Numerical modeling and forecast of channel changes on the river Lena near city Yakutsk

Abstract. STREAM_2D software package was applied to retrospective and predictive simulations of the Lena River near city Yakutsk hydraulic and channel changes during ice-free period. The modelling results indicate significant correspondence of simulated water discharges distribution and water levels with observed ones for the period 2001–2016. Model has captured main erosion and depositional zones observed in the 2009–2016 years. Combination of typical monthly average hydrographs of 1 %, 10 % and 50 % return intervals was used as an initial parameter for 10-year channel changes forecast. According to the simulation results, degradation of the Adamovskaya branch will be continued, which is the most negative impact for the Yakutsk city infrastructure maintenance. At the end of the forecast period the equal distribution between Adamovskaya and Buorylarskaya channels is possible, which is a positive trend from the point of view of the city water supply system.