scholarly journals How does the suspended sediment yield change in the North Caucasus during the Anthropocene?

Author(s):  
Anatolii Tsyplenkov ◽  
Valentin Golosov ◽  
Pelagiya Belyakova

Quantifying and understanding catchment sediment yields is crucial both from a scientific and environmental management perspective. To deepen the understanding of land use impacts and climate change on sediment load, we explore mechanisms of the suspended sediment yield formation in the Northern Caucasus during the Anthropocene. We examine how sediment flux of various river basins with different land-use/landcover and glacier cover changes during the 1925-2018 period. Our analysis is based on observed mean annual suspended sediment discharges (SSD, kg·s−1) and annual fluxes (SSL, t·yr−1) from 33 Roshydromet gauging stations (Russia). SSL series have been analyzed to detect statistically significant changes during the 1925-2018 period. The occurrence of abrupt change points in SSD was investigated using cumulative sum (CUSUM) charts. We found that SSL has decreased by −1.81% per year on average at most gauges. However, the decline was not linear. Several transition years are expected in the region: increasing trends from the 1950s and decreasing trends from 1988-1994. Correlation analyses showed that variation in SSL trend values is mainly explained by gauging station altitude, differences in land use (i.e., the fraction of cropland), and catchment area. Nonetheless, more accurate quantifications of SSL trend values and more refined characterizations of the catchments regarding (historical) land use, soil types/lithology, weather conditions, and topography may reveal other tendencies.

Water ◽  
2019 ◽  
Vol 11 (9) ◽  
pp. 1831 ◽  
Author(s):  
Donatella Pavanelli ◽  
Claudio Cavazza ◽  
Stevo Lavrnić ◽  
Attilio Toscano

Anthropogenic activities, and in particular land use/land cover (LULC) changes, have a considerable effect on rivers’ flow rates and their morphologies. A representative example of those changes and resulting impacts on the fluvial environment is the Reno Mountain Basin (RMB), located in Northern Italy. Characterized by forest exploitation and agricultural production until World War II, today the RMB consists predominantly of meadows, forests and uncultivated land, as a result of agricultural land abandonment. This study focuses on the changes of the Reno river’s morphology since the 1950s, with an objective of analyzing the factors that caused and influenced those changes. The factors considered were LULC changes, the Reno river flow rate and suspended sediment yield, and local climate data (precipitation and temperature). It was concluded that LUCL changes caused some important modifications in the riparian corridor, riverbed size, and river flow rate. A 40–80% reduction in the river bed area was observed, vegetation developed in the riparian buffer strips, and the river channel changed from braided to a single channel. The main causes identified are reductions in the river flow rate and suspended sediment yield (−36% and −38%, respectively), while climate change did not have a significant effect.


2008 ◽  
Vol 87 (2) ◽  
pp. 189-193 ◽  
Author(s):  
P.J. Ward

AbstractDespite increasing research into changes in the discharge of the River Meuse, estimates of the river’s sediment yield are less forthcoming. Three published studies (in 1883, 1982, and 1987) have estimated suspended sediment yield at the Belgian-Dutch border; the latter two studies surmise that this increased substantially between the late 19th and 20th Centuries. In this paper a more recent and longer time-series of observed discharge and suspended sediment data (1995 – 2005) is used to estimate mean annual suspended sediment yield (ca. 386,000 Mg.a−1), and the results of the previous studies are revisited. New insights suggest that those studies do not in themselves provide evidence of increased sediment yield: the higher estimates in the late 20th Century could equally be due to interannual variability or methodological differences. Furthermore, there has been no significant increase in rainfall erosivity between the late 19th and 20th Centuries, and the effect of land use change over that time would have been to cause a decrease in suspended sediment yield, rather than an increase.


2021 ◽  
Vol 145 (5-6) ◽  
pp. 249-261
Author(s):  
Tark Çtgez ◽  
Refik Karagül ◽  
Mehmet Özcan

Topography, geological structure and land use play a determinative role in the streamflow and total suspended sediment yield of watersheds having similar climate, soil and vegetation characteristics. In order to facilitate sustainable water resource management and effective land use planning, there is an increasing need for research investigating the effects of these factors. This study was carried out in forested and agricultural dominated subwatersheds of the Big Melen watershed in the Western Black Sea Region of Turkey. Hazelnut plantations are grown on most of the agricultural areas in both watersheds. The forested watershed has a steep topography and its geological structure consists of sandstone-mudstone and sedimentary rock. The agricultural watershed area is larger and unlike the forested watershed, there is argillaceous limestone in its geological structure. The precipitation, streamflow and total suspended sediment yield in the watersheds were measured for two years. The total precipitation of the study area over the two years was 2217.3 mm. The water yield of the forested watershed was 867.6 mm, while that of the agricultural watershed was 654.9 mm. In the two years, the total suspended sediment transported from the forested watershed was 19.51 t ha<sup>-1</sup> and from the agricultural watershed 7.70 t ha<sup>-1</sup>. However, except for the high values measured after an extreme rainfall event, the unit surface suspended sediment yield of the agricultural watershed was found to be higher than that of the forested watershed. These findings showed that watershed characteristics such as slope, geological structure and rainfall intensity may be more effective on the streamflow and total suspended sediment yield of the watersheds than land use.


Geomorphology ◽  
2009 ◽  
Vol 103 (3) ◽  
pp. 389-400 ◽  
Author(s):  
Philip J. Ward ◽  
Ronald T. van Balen ◽  
Gert Verstraeten ◽  
Hans Renssen ◽  
Jef Vandenberghe

Author(s):  
L. Kuksina ◽  
N. Alexeevsky

Abstract. Research into the spatial and temporal variability of suspended sediment flux (SSF, t year−1) has been conducted for rivers in the Kamchatka Krai (in the far east of the Russian Federation). The study of long-term fluctuations in SSF was based on difference-integral curve analysis. Most of the rivers in the region are characterized by two relatively long-term trends in SSF; increases from the late 1970s to the early 1980s, followed by a subsequent decline. Kamchatka was divided into regions based on similar conditions of specific suspended sediment yield (SSSY, t km−2 year−1) followed by a determination of the various factors controlling it. New maps of suspended sediment concentration (SSC, mg L−1) and SSSY for Kamchatka also were constructed and, based on this study, there currently appear to be 18 SSC and 13 SSSY regions, as opposed to 4 and 2 regions, respectively, as had been determined in the 1970s. The influence of volcanoes on SSF can be substantial, and can increase up to 5-fold after eruptions; SSC can reach 6∙105 mg L−1 in rivers draining the flanks of volcanoes.


1997 ◽  
Vol 24 ◽  
pp. 32-37 ◽  
Author(s):  
A. J. Hodson ◽  
M. Tranter ◽  
J. A. Dowdeswell ◽  
A. M. Gurnell ◽  
J. O. Hagen

This paper compares estimates of suspended-sediment yield and discharge from two glacier basins in Svalhard exhibiting contrasting glacial thermal regimes: Austre Brøggerbreen (~12 km2), which is almost entirely cold-based, and Finsterwalderbreen (~44 km2), dominated by warm basal ice. There are marked differences in the magnitude and temporal pattern of mean daily discharge and mean daily suspended-sediment concentration from the two glacier basins. Specific suspended-sediment yields from Finsterwalderbreen (710–2900 t km−2 a−1) were more than one order of magnitude greater than at Austre Brøggerbreen (81–110 t km−2 a−1). These differences are ascribed to the influence of thermal regime upon the meltwater drainage system and the predominant sources of suspended sediment. The potential significance of glacier thermal regime is further explored using studies from other glacier basins in Svalbard. Variations in thermal regime resulting from mass-balance adjustments since the termination of the Little Ice Age are also examined.


2021 ◽  
Author(s):  
Jan Henrik Blöthe ◽  
Thomas Hoffmann

&lt;p&gt;Sediment yield from lowland rivers around the globe is often dominated by suspended sediment that also acts as a carrier for pollutants and contaminants. Achieving a deeper understanding of the suspended sediment dynamics is important for river management, but often complicated by short or discontinuous time-series and scattered surveying locations. However, suspended sediment transport is highly variable in space and time, calling for decadal observations that reflect this variability. Here we make use of &gt;130,000 measurements on water discharge (Q) and suspended sediment concentration (SSC) from twelve stations that drain large parts of the central German uplands, to investigate the spatiotemporal variability in suspended sediment flux.&amp;#160;&lt;br&gt;The data has been collected during working days between 1965 and 2018 in context of the suspended sediment monitoring conducted by the Federal Waterways and Shipping Administration (WSV). The contributing catchments of the twelve monitoring stations range between 2500 and 22000 km&lt;sup&gt;2&lt;/sup&gt; and cover observation periods between 27 and 53 years.&amp;#160;&lt;br&gt;Despite roughly similar topographic and climatic conditions, average specific (suspended) sediment yield (SSY) varies between ~6 and ~29 t km&lt;sup&gt;2&lt;/sup&gt; yr&lt;sup&gt;-1&lt;/sup&gt;. Highest specific yields are observed for those catchments that drain the escarpment of the Swabian cuesta landscape. Even more pronounced than the spatial variability is the interannual variability in sediment yield, with SSY for very wet years exceeding SSY for dry years more than tenfold. Separating the hydrograph into base-flow and event-flow components, we find that sediment export during event-flows accounts for 60 to 85% of the long-term SSY, with individual floods accounting for more than 90% of the annual sediment export. We conclude that high specific (suspended) sediment yields in the central German uplands are conditioned by rapidly responding catchments (i.e. large fraction of event-flow contribution) with highly erodible lithologies of the Swabian cuesta landscapes.&lt;/p&gt;


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