L. V. Kuksina

The suspended sediment discharge of the rivers running along territories of contemporary volcanism in Kamchatka

The sediment discharge of rivers for the territories of the Avachinskaya and Northern groups of volcanoes (the Klyuchevskaya group of volcanoes, and Shiveluch Volcano), constituting zones of active volcanism on the territory of Kamchatka Peninsula was analyzed. A special model based on the principle of multiple regression relationships between the amount of suspended sediment discharge and its formation factors has been employed. This has allowed us to obtain assessments of the sediment discharge into the Pacific Ocean for the eastern coast of Kamchatka.

The structure of streams in the Lena delta and its influence on streamflow transformation processes

The structure of the stream network in the Lena delta has been studied, and its quantitative characteristics have been obtained for the first time. Taking into consideration the discharge of the branches as well as their width, we determined the conventional delta stream orders decreasing in a regular fashion toward the margin of the delta because of channel bifurcation. They have been used as the basis for determining the structural parameters of delta streams and studying the transformation characteristics of the flows of some materials and heat in the Lena delta.

Suspended sediment yield transportation by rivers of the Kamchatsky Krai into the Pacific Ocean, the sea of Okhotsk and the Bering Sea

ABSTRACT The amount of suspended sediments transported by rivers of the Kamchatsky Krai into the Pacific Ocean, the Sea of Okhotsk and the Bering Sea was estimated. The suspended sediment yield from ungauged territories was also assessed on the basis of geography-hydrology generalization and regression equations. The total suspended sediment yield from the Kamchatsky Krai territory is estimated as 11.4 Mt per year. Most part of these sediments (73.9%) are transported by rivers of the eastern coast and only 26.1% is transported by rivers of the western Kamchatka coast. Such distribution of suspended sediment yield in the Kamchatsky Krai territory is explained by position of active volcanoes there. About one third of the total suspended sediment yield is delivered by two major rivers – the Penzhina River (flows into the sea of Okhotsk, covers 16.1% of the drainage area) and the Kamchatka River (flows into the Pacific Ocean, covers 12.3% of the drainage area).

Sediment Yield of Kamchatka Krai Rivers into the Pacific Ocean and the Seas of Bering and Okhotsk

Sediment yield of Kamchatka Krai rivers into the Pacific Ocean and the seas of Bering and Okhotsk, is evaluated, including that from the drainage basins that are not covered by regular observations. Regression dependences of specific suspended sediment yield (SSSY) on factors determining it were constructed for erosion regions identified in Kamchatka Krai. The total average many-year yield of suspended sediments of Kamchatka Krai rivers into the Pacific is 11.4 × 106 t/year, 73.9% of which is transported by rivers of the eastern coast and 26.1%, by those of the western coast. Among other factors, such distribution is attributed to the location of the majority of volcanoes on Kamchatka eastern coast. About one third of all sediments transported from Kamchatka Krai territory is discharged by the two largest rivers in the region, i.e., the Penzhina and Kamchatka.

The transformation of the runoff of the suspended load in Kamchatkan rivers due to volcanism

This paper considers the influence of volcanic eruptions on the variation in the characteristics of the runoff of the suspended river load (suspended sediment concentration, discharge, rate of runoff, and grain-size distribution) on a variety of space–time scales (daily, seasonal, and long-term). The main factors that affect the yield of suspended load in rivers that flow in volcanic areas include the water runoff, drainage area, and the abundance of unconsolidated volcanic deposits. The areas of recent volcanism in Kamchatka are characterized by the maximum values of potential scour of particles, the mean long-term suspended sediment concentration, and specific suspended sediment yield. The largest increment in the transport of suspended river load in areas of volcanic activity is observed after major eruptions. The daily variations in the transport of suspended load are controlled by the water regime of rivers on the slopes of active volcanoes, namely, periodic cessations of surface runoff because of filtering into volcanic deposits.

Cloudburst floods in mountains: State of knowledge, occurrence, factors of formation

A detailed analysis is made of the current ideas concerning floods of a special type. We examine short-lasting torrential flash floods, one of the most widespread and hazardous natural phenomena in the world characterized by a high rate of development, and by a short duration. It is established that such floods are in a primitive stage of study, which is testified by the fact that there is no general consensus as to what should be treated as a flash flood. It is pointed out that a special term designating them is also absent in many countries. It is determined that the key formation conditions for flash floods include intense short-lasting cloudbursts, the occurrence of a river basin in mountainous regions and a small drainage area; on this basis, it is suggested that they be termed flash floods. It is shown that such floods are of the most widespread occurrence in the northern hemisphere in regions with a temperate and subtropical climate. We suggest the scheme of natural factors for formation of flash floods and their differences from debris flows and floods of other types. It is determined that the main problems of investigating the formation mechanisms and forecasting the aforementioned floods are associated with the small spatiotemporal scale of these phenomena.

Space and time variations of the runoff of Kamchatka Krai rivers

The current features of the space and time variations of river runoff in Kamchatka Krai have been considered. Two relatively long cycles have been shown to exist in water runoff variations in the major portion of the examined rivers. The renewable water resources were increasing until 1970–1980, while in the following years (up to 2010), they were gradually decreasing. Current data on river runoff were used to prove the existence of three zonal types of water regime in Kamchatka Krai; five azonal types of annual runoff distribution are characterized. One of them (nearly uniform annual distribution caused by the predominance of groundwater recharge) has been theoretically predicted in the classification proposed by M.I. L’vovich, though without factual confirmation. The specific features of water regime of rivers whose basins lie on the slopes of active volcanoes are considered for the first time. This type of regime typically shows alternating periods of the presence and absence of surface runoff in river channels, corresponding to the inflow of snowmelt or rainfall runoff at high level of subsoil water (when channel deposits are fully saturated with water) or at its low position (when moisture is deficient).

Ecological runoff assessment in rivers of mine areas: Case study of Koryak Plateau rivers

Methods of water runoff calculation with insufficient hydrometeorological information are discussed. The chosen approaches are used to calculate mean annual runoff of Koryak Upland rivers, flow distribution over seasons and months, and to assess the characteristics of minimum and maximum runoff. The results of calculations served as a basis for assessing the volumes of ecologically sound runoff in rivers under the condition of placer deposit development.