Civil Engineering Reference
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where
W
s
is average infiltration recharge over the whole watershed and
C
s
is the
resultant average (over the whole watershed) contaminant concentration.
According to these equations, determined by
C
s
is the formula
CWFCWF
WF WF
+
+
C
=
aaa
b bb
.
(3.3)
s
aa bb
The share of depressions in the total groundwater contamination is deter-
mined by the ratio
η
=
CWF CWF
/ .
a aa s ss
(3.4)
Using the available data on the infiltration intensity and vertical migration
of
137
Cs from the contaminated surface to the groundwater table depth for a typ-
ical depression in the CEZ and
σ = F
a
/F
s
= 0.1 (observation plot “Stary
Shepelichi”), an approximate assessment of the input of depression-related
PFMZ in the total contamination of upper groundwater was obtained
[
Shestopalov et al
., 2006] according to formula (3.4),
η
≈ 0.82. Hence, we came to
the conclusion that the share of anomalous depressions in the total radionuclide
contamination of the upper groundwater by
137
Cs may reach 80% and more. Also,
the relative share of depressions in groundwater contamination, η, was calculated
as a function of groundwater table depth for three values of the areal share occu-
pied by depressions,
σ = F
a
/F
s
: 1%, 5%, and 10%. The corresponding plots are
shown on Figure 3.16.
It is seen from Figure 3.16 that the relative share of depressions in the total
influx of the contaminant with the infiltration to the upper groundwater,
according to formula (3.4), increases from 3-30% to 80-100% with increasing
groundwater table depth. In areas with a groundwater table depth greater than
15 m, the penetration of
137
Cs into the upper groundwater aquifer proceeds mainly
on account of depression-related PFMZ (by 90% or more).
To analyze the joint effect of two types of PFMZs (depressions and linea-
ments), we have considered a pilot area of 149 ha located in the southern part of
the Kyiv region [Rokitne district, west from Bakumivka village (Figure 3.17)].
Figure 3.17A is a satellite image of the area (data Cnes/Spot Image, 2011) with
typical depressions and lineaments (elongated linear and curvilinear PFMZ).
Figure 3.17B shows the result of gridding the depressions (dark) and lineaments
(light) with a square grid spacing of 10 m.
According to our preliminary assessment for this area, it was supposed that
the depression zones received 2 times increased infiltration and predicted relative
concentration of the contaminant (
137
Cs) in the upper aquifer as compared to
background area, and the lineament zones received 1.5 times increased infiltra-
tion and contaminant concentration. As a result of counting areas of the depres-
sion-related and lineament-related PFMZs, the following data were obtained: the
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