Synthesize analyse according to the field Research and the material of bore holes, in holocene period, the Yong Ding Rivar flooded into the Xiao Qing River, only limited between the Xiao Qing River and Dashi River.

• 根据野外调查和钻孔资料综合分析,永定河在全新世期间曾泛流进入小清河,范围仅限于小清河与大石河之间。