Fine-tuning to achieve a scenario that can be approved by stakeholders
Introduction
The goal of this step is to obtain a set of potential risk management scenarios to achieve the objectives that have previously been formulated by the stakeholders in Basic RMS and to select the preferred risk management scenario.
An overview of the procedures to define and work out the potential and preferred risk management scenarios is shown in the figure below
The basic risk management scenarios (Basic RMS) are taken as the basis for derivation of the preferred megasite risk management scenarios (Preferred Megasite RMS).
These basic scenarios indicate on a generic level where (source, pathway and/or receptor) and when (short-, mid- and long-term) the measures need to be implemented. Basic risk management scenarios include an overview of technically feasible techniques.
Defining potential risk management scenarios is an iterative process, which requires a continuous confirmation with risk reduction objectives and stakeholder boundary conditions. Generally, for each cluster only a few potential risk management scenarios are suitable. Both benefits and negative effects that are associated with the potential risk management scenarios are determined and compared.
Alternative scenarios are formed for each cluster at different risk reduction levels: at a high, a medium and a lower risk reduction level. This activity is done by the Megasite Expert Team (MET). The Cost-Efficiency and Cost-Benefit analyses are carried out for the first set of potential risk management scenarios (Potential RMS). The Cost-Efficiency and Cost-Benefit analyses exclude various scenarios per cluster level and provide criteria for weighing the remaining scenarios. Finally, at each risk reduction level an alternative scenario is selected and taken into a further evaluation for selecting the final preferred RMS.
The actual decision upon the final preferred RMS is done by the group of the stakeholders (GOS). The Megasite Expert Team provides a number of scenario descriptive criteria to assist in stakeholders in selection and final judgment.
Although this procedure is uniform, there are many ways to work out potential and preferred risk management scenarios at cluster level, depending on the type of megasite, the available information and the stakeholders’ boundary conditions and objectives. Different methodologies and results are demonstrated by the examples for the Bitterfeld, Tarnowski Gory/Katowice and the Rotterdam Harbour megasites.
