The Baltic Klint: Waterfall on the Tosna river EarthCache
The Baltic Klint: Waterfall on the Tosna river
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In order to claim this cache as found one should answer two
questions: 1.At the point with given coordinates one can see a
huge stone block. In fact, that is not a natural stone but a
fragment of the railway bridge which was constructed over the
waterfall in XIXth century. The bridge was made of local limestone
and was fully demolished during the war. The fragment is composed
of several layers of brickwork. Measure the thickness of the fifth
layer from the top in centimetres. 2.Estimate the power of the
river flow at the time of your visit: strong, when the waterfall is
almost covered with a tempestuous flow; medium, when the water
pours from the steps of the waterfall; or weak, when the thin
trickle trickles down.
The Tosna waterfall in May
The Baltic Klint is an approximately 1200 kilometers long system of
erosional escarpments in Lower Palaeozoic (Cambrian to Ordovician)
sedimentary rocks between the southern end of Öland Island in
Sweden and Lake Ladoga (the estuary of the Syas` River) in Russia.
The klint follows more or less the boundary between the
Fennoscandian (Baltic) Shield and the East European Platform. On
the basis of the specific features of the escarpments, the Baltic
Klint has been divided into the following four major sections or
regional klints (from the west to the east): Öland Klint, Baltic
Sea Klint, North Estonian Klint and Ingrian Klint. Ingrian
(Ingermanland) Klint makes up the eastern part of the Baltic Klint
– approximately 250 km of the klint between the Narva River
and the Syas` River (which debouches into Lake Ladoga). The
escarpments of the Ingrian Klint are buried and mostly flattened
and bedrock crops out only in places on the banks of rivers cut
into the klint. The klint was named Ingrian Klint after the common
name of the Balto-Finnish peoples formerly inhabiting the St.
Petersburg area (Votic, Veps, Karelians, Izhoras). On the Ingrian
Klint near Koporye, the limestone plateau of the Baltic Klint is at
its highest (up to 140 m asl) and also the width of the klint zone
is the largest here (up to 50 km).
The Baltic Klint is cut by numerous rivers (including the Narva
River, Luga River, Izhora River, Tosna River), some of which form
waterfalls and rapids. Rapids on the Volchov river and Neva river
were significant dangers for merchant ships up to XIXth century.
The Klint as the natural obstacle was widely used for defensive
needs. Many old Russian fortresses, like Ladoga, Yam, Koporie and
Ivan-gorod, were built on the edge of the Klint. The limestone was
also a significant building material. There are only two waterfalls
in the Leningrad region, and both of them are located where the
flow of the river cuts into the limestone escarpment.
The Tosna waterfall near the village of Gertovo is the largest
waterfall in Leningrad region. Its height is about 2.5 to 3 meters
depending on the level of the water. The waterfall moves upstream
from 40 to 60 centimetres per year as water erodes the limestone.
The river of Tosna is quite shallow and rarely its depth exceeds
1.5 meters, but under the waterfall its depth reaches more than 4
meters, obviously, due to water erosion.
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