ОСОБЕННОСТИ РУСЛОВЫХ ПРОЦЕССОВ В СЕВЕРНОМ ЗАБАЙКАЛЬЕ ПРИ СОВРЕМЕННЫХ ИЗМЕНЕНИЯХ КЛИМАТА

• Main Author: Верхотуров, Алексей
• Format: Text
• Language: unknown
• Published: Федеральное государственное бюджетное образовательное учреждение высшего профессионального образования "Национальный исследовательский Томский государственный университет" 2013
• Subjects: ПАВОДОК,СЕЛЬ,ПРОРЫВ,КРИОЛИТОЗОНА,НАЛЕДИ,FLOOD,MUDFLOW,BREAKTHROUGH,PERMAFROST,ICE; Ice; permafrost
• Online Access: http://cyberleninka.ru/article/n/osobennosti-ruslovyh-protsessov-v-severnom-zabaykalie-pri-sovremennyh-izmeneniyah-klimata; http://cyberleninka.ru/article_covers/14492321.png

В Северном Забайкалье в межгорных впадинах и хребтах характер и интенсивность русловых процессов во многом определяются унаследованными ледниковыми и водно-ледниковыми формами рельефа. Наледи подземных вод и наледи, имеющие смешанный тип питания, здесь очень активно участвуют в формировании современной речной сети. Рельефообразующая деятельность водных потоков и наледей зависит от изменения климатических условий. На участках дренирования водотоками подпрудных ледниковых озер возможны катастрофические скорости развития руслового процесса и формирование селевых паводков. High waters on rivers and channel processes associated with it often lead to numerous emergency situations in a region. On July 27, 2001 at the place of Leprindo Railway Station due to continuous rains at the Kodar Range water-rock mudflow was formed as a result of a breakthrough of a small glacier lake, which destroyed the railway tracks at the Baikal-Amur Mainline site from 1659 till 1661 km. On July 2, 2010 the Chara River flooded 43 houses in the Chara Village. The level of the water increased highly and reached the depth of 4.76 m with the level of flood-lands of 3.6 m. The high water destroyed part of the Chara Novaya Chara highway. Its embankment was a dam to hold back flood waters. The breakthrough occurred in the culvert that did not cope with the increased flow rate and the flow threw it a few meters away from the place of installation. The length of the washed out area is greater than 50 m. A similar situation occurred in August 2011 and in July 2012. The analysis of archival materials showed that the number of high waters leading to activation of channel processes in recent years increased in Northern Zabaikalye. Studying of channel processes is an essential task at the present stage in connection with the considerable climate changes leading to transformation of hydrogeological and frozen ground conditions. Change of frozen ground conditions influences channel processes, especially within hollows of the Baikal type where the lithogenic base is presented by fine soil sand, sandy loams, loams. As a result of the increase of the average annual air temperature the temperature of rocks at the depth of zero annual amplitudes increased by 0.9 degrees, the depth of the layer of seasonal thawing of rocks increased. The increase of the latter leads to greater intensity of erosive processes. Within ranges channel processes are greatly affected by coarse-grained flow of material coming from the slopes and ice. The increase of average annual temperatures most significantly affected formation of ice of river waters and ice with the mixed type of feed. Reduction of morphometric parameters of flood ice in the long-term cycle leads to a displacement of the altitude position of nivation formation and to displacement of the level of erosion activities of the watercourse in the initial period of the destruction of flood ice. The activity of glaciers has a considerable impact on processes forming beds of the rivers in Northern Zabaikalye. In some cases above final moraine lines there are glacier-dammed lakes. The increase of average annual temperatures and degradation of long term frozen ground rocks in the areas of glacier-dammed lakes can be a disaster for Northern Zabaikalye, as in the case of Leprindo. Most of the streams of Verkhnecharsky and Muisko-Kuandinsky river basins, especially in their upper courses are not well-studied yet. Identification of potentially dangerous sites of breakthrough taking into account the high seismic activity of the area represents one of the major tasks at the present stage.