Getting things in order
The overall objective of this section is the provision of all criteria needed to define a site as a megasite and to derive the specific management tasks. The decision to proceed with the IMS is, among other factors, the presence of large-scale groundwater contaminations (deteriorations, in sense of the Groundwater Directive), which cannot be removed by technical means at reasonable costs (the proportionality principle of the Groundwater Directive)
In order to determine the specific criteria for taking the decision to proceed with the IMS and to organize the management tasks at megasite levels, the following activities need to be carried out, by a megasite expert team (MET):
- decide if the site is a megasite, and if the integrated management strategy (IMS) could be suggested as a appropriate approach,
- form a group of stakeholders (GOS),
- make an overview of boundary conditions,
- make an inventory of megasite information,
- build a conceptual model. Including hypothesis on megasite boundaries and the risk management zone (RMZ).
1. The decision whether a site of concern is a megasite should be based on the two following criteria:
the level of existing groundwater contamination,
whether or not the decontamination of the groundwater is technically, economically and/or politically impossible in a defined timeframe.
If a complete clean-up is unacceptable, a megasite approach and the subsequent application of the IMS could be useful for the cost-effective management. However, the development of such an approach must be negotiated within the group of stakeholders (GOS), including responsible authorities, site developers, problem owners etc., in interaction with the megasite expert team (MET).
2. MET and GOS supply all necessary information to describe the megasite and can be involved in the decision-making process on further managing of the site. It is important to include all competent authorities, problem owners and site developers from an early stage on, to start an integrated management strategy and to define interest conflicts. The organisation of a megasite coordination committee with responsibilities and tasks is the basis of an effective management of the site.
3. Identifying existing boundary conditions is necessary to define a megasite and to determine the appropriate management tasks. An overview of the boundary conditions must therefore be made before starting any further management tasks, and includes:
existing legislative standards (on the local, national and EU levels),
public interest,
sustainability-factors,
costs and funding options.
In this step, the IMS offers a guideline on how to create a systematic overview of all boundary conditions and their significance for the management of megasites.
4. This step includes creating an inventory of all information necessary for the further process of defining and/or managing the megasite (the risk assessment, remediation- / monitoring concepts). The input for this step is delivered by all available data sources. Information gaps are completed in subsequent steps of the IMS. Due to the tiered process of the IMS implementation, also the gathering of megasite information is a tiered process. It means, for example, that first the inventory of all information necessary for the risk assessment is to be realized. The inventory of additional information will only be necessary, if further damages are possible. The inventory of megasite information at this stage includes:
- gathering and combining all available information and expert knowledge,
- collecting, checking and managing (updating) data on the megasite,
- interpreting data with help of a Geographical Information System (GIS).
5. To conclude and visualize all gathered information, a conceptual model of the megasite, and consequently the possible risk management zone, are to be developed. This preliminary conceptual model should include all available data, and is the basis for the next steps of the IMS, such as the risk assessment in section 2. The main steps to build this conceptual model are:
identify potential resources and contaminants,
determine extent and spatial distribution of the contamination,
identify the dominant fate and transport characteristics of the site,
identify potential receptors/ land use plans,
develop a hypothesis on the planes of compliance, the borders of the megasite and the RMZ, and integrate the RMZ into a river basin management plan.
