Characteristics of the hydrological regime of the periglacial moraine lakes in the Altai

In the last decade glaciers of Inner Asia have been shrinking with acceleration, and the number of glacial lakes has been growing significantly, including those with a high probability of outburst and high-water discharge. The hydrological regime of lakes in the Altai is understudied in comparison with lakes in other high mountain countries. The article is based on our extensive field material on hydrological and morphometric characteristics of moraine lakes collected in the Russian and Mongolian parts of the Altai Mountains and combined with the Earth remote sensing data. We have proposed detailed indicators (criteria) of transgressive, regressive and post-regressive stages of lake development. It allows allow to determine at a qualitative level at what stage a lake is at and to assess its further development. The characteristics of hydrological regime of Altai lakes at different stages of development are described for the first time. Based on the criteria proposed, the classification of glacial and moraine lakes in the Altai high mountains was carried out. It shows that at present most of the lakes are in the transgressive stage. Over the last 22 years, the number of lakes has increased significantly: on the territory of the North Chuya Ridge – from 28 to 60, on the South Chuya Ridge – from 39 to 73, on the Katun Ridge – from 57 to 89, on the territory of the Tavan-Bogdo-Ola massif – from 11 to 19, and on the territory of the Mongun-Taiga massif – from 8 to 11 lakes.