Environmental Engineering Reference
In-Depth Information
POC 0
POC 0
POC 0
POC 0
POC 0
POC 1
POC 0 = POC 1
POC 2
POC 3
POC 2
boundary of
DG III
consideration
POC 3
Fig. 17.5 A cross-section of a groundwater body, as a Conceptual Model with regard to
contaminant transport (European Commission 2008 , reproduced with permission)
After the first draft of the Conceptual Model has been constructed, the first aspect
to be considered is the geometry of the geologic formations (Grima et al. 2009 ).
In the real world, groundwater bodies can range from simple aquifer formations
to very complex multilayer aquifer-aquitard systems. There is a wide variety in the
range of geometries, from a uniformmorphology with limited spatial variation (such
as tabular formations) to complex formations where processes of deformation and
fracturing of previous structures are dominant. Hydrodynamic parameters, such as
hydraulic conductivity and storage, will affect the flow pattern and the hydraulic
gradient and, consequently, the potentiometric surface and its evolution. The flow
regime is laminar in detritic aquifers, while in fractured rock aquifers the flow is
faster through preferential channels, and turbulent flow can take place when chan-
nels have a given proportion. The hydrostatic pressure of groundwater within an
aquifer is another important element that needs to be accounted for. In unconfined
aquifers, hydrostatic pressure is represented by the groundwater table, whereas in
confined aquifers the water level will depend upon the pressure head. Subsequently,
three basic aspects of aquifers must be dealt with (Grima et al. 2009 ): aquifer param-
eters, pressure head regime and the hydrogeochemical features of groundwater.
17.4.2 Mathematical Models
17.4.2.1 Role and Principles
Mathematical models have at least two separate roles. Firstly, they support the
understanding of the groundwater flow and contaminant transport system. By testing
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