Rusty river: Effects of tufa precipitation on sediment entrainment in the Estero Morales in the central Chilean Andes

Ravazzolo, Diego and Luca, Mao and Cristian, Escuriaza and Pablo, Pasten and Mauricio, Montecino (2018) Rusty river: Effects of tufa precipitation on sediment entrainment in the Estero Morales in the central Chilean Andes. Science of the Total Environment . ISSN 0048-9697

Full content URL: https://www.sciencedirect.com/science/article/pii/...

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Rusty river: Effects of tufa precipitation on sediment entrainment in the Estero Morales in the central Chilean Andes

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Abstract

Rivers and streams continuously shape and reform their channels through the transport of sediment. One of the most important parameter used to assess this transformation is the threshold for incipient grain motion. To date, limited studies have reported that several biotic and abiotic factors can affect this parameter. However, the effects of tufa precipitation on sediment entrainment and dynamics are still unexplored. The Estero Morales is an Andean stream in Central Chile affected by the phenomenon of tufa precipitation during the winter. Along the wetted channels, tufa precipitate creates a thin solid layer that covers the sediments. A series of field surveys and flume experiments were conducted to analyze the effect of tufa precipitation on the initiation of motion and sediment dynamics. Along the wetted areas of the river, a portable dynamometer was used to explore the force needed to dislocate the grains affected by tufa precipitation from the surrounding sediments. Flume experiments were conducted to compare the incipient motion of sediment covered by tufa precipitation with unaffected sediment. Geochemical analyses were conducted to study the precipitate chemistry, mineralogy and texture. The results demonstrate that greater force is needed to move sediment particles affected by tufa precipitation compared to unaffected ones. In addition, lower sediment transport rates were measured on sediment affected by tufa precipitation, especially for the largest sediment size. These results could have important implications for studies concerning sediment dynamics and contaminant fate in the environment. Moreover, the results allow us to make some assumptions regarding the long-term role that tufa precipitation can play in rivers.

Additional Information:The final published version of this article can be accessed online at https://www.sciencedirect.com/science/article/pii/S0048969718341834
Keywords:Tufa precipitation, Sediment dynamics, Flume experiments, Geochemical analysis, Andean stream, Central Chile
Subjects:F Physical Sciences > F820 Geomorphology
Divisions:College of Science > School of Geography
ID Code:33880
Deposited On:25 Oct 2018 12:29

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