Methodology of Groundwater Vulnerability and Protectability Assessment - Groundwater Vulnerability: Chernobyl Nuclear Disaster - page 78

Downward flow area Downward flow area

Upward flow area Upward flow area

Z 1 Z 1

Z 2 Z 2

Z n Z n

1 1 2 2 3 3 4 4

Figure 4.1 Flow scheme of a stored aquifer system [ Shestopalov , 1988]: (1) aquifers; (2) low-
permeable beds; (3) groundwater heads of stored aquifers; (4) groundwater flow directions.

In the same way as for equation (4.10), the resulting relative concentration of
the aquifer number n , c ( z n * , t* ), is determined by the product of separate partial
relative concentrations for each aquifer number i :

n

∏ 1

cz t (* , *) = c zt ( ) * , (4.12)

n i i

i =

It can be considered and mapped as the indicator of vulnerability of the
aquifer number n to surface contamination.
We note once again that to refine the cover vulnerability assessment of the
aquifer to a full assessment of the aquifer's groundwater, we must account also
for the additional sum of physical and geochemical barrier properties of the
aquifer represented by the hydraulic resistance, porosity, and sorption capacity
of the water-bearing rocks and deposits of the aquifer. In the course of the
corresponding modeling of the vertical contaminant transport, the following
are required:
1.

An initial setting of (as accurate as possible) flow and transport parameters such
as hydraulic conductivity, porosity, distribution coefficient b [equation (4.3)], or
K d [see equation (1.9), Chapter 1] over the whole thickness of the aquifer