Luonetjärvi is a lake in Jyväskylä, Finland, covering an area of . It is located northwest of the urban area of Tikkakoski in the far northern part of the municipality near its borders with Laukaa and Uurainen. The lake flows into Korttajärvi via the river Autiojoki.
Etymology The element Luon(n)et- is most likely derived from the verb , which in this context may refer to flooding, to the melting of ice or to the setting of a fishing net. Historically, two other hydronyms containing Luonet- were found nearby: the river name Luonetjoki referring to Autiojoki, as well as Luonetkoski, the name of some rapids, either the Tikkakoski rapids of Autiojoki or some rapids in the outflow of lake Keskinen flowing into Luonetjärvi. The latter was mentioned as early as 1544 as Lonnekoskens Koskij. The name of Luonteri, a section of Saimaa, may have a similar origin.
Geography
Luonetjärvi has an area of and a volume of . It is long and fairly narrow in shape, with a length of and an average width of . The lake is oriented northwest to southeast; its southeasternmost section, Hietajärvi, is connected to the main basin via the narrow Hietasalmi strait, which is crossed by a bridge. The urban area of Tikkakoski extends to the southern shores of the lake. The lake has 45 islands in total, most of which are very small and located near the shores, with the exception of the biggest islands Pukkisaari and Lammassaari. The average depth of the lake is , while the maximum depth is . Its deepest point is located in its mid-northern part, between the Peuraniemi and Sulkuniemi capes.
Luonetjärvi has a catchment area of , extending into Laukaa and Uurainen. The lake is fed by a stream flowing into its northwesternmost part, carrying waters from the lakes Keskinen and Vääräjärvi. The outlet of the former (before the confluence of the two) has a catchment area of , while the latter has one covering . Some smaller streams also feed the lake, including one from Kaletonlampi and Särkilampi to the north, as well as one from Kaakkolampi flowing into Hietajärvi.
The outflow of Luonetjärvi itself is the river Autiojoki, which begins at the eastern end of Hietajärvi and flows south into lake Korttajärvi in the village of Puuppola, and has a length of . The surface elevation of Luonetjärvi is from sea level, while that of Korttajärvi is , giving Autiojoki a total drop of .
The level of Luonetjärvi is regulated by a dam at the source of the Autiojoki. A dam has existed there since the late 19th century, while the modern dam was built in the 1950s. The source has an average discharge of , a maximum of and a minimum of . The lake retention time is estimated to be eight months. Plans to replace the dam with a weir that would allow fish to migrate between Luonetjärvi and Päijänne were made in 2018.
Environmental values Fishing The most common fish in the lake are perch, roach, common bream and silver bream. Other species reported include pike, zander, common rudd, smelt, burbot, common whitefish, brown trout and grayling. The European crayfish is also found. Zander, brown trout, whitefish and rainbow trout have been stocked into the lake in the 21st century.
Recreation The city of Jyväskylä maintains a paddling route around Luonetjärvi, including two lean-to shelters. The Evangelical Lutheran parish of Jyväskylä also owns a campground at the northern end of the lake.
References Citations
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