• Meteorology and hydrology
The study area sits in the transitional zone between central and north subtropical
zones. It is subject to wet monsoon climate. The temperature averages 14–17 °C
throughout the year, 3–4 °C in the coldest month January, and 28–29 °C in the
hottest month. On average, the frost-free period reaches 247 days per year and the
duration of sunshine 2048.6 h per year, and fog occurs in 16 days or less per year.
The mild climate with four distinct seasons provides abundant precipitation and
sunshine.
• Water systems
The study area is rich in water resources. There are 12 river systems that drain
926.9 km
2 , including Yangtze River, Taibo Lake, Fanghu Lake, Qiaohe River,
Langxigang River, Qilihong River and Yangzi River. Surface water resources
amount to 368 million m
3 in the dry year and 878 million m
3 in the wet year, but the
distribution is uneven because dense bays and steep channels in the mountainous
areas make storage and utilization difficult. Groundwater with a reserve of 41.96
million m
3 is widely distributed in areas up to 966 km
2 .
(b) Hydrogeological conditions
• Stratum structure
According to boreholes drilled in the landfill, the strata mainly consist of
Quaternary soft/loose soil (Q4
al
) and Sinian Nantuo sandstone (Z II
n ) (Fig. 5.9). The
lithology from top to bottom is described as follows:
Artificial soil: It is 2.00–3.50 m thick, mainly composed of brown, loose, silty
clay and covered by plant roots and gravel. The surface layers at borehole CK4
downstream in the study area are 2 m thick cultivated soil.
Sand and gravel: They form a slightly wet, saturated alluvium which is greenish
lime or yellow brown and has a lower degree of sorting and roundness. Gravel with
a particle size of 0.5–2 cm accounts for about 50%, while pebbles with a diameter
of 2–4 cm account for about 10%. There is a small amount of boulders with a
diameter of about 8 cm and sand that fills the gap. The alluvium with increasing
thickness is mainly found in the eastern landfill, and in some places, includes
boulders with a particle size of 3–8 cm.
Sinian Nantuo sandstone (Z II
n ): It is purple red and contains fine-grained sandstone. The upper part, where the original rock structure is destroyed, is comprised of
quartz, feldspar and fissures and strongly weathered as the thickness of weathering
crust reaches 8.7–32.4 m. The lower is moderately weathered and mainly consists
of quartz, feldspar, and glauconite. Clear horizontal bedding can be observed on the
rock surface. Fracture zone has been formed, which are a few meters to dozens of
meters deep and 1–5 m wide. The lithology varies widely among boreholes CK4,
CK5 and CK6. It is dominated by purple-light green metamorphosed sandstone of
different thickness, with glauconite observed in partial places and joint fissures
116
5 Application Cases
The study area sits in the transitional zone between central and north subtropical
zones. It is subject to wet monsoon climate. The temperature averages 14–17 °C
throughout the year, 3–4 °C in the coldest month January, and 28–29 °C in the
hottest month. On average, the frost-free period reaches 247 days per year and the
duration of sunshine 2048.6 h per year, and fog occurs in 16 days or less per year.
The mild climate with four distinct seasons provides abundant precipitation and
sunshine.
• Water systems
The study area is rich in water resources. There are 12 river systems that drain
926.9 km
2 , including Yangtze River, Taibo Lake, Fanghu Lake, Qiaohe River,
Langxigang River, Qilihong River and Yangzi River. Surface water resources
amount to 368 million m
3 in the dry year and 878 million m
3 in the wet year, but the
distribution is uneven because dense bays and steep channels in the mountainous
areas make storage and utilization difficult. Groundwater with a reserve of 41.96
million m
3 is widely distributed in areas up to 966 km
2 .
(b) Hydrogeological conditions
• Stratum structure
According to boreholes drilled in the landfill, the strata mainly consist of
Quaternary soft/loose soil (Q4
al
) and Sinian Nantuo sandstone (Z II
n ) (Fig. 5.9). The
lithology from top to bottom is described as follows:
Artificial soil: It is 2.00–3.50 m thick, mainly composed of brown, loose, silty
clay and covered by plant roots and gravel. The surface layers at borehole CK4
downstream in the study area are 2 m thick cultivated soil.
Sand and gravel: They form a slightly wet, saturated alluvium which is greenish
lime or yellow brown and has a lower degree of sorting and roundness. Gravel with
a particle size of 0.5–2 cm accounts for about 50%, while pebbles with a diameter
of 2–4 cm account for about 10%. There is a small amount of boulders with a
diameter of about 8 cm and sand that fills the gap. The alluvium with increasing
thickness is mainly found in the eastern landfill, and in some places, includes
boulders with a particle size of 3–8 cm.
Sinian Nantuo sandstone (Z II
n ): It is purple red and contains fine-grained sandstone. The upper part, where the original rock structure is destroyed, is comprised of
quartz, feldspar and fissures and strongly weathered as the thickness of weathering
crust reaches 8.7–32.4 m. The lower is moderately weathered and mainly consists
of quartz, feldspar, and glauconite. Clear horizontal bedding can be observed on the
rock surface. Fracture zone has been formed, which are a few meters to dozens of
meters deep and 1–5 m wide. The lithology varies widely among boreholes CK4,
CK5 and CK6. It is dominated by purple-light green metamorphosed sandstone of
different thickness, with glauconite observed in partial places and joint fissures
116
5 Application Cases