Modelling of the outburst flood hydrograph due to the moraine lakes outbursts

Catastrophic outburst floods are formed due to the destruction of moraine dams of the periglacial lakes. Outburst floods are dangerous hydrological phenomena that cause the large material damage and often lead to human losses. These dangerous hydrological phenomena are sudden and fleeting due to this the organization of observations is extremely difficult and unsafe. To study these hydrological phenomena the methods of mathematical modelling and physical modelling are most often used. This paper presents a methodology developed by the authors for calculating the outburst flood hydrograph, which is formed during the destruction of an earth dam due to water overflow through the crest. The methodology was verified using the results of physical experiments carried out on a special experimental setup and in natural conditions. The quantitative characteristics of outburst floods obtained as a result of physical experiments were used for comparison with the data obtained in mathematical modelling. Comparison of the simulated outburst flood hydrographs with obtained hydrographs as a result of physical experiments showed their convergence. The paper also presents the results of numerical experiments, which allowed to obtain the dependence of the discharge on the initial size of the breach, the specific gravity of the material from which the dam is built, the percentage of clay in this material and the roughness coefficient value. The results of the work were considered satisfactory and demonstrated the efficiency of the calculation method.

The work was supported by the RFBR grant No. 20-05-00343 A "Identification of the features of the outburst process of lakes of oases of Antarctica based on field research data and mathematical modeling."