From the data in Tables 5.76 and 5.77, it can be seen that both upstream and
downstream water quality test results meet the standards, but through comparison, it
can still be found that some quality indexes of the downstream water exceed the
upstream water, which may be due to a small amount of refuse and liquid leakage
during the operation of the garbage truck or the infiltration of part of leachate into
groundwater through the soil layer along with the rain, resulting in some quality
indexes of the downstream water being higher than those of the upstream water.
3. Groundwater vulnerability evaluation of landfill
A landfill in A city of a province in Southeast China is located at a col 500 m
west of a river crossing in Shoushan Township, a northern suburb of A city in a
province in Southeast China, at an altitude of about 480 m, 3.6 km from the urban
area, and 2300 m from a park in A city of a province in southeast China to the
south. The landform in this area is mixed low mountain steep slope and gentle slope
terrain with the structural erosion. Around the site, there are mainly two gullies
from southeast to northwest and from northeast to southwest.
(1) Depth of groundwater table
According to geological data, the depth of groundwater table in the site is 0.9–
1.7 m and is more than 3 m in most hillside fields. Groundwater flow is subject to
the landform, from south to north, and from the hillside to everywhere. The
water-bearing formations in the area are poor in water abundance, and the permeability coefficients are: 4.9 Â 10
−5 cm/s for gravel layer, 5.9 Â 10
−7 cm/s for
residual clay, 2.67 Â 10
−7 cm/s for highly weathered tuff, and <1 Â 10
−7 cm/s for
tufflava.
(2) Soil type
The main soil types of a landfill in Southeast China are red soil and skeleton red
soil. Red soil is light red to red, with heavy texture and lack of phosphorus.
Tufflava-based red soil has lower quartz content than granite-based red soil, and is
not easy to lose. Skeleton red soil is mainly distributed on the back of steep hill,
windward and dry, thin and mixed with gravel.
(3) Net recharge
Q ¼ 0:001 à a à F à A
where Q—rainfall infiltration recharge; a—rainfall infiltration coefficient; F—the
area of aquifer that receives rainfall infiltration; A—annual average precipitation
(mm).
248
5 Application Cases
downstream water quality test results meet the standards, but through comparison, it
can still be found that some quality indexes of the downstream water exceed the
upstream water, which may be due to a small amount of refuse and liquid leakage
during the operation of the garbage truck or the infiltration of part of leachate into
groundwater through the soil layer along with the rain, resulting in some quality
indexes of the downstream water being higher than those of the upstream water.
3. Groundwater vulnerability evaluation of landfill
A landfill in A city of a province in Southeast China is located at a col 500 m
west of a river crossing in Shoushan Township, a northern suburb of A city in a
province in Southeast China, at an altitude of about 480 m, 3.6 km from the urban
area, and 2300 m from a park in A city of a province in southeast China to the
south. The landform in this area is mixed low mountain steep slope and gentle slope
terrain with the structural erosion. Around the site, there are mainly two gullies
from southeast to northwest and from northeast to southwest.
(1) Depth of groundwater table
According to geological data, the depth of groundwater table in the site is 0.9–
1.7 m and is more than 3 m in most hillside fields. Groundwater flow is subject to
the landform, from south to north, and from the hillside to everywhere. The
water-bearing formations in the area are poor in water abundance, and the permeability coefficients are: 4.9 Â 10
−5 cm/s for gravel layer, 5.9 Â 10
−7 cm/s for
residual clay, 2.67 Â 10
−7 cm/s for highly weathered tuff, and <1 Â 10
−7 cm/s for
tufflava.
(2) Soil type
The main soil types of a landfill in Southeast China are red soil and skeleton red
soil. Red soil is light red to red, with heavy texture and lack of phosphorus.
Tufflava-based red soil has lower quartz content than granite-based red soil, and is
not easy to lose. Skeleton red soil is mainly distributed on the back of steep hill,
windward and dry, thin and mixed with gravel.
(3) Net recharge
Q ¼ 0:001 à a à F à A
where Q—rainfall infiltration recharge; a—rainfall infiltration coefficient; F—the
area of aquifer that receives rainfall infiltration; A—annual average precipitation
(mm).
248
5 Application Cases