[1] Wageningen Univ, Environm Sci Grp, Subdept Water Resources, Hydrol & Quantitat Water Management Grp, NL-6709 PA Wageningen, Netherlands
[2] Vrije Univ Amsterdam, Fac Sci, Div Phys & Astron, Dept Phys Appl Comp Sci, NL-1081 HV Amsterdam, Netherlands
[3] Inst Integrated Inland Water Management & Waste W, RIZA, Minist Transport Publ Works & Water Management, Directorate Gen Publ Works & Water Management, NL-8200 AA Lelystad, Netherlands
[4] Fisheries Res Serv, Aberdeen, Scotland