Indian experience in flexible geomembrane for watertightness of ageing dams

Watertightness is one of the key issues to ensure safe operation and durability of dams. The installation of geomembranes on the upstream face of large dams is in practice in India since early 2000ies with Kadamparai, a 67 m high masonry dam, that was brought back to its full operational capacity. Since 14 years of installation, the Pumped Storage Hydro Electric Generation station has gained full efficiency and is generating to its full capacity of 400 MW power limiting the leakage within the permissible limit, paving the way for similar installations in other dams. The second project was Servalar dam under DRIP - Dam Rehabilitation and Improvement Project of the Government of India, in 2018. Carpi braved the challenges posed due to erratic weather conditions and successfully installed with the same level of result of the first project. The third one, at Upper Bhavani dam also under DRIP, an 80 m high stone masonry dam providing water to a series of power houses generating over 800 MW; the same geomembrane system is being installed in phases getting completed in 2020. The paper provides details of these projects, focusing on how the geomembrane technology is proven suitable and adaptable to any kind of environment and at the same time provides the most durable solution for watertightness.