1. Research Engineer, Swedish Geotechnical Institute, Hugo Grauers gata 5B, SE-41296 Göteborg, Sweden (corresponding author).
2. Professor, Water Resources Engineering, Lund Univ., Box 118, SE-22100 Lund, Sweden.
3. Researcher, DHI Sverige AB, Drakengatan 6, SE-412 50 Göteborg, Sweden.