Abstract
The objectives of the version 1.2 site descriptive modelling (SDM) of the Simpevarp subarea are to produce and document an integrated description of the site and its regional environments based on the site-specific data available from the initial site investigations and to give recommendations on continued investigations on a continuous basis. The modelling work is based on primary data available at the time of the data freeze for Simpevarp 1.2, April 1, 2004. The local scale model area (24 km{sup 2}) for the Simpevarp 1.2 modelling encompasses both the Simpevarp and Laxemar subareas. The local model area is located in the centre of a regional scale model area (273 km{sup 2}). Surface ecosystem models in terms of pools and fluxes of carbon have been developed for the terrestrial (e.g. plants and animals) and limnic (e.g. algae and fish) systems using the Lake Frisksjoen drainage area. Furthermore, a first marine ecosystem model has been developed for the Basin Borholmsfjaerden. Three principal lithological domains have been defined in the subarea, an A domain that is dominated by the Aevroe granite, a domain B that is dominated by the fine-grained dioritoid, a C domain that is characterised by a mixture of of Aevroe
More>>
Winberg, Anders
[1]
- ed.
Citation Formats
Winberg, Anders.
Preliminary site description Simpevarp subarea - version 1.2.
Sweden: N. p.,
2005.
Web.
Winberg, Anders.
Preliminary site description Simpevarp subarea - version 1.2.
Sweden.
Winberg, Anders.
2005.
"Preliminary site description Simpevarp subarea - version 1.2."
Sweden.
@misc{etde_20633255,
title = {Preliminary site description Simpevarp subarea - version 1.2}
author = {Winberg, Anders}
abstractNote = {The objectives of the version 1.2 site descriptive modelling (SDM) of the Simpevarp subarea are to produce and document an integrated description of the site and its regional environments based on the site-specific data available from the initial site investigations and to give recommendations on continued investigations on a continuous basis. The modelling work is based on primary data available at the time of the data freeze for Simpevarp 1.2, April 1, 2004. The local scale model area (24 km{sup 2}) for the Simpevarp 1.2 modelling encompasses both the Simpevarp and Laxemar subareas. The local model area is located in the centre of a regional scale model area (273 km{sup 2}). Surface ecosystem models in terms of pools and fluxes of carbon have been developed for the terrestrial (e.g. plants and animals) and limnic (e.g. algae and fish) systems using the Lake Frisksjoen drainage area. Furthermore, a first marine ecosystem model has been developed for the Basin Borholmsfjaerden. Three principal lithological domains have been defined in the subarea, an A domain that is dominated by the Aevroe granite, a domain B that is dominated by the fine-grained dioritoid, a C domain that is characterised by a mixture of of Aevroe granite and quartz monzodiorite. A fourth domain is made up a few scattered domains of diorite to gabbro. In total, 22 deformation zones with high confidence of occurrence have been interpreted in the local scale model area. The understanding of the interpreted deformation zones of the Simpevarp subarea is considered adequate to make a preliminary assessment of available storage volumes for a deep repository. High rock stresses do not appear to be a major concern for the Simpevarp subarea. The magnitude of the maximum principal stress at 500 m in the Simpevarp subarea is estimated at 10-22 MPa. The analysis of the thermal conductivity has developed considerably since Simpevarp 1.1. In terms of interpreted mean values for the identified lithological domains, the thermal conductivity varies within a relatively narrow interval (2.6-2.8 W/(m.K)). The hydraulic properties of the Hydraulic Rock Domains are described in terms of a network of discrete fractures (DFN) with a geometrical description taken from the geological DFN model. A fracture transmissivity distribution is superimposed, and calibrated against existing hydraulic borehole data. Numerical modelling shows that groundwater flow is controlled by topography and the geometry of the system of modelled deformation zones. The modelling also identifies the Simpevarp subarea as an area of groundwater discharge (upward directed flow) at repository depth. Suggested porosities for intact fresh rock (in terms mean values in vol-%) on lithological domain level vary from 0.17 (Fine-grained dioritoid) to 0.40 (Aevroegranite). Suggested formation factors for intact fresh (reflecting diffusion characteristics, mean values) on lithological domain level vary from about 1.0x10{sup -4} (Fine-grained dioritoid) to 2.9x10{sup -4} (Aevroe granite). Important modelling steps have been taken in Simpevarp 1.2 and the main uncertainties are identified, in some cases quantified, or explored as model alternatives. Notwithstanding, some uncertainties still remain unquantified at this stage, and alternative hypotheses are retained only as hypotheses. Additional data, collected in the Simpevarp subarea following the Simpevarp 1.2 data freeze, may allow additional quantification, and may help further reduce the observed uncertainties. For the geological model various possible alternative descriptions are inherent in uncertainties related to geometry, uncertainties in characteristics/properties and confidence of existence of modelled lithological domains and deformations zones. It is obvious that changes to the lithological model have a strong impact on most disciplines (e.g. rock mechanics, thermal and transport properties). The deformation zone model in particular influences the hydrogeological and rock mechanics models. Likewise, there is a strong interdependence between hydrogeology and hydrogeochemistry, primarily through the description of mixing, proposed as being mainly responsible for the evolution of the groundwater chemistry, including the distribution of salinity, over time. The hydrogeochemical model in turn is to a limited degree dependent on the chemical composition of the bedrock and the fracture minerals. There is also the coupling between geology (mineralogy), hydrogeochemistry and the transport model, for the sorption characteristics of the rock. Other aspects on the transport model stem from rock stress effects, both in virgin rock and in drill core rock samples, on the magnitude and anisotropy of diffusion properties, possibly associated with any existing fabric (foliation) of the bedrock. However, what still remains to be better established and quantified are the interactions between the surface system and the bedrock system. This applies primarily to the turnover of water and chemical mass balances. The Simpevarp 1.2 site descriptive model is found to be in general agreement with current understanding of the past evolution. This applies e.g. to the composition of present groundwater in relation to the bedrock lithology and fracture mineralogy. Furthermore, the hydrogeological modelling of groundwater chemical evolution arrives at reasonable present day groundwater compositions when compared with borehole data. No major surprises have been noted in the Simpevarp 1.2 modelling. In summary, more quantitative data have been produced for Simpevarp 1.2 compared with Simpevarp 1.1. Some alternatives have been explored and even propagated in the analysis, but uncertainty remains, particularly in the Laxemar subarea and the regional scale model volume. The modelling for Simpevarp 1.2 is furthermore characterised by a stronger element of interaction between disciplines.}
place = {Sweden}
year = {2005}
month = {Apr}
}
title = {Preliminary site description Simpevarp subarea - version 1.2}
author = {Winberg, Anders}
abstractNote = {The objectives of the version 1.2 site descriptive modelling (SDM) of the Simpevarp subarea are to produce and document an integrated description of the site and its regional environments based on the site-specific data available from the initial site investigations and to give recommendations on continued investigations on a continuous basis. The modelling work is based on primary data available at the time of the data freeze for Simpevarp 1.2, April 1, 2004. The local scale model area (24 km{sup 2}) for the Simpevarp 1.2 modelling encompasses both the Simpevarp and Laxemar subareas. The local model area is located in the centre of a regional scale model area (273 km{sup 2}). Surface ecosystem models in terms of pools and fluxes of carbon have been developed for the terrestrial (e.g. plants and animals) and limnic (e.g. algae and fish) systems using the Lake Frisksjoen drainage area. Furthermore, a first marine ecosystem model has been developed for the Basin Borholmsfjaerden. Three principal lithological domains have been defined in the subarea, an A domain that is dominated by the Aevroe granite, a domain B that is dominated by the fine-grained dioritoid, a C domain that is characterised by a mixture of of Aevroe granite and quartz monzodiorite. A fourth domain is made up a few scattered domains of diorite to gabbro. In total, 22 deformation zones with high confidence of occurrence have been interpreted in the local scale model area. The understanding of the interpreted deformation zones of the Simpevarp subarea is considered adequate to make a preliminary assessment of available storage volumes for a deep repository. High rock stresses do not appear to be a major concern for the Simpevarp subarea. The magnitude of the maximum principal stress at 500 m in the Simpevarp subarea is estimated at 10-22 MPa. The analysis of the thermal conductivity has developed considerably since Simpevarp 1.1. In terms of interpreted mean values for the identified lithological domains, the thermal conductivity varies within a relatively narrow interval (2.6-2.8 W/(m.K)). The hydraulic properties of the Hydraulic Rock Domains are described in terms of a network of discrete fractures (DFN) with a geometrical description taken from the geological DFN model. A fracture transmissivity distribution is superimposed, and calibrated against existing hydraulic borehole data. Numerical modelling shows that groundwater flow is controlled by topography and the geometry of the system of modelled deformation zones. The modelling also identifies the Simpevarp subarea as an area of groundwater discharge (upward directed flow) at repository depth. Suggested porosities for intact fresh rock (in terms mean values in vol-%) on lithological domain level vary from 0.17 (Fine-grained dioritoid) to 0.40 (Aevroegranite). Suggested formation factors for intact fresh (reflecting diffusion characteristics, mean values) on lithological domain level vary from about 1.0x10{sup -4} (Fine-grained dioritoid) to 2.9x10{sup -4} (Aevroe granite). Important modelling steps have been taken in Simpevarp 1.2 and the main uncertainties are identified, in some cases quantified, or explored as model alternatives. Notwithstanding, some uncertainties still remain unquantified at this stage, and alternative hypotheses are retained only as hypotheses. Additional data, collected in the Simpevarp subarea following the Simpevarp 1.2 data freeze, may allow additional quantification, and may help further reduce the observed uncertainties. For the geological model various possible alternative descriptions are inherent in uncertainties related to geometry, uncertainties in characteristics/properties and confidence of existence of modelled lithological domains and deformations zones. It is obvious that changes to the lithological model have a strong impact on most disciplines (e.g. rock mechanics, thermal and transport properties). The deformation zone model in particular influences the hydrogeological and rock mechanics models. Likewise, there is a strong interdependence between hydrogeology and hydrogeochemistry, primarily through the description of mixing, proposed as being mainly responsible for the evolution of the groundwater chemistry, including the distribution of salinity, over time. The hydrogeochemical model in turn is to a limited degree dependent on the chemical composition of the bedrock and the fracture minerals. There is also the coupling between geology (mineralogy), hydrogeochemistry and the transport model, for the sorption characteristics of the rock. Other aspects on the transport model stem from rock stress effects, both in virgin rock and in drill core rock samples, on the magnitude and anisotropy of diffusion properties, possibly associated with any existing fabric (foliation) of the bedrock. However, what still remains to be better established and quantified are the interactions between the surface system and the bedrock system. This applies primarily to the turnover of water and chemical mass balances. The Simpevarp 1.2 site descriptive model is found to be in general agreement with current understanding of the past evolution. This applies e.g. to the composition of present groundwater in relation to the bedrock lithology and fracture mineralogy. Furthermore, the hydrogeological modelling of groundwater chemical evolution arrives at reasonable present day groundwater compositions when compared with borehole data. No major surprises have been noted in the Simpevarp 1.2 modelling. In summary, more quantitative data have been produced for Simpevarp 1.2 compared with Simpevarp 1.1. Some alternatives have been explored and even propagated in the analysis, but uncertainty remains, particularly in the Laxemar subarea and the regional scale model volume. The modelling for Simpevarp 1.2 is furthermore characterised by a stronger element of interaction between disciplines.}
place = {Sweden}
year = {2005}
month = {Apr}
}