Fracture Characterization for New Landfill Sites in Crystalline Bedrock: A Case Study from Rogaland, Southwestern Norway

Abstract Crystalline bedrock generally has very low permeability, preventing fluid flow; however, fractures can provide critical flow pathways. In the context of landfills developed in crystalline bedrock, a comprehensive understanding of fracture networks is a key for environmentally safe and sustainable waste storage. This study presents the interpretation of borehole logs and Lugeon tests combined with the isotopic composition of well water surrounding a rock quarry to assess its potential as a landfill site. The Rekefjord quarry is located on the southwestern coast of Norway. Structural interpretations indicate randomly distributed fractures, but also steeply dipping fractures that are not well captured by vertical boreholes. To correct for orientation biasness the Terzaghi correction was applied. Most of the borehole fractures display apertures in the range of 2–10 mm and average degrees of connection ( D ) varies between 3.09 and 1.92. The hydraulic conductivity of 5 m borehole sections range from 1.2 × 10 –6 to 1.6 × 10 –10 m/s, showing no clear relationship with depth or fracture frequency or aperture. The 87 Sr/ 86 Sr ratio measured in groundwater supports the fluid connectivity within the fracture network and indicates mixing with surface water. Although this study provides site specific results, the integrated methodology combining structural analysis, hydraulic testing, and isotopic characterization and findings provide a robust framework applicable to evaluating fracture networks and fluid connectivity in similar crystalline bedrock settings.