First of all, there is a place called Hannaoba in Zhangbei area, and there is a village called Baxia in the south. 1940, a foreign geologist visited the north of Zhangjiakou and found that there was a large area of basalt stratum exposed in the north, which was called Hannuo basalt stratum, so there was Khan Village in the local area. Personally, the dam in Zhangjiakou area is bounded by Shangyi-Chicheng structural fault, with Inner Mongolia platform anticline in the north and Yanshan mountain sedimentary structure in the south. The Inner Mongolia platform in the north of its structure can be called Bashang area, and the sedimentary area north of Yanshan in the south can be called Bashang area. From the map, Hannaoba is located just above the Inner Mongolia platform in the north of this structure. Therefore, I personally think that the dam above and below the dam in Zhangjiakou area should be distinguished by Hannao Dam. The dam in Zhangjiakou area should naturally be called Hannuo Dam. The above is purely a personal experience, I hope the professionals will give me a detailed explanation.
Literature sources: Chongli County Records and General Geology.