Civil Engineering Reference
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Figure 3.1
United States, Illinois, Monticello, 30 km SE from Klinton NPP.
depressions within the grid fracture systems (Figure 3.1); mixed-type depression
forms; depression microrelief with low primary fracturing (Figure 3.2); and
depression microrelief with no visible primary fracturing.
Sample estimate of PFMZ was performed also by images of the European
continent, especially in Ukraine. In some areas their number exceeds 200 per
square kilometer. By morphological types, the rounded and oval depressions
dominate in the region, ranging in size from tens of meters to several kilometers
(Figures 3.3-3.5).
Based on the assessment of regional peculiarities development, it was found
that the number of depression forms per definite area decreases with the degree
of area dissection.
In western Europe the depressions are also widely developed. Most depres-
sions are associated with plains of large river basins. However, because of the
often high water table, their manifestation in the relief may not be very significant.
The clearest manifestation in the relief that the depressions have on elevated areas
is shown in Figure 3.6.
As we see, even a quick review of the depression forms shows their worldwide
occurrence. Their role in groundwater vulnerability and protectability requires
special account and study.
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