About 10% of Finland's surface area are waterways. There are 190000 lakes and pands
in Finland. The minimum size of a lake is 500 m² otherwise it's a pond. There
are only three lakes which are bigger than 1000 km² They are called Suur-Saimaa,
lake Inari and lake Pielinen. Most of the lakes are only 1 km² size. The inlandwaters of Finland are
quite low, depending on the size and location of a lake. About 70% of our lakes
are less than ten meters deep. The smallest lakes (there are thousands of them) can be only a couple of meters deep. The deepest lake in Finland
is called P„ij„nne, and it's 95 meters deep. Lakes, as other forms of the ground have their own
special features. On most of our waterways some geological research has been done. With the help of research we have been
able to find out reasons for the different shapes of lakes. Iceage has had a great influence when the landscape has been transformed.
Ice has broken the weak parts of the rock and has cleanded them from erosion. The lenght of the beachlines of the lakes
vary greatly. A small lake can also have a long beachline if there are many bays. We have 179000 lakes which are bigger than are one acre.
Less than 10 percent of the waterways have lots of nutrients. 2/3 of waterways are humous the richness of humus causes entrophication in the waterways which spoils the
living conditions of some animals. However, the condition of about 80% of our waterways is considered to be good or excellent.
Lakes in which the quality of the water is bad, are usually small. Our waterways areas have lots of different plants.
The most common is common reed (Phragmites australis), common club-ush (schoenoplectus lacustris) and bulush.
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