1. Haskoning, Royal Dutch Consulting Engineers and Architects, P.O. Box 151, 6500 AD Nijmegen, The Netherlands
2. Wageningen Agricultural University, Department of Environmental Technology, P.O. Box 8129, 6700 EV Wageningen, The Netherlands
3. Institute for Inland Water Management and Waste Water Treatment, P.O. Box 17, 8200 AA Lelystad, The Netherlands