Lake Ladoga (,
Ladozhskoye ozero or ,
Ladoga; ) is a
freshwater lake located in
Republic of Karelia and
Leningrad Oblast in northwestern
Russia, not far from
Saint Petersburg. It is the largest lake in
Europe, and the
14th largest lake by area in the world.
Geography
Map of Lake Ladoga
The lake's area is 17,891 km² (excluding the islands). Its length (north to south) is 219 km, average width is 83 km, average depth is 51 m, maximum depth is about 230 m (in the north-western part). Basin area: 276,000 km², volume: 837 km³ (earlier estimated as 908 km³);. There are about 660 islands, with a total area of 435 km². Ladoga's level above the sea is 5 m on average. Most of the islands, including the famous
Valaam archipelago,
Kilpola and
Konevets, are situated in the north-western part.
Separated from the
Baltic Sea by the
Karelian Isthmus, it drains into the
Gulf of Finland via the
Neva River.
Lake Ladoga is navigable, being a part of the
Volga-Baltic Waterway connecting the
Baltic Sea with the
Volga River. The
Ladoga Canal bypasses the lake in the southern part, connecting the Neva to the Svir.
The basin of Lake Ladoga includes about 50,000 lakes and 3,500 rivers longer than 10 km. About 85% of the water income is due to tributaries, 13% is due to
precipitation, and 2% is due to underground waters.
Tributaries
(incomplete list)
Geological history
Deglaciation following the
Weichsel glaciation took place in the Lake Ladoga basin between 12,500 and 11,500
radiocarbon years BP. Lake Ladoga was initially part of the
Baltic Ice Lake (70-80 m. above present
sea-level), a historical
freshwater stage of
Baltic Sea. It is possible, though not certain, that Ladoga was isolated from it during
regression of the subsequent
Yoldia Sea brackish stage (10,200-9,500 BP). The isolation threshold should be at
Heinjoki to the east of
Vyborg, where the
Baltic Sea and Ladoga were connected by a strait or a river outlet at least until the formation of the River Neva, and possibly even much later, until 12th century AD or so.
[Davydova, Natalia N. et al. (1996). . Hydrobiologia 322.1-3, 199-204.]At 9,500 BP,
Lake Onega, previously draining into the
White Sea, started emptying into Ladoga via the
River Svir. Between 9,500 and 9,100 BP, during the transgression of
Ancylus Lake, the next freshwater stage of the Baltic, Ladoga certainly became part of it, even if they hadn't been connected immediately before. During the Ancylus Lake subsequent regression, around 8,800 BP Ladoga became isolated.
Ladoga slowly
transgressed in its southern part due to uplift of the
Baltic Shield in the north. It has been hypothesized, but not proven, that waters of the
Litorina Sea, the next brackish-water stage of the Baltic, occasionally invaded Ladoga between 7,000 and 5,000 BP. Around 5,000 BP the waters of the
Saimaa Lake penetrated
Salpausselkä and formed a new outlet,
River Vuoksi, entering Lake Ladoga in the northwestern corner and raising its level by 1-2 m.
The River Neva originated when the Ladoga waters at last broke through the threshold at Porogi into the lower portions of
Izhora River, then a tributary of the
Gulf of Finland, between 4,000 and 2,000 BP. According to some new data, it happened at 3,100
radiocarbon years BP (3,410-3,250 calendar years BP).
Wildlife
The Ladoga is rich with fish. 48 forms (species and infraspecific taxa) of fish have been encountered in the lake, including
roach,
carp bream,
zander,
European perch,
ruffe, endemic variety of
smelt, two varieties of
Coregonus albula (vendace), eight varieties of
Coregonus lavaretus, a number of other
Salmonidae as well as, albeit rarely, endangered
European sea sturgeon. Commercial fishing was once a major industry but has been hurt by overfishing. After the war, between 1945 – 1954, the total annual catch increased and reached a maximum of 4,900 tonnes. However, unbalanced fishery led to the drastic decrease of catch in 1955 – 1963, sometimes to 1,600 tonnes per year.
Trawling has been forbidden in Lake Ladoga since 1956 and some other restrictions were imposed. The situation gradually recovered, and in 1971-1990 the catch ranged between 4,900 and 6,900 tonnes per year, about the same level as the total catch in 1938. Fish farms and recreational fishing are developing.
It has its own
endemic Ringed Seal subspecies known as the
Ladoga Seal.
Since the beginning of the 1960s Ladoga has become considerably
eutrophicated.
Nizhnesvirsky Natural Reserve is situated along the shore of Lake Ladoga immediately to the north of the mouth of the
River Svir.
History
In the
Middle Ages, the lake formed a vital part of the
Trade Route from the Varangians to the Greeks, with the Norse emporium at
Staraya Ladoga defending the mouth of the Volkhov since the 8th century. In the course of the
Swedish-Novgorodian Wars, the area was disputed between the
Novgorod Republic and
Sweden. In the early 14th century, the fortresses of
Korela (Kexholm) and
Oreshek (Nöteborg) were established along the banks of the lake.
The ancient
Valaam Monastery was founded on the island of
Valaam, the largest in Lake Ladoga, abandoned between 1611 – 1715, magnificently restored in the 18th century, and evacuated to Finland during the
Winter War in 1940. In 1989 the monastic activities in the Valaam were resumed. Other historic cloisters in the vicinity are the
Konevets Monastery, which sits on the
Konevets island, and the
Alexander-Svirsky Monastery, which preserves fine samples of medieval Muscovite architecture.
During the
Ingrian War, a fraction of the Ladoga coast was occupied by
Sweden. In 1617, by the
Treaty of Stolbovo, the northern and western coast was ceded by Russia to Sweden. In 1721, after the
Great Northern War, it was restituted to Russia by the
Treaty of Nystad. Later, in 1812 – 1940 the lake was shared between Finland and Russia. According to the conditions of the 1920
Tartu Peace Treaty militarization of the lake was severely restricted. However, both Soviet Russia and Finland had flotillas in Ladoga (see also
Finnish Ladoga Naval Detachment). After the
Winter War (1939-1940) according to the
Moscow Peace Treaty, Ladoga, previously shared with Finland, became an internal basin of the Soviet Union.
Superior
mirage on Lake Ladoga
During the
Continuation War (1941-1944) not only Finnish and Soviet, but also German and Italian (see also
Naval Detachment K and
Regia Marina#Lake Ladoga) vessels operated there. Under these circumstances, during much of the
Siege of Leningrad (1941 – 1944), Lake Ladoga provided the only access to the besieged city because a section of the eastern shore remained in Soviet hands. Supplies were transported into
Leningrad with trucks on winter roads over the ice, the "
Road of Life", and by boat in the summer. After
World War II, Finland lost the
Karelia region to the USSR, and all Finnish citizens were
evacuated from the ceded territory. Ladoga became an internal Soviet basin. The northern shore,
Ladoga Karelia with the town of
Sortavala, is now part of the
Republic of Karelia. The western shore,
Karelian Isthmus, became part of
Leningrad Oblast.
Since 1996 the is an annual competition for
4x4 vehicles and
ATVs that travels through over 1200 kilometers of the mud, swamp and bog that surround Lake Ladoga .
Towns upon the Ladoga
Oreshek Fortress on Ladoga shore in Shlisselburg
