Riverine habitats are degrading at an alarming rate due to anthropogenic interventions. Construction of large dams and barrages on the Ganga River has severely fragmented the riverine habitat of dolphins. This study examines the impact of structural barriers on the habitat of the Ganga River dolphin (Platanista gangetica) in a reach between Bijnor and Narora barrage in the middle Ganga and at the Farakka barrage in the lower Ganga Plain. We use time‐series remote sensing images and flow discharge data to assess the morphological and ecological impact in the proximity of these barrages. Our result suggests that after the construction of Bijnor barrage in 1985, the total bar area of the Ganga River has reduced from 150 to 45 km², but the channel width has remained unchanged during the period between 1980 and 2010. A time‐series analysis of the discharge shows a slightly declining trend after the year 1982. However, this observed trend is not adequate to explain the habitat degradation of the Ganga River dolphins. Further width of the Ganga River in the downstream of the Farakka barrage has reduced from 4 to 1 km, and the total bar area has increased from about 5 to 35 km² during the period between 1965 and 1980. Also during this period, the pre‐monsoon discharge of the Ganga River has reduced by one‐third in the downstream of Farakka barrage. This study concludes that the loss of dolphins in the downstream reaches of the Farakka barrage could be associated with the change in hydraulic geometry, flow characteristics, and loss of longitudinal and lateral connectivity. Conversely, the impoundments of water upstream of the Narora barrage have maintained the suitable habitat conditions for the dolphins to thrive. This has resulted in a reported growth in the dolphin population during the years 1993–2010.

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评估大型拦河坝对恒河海豚栖息地的影响

由于人为干预，河流生境的退化速度惊人。在恒河上建造大型水坝和拦河坝已经严重破坏了海豚在河边的栖息地。这项研究研究了结构性障碍对恒河中部比耶诺和纳罗拉堰塞之间以及恒河平原下游的法拉卡堰的影响范围内恒河海豚（Platanista gangetica）栖息地的影响。我们使用时间序列遥感图像和流量排放数据来评估这些拦河坝附近的形态和生态影响。我们的结果表明，在1985年建造Bijnor拦河坝之后，恒河的总坝面积从150 km减少到45 km ²，但通道宽度在1980年至2010年期间保持不变。对排放进行时间序列分析后，在1982年之后显示出稍微下降的趋势。但是，这种观察到的趋势不足以解释恒河的栖息地退化。河豚。在法拉卡（Farakka）拦河坝下游，恒河的宽度从4 km减小到1 km，而总条形面积从5 km增大到35 km ²在1965年至1980年期间。在此期间，法拉卡卡（Farakka）拦河坝的下游季风前流量也减少了三分之一。这项研究得出的结论是，法拉卡（Farakka）拦河坝下游河豚的流失可能与水力几何形状，流量特性的变化以及纵向和横向连通性的丧失有关。相反，纳罗拉（Narora）拦河坝上游的水库保持了海豚壮成长的适当栖息地条件。据报告，在1993年至2010年期间，海豚数量有所增长。