Dynamics of glacial lakes in Malaya Almatinka River basin according to the ground-based monitoring data

Abstract

Monitoring of three moraine lakes (two of which are located on frontal moraines, and one is lateral) lasted some years. It was defined that each lake has individual temperature mode which depends partly by air temperature and much more by incoming melted waters, volumeof their accumulation and typeof underlying rocks. Type of underlying rock in which the lake kettleis formed has decisive importance. Direct contact of lake water with glacierice gives its temperature during ablation period of 2.54 °С or in 3.1 times lower, than in frontal lakes. That’s why the dam quicklycollapses and the lake volume increases. Dams of the lakeslocated on frontal moraines are subject of destructionmuch less. Dynamics of these lakes is caused by retreat of glaciers, and the maximum depths are fixed in the central part of a lake. Water temperatureduring the cold period remainshere steadily positive and promotesformation of filtration channels in the layer with moraine sediments which almost without ice. The increasing of lakes occurs due to ice ablation from the nearest glacier. Precipitations, if they influence to the change of water level in lakes, are not essential.