Climate Change Impact on Water Resources of Tank Cascade Systems in the Godavari Sub-Basin, India

The availability of water at the regional and river basin scales in the future will be significantly impacted by climate change. Effective water management in the sub-basin is essential for ensuring long-term sustainability in the face of changing climatic conditions. The Maner River basin is a significant contributor to the Godavari River, and agriculture serves as the primary source of income for the majority of individuals residing in the subbasin. Nearly 50–65% of irrigational fields in the Maner basin are cultivated using local Tank Cascade Systems (TCS) and reservoirs that are managed by monsoon precipitation. The regional level climate change impact on the water resources of these tank cascade systems is important for sustainable management of water resources. In this study, The NEX-GDDP RCM models of CCSM4, MPI-ESM-LR and MIROC-ESM-CHEM were utilized to examine climate patterns during historical and future periods under RCP 4.5 and RCP 8.5 scenarios. The Maner sub-basin and KTCS (Katakshapur Tank Cascade System) were modeled using the SWAT hydrological model to simulate runoff and water availability. The average monsoon (July-October) streamflow increase in the Maner basin during the near, mid, and far futures is projected to be 47%, 66%, and 114% under the RCP 4.5 scenario, and 53%, 72%, and 69% under the RCP 8.5 scenario, respectively. Excess flow may overflow from Ramchandrapur, Mallampalli, and Dharmaraopalli tanks to the downstream Katakshapur tank since it can accommodate the up to 18.91 Mm3. To enhance water management in response to climate change, one potential adaptation strategy is to utilize the surplus inflow to refill downstream artificial ponds, which can aid in the replenishment of groundwater and the provision of water supply to tail end tanks.