A differential 2.25 m-diameter, 63.96 m-high located at the top of the hill above the powerhouse. The tank is made of steel plates and is supported by six steel legs. The exposed steel penstock 1.8 m in diam. x 179 m long, convey the water from anchor block to the powerhouse through a steep slope inclined at  45deg. to 51deg. supported by concrete anchor blocks and concrete saddles  . The surge tank prevents water hammering in the event of sudden closure of the butterfly valve. Likewise, it provides the required amount of water in case of an abrupt increase in load.