Abstract
The building of a railway tunnel through the Hallandsås ridge in the southwest of Sweden resulted in sinking groundwater levels and a toxic spill for the local community. As a result, this highly technological project expanded from the addressing of technological and economic issues of rail traffic and tunnel building to include issues of environmental harm and how to assess and manage the geology of the ridge. A central concern for local residents as well as for the developer has been how to view and interpret the resource of groundwater. This article focuses on groundwater as a boundary object, bordering the domains of the technologists and the local community. In this situation, technological understanding and knowledge confronts an experience-based understanding and a symbolic interpretation of the water resource.