Distinctive features of design and construction of stilling basin of Tehri chute spillway

Big storage dams are the need of every river valley especially when the rivers are perennial in nature like Himalayan rivers. Tehri dam is such a prestigious storage dam power project under construction across the river Bhagirathi. Big dams are liable to more complex problems related to both their design and construction. Likewise, the design of Tehri dam and spillways involve very special features in their design and construction. Stilling Basin of Tehri Chute Spillway involves energy dissipation of almost 200m water head. This paper details the distinctive features of design as well as the construction of Stilling Basin of Chute Spillway. The paper discusses the hydraulic design indicating the various alternatives studied and firming up of the final alternative. The structural design is also discussed indicating the loads considered and the design scheme adopted as per the requirement. Finally, construction methodology adopted to carry out the concreting in the most critical initial portion of Stilling Basin is briefly explained.