2012:49 Hydrogeological characteristics of sites for low- and intermediate-level waste disposal

The Forsmark area with its selected two sites and the Laxemar-Simpevarp area with its two sites are broadly similar in terms of lithology, rock ages, and tectonic histories. The two areas differ in terms of degree of deformation, and tectonic fabric. Some lithologic and tectonic differences are noticeable between the two sites in the Forsmark area and between the two sites in the Laxemar-Simpevarp area.

These differences can be expected to influence hydrologic properties including the magnitude and anisotropy of effective hydraulic conductivity on various scales. However, prediction of the consequences is dependent on complex fracture-network models, and these have not been presented at the same level of development or level of detail for all sites. In this study a simple evaluation of Darcy flux and transport resistance has been made for the sites.

This evaluation indicates that the inland Forsmark-lens site has highest predicted fluxes and also the lowest minimum transport resistances, due to the very high horizontal hydraulic conductivity in the shallow bedrock. The simple evaluation also indicates that the Laxemar and Simpevarp sites have a lower minimum value of transport resistance than the Forsmark-SFR site; however, estimates are within roughly an order of magnitude.