formed. The sandstone has residual sandy property as the original rock is strongly
weathered and destroyed (Fig. 5.9).
• Groundwater type and water yield property
According to the regional hydrogeological survey reports and the existing borehole
data, the study area has medium-and low-mountain terrain with bare bedrock. With
the development of tectonic fissures, groundwater exists in the form of tectonic
fissure water. The water yield is limited as groundwater runoff modulus ranges from
1.32 to 2.91 L/s/km
2 and the spring flow from 0.01 to 0.16 L/s. The groundwater is
classified into the bicarbonate-calcium type, with salinity of 0.05 to 0.25 g/L and
pH value of 7–8.
• Groundwater recharge, runoff and discharge conditions
Groundwater in the study area is mainly distributed in erosional medium and low
mountainous areas with bare bedrock. It migrates along the slope, and emerges on
the land surface via spring at the foot of mountains. As precipitation serves as the
only source of groundwater recharge, the groundwater dynamics are obviously
Fig. 5.9 Schematic diagram of geological cross-section of Luanshiwan
5.1 Central China
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