1. a Department of Civil and Environmental Engineering, University of Strathclyde, Glasgow UK
2. b The James Hutton Institute, Craigiebuckler, Aberdeen, AB15 8QH, UK
3. c Global Water Partnership, P.O. Box 24177, SE-104 51, Stockholm, Sweden
4. d Sociology of Development and Change Group, Wageningen University & Research, P.O. Box 8130 6700 EW, Wageningen, Netherlands
5. e Sanitation, Ministry of Water and Sanitation, Government of Malawi, Private Bag 390, Lilongwe, Malawi