Lake Ladoga EUR-37

Lat.60.83 Lng.31.578 Alt.4.8
Riparian Nation(s) Russia
Surface Area 18135 km2 Mean Depth 51 m Volume 908 km3
Shoreline 1570 km Catchment Area 70120 km2 Residence Time 12.3 yr
Frozen Period Feb-May Mixing Type Dimictic Morphogenesis/Dam Glacial
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Description

Lake Ladoga is the largest freshwater body in Europe with a surface area of 18,135 km2 including the islands area of 460 km2. The volume of the lake is 908 km3, its average and maximum depths being 51 and 230 m, respectively. The shallowest southern part has a mean depth of 13 m (the lake is divided into four zones taking depth distribution into account).

Lake Ladoga is situated on the borderline between the crystalline Baltic shield and Great Russian Plain, and the geological history of its drainage basin (250,600 km2) is very complicated (1). Differences in the geological structure of the watershed are reflected in the structure of both shores and depressions of the lake. Seven types of bottom sediments were distinguished (2); blocks, boulders, pebbles and gravel, sand of various grain size, coarse-grained aleurite silt, fine-grained aleurite silt, and clayey silt. Clayey silt accumulates in the deepest areas of the lake. The other types of bottom sediments are characteristic of littoral and declinate zones.

The principal components of water balance are inflow and outflow, accounting for 86 and 92% of the total inputs and outputs, respectively. Since 1981 the annual inflow has varied between 77.8 and 89.0 km3 (3). Lake thermic regime is characterized by the existence of thermal bar in periods of spring warming and autumn cooling. Thermal bar divides the lake into two regions - thermoactive and thermoinert, whose water masses differ one from another by physicochemical characteristics (4). Lake Ladoga is influenced by wind waves. The maximal measured wave height amounts to 5.8 m and the maximal length to 60 m (3).

Ladoga water is poorly mineralized - average value of mineralization is 62 mg l-1. Once favorable oxygen regime is now getting worse under the influence of anthropogenic eutrophication during the last 10 years. Great attention is being paid to the preservation of water quality in Lake Ladoga. In 1984 the Council of Ministers of USSR adopted a resolution on protecting measures for Lake Ladoga and its basin. Implementing this resolution, a large pulp and paper plant in Priozersk was closed. The governmental program "Ladoga" has been elaborated and is being carried out by cooperation of several different institutions (Q).

Photo of Lake Ladoga
Photo: I. M. Raspopov