Integrated impacts of land use changes and climate dynamics on hydrological components in the Munneru River basin, India

Effective water management and adaptation plans depend on understanding how changing Land Use and Land Cover (LU&LC) and Climate Change (CC) will affect future spatiotemporal water availability in a river basin. However, a major challenge in hydrological modelling is accurately integrating both LU&LC and climate projections to address uncertainties in future water availability. This study evaluates how LU&LC and climate change together affect hydrology of the basin for future climate change scenarios. The future LU&LCs are projected using the Dyna-CLUE model for three user-defined scenarios such as past trend, drastic change in built-up and barren land, and restricted agricultural land. CMIP6 climate data was used under three scenarios SSP245, SSP370 and SSP585 which was then ensemble using the Reliable Ensemble Averaging (REA) method at each grid for both precipitation and temperature. The SUFI2 algorithm in SWAT-CUP tool is used to calibrate and validate the SWAT model for the years 1983-2017. The average monthly streamflow is projected for both LU&LC and SSP climate change scenarios during the baseline period (1983-2014), as well as for three future periods.: the nearfuture (2025-2040), mid-future (2041-2070) and far-future (2071-2100). Streamflow, total aquifer recharge and evapotranspiration increase in the three selected future periods when compared to baseline period in all three SSP scenarios. When combining both LU&LC and climate change scenarios, the LU&LC scenario 2 exhibits more change in streamflow, surface runoff, total aquifer recharge compared to the climate change scenario alone. In the near-future the streamflow was increased the most in the months of July by 56.13 % for climate change scenario SSP370 with LU&LC scenario 2 in the near-future period compared to the baseline period. Similarly, in the mid-future, the maximum increase was observed in June by 67.52 % for the combined impact of SSP585 and LU&LC scenario 2. In the far-future period, the maximum increase is in the month of July by 133.4 % for the combined impact of SSP585 and LU&LC2. Increasing precipitation under future climate scenarios is expected to significantly enhance streamflows, particularly from August to November, with October consistently experiencing peak flows, highlighting the need for improved flood management strategies in response to intensifying hydrological extremes. This study addresses key methodological challenges by integrating dynamic LU&LC projections, ensemble climate model data processing, and advanced calibration techniques to improve hydrological predictions. In light of projected LU&LC under climate change scenarios, the findings can be used to plan and develop short-term and long-term integrated water management strategies for the basin. Other basins in comparable physiographic regions all over the globe can use this methodology.