Is it obligatory to relocate graves that will be permanently submerged by the dam's waters, especially given their very large number, and is there a conclusive fatwa to convince citizens not to move them?

If graves have deteriorated and turned to dust, it is permissible to utilize the cemetery for construction and agriculture. However, if any trace of the deceased remains, it is not permissible to build a tank that would submerge the graves in water, because the sanctity of the dead is like the sanctity of the living, as the Prophet, peace and blessings be upon him, said: "Breaking the bone of a believer when he is dead is like breaking it when he is alive," and "Do not harm the occupant of the grave," and "For one of you to sit on a burning coal until it burns his clothes and reaches his skin is better for him than to sit on a grave." If there is a necessity to build the tank, there is no harm in it, provided that the deceased are moved if possible.