(2) Regional hydrogeological conditions
Beijing city is located in the northern part of North China Plain, in the upper reach
of the alluvial deluvial fan of the water system comprised of Yongding River, Great
River, North Canal, Chaobai River and Jiyun River. Frequent diversion of rivers led
to the formation of multi-level alluvial/deluvial fan and made the geological conditions more complicated. In general, the west part is dominated by gravelly soils,
and gradually transits to interbedded depositions of clayey, silty and gravelly soils
towards the east. The thickness of the Quaternary cap layer also increased from
several meters to several hundred meters. In this context, the occurrence of
groundwater also gradually changes from a single submerged layer in the west to a
complex state of multiple layers of groundwater in the east, northeast and southeast.
The landfill is located in the middle and lower part of the Yongding River alluvial/
deluvial fan, in the vicinity of Guqing River, as shown in Fig. 5.42. The thickness
of the Quaternary overburden is about 300 m, and the formation between the
surface and the bedrock roof is dominated by clay, silt and interbedded depositions
of sandy and gravelly soil.
Regional data show the distribution of mainly 3 layers of groundwater within
50 m below the surface of the landfill site area, respectively phreatic water, interlayer water and confined water from top to bottom. The phreatic aquifer has a
cumulative thickness up to 3 m and is predominantly composed of fine sand,
Landfill
Fig. 5.42 Distribution map of ancient rivers in the plain area of Beijing
5.5 North China
255
Beijing city is located in the northern part of North China Plain, in the upper reach
of the alluvial deluvial fan of the water system comprised of Yongding River, Great
River, North Canal, Chaobai River and Jiyun River. Frequent diversion of rivers led
to the formation of multi-level alluvial/deluvial fan and made the geological conditions more complicated. In general, the west part is dominated by gravelly soils,
and gradually transits to interbedded depositions of clayey, silty and gravelly soils
towards the east. The thickness of the Quaternary cap layer also increased from
several meters to several hundred meters. In this context, the occurrence of
groundwater also gradually changes from a single submerged layer in the west to a
complex state of multiple layers of groundwater in the east, northeast and southeast.
The landfill is located in the middle and lower part of the Yongding River alluvial/
deluvial fan, in the vicinity of Guqing River, as shown in Fig. 5.42. The thickness
of the Quaternary overburden is about 300 m, and the formation between the
surface and the bedrock roof is dominated by clay, silt and interbedded depositions
of sandy and gravelly soil.
Regional data show the distribution of mainly 3 layers of groundwater within
50 m below the surface of the landfill site area, respectively phreatic water, interlayer water and confined water from top to bottom. The phreatic aquifer has a
cumulative thickness up to 3 m and is predominantly composed of fine sand,
Landfill
Fig. 5.42 Distribution map of ancient rivers in the plain area of Beijing
5.5 North China
255