Lake Pielinen EUR-18

Riparian Nation(s) Finland
Surface Area 867 km2 Mean Depth 9.9 m Volume 8.5 km3
Shoreline 610 km Catchment Area 12823 km2 Residence Time 1.9 yr
Frozen Period Nov-May Mixing Type Dimictic Morphogenesis/Dam Natural
Related Info/Site


The basin of Lake Pielinen was formed as a consequence of the post-glacial isostatic rising of the land, which affected the development of the basin and the present location of the outflowing river.

The lake is situated in eastern Finland. About half of its drainage basin is in Finland, the other half in USSR. The data presented here apply to the Finnish part of the drainage basin.

The lake receives water from four principal areas. Water from the drainage basins of the Haapajarvi-Valtimojarvi and Saramojoki watercourses is discharged into the north-western part of the lake. Water from the drainage basins of the Rivers Viekinjoki and Lieksanjoki flows into the north-eastern side and water from the small drainage basin of the River Juvanjoki into the western side. The lake water drains southwards through the River Pielisjoki.

The landscape of the lake is diverse. The shore consists partly of barren, rocky soil and partly of beaches. There are many islands. The highland area of Koli, reaching 347 m above the sea level is situated on the western shore, and has been a popular tourist resort since the beginning of this century. The lake has great potential for recreational utilization.

Lake Pielinen is part of the large Vuoksi watercourse, which has traditionally been an important route for timber floating. There is a considerable amount of water traffic on the lake.

Larger municipalities and most industries are situated in the northern and eastern parts of the drainage basin. The effects of wastewater are observed as increased eutrophication and decreased oxygen concentrations during the period of stratification in the neighbourhood of the cities of Lieksa and Nurmes. Non-point sources account for major part of the total nutrient loading of the lake.

The water quality is good and the lake is classified as mesotrophic with signs of local eutrophication. Because of the high proportion of bogs in the drainage basin the water contains humic substances and is dark in colour, a typical feature of most Finnish lakes (2, 3, 4).

Photo of Lake Pielinen
Photo: T. Kanerva