Spillways are protection structures in a dam–reservoir system. A typical spillway for any type of dam project consists of several components comprising the approach channel, inlet and control structure, conveyance structure, and terminal structure phasing from the reservoir to the river channel. The design of each component affects the overall performance of the structure. The present paper discusses the case studies describing the role of the crest profile in determining the discharging capacity and the role of the divide walls in the stilling basin (terminal structure) in enhancing the performance of the energy dissipator. For the project proposed on the tributary of Chenab River (Case 1), the spillway was designed to surplus the design discharge of 4000 m3/s through two spans equipped with radial gates of size 12 m wide × 16 m high. In this case, modification in the crest profile increased the discharging capacity of the spillway by 13.6%. For the other project constructed on the Narmada River (Case 2), physical model studies indicated a need for the provision of divide walls in the stilling basin to separate a large number of spans into several bays. This helped in flexibility in operation, reducing the extent of return eddies formed in the basin, thereby eliminating or minimizing the tendency of deposition of material into the stilling basin and consequent damage due to abrasion. Physical model studies played a very important role in optimizing the design of various components of the spillway and ensuring the safety of the structure.