Long-term geomorphic evolution of rivers depends both on the amount of sediment supply and on the river’s ability to transport that sediment. Climate change is anticipated to change flow frequency distributions and sediment yield and could thus alter the geomorphic trajectory of many regulated rivers. We aim to examine the possible geomorphic response of the upper Godavari River, India, to climate change using two well-accepted metrics: the frequency of the sediment-transporting flows (T*) and the ratio of the sediment flux below and above a dam (S*). Soil and Water Assessment Tool (SWAT) was used to simulate streamflow and sediment yield in the basin. We calibrated and validated the model using SWAT-CUP for pre- (1971–75) and post-dam (1976–81) conditions downstream of Jayakwadi dam. The model performance was good (NS value > 0.6 for discharge and PBIAS < ± 10 for sediment) with low uncertainty (p-factor > 0.6 and r-factor <1) and it improved significantly by factoring the operation of the reservoirs into the simulation. We ran the model for 10 years consecutively in the pre and post-dam states for baseline (1971–81) and future (2090–99) climate conditions derived from NEX-GDDP climate projections (Emission scenario RCP 8.5 & 4.5). A linear relationship between T*/S* and observed erosion (m) below the dam provided the basis for estimating the amount of erosion associated with future climate states. Our simulations show substantially larger T* below the dam site in 40% of the 2090s scenarios relative to the baseline conditions. These could be associated with 4–6 times the erosion compared to the baseline. Severe erosion is indicated only under RCP 8.5. Simulations suggest that amplified peak releases from dams in the future could lead to greater downstream erosion potential.

河流的长期地貌演化既取决于沉积物的供应量，也取决于河流输送沉积物的能力。预计气候变化将改变流量频率分布和沉积物产量，从而可能改变许多受管制河流的地貌轨迹。我们旨在使用两个公认的指标来检验印度戈达瓦里河上游对气候变化的可能的地貌响应：泥沙输送流量的频率（T *）和大坝上下的泥沙通量比（S *）。土壤和水评估工具（SWAT）用于模拟流域内的水流和沉积物产量。我们使用Jayakwadi大坝下游（1971-75年）和大坝后（1976-81年）的条件，使用SWAT-CUP对该模型进行了校准和验证。模型性能良好（NS值> 0。不确定性较低（p因子> 0.6和r因子<1）的流量为6，而沉淀物的PBIAS <±10），并且通过将储层的运行纳入仿真范围，显着改善了排放。我们在大坝之前和之后的州连续10年运行该模型，以作为从NEX-GDDP气候预测（排放情景RCP 8.5和4.5）得出的基准（1971-81）和未来（2090-99）气候条件。T * / S *与坝下观测到的侵蚀量（m）之间的线性关系为估算与未来气候状态相关的侵蚀量提供了基础。我们的模拟显示，相对于基准条件，在2090年代情景中40％的情况下，坝址下方的T *大得多。与基线相比，这些侵蚀可能是侵蚀的4到6倍。仅在RCP 8.5下指示严重腐蚀。