Selenga River Runoff Projections in the XXI Century: ECOMAG-Based Simulation Results

Abstract

The Selenga River is the major tributary of Lake Baikal, which contributes about 50 to 60% of the surface water inflow into the lake (Tornqvist et al. 2014; Chalov et al. 2015). Total basin area of the Selenga River is ~450,000 km2 in the boundary region between Northern Mongolia (~64% of the basin) and Southern Siberia (Russia). Runoff formation conditions are various. The upstream part of the basin (Northern Mongolia) is covered by an extensive grassland steppe. The downstream part (Southern Siberia) is mainly covered by forest and permafrost, which is an important source of soil water in summer. Moreover, a huge part of the Selenga River Basin has mountainous topography and is characterized by the large elevation difference (from 600 to 3000 m). Local climate conditions are extremely continental. Winters are long, dry and cold. Average monthly surface air temperature of January is −23.5 ℃. Summers are short and relatively warm. Average monthly surface air temperature of July is 16 ℃. The annual precipitation amount ranges between 300 and 400 mm over the territory. Most of the precipitation falls in July and August. Rainfall is the major source of Selenga River runoff formation (Frolova et al. 2017).