The Dam of Sepuraabi and the Sunken City of Tifur
Between the Imperial Heartland and the Central Glacier lie tall mountains. Every winter the icy fingers of the glacier crawl outwards through the valleys and passes of the mountains, and every spring the furthest extensions melt and flow down into the Heartland. Once, long ago, this would have resulted in seasonal flooding in the main river valleys, but no longer.
The events that led to the control of the river originally had a different purpose. At one time there was a civil war in the Empire, between a renegade Emperor and his priesthood. The Emperor set up a new city, higher in the mountains, named Tifur. The leader of the armies opposing him was his former high priest, Sepuraabi.
The Emperor was driven back to Tifur and besieged, but the priests could not breach the defences. Sepuraabi called upon the gods to punish their recalcitrant servant, and was answered by a great rockfall that cut off the mouth of the valley in which Tifur lay. When the spring thaw came, Tifur was drowned beneath flood water.
The Dam of Sepuraabi was refined, and now controls the water supply to the Imperial Heartland. Several aqueducts lead away from it to the capital city. Behind it, beneath the still waters of the reservoir (so legend says), lies the sunken city of Tifur.
Wether this story of the dam's origin is true or not is a matter for debate. There is evidence for an Emperor whose name and face have been removed from monuments, and who has been stricken from the records. What he might have done
to offend the priests is also unknown. The story does, however, carry a pointed reminder to the Emperor about who really wields the power.