Debris Flows of the Tunkinsky Goltsy Mountains (Tunkinsky District, Republic of Buryatia in Eastern Siberia)

Abstract

On the night of June 28, 2014, near the village of Arshan in Tunkinsky district, Republic of Buryatia in eastern Siberia, two types of debris flows were formed as a result of intense storm precipitation: 1) debris floods along the river Kyngarga; 2) debris flows along the valleys originating from the cirques of the southern slope of the Tunkinsky Goltsy range, which went in the south-west direction towards the village. A year later, July 14, 2015, in the village of Arshan a debris flood occurred in the river Kyngarga. During the Holocene debris flows have occurred repeatedly, traces of which are seen in the sections of loose deposits. Their age was defined with the help of radiocarbon analysis of buried soil horizons. A historical analysis of debris flow activity on the territory for more than a century was made using published scientific works. Natural factors for the formation of debris flow situation were considered (synoptic and climatic conditions, hydrology, geology and landscape structure were evaluated). Reasons for the most recent debris flows were defined. A detailed analysis was given of the valleys of a number of rivers where results of debris flows were the most destructive. As a result of the debris flow along the river Kharimta, realignment of the river network took place. Consequences of debris flows for the natural environment and infrastructure of the village of Arshan were evaluated. It is considered that the partial destruction of the village of Arshan is a distinct possibility in the near future due to debris flows from cirque #1.

The Functioning of Erosion-channel Systems of the River Basins of the South of Eastern Siberia

“…In total, 1311 houses were taken away by flood waters, 4191 houses were declared unsuitable for living, and 3846 had to be repaired. The preliminary damage amounted to 35.152 billion rubles; 10.8 billion rubles of this was loss from lost housing, and 20 billion rubles from damage to social, administrative, and infrastructure facilities [67]. The cities of Tulun (Figure 17) and Nizhneudinsk suffered mostly from the floods, located in the Presayan piedmont depression and Iiskii and Udinskii rifts.…”