Author(s): Tomasz Kolerski; Parisa Radan; Sarah Burgess; Ayurzana Badarch; Khishigbat Batdelger; Nasanbayar Narantsogt
Linked Author(s): Ayurzana Badarch, Tomasz Kolerski
Keywords: Peak-load hydropower; Ice cover stability; Braided river; Ice jam; Numerical modeling; DynaRICE
Abstract: A new hydropower plant is planned on the Eg River, approximately 3 km upstream of its confluence with the Selenge River, with an initial design operating in a peak-load regime characterized by strong daily discharge fluctuations ranging from 60 to 490 m³/s. Such highly variable flow conditions raise concerns regarding the stability of the winter ice cover and ice-related hydraulic processes in the downstream reach of the Selenge River. This study investigates the response of the ice cover to peak-load operation using the dynamic ice model DynaRICE. The Selenge River downstream of the confluence is a strongly braided river, characterized by multiple active channels and bars, which promote ice blocking, ice accumulation, and the formation of ice jams. These processes result in local water level increases, particularly in the vicinity of the town of Selenge. Although no direct threat to human safety is identified due to the considerable distance between the river and inhabited areas, the modeled conditions indicate a high potential for bank erosion and for a possible transfer of the main flow into alternative channels. Such processes may lead to long-term changes in channel dominance and river morphology. This study focuses exclusively on ice dynamics and flow-ice interactions. Sediment transport processes, including erosion and deposition, were not explicitly simulated and should be addressed in future research. The results highlight the importance of considering peak-load hydropower operation on tributaries feeding cold-region braided rivers, where ice-induced hydraulic effects may trigger significant geomorphological responses even in the absence of direct flood hazards.
Year: 2026