Therefore, basic scenarios were combined to build up the potential scenarios, by which the defined risk reduction objectives can be achieved. This was an iterative process taking into account: revized boundary conditions, defined risk reduction objectives and technical feasibility aspects.<br/><Br/>
<strong>Revision of the boundary conditions</strong><br/><br/>
As a result of the group of stakeholders (GOS) meeting, the boundary conditions of the Tarnowskie Góry megasite were revised to reflect the following aspects.
<ol>
<li>Management within the risk clusters should be path- and receptor- oriented, and two key factors should be taken into account:
<ul>
<li>groundwater quality,</li>
<li>groundwater quantity,</li>
</ul></li>
<li>These factors should be addressed on different scales:
<ul>
<li>at the megasite,</li>
<li>at the RMZ and its risk clusters,</li>
<li>at the RMZ and the area around</li>
</ul></li>
<li>Hazardous waste removal and safe landfilling should be the basis for any potential scenario build-up as removing of the source eliminates contaminant flux to groundwater<br/><br/>
The officially established management plan for the Tarnowskie Góry megasite includes:
<ul>
<li>construction of a controlled landfill for hazardous waste of an area of 16 ha with the capacity of 1,6 million m<sup>3</sup>,</li>
<li>safe deposition of approximately 1.5 million m<sup>3</sup> of hazardous waste in a way that complies with the legal Polish and EU requirements,</li>
<li>revitalization of the Stola river valley including the construction of new bed at the length of 800 m within the area of the chemical plant,</li>
<li>revitalization of the area of 50 hectares of previous dumping sites with the allocation of ca. 10 ha for the further use,</li>
<li>continuous long-term monitoring of all environmental compartments (soil, water and air).</li>
</ul>
<u>Note</u>: The results of simulation studies show that land filling of waste has a moderate effect on improving groundwater quality in a short- (30 years) and medium-term (60-80) time frame. It guarantees that some of the risks, which occur on the surface level of the megasite, are moderated or eliminated. The remaining risk, due to the secondary sources of contamination (the Quaternary deposits) is attributed mainly to groundwater quality within the delineated RMZ. The total costs of this measure, including industrial constructions dismantling, construction of a safe landfill, waste removal and soil remediation, are estimated at the level of 12 million Euro.<br/><br/></li>
<li>Site hydrogeology should be recognized as a key boundary condition of any management scenario.<br/>
In the case of the Tarnowskie Góry megasite the dynamics of the hydrological system should be managed cohesively on a broader scale, even beyond the established RMZ (see figure below).<br/><br/>
The hydrological conditions are important for the receptors (operating wells) located in the south-western part of the RMZ. For example, changing of the water extraction regime beyond the RZM (lower extraction quantities in wells located in the western and higher in the south-western part) may result in the higher risk in the south-west of cluster IIb due to changes in groundwater flow directions. Moreover, increased water extraction of the Triassic layer II can result in groundwater deterioration.
</li>
</ol>
<center>
<img src="../images/examples/tarn/fig_31e_TG_5.jpg">
</center><br/><br/>
<ol start="5">
<li>There is no direct short-term risk for the receptors due to low groundwater flow rates, therefore the megasite management can be more flexible both in time and space.</li>
|