Kashmir- Etymology and rest.

According to this earliest traditional account the lake called Satisaran, ' the lake of Sati (Durga)', occupied the place of Kashmir from the beginning of kalpa. In the period of the seventh manu the demon Jalodbhava (' water borne') who resided in this lake, caused great distress to all neighboring countries by his devastations. The Muni Kasyapa, the father of all Nagas , while  engaged in a pilgrimage to the Tirthas in the north of India, heard of the cause of this distress from his son Nila, the king of the Kashmir Nagas.

The sage thereupon promised to punish, the evil-doer and proceeded to the seat of Brahman to implore his and other gods' help for the purpose. His prayer was granted. The whole host of by Brahman's command started for satisaras and took up their position on the lofty peaks of Naubandhana Tirtha above the lake Kramasaras ( Kounsar Nag). The demon who was invisible in his own element, refused to come forth from the lake. Vishnu thereupon called upon his brother Balabhadra to drain the lake. This he effected by piercing the mountains with his weapon, the ploughshare. When the lake had become dry, Jalodbhava was attacked by Vishnu and after a fierce combat slain with the god's war-disc.

Source: Kashmir- An Historical Introduction by James P. Ferguson.