Puruvesi

Puruvesi is a lake in Eastern Finland. The lake is located in Kerimäki, Kesälahti and Punkaharju municipalities. Part of the Saimaa lake system, it borders on the sub-lake system of Pihlajavesi to the south. As is the case of other lakes of Saimaa, it has numerous islands and consists of numerous open lake areas, of which largest are Hummonselkä, Pajuselkä, Sammalselkä, Mustanselkä, and Ruosteselkä.[2]

Puruvesi
Puruvesi
Location	Eastern Finland
Coordinates	61°50′N 029°27′E
Basin countries	Finland
Surface area	420.86 km2 (162.49 sq mi)[1]
Average depth	8.76 m (28.7 ft)
Max. depth	61 m (200 ft)
Water volume	3,655 km3 (2.963×109 acre⋅ft)
Shore length1	923.97 km (574.13 mi)
Surface elevation	75.7 m (248 ft)[1]
Islands	720
Settlements	Kerimäki, Kesälahti, Punkaharju
References	[1]
1 Shore length is not a well-defined measure.

The lake is known for its pure water and has uniquely good underwater visibility for a Finnish lake, easily extending to 6–10 metres (20–33 ft) from the surface on calm and sunny days.[2]

Recently, the Saimaa Ringed Seal, a rare freshwater seal species, has returned to Puruvesi. Sightings of this animal have occurred frequently in 2006, 2007 and 2008. At least one seal was also sighted in the winter of 2009 as having wintered and given birth in the eastern part of Puruvesi.[3]