Wet Lake (Polish: Jezioro Mokre; German: Muckersee) is a ribbon lake in the Mrągowskie Lakeland of northeastern Poland, within the Warmian-Masurian Voivodeship. It is situated in Mrągowo County, within the Masurian Landscape Park, near the village of Zgon.
Geography and Physical Characteristics
Wet Lake is of glacial origin, formed by Pleistocene glaciation processes. It is oriented along a north-south axis, with a length of approximately 7.7 km and a maximum width of 1.6 km. The lake covers a surface area of about 846 hectares (8.46 km²) and has a shoreline of approximately 25–26 km, characterized by steep, rugged banks interspersed with bays and peninsulas. The lake contains five small islands, collectively covering about 5 hectares. Its elevation is 124.9 m (410 ft) above sea level.
Depth and Hydrology
The lake reaches a maximum depth of 51 meters, with an average depth of approximately 13–20 meters. The total water volume is estimated at around 107 million cubic meters. The lake bottom is predominantly sandy, with patches of organic mud and glacial sediments. Wet Lake is classified as mesotrophic, with moderate nutrient levels. Water transparency is approximately 2.4 m.
The lake receives inflows from small rivers and streams, including the Nawiadka River and the Gałkówka, as well as connections from upstream lakes such as Uplik and Zdróżno. Its outflow is regulated by a weir at the northeastern end, channeling water into the Krutynia River, which forms part of the Pisa River system draining to the Baltic Sea. The weir, constructed before World War I, allows for up to 1 meter of water level elevation.
Ecology and Biodiversity
Wet Lake supports a diverse fishery, including species such as pike, perch, bream, vendace, roach, carp, and rudd. It also hosts relict crustaceans such as Pallasea quadrispinosa. The lake and its surroundings provide habitat for waterfowl (including swans, cormorants, and herons) and terrestrial wildlife (including deer and badgers). Nearby nature reserves, such as "Królewska Sosna" and "Krutynia," contribute to the area's ecological significance. The lake maintains Class II water purity.
Recreation
Wet Lake is a link in the Krutynia River kayak trail, which spans approximately 102 km. Popular activities include quiet kayaking, sailing (combustion engines are prohibited), birdwatching, and camping at designated sites near villages such as Zgon and Cierzpięty. Angling is permitted with a license.
