Assumptions about groundwater flow based on observations from single-well test sites and a multi-well test site were evaluated by statistical methods on a regional data set of borehole flow rates and ground checked, remotely sensed lineaments. The analysis shows that the influence area of lineaments is characterised by a three-partite flow zonation which mirrors that of the hydromechanical fault zone architecture. This flow rate zonation indicates important guide-lines for the siting of water wells in lineaments. But borehole flow rates in the most permeable zone, i.e. the damage zone of the lineaments, cannot be distinguished statistically from borehole flow rates in the less fractured background area. Contrary to the field site results, critically stressed lineaments in the current stress field are statistically equivalent to other lineament directions with respect to groundwater flow. This may relate to topographic perturbations of the regional WNW-ESE stress field, which reorient the maximum compressive stress ?H into parallelism with fjord- and valley sides in this region. The statistical analyses, which show that topography is the most important explanatory variable for the observed variations in borehole flow rates, support this view.
Fracture lineaments and their surroundings with respect to groundwater flow in the bedrock of Sunnfjord, Western Norway