Sandimirov S.S. Catalogue of lakes in the Russian, Finnish and Norwegian Border Area. Finland, Jyvaskyla: Kopijyva Oy, 2008.

2.10. LAKE N-254 Lake N-254 (watershed of the River Jacobselv) is located 19 km to the north of the town of Zapolyarny. The oval­ shaped lake is not large (the area of the lake is 0.09 km2), nor deep (maximum depth 2.5 m), and is of glacial origin. The maximum length is 500 m and maxi­ mum width 250 m. The points of maxi­ mum depth are located in the northern part of the lake. The lake forms part of a lake-river system. According to the landscape type, the watershed belongs to the tun­ dra zone, with heights of up to 405 m (Gouvdoaive fell). Boulder beds occur in almost all parts of the littoral zone. The southern shore is waterlogged. The old road to the settlement of Pechenga (Russia) passes along the northern shore. The water of the lake is colourless. 2.10.1. Hydrochemistry The proximity of the sea has a consider­ able influence on the water quality. The pH of the water in the lake is close to neutral, and the water has a low total mineralization (average 22.4 mg/l) and alkalinity (average 114 peq/1). The lake has low concentrations of base cati­ ons and anions, with sodium (average 3.09 mg/l) and bicarbonate (average 7.0 mg/l) predominating. Elevated concentrations of P and N are important criteria when estimating water eutrophication. The concentra­ tions of and relationships between spe­ cies of P and N vary according to the season and the dynamics is to a greater extent determined by the level of pro­ duction and, consequently, the trophic- ity of the water body The average con­ centrations of total P and total N during the vegetation period are 5 \xg/l and 176 |ig/l, respectively. Physico-geographical characteristics Watershed River Urdalselva— River Jacobselv— the Barents Sea Latitude 69°35.789' Longitude 30°44.545' Height above sea level, m 254.0 Maximum length, km 0.50 Maximum width, km 0.25 Maximum depth, m 2.5 Area, km 2 0.09 Watershed area, km 2 7.62 Study period 2003-2004 Hydrochemical properties pH 6.84 6.83-6.87 .... , , j Electrical conductivity, mS/cm 36 35-38 Ca, mg/l 2.05 1.92-2.14 Mg, mg/l 1.02 0.94-1.09 Na, mg/l 3.09 2.93-3.18 K, mg/l 0.31 0.29-0.33 HC03, mg/l m 6.7-7.1 S04, mg/l 4.55 4.34-4.77 Cl, mg/l 4.41 4.13-4.74 Total mineralization, mg/l 22.4 22.1-22.9 Alkalinity, |jeq/l 114 110-117 Water colour, deg. 8 7-9 NH4, цд/І 18 12-29 N03, цд/І 1 1-1 Total N, цд/І 158 136-176 P04, цд/І 1 1-2 Total P, |jg/l 5 5-5 Fe, цд/І 39.0 30.2-59.4 Catalogue o f Lakes in the Russian, Finnish and Norwegian BorderArea