Superficial moraines grew in size during the entire 32-year-long period\nof direct monitoring of water and ice balance of the Djankuat Glacier in\nthe Caucasus. The total area of debris cover on the glacier increased\nfrom 0.104 km(2) (3% of the entire glacier surface) in 1968 to 0.266\nkm(2) (8% of the glacier) in 1996. Such rapid dynamics of moraine\nformation greatly influences the ablation rate and distorts fields of\nmass-balance components. Sub-debris thawing can be calculated by means\nof a model, which describes the role of debris cover for the thermal\nproperties of a glacier. Its meltwater equivalent depends mainly on\ndebris thickness. In 1983 and 1994 the debris cover was repeatedly\nmapped over the whole glacier portion that was covered with morainic\nmaterial. Sub-moraine ablation increases (vs. pure ice surface) under\nthe thin, less than ca. 7-8 cm, debris layer, whereas the thicker debris\ncover reduces the liquid runoff due to its shielding effect. Zones\ndiffering due to their hydrological effect are depicted on the glacier\nmap and the degree of debris influence on ablation is estimated\nquantitatively. As a whole runoff from debris-covered parts of the\nDjankuat Glacier has diminished due to the dominant shielding effect.\nVariation of the terminus is also shown to be dependent on the evolution\nof superficial moraine.