Risk Assessment

Olive Oil Mills Waste (OOMW) Disposal Areas Show Labels/Borders
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In order to assess the appropriateness of the location of the Olive Oil Mills Waste (OOMW) disposal areas, two of the most used approaches to solve multicriteria problems, such as risk assessment analysis and suitability modelling, the Weighted Sum Model (WSM) and the Analytic Hierarchy Process (AHP) methods were applied in the wider area of the municipality of Nikiforos Fokas in Crete, covering actually the prefecture of Rethymno.

Seven scenarios were created both for the WSM and AHP method in order to determine the risk assessment for the OOMW disposal areas in terms of the various components of the anthropogenic, environmental, and geological criteria and moreover to fill the bulk of the diversity of the importance of these various criteria.

  • Scenario 1 – For the WSM this scenario is based only on the anthropogenic aspect of the risk assessment analysis. The importance is given only on anthropogenic sub-criteria (100%) while the rest are not taken into account (0%). As for the AHP the anthropogenic criteria are more important (73%) than the environmental and geological criteria, while the environmental criteria (22%) are also more important than the geological (5%).

  • Scenario 2 – For the WSM method only the environmental aspect of the risk assessment analysis is taken into account. The importance is given only on environmental sub-criteria (100%) while the rest are not taken into account (0%). As for the AHP the anthropogenic criteria are more important ((73%) than the environmental and geological criteria, while the geological criteria (22%) are more important than the environmental (5%).

  • Scenario 3 – For the WSM this scenario is based only on the geological aspect of the risk assessment analysis. The importance is given only on geological sub-criteria (100%) while the rest are not taken into account (0%). As for the AHP the environmental criteria are more important (73%) than the anthropogenic and geological criteria, while the anthropogenic criteria (22%) are more important than the geological (5%).

  • Scenario 4 – For the WSM the importance is given in all factors and sub-criteria (100%) which actually are normalized to have an equal weight of importance. As for the AHP the environmental criteria are more important (73%) than the anthropogenic and geological criteria, while the anthropogenic criteria (5%) are less important than the geological (22%).

  • Scenario 5 – For the WSM this scenario has given an advance in importance on the anthropogenic aspect of the risk assessment analysis (50%) while the rest are sharing the rest percentage (25% and 25%). As for the AHP the geological criteria are more important (73%) than the anthropogenic and geological criteria, while the anthropogenic criteria (22%) are more important than the environmental (5%).

  • Scenario 6 – For the WSM this scenario has given an advance in importance on the environmental aspect of the risk assessment analysis (50%) while the rest are sharing the rest percentage (25%/25%). As for the AHP the geological criteria are more important (73%) than the anthropogenic and geological criteria, while the anthropogenic criteria (5%) are less important than the environmental (22%).

  • Scenario 7 – For the WSM the importance is given in all three main factors (100%) which actually are normalized to have an equal weight of importance, but this time giving an importance in residential area criterion a 70%, and a 30% for the road network criteria. In the environmental aspect of the criteria, full importance is given to slope, aquifers and coastline, while medium importance on the rest environmental sub-criteria. For the geological aspect of the analysis only the hydrolithology sub-criterion was given an importance of 80% having the rest sub-criteria sharing the remainder percentage.  As for the AHP the environmental criteria are more important (biggest priority) than the geological, the geological criteria are more important than the anthropogenic, while the anthropogenic criteria are more important than the environmental ones, giving in such a way a balanced importance to all main factors (33%).

It has to be noted that for all the AHP scenarios the sub-criteria importance was assigned according to the AHP weighting scheme of the last scenario (scenario 7), which was considered the most suitable for realistic assumptions.

For more details see the Risk Assessment System Tool Report v1.0 (.pdf 1 MB)