MODELING OF DEBRIS FLOW TRIGGERED BY SNOW MELTING: CASE STUDY OF THE BARSEMDARA RIVER, TAJIKISTAN
V.A. Iudina1, S.S. Chernomorets1, T.S. Vinogradova2, I.N. Krylenko3,4
1Leninskie Gory 1, Moscow, 119991, Russia
2Research and Production Association Gidrotekhproekt LLC, Oktyabrskaia str. 55A, Valdai, Novgorod region, 175400, Russia
3Leninskie Gory 1, Moscow, 119991, Russia, Gubkina str. 3, Moscow, 119333, Russia
4Water Problems Institute, RAS
Keywords: debris flow, Barsemdara River, transport-shift debris flow formation model, FLO-2D model, Pamir Mountains
Abstract
The last catastrophic debris flow disaster took place in Tajikistan in the Barsemdara River valley in 2015. The aim of this study was to apply chain modeling to consider debris flow characteristics of 2015 year. This approach has also been applied to assess potential flood prone zones for future debris flows. To consider the characteristics of debris flow in the source, the transport-shift model, developed by Yu.B. Vinogradov was applied. Based on this model, debris flow hydrographs were obtained and used as input data for valley zoning based on the FLO-2D model. So, for scenario I, the debris flow discharge of the forward wave was used as the input hydrograph (maximum -1630 m3/s), the II scenario - the debris flow discharge at the source outlet (maximum 650 m3/s). The digital elevation model ALOS PALSAR (12.5 m) was used as the relief data. Since there are no rheological data, the modeling was carried out using several sets of parameters. The simulated debris flow discharges based on the most realistic option for I scenario varied from 1494 to 2860 m3/s for individual waves. Additionally, the authors carried out modeling using digital elevation model from an unmanned aerial vehicle obtained during the survey in 2019. The results showed that the considered approach makes it possible to estimate the boundaries of both actual and potential flood prone zones.
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