due to the interplay of fluvial, tidal, and wave-driven processes. This study employs remote sensing and GIS techniques to analyze morphometric parameters from 1990 to 2020. Results reveal a 34.4% reduction in active water channel area, alongside a 15.1% increase in sandbar extent, indicating significant sediment deposition and channel infilling processes. This reciprocal relationship suggests that sediment deposit is actively reshaping the channel morphology, contributing to the stabilization of certain reaches while promoting the formation of mid-channel and point bars. Riverbank migration analysis shows that the left bank is more vulnerable, with an average lateral shift of 2.40 m/year, compared to a relatively stable right bank. The longitudinal profiles and planner morphology indicate a gradual transition from highly meandering to more stable, sinuous channel patterns, influenced by sediment dynamics. The study recorded a total of 89 sandbars in 2020, compared to 65 in 1990. Sandbar stabilization has direct ecological implications, notably affecting bird nesting habitats, aquatic biodiversity, and overall floodplain health. These findings underscore the importance of integrating sediment management and ecological conservation into sustainable river management strategies.