
Grimsel reservoir
1949
1949
1965
1965
1951
1975
1969
1968
1963
1952
2002
1969
1968
1964
1968
1973
1996
1964
1978
1881
1986
1987
1983
1982
1965
1966
1984
1974
1967
1955-1959
1949
1962
1960
1967
1965
1967
1967
1964
1961
1976
1959
1969
1967
1960
1959
1963
1946
1963
1964
1962
1965