The site is located in an “U” type small plain with north gentle dip and its east side, south side and
west side are hills with altitude between ten to dozens of meter while the north side is a river. The
geologic section from bottom to top in the study area is: (1) Upper Cretaceous Pukou group with general
depths below 40-50 meters and purplish-red or gray-yellow sandy conglomerate. (2) Pleistocene series
Xiashu group loess with depth of 12-40 meters and multilayers of silty clay with interlayer of silt and
sand. The bottom of Xiashu group loess is a gravel layer and it is in discordant contact with the bedrock
of upper Cretaceous Pukou group. (3) Holocene series overly the Xiashu group and are composed of silt
and silty clay overlain by fluvial Quaternary unconsolidated sediments and soil in the top10 to 12 meters.
The aquifer can be divided into a phreatic water aquifer and a micro confined water aquifer. The
thickness of the phreatic water aquifer is 5 to 6 meters and the aquifer is constituted by silt clay with thin
interlayer of fine sand, and fine sand and silt while the micro confined water aquifer occurs in thin layers
of fine sand, medium sand in Pleistocene series of silty clay and residues of bedrock surface.