What is lake tapping ? Why it takes place?

Explanation

i). Lake tapping is a process in which a tunnel is dug out near the bottom of a lake upto the water-rock contact of the lake. The final layer of the rock is then blasted with the help of dynamite which provides the inflow of water into the tunnel with more speed.
ii). It is done to facilitate the generation of electricity when the water level goes down in peak summer.
iii). Thus it also helps the areas suffering with drought due to scarcity of water during summer.