Collapse of the Pilcomayo River

Collapse of the Pilcomayo River

The Pilcomayo River flows south-eastwards from the Bolivian Andes across the Chaco Plains, setting the border between Argentina and Paraguay. It flows down along 1000km, in principle, to finally join the Paraguay River. It spills over the plains during the rainy season from January to March. The sed...

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Bibliographic Details
Published in:Geomorphology (Amsterdam, Netherlands) Vol. 205; pp. 155 - 163
Main Authors: Martín-Vide, J.P., Amarilla, M., Zárate, F.J.
Format: Journal Article Publication
Language:English
Published: Elsevier B.V 15-01-2014
Subjects:
Alluvial fan
Alluvium
Al·luvions
Channel morphodynamics
Enginyeria civil
Geologia
Hidrologia
Log jam
Meandering
Pilcomayo River
Suspended load
Àrees temàtiques de la UPC
Meandering
Pilcomayo River
Alluvial fan
Log jam
Suspended load
Channel morphodynamics
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Summary:The Pilcomayo River flows south-eastwards from the Bolivian Andes across the Chaco Plains, setting the border between Argentina and Paraguay. It flows down along 1000km, in principle, to finally join the Paraguay River. It spills over the plains during the rainy season from January to March. The sediment load of the Pilcomayo is one of the largest in the world: 140milliontons per year, which is mostly wash load from the upland Andes. The mean concentration of suspended sediment is 15g/l. The maximum recorded concentration is as high as 60g/l. The river has built a large fan covering a surface of 210,000km2, with many abandoned channels. Today, it is a river prone to avulsion, raising border disputes between the two lowland countries, Argentina and Paraguay. Moreover, the very special feature of Pilcomayo River is that it does not actually flow into the Paraguay River. Very far upstream of the mouth in the Paraguay the channel blocks itself with sediment and wood debris forcing water and sediment to spread across the plains. Moreover, the point of blockage has moved hundreds of kilometers upstream throughout the 20th century. Many environmental issues arise because of this collapse (channel discontinuity), not the least of them is the migration of fish. The future of the river concerns Bolivia and the two lowland countries. ► The sediment load of Pilcomayo River is one of the largest in the world. ► Sediment has no choice except to raise the land and fill the channel. ► A log jam filling the channel has moved 300km in the 20th century.
ISSN:0169-555X
1872-695X
DOI:10.1016/j.geomorph.2012.12.007