《水经注·卷二十六》
应肋说：昌水发源于东莱昌阳县，因昌阳县路远不易到达，取了这个美名。
应劭曰：昌水出东莱昌阳县，道远不至，取其嘉名。
Ying Lei says: the Changshui River originates from Changyang County of Donglai, but since Changyang County is far and difficult to reach, this good name was adopted.