Dams and barrages are built for storage/diversion of water for irrigation or generation of electric power. In concrete dams, tunnels/spillways, the head regulator of hydel channels, forebay intake structure, by-pass channels and draft tube of the powerhouse, the flow of water is controlled with the help of hydraulic gates.

To prevent the flow of water past a closed gate, seals are provided either on the gate or on the metal frame in the gate slot. Rubber is the most commonly used material for seals, as it is elastic, deforms readily and regains its original shape on removal of load.