This lake is located 4 km from Dieng Plateau. This lake was a crater and then filled by water. This lake covers 20 hectares and the depth is 25 m. Merdada derives from Madera, an amulet name owned by Resi (ascetic) Gautama in a local legend. Resi Gautama has twin sons and a daughter. He loves his sons very much and his wife loves the daughter very much. Hobby of the sons is hunting and one day they caught a deer. They give the deer to their sister. But unlike usual, their sister does not really paid attention on what they give, finally they found out that the girl is looking at something, an amulet called cupu manik astagina owned by gods. This amulet has window, if it opens the world can be seen and if closes heaven can be seen.
The amulet is actually for the twin sons as it is given by a god who loves their mother. The twin sons try to have the amulet. Their father find out about the fight and calls his wife and asks about where the amulet comes from. But his wife does not want to tell him as she was asked not to tell anyone about it. The ascetic is angry as she keeps silence and the he curses her to be statue. He throws the amulet to the air, the lower part (merdada) of the amulet falls and becomes Lake Merdada and the upper part falls on the otehr side and become Lake Dlingo. The statue then throws and falls nearby Lake Merdada.