The Greenland Analogue Project
A deep geological repository is designed to keep radiotoxic material separated from mankind and the environment for several hundreds of thousands of years. Within this time perspective glacial conditions are expected in regions that have been glaciated in the past. Climate induced changes such as the growth of ice sheets and permafrost will influence and alter the ground surface and subsurface environment, which may impact the repository safety. Glaciation assessments have to date used over-simplified models of e.g. ice sheet hydrology that does not reflect the complexity of the real world. This is largely due to lack of direct observations of such systems from existing ice sheets. In order to understand how climate change, particularly cooling and glaciation, might affect the repository in the long term the use of a present-day analogue could help support the assumptions made in the safety assessments and reduce uncertainties. Moreover, evidence of glacial hydrological processes from present-day ice sheet analogues, which could provide a strong scientific basis for a safety assessment of possible glacial impacts, does not exist.
Our current understanding of the hydrological, hydrogeological and hydrogeochemical processes associated with glacial cycles and their impact on the long-term performance of deep geological repositories will be significantly improved through the Greenland Analogue Project. The Greenland Analogue Project also presents an opportunity to study the periglacial environment in situ where biosphere conditions and exposure pathways can readily be observed. Morover, this project concerns the first in situ investigations of the vital parameters needed to achieve a holistic and realistic understanding of how an ice sheet may impact a deep repository, and will provide measurements, observations and data that may significantly improve our safety assessments and risk analyses of glaciation scenarios.
Aim and project structure
The overall aim of the Greenland Analogue Project was to improve the current understanding of how an ice sheet affects the groundwater flow and the water chemistry around a deep geological repository in crystalline bedrock during glacial periods. Through the execution of the project we were able to improve our understanding of hydrogeological and hydrogeochemical processes associated with glacial periods and with the presence of permafrost. This will improve our safety assessments and risk analyses by reducing the large uncertainties and pessimistic assumptions in the glacial scenarios.
The Greenland Analogue Project started in 2008 and the large-scale field investigations were concluded in the autumn of 2013. The project has now released the two final reports (SKB R-14-13 and SKB TR-14-13), which presents the datasets collected and the key findings of the GAP.
The project included three sub-projects (A-C) with specific individual objectives, which collectively aimed at contributing knowledge and input to the overall project aim. The purpose of subdividing the project was that insights and data obtained from the different sub-projects constitute self-consistent data sets, which were tested and implemented in the individual sub-projects. Such a project setup allowed a more efficient project execution. The overall idea was that the results of all sub-projects used and analysed together would result in large synergistic effects for the understanding of hydrological conditions under glacial periods. That is also the reason why all sub-projects were performed within the same geographical area.