1. harry.hosper@rws.nl Centre for Water Management Budapest, 12 October 2007

2. Characteristics of lakes Ecosystem approach in restoration What are the results sofar? Prospects for 2015?

7. River IJssel 1932 Afsluitdijk 1942 1957 1968 1976 1930 IJsselmeer Markermeer

18. P-inflow P-lake algae turbidity nutrient management hydro- morphology fisheries management

19. Total Phosphorus Rhine at D/NL border

21. Means apr-sep 2000-2005

25. 100 m-2 400 m-2 Dreissena mg.m-3 secchi in mm Fisheries

26. Bream kg.ha-1 mussel N.m-2 Fisheries

27. fishery bream disturbance sediment turbidity Chara beds Dreissena mussels After Lammens et al. (2004) + + - -

31. Conditions today: positive trends in P, N, CHL and Secchi some clear water, macrophyte-dominated lakes still many turbid water lakes, no macrophytes Short-term action: Sewage: 4-th step in treatment plants in some catchments Agriculture: reduce surface run off by smart agr practices Fishery: reduce bream to help macrophytes & mussels

32. Clear water lakes 2015? Yes, … if bream fishery is accepted as management tool Long-term perspectives? Natural water levels Flooding of adjacent land areas (following sea level rise) Letting the sea back in?

33. Mission: learning, inspiration, helping,.. Integrating water policy, lake science and lake management,.. Organization: - 140 members on list - national/local government, consultancy, universities, stake holders - informal platform, no membership dues, free meetings/lunches (rotating hosts pay for that) - programme committee (<0.5 ftu), administration by CWM (Centre for Water Management, = ex RIZA)

34. Activities: - meetings 2x per year, field excursions - international excursions (Broads UK, Müritzsee D, Jutland DK?) - sounding board for case studies/restoration plans - national eutrophication survey - website (www.shallowlakes.net, under restoration )www.shallowlakes.net

37. - EU network of national networks Social network & virtual network Sowing the seeds for: European Lake Management Society (ELMS)? First EU Lake Management Conference 2010? See also: www.nalms.org