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The catchment area

Catchment area is the area from which all the water is arriving to the Archipelago Sea. On the map it looks like this.

Samu Numminen joki01

Photo: Samu Numminen



Importance of the catchment

Along with the water in the aquatic cycle in the catchment area, the emissions arrive through the rivers and atmosphere into the Archipelago Sea.  The impacts of the pollution are seen on our coast. It is possible to influence on the load generated in the catchment.


About ten rivers flow in the catchment area of the Archipelago Sea. What ends up in the river easily ends up also in the sea. Usually the bays, where the rivers empty into, are badly eutrophicated. 


The soil in the catchment area of the Archipelago Sea is often very susceptible to erosion. Rainfalls and snow melting are eroding the earth and transporting soil and nutrients to the water system. Steep riversides are increasing the susceptibility to erosion, and they are often cultivated.


The most significant centres of the population and industry are concentrated near the coastline. In the catchment area of the Archipelago Sea live about 400 000 inhabitants. The more dense and used the area is, the bigger impacts it has on the water system.


The catchment area of the Baltic Sea

The Baltic Sea is a small sea, with relatively large catchment area. The acreage of the catchment area is about four times bigger than the water basin. The catchment area consists of fourteen countries. 250 rivers empty into it and there are over 90 million habitants.


There are a lot of heavy industry and agriculture, big cities and waste water, heavy traffic and coastal construction in the catchment area of the Baltic Sea. Among others, the sea itself is heavily operated. The whole catchment of the Baltic Sea is significant to the Finnish waters for currents are transporting load also here.



The worst polluters of the Baltic Sea are listed by Helcom. Find out


A) What kind of hot spot -targets there are in the Baltic Sea area?
B) Whether some of the targets are located in the Archipelago Sea or in its catchment? 


More information:
Finnish Environment Institute: Baltic Sea

Helcom: The Baltic Sea Joint Comprehensive Environmental Action Programme

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