• Characteristics of lakes
• Ecosystem approach in restoration
• What are the results sofar?
• Prospects for 2015?
River IJssel
1932 Afsluitdijk
19421957
1968
1976
1930IJsselmeer
Markermeer
P-inflow
P-lake
algae
turbidity
nutrient management
hydro- morphology
fisheries management
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
1,8
2
1967 1971 1976 1981 1986 1991 1996 2001 2006
TP
in m
g/l
Total PhosphorusRhine at D/NL border
0,00
0,05
0,10
0,15
0,20
0,25
0,30
0,35
1980 1985 1990 1995 2000 2005
tota
al-P
(m
g/l
)
0
20
40
60
80
100
120
140
1980 1985 1990 1995 2000 2005
chlo
rofy
l-a
(mg
/l)
0,00
0,50
1,00
1,50
2,00
2,50
3,00
3,50
4,00
4,50
1980 1985 1990 1995 2000 2005
tota
al-N
(m
g/l
)
0,00
0,10
0,20
0,30
0,40
0,50
0,60
0,70
0,80
0,90
1,00
1980 1985 1990 1995 2000 2005
do
orz
ich
t (m
)
1
10
100
1000
0.01 0.10 1.00 10.00
totaal-P (mg/l)
chlo
rofy
l-a (u
g/l)
A (n=13)
D (n=49)C (n=22)
B (n=2)
Means apr-sep 2000-2005
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1980 1985 1990 1995 2000 2005 2010
do
orz
ich
t (m
)
Wolderwijd Veluwemeer Eemmeer
Gooimeer Zwarte Meer norm
0
100
200
300
400
500
600
700
800
900
1000
TP
CHL
Secchi
100 m-2
400 m-2
Dreissena
m
g.m
-3
se
cchi in
mm
Fisheries
0
50
100
150
200
250
300
350
1969 1972 1975 1978 1981 1984 1987 1990 1993 1996 1999
0
0,2
0,4
0,6
0,8
1
1,2
1,4
1,6
Se
cc
hi
(m)
bream mussel Secchi
Veluwemeer 1969-2000
Bre
am k
g.h
a-1
mu
ssel
N.m
-2
Fisheries
fishery
bream
disturbance sediment
turbidity
Chara beds Dreissenamussels
After Lammens et al. (2004)
+
+-
-
0
200
400
600
800
1000
1200
1400
1600
1969 1974 1979 1984 1989 1994 1999
Inte
rnal
cov
erag
e (h
a, 1
00%
den
sity
)
0,0
2,0
4,0
6,0
8,0
10,0
12,0
14,0
Sec
chi (
dm)
Chara spp.
Potamogeton perfoliatus
Potamogeton pectinatus
transparency
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
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?
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)
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)
- 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