Description

The changes in hydrology and hydrogeology, e.g. recharge, sediment load and seasonality, in response to climate change within the region/locality of the repository. Potential effects include climate-induced evolution of surface water bodies, such as the formation of lakes and rivers, or their loss by sedimentation and infilling, river-course meander and long -lasting flooding or drying of low-lying areas.

Category

Categorisation as a Feature, Event and/or Process.

  • Features are physical components of the disposal system and environment being assessed. Examples include waste packaging, backfill, surface soils. Features typically interact with one another via processes and in some cases events.
  • Events are dynamic interactions among features that occur over time periods that are short compared to the safety assessment timeframe such as a gas explosion or meteorite impact.
  • "Processes" are issues or dynamic interactions among features that generally occur over a significant proportion of the safety assessment timeframe and may occur over the whole of this timeframe. Events and processes may be coupled to one another (i.e. may influence one another).

The classification of a FEP as an event or process depends upon the assessment context, because the classification is undertaken with reference to an assessment timeframe. In this generic IFEP List, many IFEPs are classified as both Events and Processes; users will need to decide which of these classifications is relevant to their context and its timeframes.

  • Event
  • Process

Relevance to Performance and Safety

The “Relevance to Performance and Safety” field contains an explanation of how the IFEP might influence the performance and safety of the disposal system under consideration through its impact on the evolution of the repository system and on the release, migration and/or uptake of repository-derived contaminants.

Hydrological and hydrogeological responses to climate change could influence the performance and safety of a repository by: 1) influencing the groundwater flow regime in and/or around the repository; 2) influencing the chemistry of groundwater in and/or around the repository; 3) influencing the separation of the repository from the biosphere; 4) influencing the processes by which radionuclides or other contaminants are concentrated or dispersed within the biosphere; and 5) influencing the nature and spatial distribution of receptors that could be impacted by any radionuclides or other contaminants that are transported from the repository. Changes in the amount of precipitation and evaporation, seasonal ice and snow cover will change the recharge to groundwater. These processes could also result in changes in groundwater chemistry, such as freshwater penetrating to greater depth in times of greater recharge. Additionally, there could be modifications to the quantities and patterns of runoff and the existence / spatial distributions of surface water bodies. In turn, these factors would influence the patterns and rates of erosion, sediment transport and deposition. A consequence of these processes could be changes in the thickness of overburden above and/or near a repository (increasing if sedimentation occurs, decreasing if erosion occurs). A possible result of the hydrological responses to climate change is that topography is modified. Modified flows (quantities and directions) of surface water and groundwater, and associated changes in erosion and sedimentation, accompanied by ecosystem changes, could affect the concentration or dispersion of radionuclides or other contaminants. Hydrological responses to climate change could also cause changes in the character / spatial distributions of ecosystems that could be impacted by any radionuclides or other contaminants that might leave a repository.

2000 List

A reference to the related FEP(s) within the 2000 NEA IFEP List.

1.3.07

Related References