Why Runan Was on the North of Ru River
- 人文学院－已发表论文 
西汉汝南郡大多数土地在汝水以北,郡治也在汝水北面,但是汝南郡不叫汝北郡,其得名缘于汝 水故道流经汝南郡北部.考古学成果为考证汝水故道的流向提供了部分依据.约在西汉晚期,汝水干流西 移,不过汝水故道仍未断流.曹丕在召陵县开凿讨虏渠,阻断南流的汝水故道,引汝水东流与颍水的支流小瀧 水汇合,从此汝水故道断流,成为《水经注》所说的死汝,这是汝水、额水水系的重大变迁.从汝水到额水的这一段河流被称为大滌水,即今沙河.三国之后讨虏渠一名很快消失,颍水又有改道,所以这一带的原貌模糊不 清.The majority land of Runan County and the county seat were on the north of Ru River, however the name of this county was not Rubei, because the ancient Ru River was on the north of Runan County. W e can research the ancient Ru River according the archaeological site . Ru River moved to the west during the late Han Dynasty, andthe ancient river had not dried up. The Emperor Cao Pi excavated Taoru Canal in Zhaoling, blocking up the southwardRu River and diverting the water eastward to Small Yin River which was the branch of Ying River. The ancient RuRiver dried up, then became Dead R u. The new river from Ru to Ying was called Big Yin River, and evolved tonowaday Sha River. The name Taolu Canal soon disappeared after the Three Kingdoms, and Ying River changed its course, so the original appearance of this area disappeared.