It looks like they may have found evidence
of Yu the Great's flood; if it's correct, then they push him a bit later, to about 1900 BC.
If their theory is correct, a rockslide dammed up the Yellow River's Jishi gorge (about the midpoint of the Jincheng/Longxi border, two commanderies on the western edge of southern Liangzhou -- or, if you prefer, a third of the way form wei river's source to lake Qinghai). Water built up behind the rocky dam until it burst 6-9 months later, flooding everything downstream.
Unless I specifically say otherwise, assume I am talking about historical Three Kingdoms, and not the novel.