A GIS model for landfill siting

The use of Geographical Information Systems (GIS) for Landfill Sitting is studied. The
necessary spatial information required to determine the candidate sites for any type of
terrestrial area (Community/Prefecture/Region/Country) is examined. This spatial information
is then used for site selection via successive spatial operations: Buffering, overlaying and
attribute calculations. The method is tested for the whole region of the island of Crete,
producing spatial numerical results, which can be used as points of reference for any future
Landfill Sitting study for this area.
In our study, the main spatial information required for Landfill Sitting is determined in such a
manner, so that the spatial development of the region is assured to be sustainable for the
future generations. This means that we try to include as much as possible Environmental /
Ecological / Economic factors characterizing the region under consideration. These factors
take the form of spatial information, organized in spatial layers. The layers are then inserted
into the GIS model for (a) Landfill site exclusion, and (b) Landfill site evaluation. All spatial
layers correspond to subcategories of the main categories, defined as follows (GIS model
setup): A. NATURE / ECOSYSTEM, B. HUMAN ACTIVITIES, C. WATER RESOURCES /
HYDROLOGY, and D. ANTIQUITIES.
The exclusion “rules” are then defined by varying buffer distances surrounding each of the
above layers separately (distance maps). The total areas to be excluded for each Category
are defined by overlaying (union) the various distance maps in a sequential order, with the
final “exclusion” map to be the union of all the above sub/distance maps. The remaining areas
are then to be evaluated individually.
The GIS model results showed that, for the island of Crete, and a moderate buffer distances
(“restrictions”) scenario, a total of 47.73% of the whole area is excluded when we consider
restrictions residing from Category A. NATURE/ECOSYSTEM, 61.40% is excluded due to
the HUMAN ACTIVITIES (Category B), 16.03% is rejected due to WATER
RESOURCES/HYDROLOGY protection considerations (Category C), and only 1,04% of the
total island area is excluded due to existence of ANTIQUITIES (Category D). If we are to
combine the above Categories (A-D), a total of 82.65% of the total area is to be excluded, or
a total of 17.35% of the island area only is suitable for Landfill Sitting. The GIS model results
defines precisely which these areas are, so small-scale research, based on these results, is
required for the final site ranking and selection.