Key factors of sediment yield formation and variability
in the Kamchatsky Krai are relief characteristics and climate (especially
precipitation). The last research in climate change in Kamchatka
demonstrates climate warming – mean annual air temperature has increased on
1.5
The current climate change occurs all over the World and leads to increase of air temperature, amount, intensity and frequency of precipitation, and rainfall erosive factor, and as a consequence to growth of severe floods and erosive events (landslides, mudflows (including lahars)) causing the increase of sediment yield, basin component of sediment yield, and channel transformations. According to the last Report on climatic risks in the Russian Federation (Report on climate risk, 2017) climate changes are faster in Russia in comparison to the Earth, and severity of hydrological events and their damage growths correspondingly. Increase of high precipitation frequency (Groisman et al., 2005) and warming climate (Huntington, 2006) leads to the growth of power and frequency of floods, relief reformation and high sediment yields (Kuksina et al., 2017; Mueller, Pfister, 2011), and these extreme hydrometeorological events rank the first position among global risks threatening humanity (Report on climate risk, 2017).
The Kamchatsky Krai could be very vulnerable to climate change due to natural features of the territory including vast distribution of friable volcanic deposits which are very easy-portable by water (Kraevaya, 1969), and specific exposed landscapes (repetitive catastrophic landslides in Geyser Valley in 2007, 2014, and 2017 due to unstable rocks on its flanks, Leonov et al., 2014). Volcanic activity is specific feature of sediment yield formation and spatio-temporal distribution in Kamchatka (Kuksina and Alexeevsky, 2017). Volcanic eruptions are the first-rate source of sediments in planetary scale. Among the whole natural phenomena leading to extreme increase of sediment yield (volcanic eruptions, earthquakes, heavy rains, and dam failure), volcanoes are the absolute leaders (Korup, 2012). Highly erodible volcanogenic deposits fall in the river basins during volcanic eruptions due to ashfalls, pyroclastic flows, and lahars (Carrivick et al., 2010; Gran and Montgomery, 2005; Lavigne and Thouret, 2002; Major, 2004).
Volcanic eruptions lead to extreme increasing of suspended sediment yield in rivers draining flanks of volcanoes. Annual suspended sediment yield exceeded background level in 500 times after the catastrophic eruption of Mount St Helens in 1980. Volcanic eruptions impact on hydrological regime of rivers. Within 5–10 years after the catastrophic eruption of Mount St Helens on the 18 May 1980 increasing of peak discharges was observed in autumn and winter due to decrease of lag-time and increase of channel efficiency (Major and Mark, 2006). In some cases the processes of water transfer changes in comparison with the period before eruption. In the post eruption period loss of canopy interception, the greater amount of precipitation reaching the ground surface, reduced evapotranspiration, the reduction of surface infiltration and more prominent overland flow were observed (Major et al., 2009). Thereby volcanic activity could be the separate reason of water runoff and sediment yield fluctuations in Kamchatka rivers, and it can influence on river runoff characteristics through increasing precipitation. Combination of such events as high precipitation, increase of air temperature and intensification of snow and ice melt, and volcanic eruptions could lead to catastrophic natural events and great increase of sediment yield (lahars, lake burst, etc.) (Korup, 2012). Most part of the rivers in Kamchatka is spawning area for valuable salmon species (such as king salmon, red salmon, silver salmon, etc.), and for some of them catch of fish exceeds 90 % of the total amount in the Russian Far East. River ecosystems and spawning areas depend on hydrological conditions including suspended sediment concentration.
The last research in climate change in Kamchatka (Shkaberda and Vasilevskaya, 2014)
demonstrates climate warming – mean annual air temperature has increased on
1.5
Key factors of sediment yield formation and variability in the Kamchatsky Krai are relief characteristics and precipitation (Kuksina and Alexeevsky, 2018). Thereby described climate changes in Kamchatka influence on sediment yield characteristics directly (influence of precipitation on surface washout formation) and indirectly (through water runoff and hydrological regime of rivers changes). Thereby climate change influences on suspended sediment yield in multiple-valued way. Income of friable volcanic deposits on the catchment surface is the key factor of suspended sediment yield formation and variability in some river basins under the impact of volcanic eruptions.
The main goal of this paper is analysis of the features of spatial and temporal variability of suspended sediment yield in the state-of-the-art (current) hydroclimatic conditions.
This study is based on stationary monitoring data on air temperature, precipitation, water runoff and suspended sediment yield characteristics. The data on air temperature and precipitation contains information for 21 stations (Fig. 1), and duration of observations varies from 80 (Oktyabrskaya) to 174 years (Petropavlovsk-Kamchatsky) for air temperature, and from 16 to 51 for precipitation.
Distribution of suspended sediment yield and meteorological monitoring stations in the Kamchatsky Krai. Rivers: (1) Paren', (2) Pakhacha, (3) Penzhina, (4) Avacha, (5) Talovka, (6) Tigil', (7) Udova, (8) Asacha, (9) Bol'shaya Vorovskaya, (10) Bol'shaya (Bystraya), (11) Bryumka, (12) Phchyn, (13) Voyampolka, (14) Vyvenka, (15) Zhupanova, (16) Icha, (17) Kamchatka, (18) Kronotckaya, (19) Oblukovina, (20) Ozernaya, (21) Ozernaya, (22) Palana, (23) Khairyuzova.
There were 269 monitoring stations that measured water runoff and levels in
the territory of the Kamchatsky Krai for the period of hydrometeorological
observations (since 1930). 86 gauges operated in 2010. The average duration
of the observations is 22 years. The majority of the water runoff gauges are
situated in river basins with areas less than 2000 km
Regular monitoring of suspended sediment yield characteristics in rivers of
the Kamchatsky Krai was started in 1940 in the Kamchatka River (gauge
Kliuchi) and the Avacha River (gauge Elizovo). Between 1941–2015, suspended
sediment yield monitoring was implemented in 69 stations. 6 of them had only
episodic data, and they were excluded from this study's analysis. The
duration of observations vary from 6 to 74 years for 63 selected gauges (see
Fig. 1). More than half of the gauges (54 %) were situated in river basins
with catchment areas greater than 500 km
Trends in air temperature change in the western coast
(Ust'-Khairuzovo station,
The representativeness (Helsel and Hirsch, 2002) of all of the series of observations was evaluated, and even measurement periods as short as 6 to 10 years appear to be representative (probably the observation data hit into the water- and sediment-average period with absence of significant hydrological events). As a result, these data were used for defining water regime types and zones having similar suspended sediment yield characteristics.
The long-term trends of water runoff, suspended sediment yield, precipitation and air temperature variability were determined using a difference-integral curves analysis (Evstignnev, 1990; Manh et al., 2013).
The last research in climate change in Kamchatka (Shkaberda, 2014)
demonstrates climate warming – mean annual air temperature has increased on
1.5
Analysis of climate change in Kamchatka was implemented on the basis of annual air temperature and total annual precipitation fluctuations in 21 stations in the Kamchatsky Krai.
Analysis of all temperature ranges revealed intensive increase of that
characteristic all over the Kamchatsky Krai. The mean annual air temperature
has increased on 1.5
Trends in precipitation change in the northern
(continental) part (Verkhne-Penzhino station,
The most intensive growth of air temperature has been observed since late 1970, and in some stations the tendency even changed to the opposite one. For example, air temperature decreased till the late 1970 in Kamenskoe, Petropavlovsky Mayak, Lopatka Cape and other stations, and then it started to increase rapidly (Fig. 2f).
Geographical position of the Kamchatsky Krai and orography of the region
determine amount and distribution of the precipitation in the territory. The
most intensive cyclonic activity is in the south; it subsides significantly
to the north and decreases the mean annual amount of precipitation
correspondingly. There are more precipitation on windward eastern flanks of
mountains, while on leeward western flanks and protected river valleys.
Analysis of precipitation data demonstrates variability of mean annual
values from 300 mm yr
Rainfall erosive factor distribution in the Kamchatsky Krai territory.
Variability of precipitation can influence on sediment yield directly (through intensity of sediment washout from the river basin territory) and indirectly (through variation of river water runoff). According to (Shkaberda, 2014) research the annual amount of precipitation varies in multiple-value way in Kamchatka. She mentioned decrease of precipitation was observed in the north, western and north-eastern coast, and in the Kamchatka River valley. Increase of them was observed in the eastern coast and in mountainous regions.
Our estimations demonstrate decrease of precipitation all over the Kamchatsky Krai territory but intensity of the process varies (Fig. 3a, b, c, d). The only one exception is Petropavlovsky Mayak station. In (Shkaberda, 2014) the increase of precipitation in that case is explained by positive anomaly in precipitation according to difference-integral curve (see Fig. 3e, f).
Trends in water discharge (1,
Changes in precipitation amount influence on rainfall erosive factor
Correspondence of water runoff (1), suspended sediment
yield (2), precipitation (3) and air temperature (4) variability in the
Penzhina River (Kamenskoe,
The main factors of the sediment yield formation and variability in the
Kamchatsky Krai are precipitation (amount, intensity and frequency), relief
characteristics, soil and vegetable cover, and volcanic processes (Kuksina
and Alexeevsky, 2018). And while such factors as relief, soil and vegetation
are relatively stable in the region (expect endogenous volcanic activity
with its occasional revelation), precipitation characteristics varies
greatly in space and time in the territory, so precipitation, its
characteristics, i.e.
Significant trends in suspended sediment yield variability were revealed on the basis of difference-integral curves analysis. These fluctuations were compared with changes in water runoff and meteorological characteristics. Analysis of difference-integral curves for river basins of various areas demonstrates these patterns in Kamchatka rivers appears to be independent of basin area.
Analysis of difference-integral curves for rivers in the north of the
Kamchatsky Krai (continental part of the region) was implemented on the
basis of data of 59 years duration for the Penzhina River (Kamenskoe gauge,
basin area is 71 600 km
Rivers in the western part of the peninsula are characterized by synchronous
variation in long-term trends of water runoff and SSY. The maximum duration
of observations (57 years) is in the Khairuzova River basin (Khairuzovo
gauge, basin area is 6680 km
Rivers in the south-western part of Kamchatka are characterized by less coincidence in water runoff and suspended sediment yield variations. River runoff increased till the late 1970 – early 1980 in the region, and then it started to decrease, and water runoff continue to decrease nowadays, while suspended sediment yield started to increase in 2010 (Fig. 5c). Reduction of water runoff in average reached 25 %, sediment yield – 32 %.
Long-term trends in water runoff and suspended sediment yield are
synchronous for rivers in the eastern part of the peninsula (with shift in
start and end of phases with characteristic variation in river runoff). The
longest observations are in the Avacha River basin (Elizovo gauge, basin
area 4750 km
The maximum amount of gauges (21) with representative monitoring data on water runoff and suspended sediment yield with duration of observations from 37 to 78 years is in the central Kamchatka region. In this part of the peninsula two phases of water runoff and SSY fluctuations occurred; increased runoff was observed till the late 1970s, followed by a period of reduced runoff (till 2009); the tendency changed to increased runoff again in 2010 (Fig. 5e). Variability of precipitation amount, water runoff and suspended sediment yield are synchronous (against the background of heightened annual precipitation variability). Reduction of water runoff in average reached 2, sediment yield – 21 %. This regularity is disturbed in rivers under impact of volcanic eruptions. For these rivers two phases of water runoff and SSF fluctuations occurred; reduced runoff was observed from the mid 1950s to the 1960s, followed by a period of increased runoff (Fig. 5f). Such response is mainly connected with the major eruption in Kamchatka in XX century of Bezymyanny volcano in March, 1956 (Gorshkov and Bogoyavleskaya, 1965). Rivers draining flanks of active volcanoes are characterized by quite synchronous fluctuations of water runoff and sediment yield.
Air temperature variability is in antiphase with water runoff and suspended sediment yield characteristics fluctuations (Fig. 6a, b).
On the basis of data on air temperature, precipitation, water runoff and
suspended sediment yield analysis the main trends in sediment yield
variability were revealed for the Kamchatsky Krai territory. Precipitation
influences on sediment yield variability significantly through rainfall
erosive factor (direct influence on sediment yield through sediment washout
from river basins) and precipitation amount (indirect influence on sediment
yield through water runoff), while variation of air temperature is in
antiphase with water runoff and sediment yield characteristics. The decrease
of precipitation is observed all over the Kamchatsky Krai territory (expect
one station in the eastern coast with positive anomaly of precipitation),
and it's very well coincided with fluctuations of water runoff and sediment
yield in the territory. Most part of the rivers in the region is
characterized by two relatively long-term trends in water runoff and
sediment yield fluctuations. Increase of these characteristics was observed
till the late 1970 – early 1980, and than decrease of them
was registered till 2010. Analysis of the data after 2010 (till 2015)
revealed new increasing trend in water runoff and sediment yield which is
confirmed with precipitation variability. According to decrease of
precipitation amount decrease of
Underlying research data on air temperature and precipitation in available at
Author collected and processed data on air temperature, precipitation, water discharge and suspended sediment yield in Kamchatka and revealed main regularities in those characteristics variability in the region.
The authors declare that they have no conflict of interest.
This article is part of the special issue “Land use and climate change impacts on erosion and sediment transport”. It is a result of the ICCE Symposium 2018 – Climate Change Impacts on Sediment Dynamics: Measurement, Modelling and Management, Moscow, Russia, 27–31 August 2018.
I'm grateful to Nikolay I. Alexeevsky (deceased), my supervisor, with whom we started that research of Kamchatsky Krai rivers and sediments.
This research has been supported by the Russian Scientific Foundation (project no. 17-77-10047).