Geography Reference
In-Depth Information
COP
index
C
O
P
(33)
Scores to all three factors are assigned according to their relative impact
on the vulnerability of the karst aquifers. The numerical representations of the
C, O and P factor values (or scores) are then multiplied to assess the
vulnerability. In general, the final values of the COP index indicating the
intrinsic vulnerability range from 0 to 15, which can be suitable classified into
five vulnerability classes, i.e. very high, high, moderate, low and very low
vulnerability (Vrba and Zaporozec, 1994).
The COP method is evaluated as the most effective in comparison to other
methods such as DRASTIC, GOD, AVI, SINTACS, EPIK, and PI for
assessing the prevailing vulnerability in the southern Spain (Longo et al.,
2001; Brechenmacher, 2002; Vıas et al., 2005, 2006; Andreo et al., 2006)
based on actual hydrogeological understanding of the aquifers.
7.
GIS-B
ASED
W
ATER
Q
UALITY
I
NDEX
Water Quality Index
(WQI) technique is very useful for evaluating the
water quality (Abassi, 1999; Adak et al., 2001; Pradhan et al., 2001),
especially in resource-poor countries where cost is a major issue for water
resources management. In one of the pioneer work, Horton (1965) developed
general water quality indices by selecting and weighting several parameters.
Although there are no hard and fast rules for constructing a water quality
index, a WQI should be specific to a water use or a set of goals (Schultz,
2001). In general, two steps are required for developing a WQI. First, a set of
parameters need to be selected that measure the important physical, chemical,
and microbiological water characteristics. Of course, the selection of such
parameters depends on the intended use of the water.
Once information about that set of parameters is available, a rule is needed
to summarize all the information in a unique number, i.e., ‗water quality
index'. The usefulness of water quality indices has been demonstrated in water
quality interpretation (e.g., Melloul and Collin, 1998; Soltan, 1999; Stigter et
al., 2006; Babiker et al., 2007; Ramesh et al., 2010; Machiwal et al., 2011;
Machiwal et al., 2013). Provencher and Lamontagne (1977) proposed one
pioneering WQI, which is based on several parameters scored using the same
transformations, generally but not always linear, and a final global score is
