《水经注》湿余水和易荆水新考——兼论军都故城和昌平故城位置

A New Study on the Shiyushui and Yijingshui in Shui Jing Zhu:Also on the Location of the Ancient City of both Jundu and Changping

《水经注·湿余水》是研究北京北部地区古代水系变迁和历史地理的重要文献,其中关于湿余水和易荆水的记载涉及军都故城和昌平故城位置的判定。北魏时湿余水从今关沟发源,流经居庸关,在南口出山,即渗入冲积扇地表下成为地下潜水,东南行十余里后“重源潜发”从地下溢出,并积水成湿余潭。湿余潭的位置应在今昌平区百泉庄一带,进而可确定昌平区虎峪古城为秦汉军都故城,昌平区土城村古城为北魏军都故城。而古易荆水与今清河和万泉河存在继承关系,北魏时期易荆水发源于今海淀区的樱桃沟,出山后东南流,至海淀台地北侧,沿着今万泉河和清河一线注入湿余水。考证海淀区朱房古城、清河和蓟城的相互位置关系,可确定朱房古城为汉魏昌平故城,易荆水流经的郁山为今玉泉山,孤山为今颐和园内的万寿山。

The volume about Shiyushui in Shui Jing Zhu is an important document to study the changes of ancient water system and historical geography in northern Beijing.The records of Shiyushui and Yijingshui involve the determination of ancient city locations of both Jundu county and Changping county.Shiyushui in the Northern Wei Dynasty originated from today’s Guangou valley,flowed through Juyongguan,and came out of the mountain at Nankou,,then it penetrated into the surface of the alluvial fan and became underground diving.After traveling more than 5 kilometers southeast,it overflowed from the underground and accumulated water into Shiyu Pool.The location of Shiyu Pool should be in Baiquanzhuang village,Changping District,this paper holds that the ancient city ruins in Huyu village in Changping District is the place where Jundu county of the Qin and Han Dynasties lay,and the ancient city ruins of Tucheng village in Changping District is the place where Jundu county of the Northern Wei Dynasty lay.In the Northern Wei Dynasty,the Yijing River originated in Yingtaogou valley in Haidian District,flowed out of the southeast behind the mountain to the north of Haidian platform,and flowed into Shiyushui(Wenyu River)along current Wanquan River and River Qing.Based on the research of the relationship between ancient city ruins in Zhufang village,River Qing and Jicheng in Haidian District,this paper holds that ancient city ruins in Zhufang village is the place where Changping county in the Han Dynasty lay,Yushan mountain,through which YiJing water flowed,is now the Yuquan mountain,and mountain Gu is the Wanshou mountain in the summer palace.