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

2.6. LAKE HOLMVATN Lake Holmvatn (watershed of the River Kobbholmselva) is located 32 km to the north of the town of Zapolyarny. The almost oval-shaped lake is relatively small (area of the lake 0.94 km2), not deep (maximum depth 15 m), and is of glacial origin. The maximum length is 1.95 km and maxi­ mum width 0.85 km. The points ofmax­ imum depth are located in the central part of the lake. The lake forms part of a lake-river system. According to the landscape type, the watershed area belongs to the tundra zone, with heights of up to 349 m. The lake shores are high and covered by grass and shrub vegetation. The water of the lake is colourless. Physico-geographical characteristics Watershed River Kobbholmselva— the Barents Sea Latitude 69°42.60Г Longitude 30°45.909' Height above sea level, m 156.0 Maximum length, km 1.95 Maximum width, km 0.85 Maximum depth, m 15 Area, km 2 0.94 Watershed area, km 2 15.25 Study period 2004-2005 2.6.1. Hydrochemistry The proximity of the sea has a consider­ able influence on water quality. The pH of the water in the lake is close to neu­ tral, and the water has a low total min­ eralization (average 17.6 mg/l) and al­ kalinity (average 44 |ieq/l). During flood periods the pH drops slightly, i.e. oxida­ tion processes do not develop due to the buffering capacity of the water. The lake has low concentrations of base cations and anions, with sodium (average 3.17 mg/l) and chloride (average 5.07 mg/l) predominating. The annual chemical cycle of the lake is characterized by a slight reduction in the oxidizability and pH of the water during flood periods when the amount of precipitation and inflow of humic wa­ ter increase. Hydrochemical properties pH 6.53 6.44-6.58 Electrical conductivity, mS/cm 32 32-33 Ca, mg/l 1.52 1.44-1.59 Mg, mg/l 0.74 0.73-0.75 Na, mg/l 3.17 3.14-3.24 K, mg/l 0.31 0.29-0.33 HC03, mg/l 2 1 2.7-2A S04, mg/l 4.08 4.00-4.12 Cl, mg/l 5.07 5.02-5.11 Total mineralization, mg/l 17.6 17.5-17.7 Alkalinity, цед/І 44 44-45 Elevated concentrations of P and N are important criteria when estimating water eutrophication. The concentrations of and relationships between species of P and N vary according to the season and the dy­ namics is to a greater extent determined by the level of production and, consequently, the trophicity of the water body. The average concentrations of total P and total N during the vegetation period are 5 |ig/l and 100 jag/l, respectively. According to the concentrations of minewral nutrients, the lake is classified as oligotrophic. The colour values and organic matter (2.4 mg/l) and Fe concentrations (average 7.1 |ig/l) are typical of small water bodies in the region. During flood pe- Catalogue of Lakes in the Russian, Finnish and Norwegian BorderArea