Geography Reference
In-Depth Information
Before 1980s, there had been several attempts to formulate and establish a
methodology to assess the vulnerability in order to present it in a map.
However, the successful results could be obtained during the mid 1980s when
two of the pioneer indices called DRASTIC (Aller et al., 1987) and GOD
(Foster, 1987) were reported.
There are many kinds of vulnerability identified by different methods
associated with a wide range of index values and labelled qualitatively. The
categorization of vulnerability into different classes depends upon the index
values and appropriate number of categories decided by a person.
The groundwater vulnerability assessment has rapidly developed over the
past 20 years; many new tools and techniques are introduced for the
groundwater vulnerability assessment along with specific applications being
thoroughly analyzed and tested for different environments (Cramer and Vrba,
1987; Meinardi et al., 1995; Secunda et al., 1998; Lasserre et al., 1999; Al-
Adamat et al., 2003; Lake et al., 2003; Rodriguez et al., 2003; Thapinta and
Hudak, 2003; GEAM, 2005; Allen and Milenic, 2007; Zhou et al., 2010).
Moreover, many studies have used different scales and sources of
information for the application of these techniques (Secunda et al., 1998;
Foster et al., 2002; Civita and De Maio, 2004; Wang et al., 2007).
The widely-used models of index methods include DRASTIC (Aller et al.,
1987), GOD (Foster, 1987), AVI rating system (Stempvoort et al., 1993),
SINTACS (Gogu and Dassargues, 2000) and EPIK (Doerfliger et al., 1999).
Conventional methods, e.g., DRASTIC, GOD, AVI, SINTACS, etc. do
not take into account the peculiar features of karstic (or carbonate) geological
formations. Thus, to address pollution vulnerability assessment in karstic
aquifers, few specific methods, e.g., EPIK (Doerfliger and Zwahlen, 1998;
Doerfliger et al., 1999), PI (Goldscheider et al., 2000) and COP (Vias et al.,
2006) have been developed. Available methods (conventional as well as non-
conventional) for groundwater vulnerability mapping can be classified into
two groups as shown in Table 4.
Three major limitations of overlay and index methods are: (i) defining
groundwater vulnerability in qualitative terms, which is opposed by
quantitative terms (Gogu et al., 2003; Frind et al., 2006; Popescu et al., 2008),
(ii) finding it difficult to quantify exact amount of uncertainty involved in
vulnerability assessments in order to handle inaccuracies incurred in analysis
(Gogu and Dassargues, 2000), and (iii) strong homogeneous results observed
over large areas in many parts of the world, which restricts for discrimination
and delimitation of areas of different vulnerability to pollution.
