Palokkajärvi () is a lake in

Jyväskylä Jyväskylä () is a city in Finland and the regional capital of Central Finland. It is located in the Finnish Lakeland. The population of Jyväskylä is approximately , while the Jyväskylä sub-region, sub-region has a population of approximately ...

Finland Finland, officially the Republic of Finland, is a Nordic country in Northern Europe. It borders Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bothnia to the west and the Gulf of Finland to the south, ...

, covering an area of . The lake is mostly open in shape, with the exception of the Tyyppälänlahti bay in its eastern part extending towards Seppälänkangas. There is also a single island called Palosaari in its mid-western part. Palokkajärvi is surrounded by urban area, including the districts of

Palokka Palokka is a district of Jyväskylä and the largest area by population in the Palokka-Puuppola ward. Until 31 December 2008, it was a part of Jyväskylän maalaiskunta. The greater Palokka area has a population of ~14000. Palokka is approximatel ...

in the north and

Lohikoski Lohikoski is a district of Jyväskylä, Finland Finland, officially the Republic of Finland, is a Nordic country in Northern Europe. It borders Sweden to the northwest, Norway to the north, and Russia to the east, with the Gulf of Bothnia ...

in the south. The district of Mannila is located to its west, however, its buildings are separated from the lake by the national road 4, the longest highway in the country.

Etymology

The names of Palokkajärvi and

are clearly connected, but whether the settlement was named after the lake or vice versa is unclear. In either case, the name is taken to refer to

slash-and-burn agriculture Slash-and-burn agriculture is a form of shifting cultivation that involves the cutting and burning of plants in a forest or woodland to create a field called a swidden. The method begins by cutting down the trees and woody plants in an area. The ...

(cf. "to burn"), and may have been given either by early settlers or hunters preceding permanent settlement in the area. Palokka was first mentioned as a village in 1557, having been separated from the village of ''Jyväsjoki'', later Jyväskylä.

Geography

Palokkajärvi has an average depth of and a maximum depth of . The deepest part of the lake is located in the Tyyppälänlahti bay. Three rivers discharge into the Palokkajärvi: Pappilanjoki from Alvajärvi in the north, Löylyjoki from Tuomiojärvi in the west and Karjujoki from Tyyppälänjärvi through Heinälampi in the east. The levels of Palokkajärvi, Alvajärvi and Tuomiojärvi are nearly the same at approximately , while Tyyppälänjärvi is smaller and located further away from these three, having an elevation of . The outflow of Palokkajärvi is the river Tourujoki, which discharges into the

Jyväsjärvi Lake Jyväsjärvi () is a lake situated in the centre of Jyväskylä in Finland. The lake is sometimes seen as a part of the Päijänne, as both lakes are on the same level ( from sea level) and are connected by the Äijälänsalmi strait. Par ...

. It has an average flow rate of and an average maximum flow rate of . Both the flow rate and the lake's level is regulated by a dam at a hydroelectric power plant on the river's upper course. The plant is also allowed to regulate the level of Tuomiojärvi, Alvajärvi and Korttajärvi. Palokkajärvi is the lowest lake of the Tuomiojärvi-Palokkajärvi catchment area, itself part of the

Kymijoki The Kymi (, ) is a river in Finland. It begins at Lake Päijänne, flows through the provinces of Päijänne Tavastia, Uusimaa and Kymenlaakso, and discharges into the Gulf of Finland. The river passes the towns of Heinola and Kouvola. The to ...

main basin and its subordinate Päijänne catchment area.

Water quality

Until the late 1970s, wastewater from

Tikkakoski Tikkakoski is an urban area (a '' taajama'') and a district of Jyväskylä, Finland, about north of the city center. Before 2009, Tikkakoski was part of Jyväskylän maalaiskunta. Having originally been part of Tikka-Mannila, Tikkakoski beg ...

was directed into the river Autiojoki, causing phosphorus levels to rise further down the watercourse, including Palokkajärvi. After wastewater began to be directed to the water treatment plant in Nenäinniemi, the phosphorus level of the lake began to drop, decreasing from a peak of nearly 90 μg/l in 1977 to slightly above 20 μg/l in 2015. However, Palokkajärvi remains more

eutrophic Eutrophication is a general term describing a process in which nutrients accumulate in a body of water, resulting in an increased growth of organisms that may deplete the oxygen in the water; ie. the process of too many plants growing on the s ...

when compared to Tuomiojärvi.

Fishing

Recreational and subsistence fishing are practiced on the lake using rods, nets and traps. Fish found in the lake include

pike Pike, Pikes or The Pike may refer to: Fish * Blue pike or blue walleye, an extinct color morph of the yellow walleye ''Sander vitreus'' * Ctenoluciidae, the "pike characins", some species of which are commonly known as pikes * ''Esox'', genus of ...

zander The zander (''Sander lucioperca''), sander or pikeperch, is a species of ray-finned fish from the Family (biology), family Percidae, which also includes perch, Gymnocephalus, ruffe and Darter (fish), darter. It is found in freshwater and brackis ...

perch Perch is a common name for freshwater fish from the genus ''Perca'', which belongs to the family Percidae of the large order Perciformes. The name comes from , meaning the type species of this genus, the European perch (''P. fluviatilis'') ...

common bream The common bream (''Abramis brama''), also known as the freshwater bream, bream, bronze bream, carp bream or sweaty bream, is a European species of freshwater fish in the family Leuciscidae. It is now considered to be the monotypic, only speci ...

, roach,

burbot The burbot (''Lota lota''), also known as bubbot, mariah, loche, cusk, freshwater cod, freshwater ling, freshwater cusk, the lawyer, coney-fish, lingcod, or eelpout, is a species of coldwater ray-finned fish native to the subarctic regions of ...

common whitefish ''Coregonus lavaretus'' is a species of freshwater whitefish, in the family Salmonidae. It is the type species of its genus ''Coregonus''. There are widely different concepts about the delimitation of the species ''Coregonus lavaretus'' and abou ...

ruffe The ruffe (''Gymnocephalus cernua''), also known as the Eurasian ruffe or pope, is a freshwater fish found in temperate regions of Europe and northern Asia. It has been introduced into the Great Lakes of North America as an invasive species ...

and

crucian carp The crucian carp (''Carassius carassius'') is a medium-sized member of the common carp family Cyprinidae. It occurs widely in northern European regions. Its name derives from the Low German ''karusse'' or ''karutze'', possibly from Medieval Lat ...

. Zander are introduced into Palokkajärvi and Alvajärvi, a total of 13,100 juvenile fish were introduced between 2012 and 2015. The

rainbow trout The rainbow trout (''Oncorhynchus mykiss'') is a species of trout native to cold-water tributary, tributaries of the Pacific Ocean in North America and Asia. The steelhead (sometimes called steelhead trout) is an Fish migration#Classification, ...

Etymology

Geography

Water quality

Fishing

Notes

References

Citations

Cited sources