Spillways are hydraulic structures designed to safely discharge excess water from reservoirs and prevent potential damage caused by uncontrolled overflow. With changing climate patterns and associated more frequent and intense rainfall events, many spillway structures are being exceeded in terms of their original design capacities. Modifying existing spillways to safely handle increased discharge is of foremost importance. This study focuses on analyzing hydraulic characteristics and flow patterns of a modified spillway of the Dhanikhari da, using Computational Fluid Dynamics (CFD) simulations. Flow characteristics are investigated using the SST K-omega turbulence model. The model is validated by comparing the simulated flow depth and velocity at the toe of the spillway with that reported in the literature. The model is subsequently employed to examine the pressure and velocity variations over the spillway. With the appropriate design of the spillway profile, it has been observed that cavitation does not form in the case of the modified spillway while passing the augmented design discharge. The insights gained from the CFD simulations can help in retrofitting and upgrading existing spillway structures, ensuring the functionality in the face of change in hydrological conditions.