Application of geomorphological mapping and fingerprinting to identify the different suspended sediment sources of the glaciated Djankuat catchment, Caucasus mountains

Author(s):  
Anatoly Tsyplenkov ◽  
Sergey Kharchenko ◽  
Matthias Vanmaercke ◽  
Valentin Golosov

<p>Suspended sediment yield values from glaciated mountain catchments are often among the highest in the world. Nonetheless, the sediment sinks, sources and dynamics can be highly variable in such environments under climate change. The aim of this study is to quantify the different suspended sediment sources of the Djankuat river catchment (A=9,1 km<sup>2</sup>). This small high mountain stream is located in the Caucasus mountains. It is partly glaciated with steep slopes, alpine meadows and glacial-nival terrains. Large scale geomorphological mapping of the catchment was undertaken using drone images and field surveys. This allowed to identify the main sediment sources as well as key pathways of the sediment to the river. In addition, about 50 composite surface (topsoil) and subsurface (riverbanks) samples were collected within the catchment area to characterize the different sediment sources. Two different mixing models (fingerPRO and SIFT) were applied to evaluate the relative contribution of these sources to river suspended sediment yield. Furthermore, direct measurements of water discharge and turbidity were undertaken at two gauging stations. One of them was located near the edge of glacier and the other about 1 km downstream. This allowed to evaluate the relative contribution of the glacial and proglacial part of the catchment to the total suspended sediment yield. Overall, these independent approaches resulted in relatively similar estimates of the relative importance of the different sources to suspended sediment yield. It has been established that the proportion of glacial material (generated by glacier erosion, including subsurface and supraglacial runoff) in total suspended sediment load decreases from 80-90% at the first 50-100 m from the glacier edge to 60-70% at a distance of 700-1000 m.</p><p><em>This study was funded by the Russian Science Foundation, project no. 19-17-00181</em></p>

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.


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.


2013 ◽  
Vol 17 (11) ◽  
pp. 4641-4657 ◽  
Author(s):  
S. B. Morera ◽  
T. Condom ◽  
P. Vauchel ◽  
J.-L. Guyot ◽  
C. Galvez ◽  
...  

Abstract. Hydro-sedimentology development is a great challenge in Peru due to limited data as well as sparse and confidential information. This study aimed to quantify and to understand the suspended sediment yield from the west-central Andes Mountains and to identify the main erosion-control factors and their relevance. The Tablachaca River (3132 km2) and the Santa River (6815 km2), located in two adjacent Andes catchments, showed similar statistical daily rainfall and discharge variability but large differences in specific suspended-sediment yield (SSY). In order to investigate the main erosion factors, daily water discharge and suspended sediment concentration (SSC) datasets of the Santa and Tablachaca rivers were analysed. Mining activity in specific lithologies was identified as the major factor that controls the high SSY of the Tablachaca (2204 t km2 yr−1), which is four times greater than the Santa's SSY. These results show that the analysis of control factors of regional SSY at the Andes scale should be done carefully. Indeed, spatial data at kilometric scale and also daily water discharge and SSC time series are needed to define the main erosion factors along the entire Andean range.


Water ◽  
2021 ◽  
Vol 13 (22) ◽  
pp. 3173
Author(s):  
Valentin Golosov ◽  
Anatoly Tsyplenkov

This paper discusses the joint impact of catchment complexity in topography, tectonics, climate, landuse patterns, and lithology on the suspended sediment yield (SSY, t km−2 year−1) in the Caucasus region using measurements from 244 gauging stations (GS). A Partial Least Square Regression (PLSR) was used to reveal the relationships between SSY and explanatory variables. Despite possible significant uncertainties on the SSY values, analysis of this database indicates clear spatial patterns of SSY in the Caucasus. Most catchments in the Lesser Caucasia and Ciscaucasia are characterized by relatively low SSY values (<100–150 t km−2 year−1), the Greater Caucasus region generally have higher SSY values (more than 150–300 t km−2 year−1). Partial correlation analyses demonstrated that such proxies of topography as height above nearest drainage (HAND) and normalized steepness index (Ksn) tend to be among the most important ones. However, a PLSR analysis suggested that these variables’ influence is likely associated with peak ground acceleration (PGA). We also found a strong relationship between land cover types (e.g., barren areas and cropland) and SSY in different elevation zones. Nonetheless, adding more gauging stations into analyses and more refined characterizations of the catchments may reveal additional trends.


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