Lake Maggiore

Limnological research on Lake Maggiore as a
contribution to transboundary cooperation between
Italy and Switzerland
Rosario Mosello, R. Bertoni & P. Guilizzoni
C.N.R. - Institute of Ecosystem Study
Verbania Pallanza
The Institute of Ecosystem Study
Verbania Pallanza
Main research activities
Structure and functioning of aquatic and terrestrial
Pisa
ecosystems
Firenze
Aquatic and terrestrial ecosystems and global
change
Sassari
Soil quality and ecology
Lake Maggiore
Ticino, Valais,
Grisons
River Po watershed
Piedmont, Lombardy
Maggiore
Lugano
Como
Monte
Rosa
Iseo
Garda
Lago di
Mergozzo
go
La
re
io
Lago di
Lugano
Lugano
Lago di
Varese
Ad
da
VENEZIA
Og
lio
Orta
Lake Maggiore
a
N
MILANO
n
Olo
Varese
Mi
nc
io
Po
aro
Pan
ro
Ta
Mediterranean
sea
ia
cch
Se
Po
Mediterranean
sea
Po
Ta
na
Bo
ro
rm
id
a
Po
ino
Tic
TORINO
si a
Se
ra
Do tea
l
Ba
Dora Ripa
ria
Lago
d’Orta
g
ag
M
Characteristics of the watershed
Monte
Rosa
Lago di
Mergozzo
Lago
d’Orta
go
La
e
or
gi
ag
M
Lago di
Lugano
Lago di
Varese
• Well developed hydrography, with 32 natural and artificial lakes and 14 main
tributaries
• Mild climate (heat-regulating effect of the lake and sheltering effect of the
Alps), but damp, with high atmospheric precipitation (1700 mm/y)
• Just over 50% of the drainage basin is in Switzerland, while 80% of the lake is in Italy
• 670,000 residents (200,000 near the shore line) + 30,000 temporary residents
(visitors)
Lago Maggiore morphometric and hydrological
features
drainage
area
basin
6599 km2
lake area
212 km2
lake volume
37 km3
mean level
194 m a.s.l.
max depth
370 m
mean depth
177 m
drainage basin /
lake area ratio
theoretical
renewal time
31.1
4.0 years
Lake Maggiore resources and uses of the waters
Environmental value
high
Hydraulic regulation
present
Tourism recreation
15 Million y-1
Bathing
high
Drinking
present
Public navigation
high
Private/recreational
navigation
high
Water for agriculture
high
Sport fishery
high
Professional fishery
high
Hydroelectric production
Artificial
lakes, outlet,
Management of the lake and its watershed
1882
International Commission for
the Fisheries in Italian Swiss
waters
1946
International Commission for
the outflow regulation
1972
International Commission for
the protection of Italian Swiss
waters (CIPAIS)
Total catch (2004-2006) :
120 tons
15 tons
1882
whitefish + shad
coarse fish + perch + trout
Perch
Landlocked shad
2,3%
International Commission for
the Fisheries in Italian Swiss
waters
Coarse fish
7,9%
12,4%
Trout
0,7%
76,7%
Whitefish
Water level fluctuations: flood
1946
International Commission for
the outflow regulation
Floods are the historical threat in the Lago Maggiore
area, because of the high amount of
precipitation. Main hydrogeological damages
are in the watershed, but flooded material on the
lake surface causes problems to the navigation.
1882
Lake trophic evolution
International Commission for the
Fisheries in Italian Swiss waters
Up to Fifties
Low algal productivity
OLIGOTROPHIC
1960 – 1969
Increase of algal productivity
MESOTROPHIC
1970 – 1980
Further increase of productivity
MESO-EUTROPHIC
1981 – 1990
Slight decrease of productivity
MESOTROPHIC
1991 – 1997
Strong decrease
Since 1998
Low biological productivity
MESO-OLIGOTROPHIC
OLIGOTROPHIC
-1
µg P l
40
Reactive phosphorous
Total phosphorous
30
20
10
0
1955 1960 1965 1970 1975 1980 1985 1990 1995 2000 2005 2010
µg P l-1
40
µg Chl l-1
6,0
[TP] 0-370 m
[Chl] 0-20 m
30
5,0
[TP] 0-20 m
20
4,0
10
3,0
0
2,0
'78
'80
'82
'84
'86
'88
'90
'92
'94
'96
'98
'00
'02
In summer 2005, 2006
and 2007 the presence
of the cyanobacteria
Anabaena
lemmermannii was
observed in Lake
Maggiore
Lake Maggiore
Heat content in the mass of water (MJ m-2)
1500
1450
1400
1350
1300
1250
1200
1960 1964 1968 1972 1976 1980 1984 1988 1992 1996 2000 2004 2008 2012
Commissione Internazionale
Commissione Internazionale
per la protezione delle acqua italo-svizzere
per la protezione delle acqua italo-svizzere
Ricerche sull'evoluzione del Lago Maggiore
Monitoraggio della presenza del DDT e di altri contaminanti
nell’ecosistema Lago Maggiore
RAPPORTO ANNUALE
APRILE 2005-MARZO 2006
Aspetti limnologici
Programma quinquennale 2003 – 2007
a cura di Roberto Bertoni
Consiglio Nazionale delle Ricerche
Istituto per lo Studio degli Ecosistemi
A cura di P. Guilizzoni & A. Calderoni
Pallanza 2006
Sede di Verbania
AGONE
12,4%
PERSICO
2,3%
PESCE
BIANCO
7,9%
TROTA
0,7%
COREGONE
76,7%