Description
The characteristics of aquifers and water-bearing features within a few metres of the land surface and their evolution.
Relevance screening
Records the decision as to whether or not the FEP is relevant for consideration in the assessment. If not, a brief justification is given. If so, it is indicated to which compartments the FEP may a priori be relevant (near field, geosphere, biosphere, direct exposure).
GEO/BIO/DE
NF consideration
Briefly records whether and in what way the FEP is considered in the near field part of the scenarios and models. These include the gradual release/leaching scenarios, i.e. the expected evolution, alternative evolutions and human intrusions in terms of effect on the containment capacity of the disposal system.
n/a
GEO consideration
Briefly records whether and in what way the FEP is considered in the geosphere (hydrogeology) assessment basis and models for leaching scenarios.
Both the upper and lower aquifers in the vicinity of the Dessel site - separated by the Kasterlee clay aquitard - are included in the modelling for the well/extent of contamination assessment. The focus is on the upper aquifer and the models for the wetland receptor are restricted to this.
BIO consideration
Briefly records whether and in what way the FEP is considered in the biosphere models associated with gradual release/leaching scenarios. In summary, a biosphere model is described for three biosphere receptors: a hypothetical well at the foot of the eastern tumulus, the river north of the site, and wetland zones between the disposal site and the rivers. The well yields the highest impact, and compliance with the equivalent skin dose limit needs to be demonstrated as well. The impact to non-human biota belonging to ecosystems associated with all three receptors is also assessed by means of an ERICA assessment.
Aquifer concentrations are a starting point for establishing soil concentrations/BCFs but the BCF is essentially independent from the actual concentrations
DE consideration
Briefly records whether and in what way the FEP is considered in the direct exposure scenarios and models. These include human intrusion scenarios as used in impact calculations, human intrusion scenarios considered in performance analysis to assess the potential contribution of intrusion barriers, alternative evolutions in which direct exposure could occur (crater formation following a large passenger plane crash), penalising conditions beyond 2000 years.
Relevant when considering leaching from repository-derived material in the surroundings of the disposal site. A drinking water well located downstream the source in deferred-effect intrusion scenarios.