Protecting groundwater with geomembranes in Swedish highway expansion

Published On: January 18, 2022
Integrated into a highway expansion project in Ljungby, Sweden, an HDPE geomembrane protects groundwater feeding the drinking water supply of 70,000 Swedes. Photograph courtesy of Solmax

The E4 highway in Sweden meanders 346 miles (557 km) between Helsingborg and Stockholm. It is one of the country’s most important traffic and transport routes.

Trafikverket (Swedish Transport Administration) sought to upgrade an 18.6-mile (30-km) stretch of this highway at Ljungby, 267 miles (429 km) southwest of Stockholm. This section of the highway passes through a protected area, which is the source of drinking water for the 70,000 residents of the cities of Växjö and Alvesta. In addition to widening the road and adding several bridges and intersections, Trafikverket planned to integrate water-protection measures into the upgrade.

Svenska Geotech of Uddevalla, Sweden, selected and installed Solmax geomembranes to line the ditch alongside the E4 prior to expanding the highway. Over a two-year period, Solmax manufactured 2 million square feet (185,000 m2) of smooth 60-mil (1.5-mm) high-density polyethylene (HDPE) geomembrane at a plant in Rechlin, Germany.

The geomembrane contains the runoff collecting in the ditch, protecting the groundwater from contamination. A protective layer of geotextile was placed under and over the geomembrane to prevent puncturing. A protective layer of sand and a drainage layer of aggregate were placed on top of the multilayer geosynthetic solution.