史载,江汉-洞庭平原在秦汉以前,迟至隋唐,曾经是一个相连成片的浩瀚内陆湖,后经长江及其支流湘、资、沅、澧、汉的泥沙淤塞和分隔,逐渐形成现今的内陆三角洲和众多的湖泊,是有汉江三角洲和洞庭平原之称。有些地质地理学者认为,这个大湖早在史前时期就存在。有人认为:“这个大泽在白垩纪显然就已经存在”。有的学者说得更明确: Before the Qin and Han dynasties, as early as the Sui and Tang dynasties, the Jianghan-Dongting Plain was once an inland lake connected by patches of sediment. After the silting and separation of the Yangtze River and its tributaries, Hunan, capital, Yuan, Han and Han, Inland Delta and numerous lakes, known as the Han River Delta and Dongting Plain. Some geologists believe that this great lake existed as early as prehistoric times. Some people think: “This Dazawa clearly existed in the Cretaceous.” Some scholars put it more clearly: