| Summary: | The flux of total suspended matter (TSM), <i>F</i><sub>TSM</sub>, output by several large rivers in Asia, has been in decline due to human activities. As the estuary of the Ganges–Brahmaputra River, the Padma River transports a significant amount of suspended matter (SM) to the Bay of Bengal each year. In this study, the TSM concentration (<i>C</i><sub>TSM</sub>) and <i>F</i><sub>TSM</sub> in the Padma River in the period 1991–2019 were calculated based on the data acquired by the Landsat series satellites and an empirical TSM algorithm model for large, high-turbidity rivers. The results showed that the maximum and minimum <i>F</i><sub>TSM</sub> values (318 ± 62 and 73 ± 29 mt, respectively) in the Padma River occurred in 2011 and 2015, respectively. On average, <i>F</i><sub>TSM</sub> in the Padma River decreased at an annual rate of 3.3 mt (<i>p</i> < 0.01). The impact of human activities on <i>C</i><sub>TSM</sub> contributed more significantly to the changes in <i>F</i><sub>TSM</sub> (<i>R</i> = 0.76) than natural factors (<i>R</i> = 0.44). Due to a lack of water conservancy facilities within the river basin, changes in the water and soil retention capacity due to the changes in vegetation coverage were an important human factor (<i>R</i> = −0.79).
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