Buddhist Dictionary of Pali Proper Names by G P Malalasekera
Kāragangā
Kāragangā:A river in Ceylon.It was dammed between the hills with a great barrier by Parakkamabāhu I.,and its waters were conveyed by a canal,the Akāsagangā,to form the Parakkamasamudda (q.v.) (Cv.lxxix.24).Another canal,the Godāvarī,is mentioned as branching off from the Kāragangā and flowing into the Parakkamasagara (Cv.v.57).