Great Tragic

From Glen Cook Wiki

The Great Tragic is a river which runs through the Great Forest, originally several miles away from the Barrowland. By the time of the third book, the Dominator has managed to influence the weather sufficiently to cause the river to flood, shifting towards the Barrowland and eroding the land beneath the Great Barrow. Apparently neither the White Rose nor Lady foresaw this contingency, and by the time the implications of the flooding become apparent it is too late to undo the damage, forcing Lady to take action to handle the Dominator's release.